WEATHER MADE CLEAR FOR ALL TO HEAR

"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

"The wind blows to the south and turns to the north; round and round it goes, ever returning on its course".

Monday, January 31, 2011

Severe Weather Awareness Week 2011 Begins Today - Lightning

In this morning's post we'll cover the local forecast through the upcoming week as well as begin what will be a week's worth of Severe Weather Awareness Week 2011 for the state of Florida coverage, with today's focal point being on lightning awareness. Some important facts that all should be at least minimally aware of for each topical discussion will be included.

TODAY: Mid-level shortwave trough is crossing North Florida and other eastern parts of the Deep South this morning as I type. Rain, some heavy, is being observed in the Florida panhandle, but the net affect across a broader expanse of the peninsula is merely abundant mid-level clouds. In viewing satellite imagery this morning and comparing with overnight model runs, I see no supply shortage of these clouds until at least early afternoon; they may in fact stream overhead from dawn til dusk which is a little more uncertain. Otherwise, no issues.

Expect, like yesterday, a sea breeze just strong enough for a flag to show a wind direction but nothing more (less than 10 mph). Afternoon high temperatures most locations will be in the low-mid 70s, barring the A1A Strip from Ormond Beach to Sebastian Inlet (beach side) where the light onshore wind component combined with the off and on clouds down to the 67F (north) to 73F (south) range. Temperatures away from the sea shore though, even Merritt Island as well as south of Brevard will make it into the mid-70s, and maybe even some upper 70s far south and southwest Florida.

TONIGHT: Very mild overnight with clouds clearing. Weak inverted trough extension from the Cape and off the coast will aid in keeping an onshore wind component (very light) over night in the wake of the short wave trough as a mid-level short wave ridge passes overhead. Coastal overnight low near or just above 60F and a little cooler inland.

TUESDAY: BIG SHOW unfolds overnight Monday into Tuesday morning leading to a Storm Jamboree Event from Eastern Texas, Oklahoma, Kansas eastward. Severe weather potential in the form of thunderstorm related activity for the Houston area north and east into all of Louisiana, Southern Arkansas, Mississippi spreading eastward through the day approaches the Florida Panhandle late in the day. Elsewhere, ice/snow/wind/very cold air will impact a broad expanse from South Central Plains states spreading east and north into the Ohio Valley and Southern Great Lakes region, eventually reaching the Northeast states into Wednesday. Won't go into breaking down where the greatest 'potential' threat for actual tornadoes will be as it's too soon to say for sure (beside, that topic in and of itself could be an entire dissertation), but there does appear to be an enhanced threat over Southeast Louisiana into Southern Mississippi with another area to the north of that for two distinctly different reasons. No impact to Central/South Florida so will leave it at that.

This will be a long, ongoing event all day impacting over 100 million United Statesans in major metropolitan areas such as Kansas City and Chicago (for starters). Power outages due to strong wind blowing upon heavily ice covered power lines and trees falling on them are a given. Folks are taking note and stocking up on supplies in preparation.

WEDNESDAY: The potent storm system will be impacting the Ohio Valley and approaching the NE states. It's worth noting that parts of the NE will already be receiving light snow well in advance of the actual storm itself. The potent surface low/upper level high energy duo will tag team with plentiful Gulf of Mexico moisture as well as that from the Pacific throughout this event, spreading a potent dose of life threatening winter weather. Life threatening, that is, for those who choose to venture out in it.

Personally, I'll be kicking back with a bowl full of Bon-Bons watching all frozen-over hell break loose, with a hint of intrepidation for those poor folks. But what about Central and South Florida?

No worries to cut to the chase. All the ingredients will be delivered away from the peninsula proper, although the Panhandle could see some of the severe weather into early Wednesday. The front will progress into Central during the afternoon as barely a shadow of its more nasty northern extent counterpart. The Storm Prediction Center has almost the entire peninsula outlooked in a "See Text" on their graphic for strong and maybe severe thunderstorms on Wednesday, which means they are watching for strong storms here. But at this time I do not see it. If anything, some rain showers are all I'm going to throw in until later numbers come in during the course of today and early tomorrow. There's still plenty of time to reassess the situation before then in other words, but nothing stands out to sound an 'all hands on deck' alert out just yet.

Otherwise, temperatures Tuesday and Wednesday will generously donate mild overnights with lows in the low-mid 60s and highs in the 70s, especially overnight Tuesday into Wednesday. Cloud cover will keep overnight lows warmer, but day time highs are a bit sketchier, especially on Wednesday along A1A when by that time we will have lost the onshore wind component with a pre-frontal southwest wind. Wednesday could be an upper 70s to near 80F day, but at this time think that clouds will be an issue for 80F to occur, expect over South Florida.

WEDNESDAY LATE/THURSDAY: Looks like we'll eke out frontal passage, uh sort of, for about 18-24 hours. But keep in mind that storm potential otherwise noted above. It'll be a wimpy one though in regards to cold air, and probably never make it much further south than the southern shores of Lake Okeechobee as the surface features essential 'undercut' any upper level supporting features/dynamics for a clean fropa (frontal passage) . Down that way (somewhere) the front remains until overnight leading into Friday morning. This will be a very 'shallow' frontal passage depicted purely by surface wind direction in the lowest few thousand feet. Should mid-upper level clouds clear we could be looking at a very foggy Friday morning. Otherwise, hardly noticeable in the temperature category, although Thursday could fee cool with highs in the 60s under cloudy skies with a northeast wind gradually increasing and veering to east then southeast by the post-sunset hours.

FRIDAY/SATURDAY: Front retreats northward as a warm front as a surface low takes shape in the Central Gulf close to the loop current and moves ENE toward the Florida Big Bend. We'll be in warm sector air all day, so could be a warm one with a good SSW wind of 15 gusting to 25mph all day (big change from Thursday). The low will shift off the Florida NE Coast near the Florida / Georgia border leading into Saturday, with yet another cold front extending hencefrom which will cross the state Friday night through late Saturday, with the rain for Central ending by early afternoon. I think if we're going to be hearing thunder, it will be with this boundary.

SUNDAY: Pleasant, post cold frontal weather as high pressure builds eastward across the Deep South into the Atlantic to our north. Cooler Saturday afternoon (post cold front) and all day Sunday, but totally no big deal with the east coast not even getting below the low 50s at sunrise, Sunday.

NOTE: The details for Wednesday and beyond are still in the 'being ironed out' stage, so inevitably it stands to mention that further refinement of the Wednesday - Sunday time frame will require much further scrutiny.

Side Order: In regard to lack of a strong frontal passage this go around and beyond the upcoming week, we'll be watching strong mid-surface high pressure over the Dominican Republic toward the southeast Bahamas and just to the north of there holding fast, thus precluding this currently developing scenario early this week as well as those in the near future further upstream into next week from significantly impacting South and Central Florida in regards to cold air.

TODAY'S TOPIC FOR SEVERE WEATHER AWARENESS WEEK FOR 2011 IN FLORIDA IS LIGHTNING. I have simply done a copy/paste from the Public Information Statement put out by the National Weather Service who deserves the credit for the following. Please read word for word. There's some good tidbits here. To see a website which addresses the entire week, refer to:


WHETHER A THUNDERSTORM PRODUCES 10 BOLTS OR 10,000 BOLTS...THEY ALL 
ARE POTENTIAL KILLERS. A DISTANT...DEVELOPING...OR WEAK THUNDERSTORM
MAY NOT APPEAR THREATENING...BUT STATISTICS INDICATE OTHERWISE.
STUDIES HAVE DISCOVERED THAT STORMS WITH INTENSE LIGHTNING TEND TO
STRIKE FEWER PEOPLE THAN STORMS THAT ONLY PRODUCE OCCASIONAL
LIGHTNING. THIS IRONIC FACT SUGGESTS THAT PEOPLE RECOGNIZE THE
LIGHTNING THREAT ASSOCIATED WITH STRONG STORMS BUT FAIL TO PERCEIVE
THAT VERY SAME THREAT WITH WEAKER ONES.

ONE CHARACTERISTIC THAT MAKES LIGHTNING SO DANGEROUS IS ITS EXTENSIVE
RANGE. OF ALL THUNDERSTORM THREATS...ONLY LIGHTNING HAS THE ABILITY
TO STRIKE OUTSIDE THE STORM PERIPHERY...MAKING IT THE FIRST STORM
HAZARD TO ARRIVE AND THE LAST TO LEAVE. LIGHTNING CAN STRIKE MORE
THAN 10 MILES FROM ITS PARENT STORM. BY CONTRAST...MOST THUNDER IS
INAUDIBLE BEYOND 10 MILES. THEREFORE...IF YOU CAN HEAR THUNDER...YOU
ARE ALREADY AT RISK.

