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".

Thursday, May 19, 2011

Love Bugs Sends Author Far Away Due to Allergies




Due to on-going pesky love bugs, the author will be fleeing to somewhere in the blue area for a while. This weather forecast blog for North Central through South Central Florida will return in June once this portion of the season has cleared the area and humans are once again free to roam the region.

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Monday, May 16, 2011

Over 400,000Spectators Disappointed, Severe Weather Forecasters Relieved

WEATHER PATTERN OVER FLORIDA THROUGH MID-DAY WEDNESDAY.
SWATH OF STRONGEST WINDS ALOFT INDICATED TOMORROW. TWO IMPULSES NOTED BY ARROWS.
TWO DISTURBANCES (the "Ls" TO MOVE ESE THEN LIFT NORTH AND EAST, THEN OUT OF THE PICTURE ENTIRELY BY FRIDAY


TODAY: Why the Title today? The Launch of the second to last Space Shuttle went today with out a hitch, but it could have been MUCH worse...and not have gone at all. In fact the Shuttle could have been damaged irreparably had weather conditions been a bit different between today and tomorrow.  ***See below for more.


 Instead though, due to how the systems through the atmosphere were aligned, they brought on another disaster of very large societal ramifications rather than meteorological. Folks from far and wide, from across the globe who spent vast amounts of money/time/resources just to be there to watch...had hopes dashed 5-10 seconds after lift off. Only those right within the secured area got a good view..the percentage of which is likely 10% of all those who were in the area.
To ADD to the impeccable timing of this "event of disappointing proportions", the clouds had cleared to the crowds delight, only to move back in during the final 3 minutes prior to lift off!! How is that possible?  Crowd control was out en masse too. Lesson learned obviously from the previous launch. 

It is easy to see where the arrow is pointing the contrail produced by the contrail ice crystals (over simplification), but also easier to see is the deck of clouds all around the launch area. In fact, now that I looked closer, you can see the ripples going through the top of the cloud deck indicative of the stronger winds aloft accompanying that patch of moisture!!


How could this  meteorological situation have resulted in severe weather that would damage the Shuttle? Note those two upper level lows. Winds aloft, for this time of year associated with them, are not at all uncommon like those we'd expect to find in January or February. Additionally, upper level disturbances are embedded in this flow that could trigger severe weather. But we are now in May...very very rare situation.


 So where's the storms?  For one, there is not enough moisture for deep convection,  just enough to generate clouds. What ever ample moisture there is for storms is getting stretched to far thin out flat rather than up.  The winds are entirely unidirectional with height..so there is no vertical turning, only horizontal stretching. This adds some lift, but not at the lowest levels.  Instead, the forces combined generates  period of clouds  


There are  no low level boundaries as well, including a mere sea breeze. Only a cold front that moved through near sunset last night..but it too was parallel to the flow, so there was no upward forcing at the lowest levels (aptly termed 'convergence').  Had these winds been associated with a surface front aligned differently with more moisture, this could have ended up being an near epic severe weather outbreak to at least include large, damaging hail (for instance) for this two day period. But as we can see...nothing is happening. 


One thing, we are close to setting record low temperatures across the state in the mornings. Followed by very pleasant a drier afternoons. It is a bit breezy too, but nothing beyond improving kite flying and water related wind sport. Certainly not destructive to build structures.


The first wave of moisture arrived this morning along and ahead of the first surge of stronger winds aloft. This moisture / wind team produced the cloud deck that simultaneously hampered clear sky conditions while dampening the otherwise energized hordes of on-lookers who arrived to Central Florida to view the launch. Even the announcer I heard on the radio while hoping to get some good video was awe inspired, until, that is, I heard her exclaim, " It's is AWESOME..INCREDIBLE...(pause) Oh, it went into the clouds"  ;-(. (a few times).