THE OTHER CHARACTERISTICS THAT MAKES LIGHTNING SO DANGEROUS ARE ITS
TREMENDOUS POWER AND SPEED. THE AVERAGE BOLT CARRIES 20 THOUSAND
AMPS OF ELECTRIC CHARGE...100 MILLION VOLTS OF ELECTRIC
POTENTIAL...AND GENERATES A TEMPERATURE THAT CAN EXCEED 50 THOUSAND
DEGREES FAHRENHEIT. FURTHERMORE...ALL THIS ENERGY IS CONCENTRATED IN
A CHANNEL WITH A DIAMETER NO LARGER THAN A U.S. QUARTER. THIS ENERGY
DENSITY IS UNMATCHED IN THE HUMAN WORLD...EVEN INSIDE A NUCLEAR
REACTOR. FURTHERMORE...IT TRAVELS AT SPEEDS THAT APPROACH FOUR
THOUSAND MILES PER SECOND.

THE INSTANTANEOUS NATURE OF A LIGHTNING STRIKE MEANS YOU CANNOT AVOID
A STRIKE THE SAME WAY YOU WOULD A TORNADO OR HURRICANE. OUTRUNNING A
LIGHTNING BOLT IS NOT AN OPTION. FEW LIGHTNING SURVIVORS REMEMBER
EVEN BEING STRUCK...LET ALONE REMEMBER SEEING THE BOLT THAT STRUCK
THEM.

LIGHTNING IS MOST DANGEROUS NEAR THE EDGE OF A STORM BECAUSE PEOPLE
OFTEN ASSOCIATE ITS THREAT WITH PEAK RAINFALL. HOWEVER...STUDIES
HAVE SHOWN THE MAJORITY OF LIGHTNING VICTIMS ARE NOT STRUCK DURING
THE HEIGHT OF THE STORM AS ONE MIGHT EXPECT. INSTEAD...THEY ARE
STRUCK BEFORE THE STORM REACHES ITS PEAK BECAUSE PEOPLE DO NOT SEEK
SHELTERS QUICKLY ENOUGH...OR SHORTLY AFTER THE RAIN HAS ENDED
BECAUSE PEOPLE LEAVE SHELTER TOO SOON.

ABSOLUTELY NO PLACE OUTDOORS IS SAFE FROM LIGHTNING. IN FLORIDA...
MOST PEOPLE WHO HAVE BEEN STRUCK WERE NEAR A BODY OF WATER.
THEREFORE...PEOPLE VISITING THE BEACH OR INVOLVED IN ANY WATER
ACTIVITIES NEED TO PAY PARTICULAR ATTENTION TO LOCAL WEATHER
CONDITIONS. OTHER VULNERABLE LOCATIONS INCLUDE OPEN AREAS SUCH AS
ATHLETIC FIELDS...PLAYGROUNDS...OR GOLF COURSES.

NO ONE CAN PREDICT WHERE LIGHTNING WILL STRIKE...BUT FORECASTERS CAN
PREDICT THE CONDITIONS THAT WILL PRODUCE IT. WHILE THE NATIONAL
WEATHER SERVICE DOES NOT ISSUE LIGHTNING WARNINGS...PRODUCTS SUCH AS
THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK DESCRIBE IN DETAIL THE DAILY
LIGHTNING THREAT ON A SCALE RANGING FROM NONE TO EXTREME.

IN ADDITION...SHORT TERM WEATHER FORECASTS INFORM WHEN AND WHERE
STORMS ARE FORMING OR ARE EXPECTED TO FORM...WHILE SPECIAL WEATHER
STATEMENTS ARE ISSUED TO WARN WHEN A STORM IS PRODUCING OR EXPECTED
TO PRODUCE EXCESSIVE LIGHTNING. THESE PRODUCTS ARE AVAILABLE TO THE
GENERAL PUBLIC THROUGH THE INTERNET AND THE NOAA WEATHER RADIO AND
SHOULD PLAY A CRITICAL ROLE IN DETERMINING WHETHER OUTDOOR
ACTIVITIES SHOULD BE DELAYED OR CANCELLED.

IF OUTDOOR ACTIVITIES ARE PLANNED...GET CONTINUOUS WEATHER UPDATES IF
THUNDERSTORMS ARE PREDICTED. BE PREPARED TO TAKE SHELTER INSIDE AN
ENCLOSED BUILDING IF A THUNDERSTORM APPROACHES OR FORMS NEARBY.
PEOPLE SHOULD HEAD INSIDE WHEN DARKENING CLOUDS APPEAR...EVEN IF
THUNDER HAS NOT BEEN DETECTED.

IF THUNDER IS DETECTED...HALT OUTDOOR ACTIVITIES IMMEDIATELY AND MOVE
INDOORS. REMAIN INDOORS UNTIL 30 MINUTES AFTER THE LAST CLAP OF
THUNDER IS HEARD. PICNIC PAVILIONS...BASEBALL DUGOUTS...BEACH
SHACKS...AND ISOLATED TREES SHOULD BE AVOIDED. IF AN ENCLOSED
BUILDING IS NOT AVAILABLE...THEN AN ENCLOSED METAL VEHICLE IS THE
NEXT BEST ALTERNATIVE. CONVERTIBLE AUTOMOBILES AND GOLF CARTS DO NOT
PROVIDE LIGHTNING PROTECTION.

FOR FURTHER LIGHTNING INFORMATION...HAZARDOUS WEATHER OUTLOOKS
INCLUDING THE DAILY LIGHTNING THREAT ACROSS EAST CENTRAL FLORIDA...
AS WELL AS SPECIAL WEATHER STATEMENTS...PLEASE VISIT THE NATIONAL
WEATHER SERVICE IN MELBOURNE WEBSITE AT
HTTP://WWW.WEATHER.GOV/MELBOURNE


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Sunday, January 30, 2011

No News is Great News for Central/South Florida!

Very Short Post Today Due to lack of Weather You Say? That's right...at least in regards to Central and South Florida. I'm taking a break from going into details regarding chances of rain (which begin for Central late Wednesday), cloud cover (minor impacts but occasional bouts of those beginning late Monday becoming cloudy into midweek), winds (light to a breeze), and temperatures (coolest along the coast even so, pleasant everywhere), to precipitation (chances begin Wednesday afternoon).

It's going to be a 'big weather week' for much of the country in regards to the potential for severe weather over a portion of the Deep South, but the bigger story will be huge snow fall totals (in the double digits to over 2 feet!) and icy layers depending on where one lives. We'll be hearing all about this all week from Oklahoma eastward through the Ohio Valley and the northeast. We'll be hearing about the frigid wind chills, people being buried in mass quantities of snow flakes, some power outages, the whole shebang. We'll be hearing about flight delays, people stocking up on supplies, and traffic accidents.

The image above is the forecast for low temperatures Saturday morning. This sums it up for what will matter most here in regard to all of the above stated by looking at the nice 'orange, warm' color of South and Central Florida. Granted, like I said, we will introduce rain and clouds into the equation during mid-week. But the big news for today is regard to what we WON'T have here. Will return to the regularly scheduled post tomorrow. It's Sunday. Enjoy...I'll enjoy watching the show unfold with shorts and flip-flops on. I'll trade not having exciting weather for not have winter weather at this time of year.

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Saturday, January 29, 2011

Broad Expanse of a Significant Mixed Bag to Impact The U.S.

Image: This is the latest enhanced water vapor image taken from space around noon time (EST) today, Saturday. The yellow areas shown are the areas in play that are of relatively minor potential weather impacts in comparison with the red circled areas being the harbinger of what's to come. At time, the most significant event will be unfolding Tuesday morning over the Deep South and a portion of the Southern Plains, but there are other areas of interest from Oklahoma to New York during the course of next week as well...the precursor will begin tonight over Southern-Central Texas.

TODAY: Doesn't take a weather man to see it's an awesome day over all of Florida early this afternoon. No issues worth mention as high pressure centered across the Central Gulf continues to slide east and across the peninsula, with the axis running across South Central Florida. Broad expanse of mid/upper-60s to low 70s under full sunshine with a light west wind. The area of high pressure will continue to slide east through Sunday and exit, for the most part, the east coast overnight Sunday night into the first part of Monday.

Meanwhile, a series of shortwave troughs in the mid-levels will ride over the top of the ridge as they enter the U.S. over Northern Mexico (passport in hand), cross Texas, then head toward the NE / Mid-Atlantic region, skimming North Florida along the way.

TONIGHT: Similar overnight lows tonight as was felt this morning and a few degrees warmer tomorrow. Maybe some high cirrus clouds overnight with the most of them over North Florida where light rain might fall where atmospheric moisture is most concentrated... but which could aid in keeping the temperature up a couple of degrees on top of the already having warmed temperatures Central and parts of South. The most interesting weather overnight into early Sunday will be over South Central and Eastern Texas as the first short wave trough is now approaching that area (shown in the yellow circle above).

SUNDAY/MONDAY: Similar day through mid-afternoon as today and a bit warmer. Light west wind. High pressure to exit into the western Atlantic for the most part early Monday will permit a weak sea breeze to begin Monday. Good shot of mid-upper level moisture could generate a period of totally cloudy skies on Monday, and maybe even a sprinkle near the Cape Monday afternoon as an inverted trough begins to establish from the Cape and northeastward, under the cloud deck (assuming it manifests). Otherwise, no issues other than the potential for a lack of abundant sunshine.

INTO TUESDAY: Tuesday? BIG DAY for much of the Deep South, portions of Oklahoma, Eastern Texas, Louisiana, Mississippi, Arkansas, and Western Tennessee (to name a few) to include possible tornadoes, snow, ice, strong wind, hail, and lightning. This system will not be impacting Florida through at least early Wednesday, but the panhandle may very well start to see the weather move in during the day as thunderstorms/rain. Expect a surface low forming over Eastern Texas at sunrise Tuesday to EXPLODE during the day and move generally ENE-ward during the day. Very sharp dew point temperature gradient, shearing wind profiles, very high helicity/vorticity values (which are indicators of horizontally spiraling wind fields and their gradients aloft) to create meteorological havoc just ahead, along and behind an 'OBSCENE' surface boundary...but again, well out of the reach of the Florida Peninsula. This will occur as those areas circled in red will have moved in and start to phase with surface features to put it in the simplest of terms.

Otherwise, continued warming locally with the winds notably picking up from the ESE-SE-SSE through the course of the day which will advect deep moisture across the state and far to the north. By this time Tuesday a warm front will be draped across a region much further to the north of the state and now where in reach. No temperature issues at all with highs in the mid-upper 70s and lows along the coast in the low 60s, some low 80s possible south and coolest along A1A due to an onshore wind component. It will start to feel 'gooey' though by late Tuesday afternoon and all of Wednesday with the prolonged moist air flow having been in place.

WEDNESDAY -FRIDAY: For now, will leave this period broad brushed due to the complexity of the unfolding situation which will have occurred and reveal more in later model runs. But the trend is this.

The surface low will be passing to the north toward the mid-Atlantic and Northeast States creating winter weather craziness along the way north and along the warm frontal boundary, with the surface boundary (cold front) draped across the northern central Gulf of Mexico into North Florida for starters, dragging east ward and elongating a bit in a more latitudinal fashion (from NE to SW...maybe event more east/west than that. The peninsula will be fully entrenched in high dew point air, but little to work with in the way of dynamic wind profiles, thermal gradients, or any gradients of meteorological nature for that matter.

Expect at least one weak surface low to initiate in the far SW Gulf and becoming more discernible at the surface as the impulse (s) cross the warm waters of the Loop Current and head toward North and Central Florida These will be the 'core' weather makers.

Overall falls (decreasing values) in the 850mb through 500mb heights to the north and west of this cold front boundary will be reflected by the 'usher-ance' of very cold air into all of the Plains states and eventually into the Deep South during this time period, which for the most part (and thank goodness) will be mostly diverted from Florida, but look out New York City!

Do my eyes deceive me?! The GFS is painting temperatures as cold as -20F in New York leading into next Saturday. But that's going beyond jumping the gun. Heck, we're not even at the starting line yet.

In any case, the models of course are varying widely in regards to the finer (and inevitably) details, even for those to be first impacted tonight over Texas. Another way of explaining it is, 'The closer to the flame, the hotter the fire". This certainly holds true when active weather of any nature approaches..and the flame gets warmer on an hourly basis.

Lots to be ironed out in days ahead. But locally, the trend has been to lay the cold front across Central Florida (somewhere) for a time frame of 18-36 hours before clearing the state. This could prove beneficial for the current drought situation on top of the rains last Tuesday if nothing else.

Severe weather potential Central/South? Not much of one just yet. Most likely just a chance of thunder, if there's going to be one, would be Wednesday afternoon through Thursday morning. More toward Friday South Florida. The cards are still being shuffled, but don't think we'll be dealt much more than a "pair of fives" for what that's worth. But time will tell.

Last thing, cold air on the way? Ugh...Friday is not looking good...not extremely cold, just prolonged (an all day deal). Right now, I'm considering us blessed in comparison to the rest of the country....as a significant frigidly cold event for Central or South Florida is not, as of this morning, being portrayed. Even after turning the Magic 8-Ball several times. Think I'll quit while the luck is running.

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Friday, January 28, 2011

Increasingly More Pleasant Through The Weekend























Images/recap: Mid level short wave trough crossed the state overnight and is clearing Central Florida early this morning. This is portrayed by the mid and upper level clouds on satellite imagery, density of the clouds picked up as light rain by radar in the second image (last night), and the lack of any appreciable wind shift in the surface winds in the third image. If we compare the third image (temperature profile) with those clouds, we see the coldest temperatures this morning at 7am are where the clouds had cleared earlier during the course of the wee-morning hours permitting allowing for some radiational cooling before sunrise.

Otherwise, under the clouds, the temperature fell (on the average) about 5 degrees at most after 10pm, resulting in wide spread mid-upper 40s. The final 4th image is a forecast surface weather system plot for 7am Sunday morning.

High pressure that currently encompasses a broad expanse from the Intermountain Region of the Rocky Mountains through Texas into the Western Gulf will be weakening over the continental landmass as the ridge continues to build east and across the Florida peninsula through the weekend, only to be replaced near SW Kansas by a surface low and a very nice warm front stretching eastward from it, symbolizing a very nice, long-over due warm up for the Southern Plains States over the weekend.

TODAY: Rapid clearing by early this morning Central. The sky is just about to clear as I'm typing. South Florida will see the clouds until at least late morning into the early afternoon hours, clearing from north to south. A mid-level trough of low pressure (which I referred to yesterday as an "elevated cold front") is clearing the area and damping out with no other weather impacts today. Winds after passage will be much like yesterday's under a mainly clear sky and similar afternoon temperatures. Honestly, though, I didn't look into the nitty-gritty regarding the temperatures as all other factors remain essentially constant and there really is no reason to dwell on this aspect.

WEEKEND WEATHER: Surface high pressure will pulse across the Gulf and Florida through the weekend with the tail end of the ridge exiting the Florida East Coast late Sunday. Sometime during the weekend we might see another mid-upper level trough cross the state, but it will likely be even weaker than the one last night/this morning that has generated the clouds and be of no impact in regards to rain, winds, or temperature.

Coolest morning will be Saturday 'over all' as skies will be clear tomorrow morning in the wake of the passing trough and winds settle down appreciably early this evening at the latest. Temperatures along A1A will be close to that of this morning, mid-upper 40s but cooler inland than what was felt their this morning, mainly lower 40s with a broad expanse of temperature readings within reach of each other over much of the peninsula other than far south (warmer) and far north (colder).

MONDAY: Air mass modification begins overnight Sunday into Monday morning as the last of the high pressure ridge will be fully exiting the Florida east coast with a warmer coastal overnight low for starters and more low level moisture in the low levels of the atmosphere beginning to manifest.

REGARDING MONDAY AND BEYOND: Lots of time still for the information that came in overnight to reach closer agreement during the next 48-hours. Not foreseeing any rain at this point until almost Thursday now as the GFS continues to delay the next system. Interestingly, it is forecasting more mid-upper level energy to cross the state on Monday than what it forecast for the storm system of last Tuesday when we had the severe weather, but it remains dry due to lack of moisture for that energy to work with. The NAM, on the other hand, brings in showers. So we'll see what starts to evolves first, then take it from there with the model forecasts.

In general though, beyond Monday into Wednesday, I'm hoping we will see official forecasts take the afternoon high temperatures higher than what is being advertised on TV. Hoping to see a broad expanse of mid-upper 70s, even for North Florida and into SE Georgia if not further not further north. A lot depends on what happens on Monday and beyond in regards to the temperatures with that potential for clouds being a potential thorn-in-the-side.

Also note that, for example, the GFS has fluctuated rather vastly in each and every model run for the period beyond Sunday night. Public weather forecasts are unlikely to change (or will remain relatively constant) on TV despite the rather significant fluctuations and differences in the various model solutions for this time period. They, as well as I in the case of today's predicament, will essentially remain mute until a greater level of confidence is reached. For kicks though, and for example, just watch The Weather Channel today and tomorrow to see what is shown in the extended period. I noticed this morning it is basically a "CYA"...showing thunder for Wednesday and Thursday. Unlikely. For now though, one of those two days does appear will be wet if nothing else. Could it be delayed even more, AND, will it ever thunder at all? Rain possibly, yes (sometime mid-late week), Thunder though? Even bigger question mark. But again, nothing is pointing toward a severe weather event. At worst, a strong storm or two.

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Thursday, January 27, 2011

Tuesday's NWS Storm Reviews, Pleasant Weather Through Weekend



Images: (1) Possible funnel sited in NE Sumter County, via Twitter link sent from a generous contact of mine. Doppler radar indicated storm rotation near this location and as it crossed near The Villages. For a radar review showing the height of the storm (s) with warning box issuances see: http://www.srh.noaa.gov/mlb/?n=012511 (Storm Survey and total event summary generated by the NWS, Melbourne, FL) or click on the Title of this post. (2) Synoptic set up tonight near midnight

TODAY: Pleasant and cool with a high temperature generally in the mid 60s, mainly clear until later this afternoon. We see that the low pressure system that impacted Florida on Tuesday in the second image above will be passing just east of Maine today, after having dropped copious amounts of snow (with some thunder snow reported from Virgina, to Maryland, Pennsylvania, and New York at a minimum during its passage).

TONIGHT/ EARLY SUNDAY: We see in the second image, and as noted yesterday, that high pressure will be building southeastward from the Intermountain Region, across Texas and into the Western Gulf of Mexico, then east across Florida. This will be our predominant weather influence through early Sunday. In the meantime, a more 'elevated cold front' (used very loosely) will pass the state over night tonight with another to follow about 24-36 hours later. These are also shown on the image.

The only impacts from these systems as they ride over the surface ridge building across the Gulf of Mexico and Florida will be increased high level cirrus clouds as soon as late this afternoon but mostly overnight tonight with early clearing Friday accompanied by a temporary backing of the surface wind from NNW to W or WSW. Wind speeds 15-20mph at their height. The only impact from these fronts will be to re-enforce the cool, and somewhat (but not overly) dry air over Florida. Thus, continued overnight lows in the low to mid 40s and highs in the mid 60s, more toward the upper 60s and low 70s SE Florida (West Palm and south) and the Keys. Temperature spreads over Central and much of south will be fairly uniform with many areas seeing tempeartures in the 40s, even far south. Coldest far North Florida of course, where it was below freezing across the Panhandle and over to Tallahassee this morning. Other cold pockets extended as far south as Brooksville with Gainesville hovering near freezing at sunrise.

LATE SATURDAY: High pressure center will be passing directly over Florida after the second front clears to the east resulting in near calm winds into Sunday morning, with a warming trend becoming more evident Sunday afternoon to continue through Wednesday. The trend will be first most assuredly noticeable along the east coast overnight Sunday into Monday when overnight lows will fail to drop into the 40s there, mid-upper 50s perhaps, as winds becoming light from the east initially and gradually southeast into Tuesday then south and increasing.

TUESDAY AFTERNOON - WEDNESDAY NIGHT: At this time, it appears an area of low pressure will again track from off the Texas Coast and is then forecast to ride along a similar track as the system which impacted Florida on Tuesday, with again, an attendant cold front extending into the Gulf and a warm front extending eastward from it across Florida and eventually north of Florida. Timing on just exactly when all of this should occur is easy to see on paper, but just exactly how this system will evolve and where it will track is too soon to say. The information on paper could be as much 24-48 hours off in regards to timing, let along the location of even the most general surface features.

But as portrayed based on last night's 7pm (00 Zulu time) model runs, the low would track just along or north of I-10. This system may again be a severe weather maker, namely for Southern Louisiana, Mississippi, Alabama, and perhaps a portion of the Florida Panhandle. Again, and as shown by current dreamcasts, Central Florida north of a Tampa Bay region east to the Beach Line Corridor toward Cape Canaveral line could hear some thunder from this system Wednesday afternoon/evening. But that chance looks very slim. South of that line, even the chance of any rain at all looks pretty darned slim.

This does not appear currently to be another "Heavy Weather" deal for numerous reasons. This appears it will be a moderate instability and low wind speed/directional shear profile situation which would not result in rotating storms. I'd throw in the chance of thunder for Central Florida because the main weather impacts are forecast to be moving in during peak heating hours, so we'll have some thermal instability to play with.

Another area to watch will be the Keys and extreme South Florida (Miami metro and south) on Thursday as the front will be clearing Central at sunrise on that morning and will have yet another day to clear this area later Thursday. Additionally, the Keys and South Florida might have an additional boost of tropical moisture shoot in overnight Wednesday night in advance of the approaching cold front.

But this is all VERY preliminary, and there is ample time for some big time adjustments to timing, precipitation/storm intensity locations, etc, etc. Again, and in case you missed the link provided above, here is a link to the Melbourne storm situation of Tuesday. Some additional images will be added to this web page some time today.


The National Weather Service (NWS) out of Tampa, Fl also has completed their storm survey:

http://www.srh.noaa.gov/images/tbw/TopNews/PDF/January25survey.pdf




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Wednesday, January 26, 2011

Big Weather Gone Now - But What Really is SEVERE Weather?




Images:
(1) Squall line associated with a pre-cold frontal trough of low pressure is embedded with weakly rotating storm pockets is shown in the first image as it crossed East Central Florida during the early evening yesterday.
(2)The second image is taken from WESH TV (Channel 2) with my digital camera as the area approached the intracoastal of Brevard County. The black boxes show the tornado warnings in effect at the time due to the rotations aloft being displayed by Doppler Radar at the NWS in Melbourne, FL
(3) In sharp contrast, the third image is the radar display at 9:15AM this Wednesday morning showing a line of light rain showers associated with the actual cold front proper . BIG difference in radar displays, huh?!
(4) Lastly, the final image is the average mid-level winds and moisture content of the atmosphere throughout just after the time of that second radar display. We see that there is definitely a cold front with moisture decreasing pretty quickly at those levels behind the boundary defined by the drying air mass as it continues moving toward the Southeast. The front was accompanied by an up tick and slight shift in the surface winds and some partial clearing sky conditions. Gusts near 40mph I read somewhere were reported.

RECAP: For the most part, Florida was spared from a situation that could have evolved into a situation much worse than what eventually materialized yesterday. From my perspective, it made for some fun radar viewing, but when the actual activity reached my spot the actual event was nothing more than some rain and a few in cloud lightning flashes. From radar you'd swear it would be much worse. Not everyone had the same experience though.

It is important to understand, that in all discussions here, to recall that the words "Probable' "Could" and "Should" are used most often. Had this been a situation with a high degree of confidence, you would have read (and likely heard though the media) worlds like WILL and IS GOING TO. The potential was there, and could have been higher, for a wide spread severe weather event on Tuesday, but all the elements never did come together over a broad expanse, and just barely did in isolated fashion and when they did the weather elements were poor considering what they are in a certain severe weather event. Which in Florida, compared to the Great Plains, is relatively rare.

But in looking at the Storm Prediction Center's (SPC) Storm Log and the National Weather Service (NWS) Storm reports, the worst of the weather did occur in the area that I had highlighted for yesterday and the day before that, as having the greatest potential for active weather. (note that I just used the word "potential" in that last sentence). The Big Daddy of weather elements was in the form of the expected marginally severe wind gusts, and in at least one wind event recorded near Tampa, flat out straight line winds perhaps as strong as 90 mph for a very brief time.

I am having a hard time getting down to EXACT details this morning, since the SPC storm logs aren't quite in sync with the Storm Reports just yet, namely because new information is still filtering in 'the morning after' while NWS employees head out to assess damage in a few locations and determine what caused that damage (winds or a tornado).

A funnel cloud was observed from Patrick AFB during the storm cell that traversed across the Viera (and lofted someone's backyard trampoline down the street for several hundred yards). Interestingly, the funnel was observed through the use night-time vision goggles!

With this given, best I can tell there was either 2 or 3 tornadoes and a waterspout all over by the Tampa Bay Region, and a tornado near Alva, FL in Lee County (which originally came in as wind damage last night). A few funnel clouds were reported, but whether those were truly funnels or someone not knowledgeable of what they were seeing will remain the great unknown, but pictures would help (even though those can be misleading too, and have been used in the past to "fool" the unwary as portraying a "Sheriff 'Nado"...or tornado look alike that is acutally just scud clouds).

There was 1 injury related to wind damage. My guess is that the tornado that caused damage (I believe the other/others were over open areas) will be rated either EF0 or EF1 on the Enhanced Fujita Tornado Rating Scale. That information will probably be made known today if it isn't already. Far cry from the EF3 tornadoes that hit Central Florida in late February, 1998 and the last strong one I can recall more recently on Ground Hog's Day, 2007.

There was a few hail reports of 0.70" (dime sized) hail (non-severe), and I believe one of 1" near Brooksville (which is considered a size that can be damaging, thus appropriately deemed severe sized). But if you were watching TV last night, you might have noticed that 1, 2, and did is see a 3" (?!) hail size potential being broadcast? These are radar based estimates and measured by Doppler radar well aloft in the atmosphere. But I didn't hear the word "potential' much. Had hail of that size reached the ground as widespread as some folks might have been misled to believe was occurring, this would have been a significant weather event (not even touching the wind side of the story).

Same thing goes with the wind being portrayed. Use of the Doppler Radar came in very handy for providing more than sufficient lead time warnings to the public. Indeed, wide spread marginally severe winds were measured across Central Florida, and a high percent of those state wide occurred in the greatest threat area outlined in previous blog posts (Central Florida from Tampa to Brevard) . There was something like 20 -21 wind reports that have been officially categorized 'Severe" - equal to or greater than 58 mph.

The "severe" category comes in to play for both the wind and hail category because it has been determined through extensive research that when either of those parameters reach a certain threshold damage can result. Thus, as interesting as a deluge of pea sized hail can be while experiencing almost constant lightning and a hard blowing wind, that is not 'severe' by definition. It might be scary, but "Scary Doe Not Equal Severe" (all the time).

RAINFALL: I received 1.60" inches of rain, most of which fell with passage of the squall line. In viewing over civilian/volunteer reports transmitted to COCORAHs (The Community Collaborative Rain, Hail, and Snow Network)...this total was just above averaged totals reported over a vast expanse of Florida. The area that received the least was the Panhandle There were a few reports over 3", but not where the Doppler Radar estimate showed it to be (NW of Daytona Beach). Probably because no one lives at that location who reports or has a rain gauge.

TODAY: As noted by the images above, a cold front went through close to 10AM this morning. Winds just over head are 30-55mph today and some strong gusts accompanied the front as a result. But as the low pressure center culprit for yesterday's weather pulls away during the course of this afternoon along the Atlantic Coast to just east of New York City by this evening, the pressure gradient will relax by late afternoon and the mid-level trough supporting those winds and overhead early today will also be lifting north. So essentially, winds will decrease most notably after peak heating today.

Cloud Cover: It is totally cloudy as I type right now. But in looking at the latest surface observations, and viewing the visible satellite imagery, as well as other upper level information...skies may very well be clearing over my head as I click on the " Publish Post" button for this very post. In other words, rapidly clearing sky conditions early in the afternoon, working South during the afternoon.

Temperature/Wind Regime: Wind to remain mainly due west today at 12-20mph with gusts to just above 30mph early, with winds and gust progressively decreasing throughout the day. Winds becoming more NW over night but light. No wind over 15mph foreseen beyond today through this time next week. Temperatures today will portray wide spread mid-and some upper 60s (warmer start further south so they will see low-mid 70s before frontal passage then level off). Temperature will fall below 60F as the sun sets and only slowly fall through the course of the mid-late evening, with the majority of our remaining woken hours in the mid 50s.

THURSDAY: Temperature will take a steeper drop after midnight when the driest air will have moved in. Cool to cold (depending on one's sensitivity to the lower dew point air/some light wind/temperature combination), with the mercury in the low-mid 40s over a vast expanse of Florida real estate. Colder far north.

High pressure will be nosing SE from the U.S. InterMountain Region toward the western Gulf of Mexico, then east across the Gulf of Mexico during the weekend with no other systems of 'wet nature' to impact the state for quite some time to come. The Caboose to the Train of Weather Makers the past two weeks has pulled out of station as of Frontal Passage this morning!!

BEYOND: We will see perhaps two or three more weak, elevated cold fronts pass across the state in days to come which will break through (at the surface) the high pressure building east ward across the Gulf of Mexico. At time, high pressure will be directly overhead the state which would lead to a few mornings of a frost potential further north if it is overhead at daybreak, but either way the net affect of the two combined will mean a brief period of more northerly winds and colder air, followed by westerly winds and modifying (slowly warming) temperatures. But all in all, once we take the baby out with the bath water, on average we'll have lows in the 40s and highs in the 60s with temperatures uniformly spread a few times to even the far Southern Portions of the state. A morning or two might have the same morning low in Central as what is felt as far south as Miami. But they'll see the warmer afternoon highs back into the 70s first. Some periods of high cirrus clouds will be thrown into the mix as well, but lack of a more moist, onshore wind component for any respectable length of time will preclude formation of a prolific, coastal stratocumulus deck of clouds.

BEYOND, BEYOND?: Don't forget, I keep the Magic 8 Ball handy for those long range outlooks, that are so far "Out There" that even a High Powered Telescope strong enough to see craters on a planet in another galaxy (do those exist?) can see them with clarity. But we are likely still in a drought despite the rainfall of yesterday that equated to probably no more than a drop in the bucket in the long run. Thus, we need to look for another chance of rain. Right?!

For now, watching the storm breeding ground of the Texas Gulf Coast by this time next week. Chances are appearing, but the view is still fuzzy and the 8-Ball is getting dusty, that another short train of systems might be in the making after 6-9 days rest of vacation time away from the state. But wet storms in Florida in February? Sometimes, not so good from the severe weather aspect.

More concerning Florida's Severe Weather Potential in the weeks to come in another post before the weekend. We are just now entering the more climatologically favored time period for Synoptic Scale Severe Weather (i.e, not of the small scale/micro-mesoscale type associated with summer thunderstorms).



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Tuesday, January 25, 2011

Severe Weather 'Potential' Remains Likely For Florida Afternoon/Overnight



If seeing this post on Facebook, you can read the description of what the lines I have drawn in the first (of two images) indicate by opening the link. These are solely of my own doing and are not official by any means. But I would like to mention that this graphic was created prior to seeing the latest official outlook. Also included in this brief post is the latest official Outlook issued by the Storm Prediction Center (SPC) located in Norman, Oklahoma this morning around 7:30AM. Note the similarities in the two images.

The time period for the official outlook is roughly valid from 8AM today to 7AM Wednesday.
morning. The image I have drawn is valid from Noon Today through 2pm Wednesday. So what do those lines mean?

QUICKLY LET'S CUT TO THE CURRENT: To get current this morning, very little change from yesterday's post in regards to when, where, how activity will manifest today/overnight. As we see, I've chosen a wind shift line correlated with the 2 meter ambient air temperature to determine where a developing warm front is located at 7:45AM this morning (the time does not show on the cropped image extracted from the NWS MLB website). It is located very close to where it was reckoned it would be at this time today in yesterday's post. The front is merging with that persistent inverted trough (that was located near the Cape yesterday and the day before at this time) and is pressing north.

By shortly after noon time it will be along the I-10 corridor and eventually make it as far north as South Central Georgia by late this afternoon. Highest dew point air is along the East Coast from just north of KSC to Miami and through the keys. Not much different far south if at all from that at KSC where close proximity of the Atlantic has made all things equal. Expect that within a few hours the entire 60F degree dew point isotherm will be where the warm front is drawn on the image with low and mid 60s dewpoints across the entire state, rising throughout the day. Otherwise, gusty SE-SSE winds becoming southerly late in the day. Highs in the low-mid 70s, warmer South Central and inland.

TODAY: We will have innumerable items of interest at play today and overnight each contributing to storm activity in a variety of convective modes within two distinct time periods. Now for the lines on the first image:

1) The yellow lines depict mode 1 to begin near noon time toward the west coast with conditions conducive for additional development quickly spreading east across all of Central within the bounds of those lines between 1pm -3pm. This will be discrete rain shower and thunderstorm activity, some strong with isolated severe activity. Storm motion should be from the S-SSW around 30-35mph, perhaps even faster. Believe that by this time Central will possibly be in a Severe Thunderstorm Watch, although it may be deemed by SPC that such level of intensity in the storms will be too spotty for a watch issuance, and as such leave it up to local National Weather Service offices to issue warnings as they deem fit (like is done during the summer).

2) We could see a brief break in activity over the east side of the peninsula for a time early evening when an already developed broken squall line will be entering the west coast between 7-8pm along a pre-cold frontal trough. Associated with that boundary will be the strongest combination of mid-level winds which will rapidly overspread the peninsula. Believe that by late afternoon a Tornado Watch will have been issued if not sooner.

WHITE LINES: At this point it is likely we will have to switch solely to mesoscale mode and constant monitoring to watch boundary interactions within the broad line itself for the most active weather as it crosses the state. With that in mind, be attuned to your most favored media outlet, as I highly doubt folks will be glued to the computer for the intricate details concerning the 'why's in regards to what or will shortly unfold.

Although a broad expanse will be impacted in some form or another by this 'line', it looks the best ingredients combined for a potential tornado and strong straight line winds will occur within the bounds of the white lines drawn although as said activity could occur outside of these bounds as well. This would be for the 7-8pm (west side) Curtain Call through the final 5AM Encore (East Central side). 7AM - main show's over.

BLUE LINES: Additional areas of potential severe weather ending far southeast by early-mid afternoon. Believe the brunt of 'the worst' will be off the coast at sunrise Central, if not sooner. But the line of activity will have yet to clear the Southeast zone from West Palm to the Keys.

BLACK LINES: Entire area from beginning to end of period that could have strong storms.

Do not believe hail will be an issue this go around, although some small-non severe sized hail is always possible. Believe this will be primarily a marginally severe wind event. Although shearing wind profiles (and veering with height initially along and ahead of the pre-cold frontal trough) will be at play, they won't be tremendously strong. However, due to the broad swath of these profiles coexisting within a homogeneously moderately unstable atmosphere sustained, rotating storm structures are easily possible which could result in a tornado. Should wind fields come together just right in a concentrated area within this environment, a single storm entity could produce more than one tornado as it takes the trek across the state, or simply put one down and keep it there.as it rides along a mesoscale boundary laid out by surrounding activity.

RAINFALL: Virtually, at some poin,t everyone will have had measurable rainfall when all is said and done. Although there is a touch of doubt extreme far SE. But rainfall totals will vary tremendously contingent upon where the heaviest storms track over Central and South. To the north, the rainfall will be most persistent thanks to strong isentropic lift along and north of the warm front and insanely high helicity values north of I-10.

Big totals seem guaranteed near the north side of Tampa Bay toward the Brevard/Volusia County border, approaching 2.5 -3' here and there , then spottier 1- 1.5" amounts along where the southern extent of the yellow line is drawn, with the most common rainfall totals surrounding these higher totals between 0.5 to 0.75".

New data is yet available at the time of this post, so an additional post or two could follow later today. But do believe, and hope, that folks stay tuned to the TV or have an operational weather radio (with S.A.M.E. alert) in stand-by mode nearby.

BE ADVISED!!: Storm motion will be fast around 30-35mph at least, perhaps up to 40mph at times, so if you can hear thunder approaching, the storm is only a few minutes away! If you are in a severe thunderstorm or heaven forbid, a TORNADO WARNING, heed them! Severe Thunderstorms (particularly the ones that might form over night) can suddenly evolve into tornado producers as they are about to cross over any particular spot on the map, lest that be your house.

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Monday, January 24, 2011

High Level Of Awareness Urged For Strong Weather Tuesday Overnight

Image: Shown in this image is the Storm Prediction Center forecast (between the green lines) for a risk of severe weather between 7AM Tuesday to 7AM Wednesday. This is officially released to the general public. I have added further elaboration, with a higher likelihood of severe between the black lines, and even higher between the red lines. Those are of my own doing based strictly on morning model information at this time overlay-ed mentally with other parameters which could evolve outside the scope of weather model guidance this morning, to address what could evolve. Fact or fairy tale? Stephen King or Mother Goose? Time will tell.

RECAP: Outside of the obvious concern (noted above) everything in the weather world is evolving right on cue in regards to South and Central Florida weather this morning. Morning low temperatures were reached at the coast along the Barrier Islands at 8pm last night, from which point they slowly rose through sunrise as the marine layer slowly modified the coastal air mass. Namely in regards to rising the dewpoint temperature and moisture level (humidity).

Otherwise, indeed an inverted trough developed from near Cocoa Beach, up along A1A, then off the Cape and out to sea. Wind convergence along that boundary, a strong inversion at 850mb, and ample low level moisture generated the cloud deck we see up and down the Florida East Coast with the highest moisture concentration close to Port Canaveral where some light rain fell. There's been some other spotty trace amounts elsewhere under the cloud deck. I noticed some high level helicity values were interpreted by local data (LDIS) just to the north of this boundary, further enhancing the cloud deck. Those values are forecast to move north through the afternoon, and as such believe so will the minimal chance of non-impact rainfall. We could see some big cloud breaks this afternoon, but the general mode will be partly cloudy and sometime cloudy skies with warming temperatures. Surface low pressue begins to form along the Texas Coast which will move east along the Northern Gulf during the next 48 hours as it strengthens along the way.

TONIGHT: Warm front to evolve South Central and lift north with even higher dew point air behind it, (mid 60F s) as well as stronger SSE -SE surface winds by mid morning through afternoon. Warm front to be just north of SR 520 at sunrise continuing north. Small rain chance very early morning hours will likely be all but gone shortly after sunrise as Central Florida and South are fully within the "warm sector' south of the warm front. Over night lows in the mid-upper 50s but may go up a few degrees from South to North with passage of this boundary. Might only get down to the low 60s from Vero Beach and south.

TUESDAY: Fully in warm sector air all day long with high dew points (low to mid 60s) (humid) and breezy winds from the SE-SSE at 15-25mph during the afternoon (magnified along the causeways during peak heating). Low pressure which had evolved off the Texas Coast will be passing south of Louisiana with the warm front extending eastward across I-10 (or further north) with a cold front extending south from the low. Another mid-level trough from the Central Plains will join forces with this system during the next 24 hours and beyond to become a single entity over Georgia/South Carolina.

FIRSTLY: Granted, it will be relatively warm, breezy and humid Tuesday afternoon, so a chance of rain showers is possible, especially shortly after lunch time and beyond. Although parameters are not yet fully in play for severe weather during this time frame (mid-late afternoon), it bears watching for at least some thunderstorms. Should any thunderstorms evolve, they could be marginally severe, so it doesn't hurt to keep this in mind. At this time, rain showers appears will be the more likely mode though. During this time, we will be seeing lightning strikes well out in the Gulf and over the Florida Panhandle.

EARLY TUESDAY NIGHT: The Gulf Low continues east and the vertical wind profile aloft becomes ever oh so interesting. Surface winds remain SSE-S and remain at 15-25mph as mid-level winds increase from the SSW from 15kts to 30-35kts by afternoon while a sliver of winds above that level could increase to nearly 60kts from the WSW. See where we're heading? Picture the veering of winds with height. We may see a lull in any rain chance whatsoever for a time during the early evening, maybe not. Meanwhile, not far to the north along the I-10 corridor they will likely be getting pounded with heavy rains/thunderstorms along the warm front.

Elsewhere, the mid-level trough approaches the Central Gulf and the West Coast overnight, and in doing so crosses the warm waters of the Loop Current where thermal instability will be greater. This will likely feed the storms to the north originally with additional moisture and further amplify an already wet situation there. This will also quickly eject considerable cloud cover across South Central and Central Florida late if there wasn't enough already due to overspreading of thunderstorm anvils caught up in jet stream level winds.

As the trough approaches the West Coast toward 8pm the upper level portion to the north becomes slightly 'negatively tilted', with the net affect of actually backing and increasing the mid-level winds over Central Florida to a small degree as stronger upper levels remain veered from the West and increase high over head.

9pm and Beyond: A lot of suppositions have already been made, so will state some further assumptions in regards to the potential for tomorrow at this point before walking any further toward the end of the plank with a blind fold on.

However, as it appears at this time, the weather over Central Florida could go rapidly down hill from west to east from around 11:30pm - 6AM (give or take 2 or 3 hours) Tuesday night into Wednesday morning. Whether storms that do evolve (assuming they do) take on a character of bowing line segments on radar imagery or as little round purple balls (rotating supercells) cannot be yet ascertained. The reasoning behind the rapid weather transition is due to a literal "Surging" on mid-upper level wind strength first to the west and rapidly over-spreading the peninsula after midnight.

Either way, with such strong veering wind profiles/winds aloft, plentiful moisture, moderate thermal instability (which is the least of my worries at this point) any storm will be capable of producing damaging wind gusts/straight line winds or a tornado (s) and hail. Regardless, even at night the Convective Available Potential Energy (CAPE) over Central Florida (namely East Central) remains up around 500-750j/kg (or from where it will be at sunset) and maybe even rises a bit. Another concern for far East Central (Orange County and East) is that surface winds could be a bit more backed due to the influence of the coast/intracoastal waterway. This would add a third beater to mix the batter and be the icing on the cake for low level spin.

Another thing to watch will be the storm activity far to the North. As was the case last Monday while we were in a Tornado Watch, this activity could generate an Outflow boundary during the wee hours that will shove South and interact with the parameters already in play over Central. Additionally, due to the early morning timing, a nocturnal low level jet could be established that will be stronger than indicated by model data in conjuction with lower, night time Lifting Condensation Levels (LCLs). Net result, thunderstorms will have very low bases toward the ground that erupt into an atmosphere that is essentially "spinning' aloft.

It is interesting to note that the past two runs of the NAM model have shown a very heavy precipitation band running from near Tampa to Port St John separate from the activity further north. Could this be caused by a storm, or group of them, generated by all the factors cited above? Maybe, maybe not.

Now, IS what is being forecast (as unlikely as that is considering that would be a mesoscale meteorlogical event which wouldn't be captured by a mid-range model but rather by hourly data)...a sign that even this model is picking up on the unfolding of 'something wicked this way comes"? If so, we could be looking at a few long tracking supercell thunderstorms that track from WSW to ENE (or maybe even W to E) across the entire state from around 10pm - 6AM. The storms would ride along the mentioned outflow boundary mentioned previously.

SUMMARY: No worries now, but be advised that a potentially severe weather situation could be in the making beginning Tuesday afternoon and especially between the hours of 9pm - 7am from West to East Tuesday night through Wednesday morning if you haven't figured that out yet already.

SOUTH FLORIDA: At this time it does not look like extreme South Florida will see Severe Weather, but some strong thunder is not out of the equation there either, as we can see by the graphic in this post supplied by the Storm Prediction Center where the green lines are drawn. The best chance for severe there appears will be late morning through the afternoon hours Wednesday ahead of the front with ample daytime heating creating thermal instability. Wind fields there for rotating storms look minimally to zero conducive for any organized severe.

WEDNESDAY: Next question, when will the rain chances end? Good one. Best bet is to expect it to be wet until at least early afternoon (Central), sunset (South) at this point. The time frame keeps extending to later in the day as the system was initially forecast to be through by sunrise Wednesday and long gone, could take all day to clear the area. Otherwise, quite windy behind the system Wednesday afternoon, with gust perhaps exceeding 35mph before the last of the mid-level winds pulls out and the system rapidly clears the state. No big cold air in the picture yet, not until at least Friday and even then nothing down to freezing.

Remember when this system was first brought up several posts ago, the statement was made that the longer it takes to get here the worse it could be? Uh oh.

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Sunday, January 23, 2011

Rain and Storms (Some Possibly Strong/Severe) Statewide Tuesday - Early Wednesday

Image: Image roughly depicts the temperature regime at 7:45AM this Sunday morning with widespread mid-upper 30s and pockets of freezing west central, totally below freezing NW Central and all North. Warmest along A1A from the Launch pads down A1A to Miami and thru the Keys.

RECAP: Everything unfolded as expected yesterday, with (in my mind) the true cold front right across Central Florida at 1pm yesterday. During that time frame a wind gust of 38mph was recorded on the hour at KSC landing strip with other gusts observed of near equal value at other Central Florida observation locales. The strongest winds occurred along and just behind the leading edge of lowest (driest) dew point air while the base of the mid-level trough and strongest winds aloft rounding it crossed the state.

The same scenario unfolded later in the day further south during the late afternoon and early evening as this boundary continued southbound. With the dry air fully in place across Central Florida by late afternoon and a continuing good dose of NW winds harboring in full cold air advection, the mercury fell in perfect accordance with the setting sun. Winds remained most elevated overnight on the east side of the intracoastal waterway, keeping overnight temperatures from falling much after midnight from KSC and south along A1A. In fact, at sunrise the temperature at Patrick AFB was the same as that monitored at Miami International Airport, 45F. KSC and Canaveral (my porch) both showed a low of 41F, with widespread mid-upper 30s inland. The coldest temperatures South and Central were on the west side of the state (west of Orlando) down to Okeechobee and over toward Punta Gorda (34F both locations).

TODAY: High pressure centers over Southern Georgia northward to Canada will move east during the day but remain generally in firm control over the Florida peninsula today. A north wind today will slowly abate in strength during the day, although we might see a pick up during and just after peak heating as it nearly parallels the coastline. By late afternoon it will most significantly decrease as it slowly veers toward the NE throughout the evening. Skies remain mainly clear, although some stratocumulus could begin to move onshore from Ft. Pierce and south along the coast. It will be cool today with afternoon highs similar to those of yesterday (low 60s) expect far south where it will be cooler than yesterday due to the delayed 'true frontal' passage south of West Palm...in other words mid 60s down there. Wide spread low -mid 60s should be the rule though, cooler north but not by much until as far north as I-10.

TONIGHT: Light NE-ENE wind overnight will advect higher dew point air temperatures onshore to approach I-95 by daybreak, Monday. This will keep coastal temperatures a good 8 degrees warmer than last night. Pretty quick sunset temperature drop should level off at the coast by 10pm as the now prolonged NE'ly component wind continues to modify mainly the coastal air mass, with a low in the upper 40s there as opposed to much cooler temperatures inland. Frost possible Monday morning North and west of I-4 where the richer dew point air will have permeated and overnight lows will fall into the mid-upper 30s with near calm winds there.

MONDAY: Air mass modification, which to a small degree has already begun this morning will show its true colors during the day in a most uneventful way, namely in the form of higher dewpoints, warmer afternoon temperatures, and some stratocumulus clouds. Low 70s could be realized far south, with mid-60s very close to the coast and upper 60s away from the coast. A few degrees warmer yet from West Palm and south, especially over SW Florida. Winds very light from the ENE-E and partly cloudy. Additionally, an inverted trough along the coast will be setting up very close to the coast from Miami to the Cape, which will strengthen during the afternoon. A shower is possible SE Florida (and models show this to occur as well near the Cape by late afternoon). This might be stretching it a bit though, and will leave it at that there could be periods of enhanced clouds to mostly cloudy conditions periodically...but predominantly partly cloudy.

MONDAY NIGHT-TUESDAY EARLY: Phase two of air mass modification in full swing at sunrise with a warm front developing far South overnight late and located nearly across dead Central Florida at sunrise. SSE winds all day south of this boundary as it heads north through the day toward I-10. Mild overnight temperatures with increasing moisture. Will introduce a small rain chance along the coast as the warm front passes and crosses along the inverted trough which should be located right at the coast from Miami northward with time. Rain chance should disappear for a time from mid-morning to early afternoon while a low pressure system RAPIDLY develops in the northern Gulf south of the mouth of the Mississippi River.

TUESDAY AFTERNOON AND BEYOND: By Tuesday afternoon we continue with a healthy SSE-S wind at the surface with a veering wind profile as one goes up in the atmosphere (more from the SW-W as one goes high up in the atmosphere). This would favor rotating storms by late afternoon but the amount of overall instability is highly debatable, but certainly rain chances increase as a shot of mid-level moisture crosses South and Central Florida as a totally separate entity from the developing storm system which will be ever-evolving in the Northern Gulf. Won't bring in the thunder word at this point, but bears watching. Time to keep advised of the weather though if one hasn't already.

TUESDAY NIGHT: Leaving this period in general discussion mode until the finer details can be ironed out between various models. But the very general consensus is for the weather to go downhill continuously (west coast and north first) spreading east overnight. Low and mid-level winds strengthen to 50+ knots across Central Florida by late afternoon Tuesday, and get stronger in the upper levels over night.

Looks like the peak of any strong/severe activity (if it's going to occur) will happen while it is dark. First on the west side then approaching the east side of the state after midnight. This could occur in at least two waves of activity. Should note that heavy weather will have already been occurring over North Florida for quite some time prior to that over Central Florida, and any outflow boundary generated by that activity further north that works south toward Beach Line Alley (Tampa to Cocoa Beach) could create havoc in not only the timing forecast but also the intensity of storms. It is simply too soon to dig into these intricate details this morning, considering this is still a good 60 hours (at least) away. And we haven't even touched on what could occur over the Loop Current off the west coast during the late afternoon Tuesday into the late evening hours.

Tuesday temperatures will be close to the low 70s (especially south where cloud cover will be less an issue)...regardless, no temperature issues Tuesday anywhere rain or shine. Do believe that at a minimum Central and definitely north Florida which will already be being impacted by heavy rains will see increasing cloudiness during peak heating which will temper down what other would otherwise be a downright pleasant day.

POINT IS: Remain advised on the weather situation during lunch time on Tuesday!! I expect to see lightning strikes over the Panhandle south to the East Central Gulf by that time at a minimum. This is still an evolving forecast situation, and yet to evolve actual one which leaves plenty of room and time for forecast consistency. It's going to come right down to the hour(s) as various ingredients pull together.

The trend has been for favorable wind profiles to evolve which would favor near severe to severe strength wind gusts with one or perhaps two periods of rotating storm structures, so tornadoes are not out of the realm of possibility. Expect that various portions of the state at some time or another will see either a Severe Thunderstorm or Tornado Watch, especially north of a line running from Palm Beach County on the east side toward Sarasota on the west side. An additional fly in the ointment might evolve for Extreme South Florida as well due to even less than obvious reasons than the ones presented at this time than what have been barely hinted at yet. In these situations though, I always watch the Keys toward Miami for an unstable air mass erupting northeastward from off the Yucatan over toward Western Cuba which impacts South Florida/Keys.

I am expecting to see the chance of rain in publicized forecasts for Tuesday go up possibly a couple of times between early today and Tuesday morning. In my mind, the chance of measurable precipitation to occur some time over the entire state is 100% between mid-day Tuesday through Wednesday morning. South Florida and the Keys will be the last to see rain exit the state, perhaps as late as sunset (or later) Wednesday. But Central should be clear of the worst by early-mid morning Wednesday. Don't hold fast to these 'notions' at this time, as they are simply that. But do remain advised at your leisure for the time being.

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Saturday, January 22, 2011

"Three Front Week" (aka "Three Dog Night")


IMAGE: Shallow surface boundary clearing the state (SOUTH) with upper level dry air already fully in place well aloft. This image shows generally the location of the shallow surface boundary (South Florida) which is dictating the wind direction and slightly dew point air (Central). The low pressure area is shown off to the east of Florida. The true front now approaching is shown solid.


TODAY: Windy this afternoon, with partly to mostly cloudy skies early with rapid clearing to widely scattered clouds within 1 hour of noon time as the second, true cold front crosses first the I-4 corridor and then Beach Line Alley during lunch time, continuing to South Central by late afternoon. In deed it is there, if you have any doubts just investigate the upper 20F degrees morning they had from the Western Panhandle to Tallahassee.

The true front crossing Central around noon time is a reflection of the mid-level trough location as well, and to some degree the upper level one (although slightly behind the former) during today and into tonight. Mid-level speed max of winds aloft round the base of the mid-level trough during the course of the day during the normal 'peak heating' hours of 12-2:30pm. Given the coincidental timing of drier air gradient, peak heating, and winds aloft, (all of which will generate a prime, but brief cold air advection pattern); mid-upper level vorticity (energy) rounding the base of both through early this afternoon through early this evening (which will increase mixing)...as well as with strengthening of the surface low shown in the image with high pressure building in from the west across the Northern Gulf of Mexico...could be windy today. Wouldn't be surprised to see the wind really start to pick up around 1pm with gusts up to 32-38mph from the WNW-NW for a view hours through 5:000pm, mainly over the intracoastal waterways and near the coast. This is stronger than I'm seeing forecast officially though, but I was tempted to think the wind could get even stronger then this. For now, we'll leave it as "there will be a good breeze today", totally good day for Kite or Para-Surfing.

Temperatures will level off early near noon, if not sooner...then take a couple degree fall after 2:30 pm as the winds filter in the much drier dew point air and flat out colder air as high pressure building in from the west filters those temperatures down from the north along its leading edge.

TONIGHT-TOMORROW: High pressure along the northern Gulf of Mexico and Deep South continues east, then takes more of a ENE-NE trek across South Central Alabama and Georgia tomorrow by which time that low pressure area to our ENE will be totally out of the picture. Additional, the mid-level trough will be lifting back to the north. This combination will relax the pressure gradient and in turn the wind speed significantly, most notably late night and more so after around 3am. Daybreak winds Sunday should be from almost due north around 10-13mph with chilly morning lows.

No change from yesterday prognosis in regards to temperatures. To repeat them, widespread mid-upper 30s Central, near freezing North and west of I-4. Of course freezing far North Florida across I-10, which might as well be known as "The Freezer Door". Secondary cold spot down the Florida Ridge especially to where it tapers off at Okeechobee city and over to the WNW side of the Lake where just above freezing might be felt. Warmer east of US1 from KSC south through far east Brevard County with a low near 40-43F at the Beaches. Warmest of course all locales from West Palm south to the keys. Do we really need to repeat the temperature regime for that area in every post? Fact is, this is ALWAYS the warmest area.

SUNDAY AFTERNOON: Wind to remain below 10mph all day and gradually veers to the NE during the day under partly cloudy skies. Temperatures comparable to those of today in the afternoon, but with significantly less wind it will feel better to the skin. Cooler tomorrow afternoon far SE and Keys then today's afternoon will feel, considering the peak of cold air associated with this system won't reach down there until after peak heating today. All in all, Sunday will be a nice day.

MONDAY: Still no change from previous thinking. Warmer everywhere, but not tremendously so. In other words, not as warm (for quite some time now), as it was this past week. Lows inland in the upper 30s to mid-40s but closer to upper 40s to low 50s at the coast Monday morning (in other words, maybe just a few degrees cooler there than it was this morning).

TUESDAY and BEYOND: Remembering the discussion about whether the next system would come through around Tuesday with storms or Friday time frame with storms. Looks like BOTH were correct, but minus the storms. Believe at this time the air mass of Florida will have too little time to recover from today's system to support storms for Tuesday's system (not to mention a plethora of other factors that will be absent which would be required for them to manifest).

In fact, the chance of even a rain shower is looking pretty skimpy right now. Again though, 'another front this way comes' (week's end) with again a reinforcement of cool air with barely enough time to recover from that one on Tuesday/Wednesday. Don't see any big warm ups for South Florida either if one is looking for mid 80 degree readings again like was felt down there this past week.

Even anything above 76F at all might be hard pressed to be found anywhere in the state through next weekend. Rain chances look pretty 'weak', but I do see The Weather Channel showing the little icon with a thunderstorm on us for Tuesday, and this is likely seen on everyone's TV that lives in Central and South Florida this morning. I don't believe it though. I'd put a 'Cloudy" icon there instead.

In general, from today and beyond looks like a very cool mornings and mild afternoon temperature regime, predominantly dry. Could all change of course, but "Just for Today". To sum it up, Three Fronts this week: Today, Late Tuesday, Friday.

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Friday, January 21, 2011

Limbo Today Before 36 hours of Winter Returns
















Images: Low level relative humidity (very moist) overlapped with very generalized surface features at 11:45AM late this Friday morning.

RECAP: The image above by no means portrays everything that's happening in the atmosphere, but the greatest impact of the current state of affairs is captured in this image...mainly, moisture. We see the pre-frontal trough that crossed Central Florida bringing some periods of moderate to heavy rain and thunder has sunk south to around the line shown by the dashed red line (roughly). It will sink only ever so slowly further south through the remainder of the day now that it is caught up with parallel flow aloft to that at the surface.

Over Central Florida, at the low levels a very weak boundary consisting of mainly just a weak wind shift along it can be seen (drawn as a pseudo-stationary front) which technically is not necessarily correct, but it sums up the situation in any case. The boundary is awaiting mid-upper level support to move out, but that does not arrive in earnest until the overnight hours. There is zero low level upward forcing in this zone nor lifting mechanisms aloft to support any thing more than a random rain shower over Central the remainder of most of the day, but lots of the correct ingredients for clouds, as we can see.

Most of the South Half of the state (south of the stationary boundary) is encompassed in a broad area of low pressure of which a center is difficult to discern, that will remain there the remainder of almost daylight hours. Perhaps the best chance for any real rain and thunder will be over the Florida Keys toward Miami-Dade and up the East coast toward West Palm this afternoon ahead of the pre-frontal trough, but don't really see any severe potential there.

AFTER 6PM: Shortly after or near sunset, expect the broad area of low pressure over Florida to essentially flee its heat source (the landmass/Lake Okeechobee) in search of more food. That will be over the warmer Gulf Stream waters.

As such, the low will exit the state near West Palm/Ft Lauderdale and become re-situated and quite a bit more organized once it reaches and resides over that area, and then begins to follow the bread crumb trail (the warm water food source) northward to well off the coast of Brevard County. Otherwise, little else changes in regards to local weather. As the low begins to coalesce, we may see a brief period of a NE wind during the early evening along the coast, and another chance of rain showers as well where the stationary boundary is located within the backwash circulation of the off shore low any where from Brevard to Miami.

AFTER MIDNIGHT- 11AM, SATURDAY: Low begins to gather strength in place over the Gulf Stream with continued cloudy skies and a better chance of overnight showers but light in nature Who cares anyway, it'll be the middle of the night. Good for sleeping. Temperature to remain mild with a low near 60 Central, warmer South. By daybreak the low will be 'wound up' enough for circulation to have acquired a NW wind component across North and Central, continuing from the west to WSW South.

Showers ending by mid morning at the latest, Saturday, everywhere but far South and rapid clearing will ensue shortly after that time as well.

SATURDAY-SUNDAY:...But clearing comes with a cost, namely much drier, colder air, heralded across the peninsula by upper level support passing to the North which will in turn eject our low pressure area off to the NE beginning mid morning and out of the picture. Cool air advection all day from noon time on all day with a NW wind getting a bit overly breezy between 1pm -6pm due to the tightening pressure gradient between impinging high pressure from the NW and the strengthening low pressure area to the ENE. Temperature will change very little all day from that at sunrise, perhaps even cool a few degrees Central, but not so much far south where the coolest air will not arrive until later in the day.

By Sunday morning, winds will have died down significantly from the NNW at 10mph or less, but it will be kind of cold with wide spread mid-30s interior, upper 30s from I-95 to US1 and closer to 40-43F Barrier Islands. Closer to freezing north of I-4 and possibly on the North Shore of Lake Okeechobee (far interior south). Clear most of the day and cool with highs in the low 60s along the coast, a little warmer further inland and south.

SUNDAY NIGHT-MONDAY: Another very cool morning, but not nearly as much so as Sunday morning, especially at the immediate coast with a light NNE - NE wind. Perhaps up to 10F degrees warmer than Sunday at the coast, but not quite the warm up inland. All comes at equal by early afternoon though as air mass modification begins in regards to departure of the coldest air. Our 36 hours of winter ends promptly at 11AM Monday morning.

BEYOND: Pedaling back to a possible active Tuesday as was thought would be the case two days ago. Don't believe a thing you hear today in regards to Tuesday/Wednesday just yet. Latest GFS has totally shifted gears with the last three model runs going from one extreme to the next, so not ready to bite on anything yet. Will weed through the mess with something better to chew on tomorrow morning. Regardless of this morning's run, though, I'd still be prepared for a wet period from Early Tuesday through the first half of Wednesday with a tremendous amount of details to be sorted, ironed, pressed, and neatly stowed.

One thing that does look consistent so far in regards to "BEYOND", the gravy train of rain producing storm systems passing over every 3-4 days looks like it may be about to reach its end, with the final system being the caboose. Will it go out with a bang?!! Maybe. Which could come, if it does, in the form of either a big thundery line of storms, or Winter, Part II OR, both or neither. Not going to sweat it out today though.

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