EARLY THIS EVENING/TUESDAY: The next of disturbed areas will pass across Central Florida near sunset. During that time I'm expecting cloud coverage could again increase. If it were day time it would be more so, and winds would pick up more as well. But it will be perfectly timed to have little impact other than to sustain the winds a bit longer than one would otherwise expect, and bring some more clouds in. This will mostly occur after dark, and won't be noticed. No rain.


WEDNESDAY: The second low will rotate around the first as it lifts north and east. This low will again bring even stronger winds aloft and even more lift. It is also accompanied by a shot of moisture. This one will mostly impact South Florida to the degree that showers could be in their midst at sunrise through early afternoon. Due to timing of this disturbance (early day), and no sea breeze, I do not expect there would be thunderstorms. There is even more moisture associated with this system as well as some accumulating at lower levels, temperatures aloft are expected to warm..so instability will be limited especially considering the time of day (early)


But note: We can't really know what the impacts of this disturbance can be since it has not interacted with any other land mass other than well to the north in much cooler air and under an altogether configuration, perhaps that chance of a quick moving storm should not be entirely discounted. However, the chances of such as extremely slim; not entirely negligible. The concern with storms, or even the expected (as of time today) rain showers, would be wind in and near rain showers...perhaps thunderstorms (as noted). For the most part, by current guidance, thunderstorms almost could not occur at all, but if one little thing were to change..


THURSDAY: Big pattern change as the the passive twin lows lift further north and start to open up. This will open the gate for another system on the West Coast of the U.S. to spread rapidly into the Plains.


At this time, it looks like it will be too much, too fast...And ram into the ridge behind the depart "Team Low". Uniformly directed winds could spark some severe weather here or there initially, but it looks a bit like the biggest concern will be more rains to the already flooded Mississippi River Valley Basin. Just one single drop more is not needed there.  It is forecast to get back logged behind the previous one..which makes perfect sense...unless, it completely punches into and through the ridge ahead of it, at which point all meteorological chaos could ensue. Bears watching, but as of now...the trend seems to be set in stone. Will team 'Tornado Hunt" on The Weather Channel get to see good storms. My best guess is that they stop chasing rainbows and head to Texas ..namely Abilene to Del Rio to Dallas south of the Red River. The dam might be jammed, but the back log ends up well to the south at the bottom of the bowl.


WHY ARE ALL THESE SYSTEMS DOING THE SAME THING? It a big huge blocking pattern of Epic proportions. Just like the drought in Texas and other parts of the country (which by the way is expanding). Just like the Epic Flooding in the Mississippi River Valley Basin (and I do not think that has ended yet...there will be a brief reprieve though), and just like the EPIC Tornado Out Break in the Deep South recently. Everything is over-inflated and over blown. I think we can blame  this blocking pattern's team mate as well. IT'S A DOUBLE BLOCKING BLOCK OF ALL BLOCKS. Another stubborn block..over Siberia (of all places).  What will it take to break the pattern.  I've nicknamed the one over Siberia, because of its fixture, "Blockhead". Even though it could be called something more appropriate (perhaps vulgar), being as stubborn as a 'mule'.


My best guess after all is said and done,  having whittled through listening to forecaster  fails, after repeated long range model FAILS...my guess,...is longer days and the hence, warmer times.  Eventually, something minute as an atom hiccup could disrupt this delicate balance and send the ball rolling which would expand so logarithmically fast it would blow an Atom Bomb's mind.

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Sunday, May 15, 2011

Late Season Cold Front To Clear North Central At Sunset

SYNOPSIS: A cold front near to just north of the I-4 will sink south and east during the course of today.
Preceding the front will be pleasant SWS winds at 10-20mph at times under sunny to partly cloudy skies.
The front will lie very close to the Beach Line, the Great Divide, at sunset.

EARLY MORNING LOCATION OF FRONT. SOME THUNDERSTORMS WERE OCCURRING WHEN  WE SAVED THE IMAGE. THIS FRONT WILL BE VERY NEAR THE BEACHLINE AT SUNSET. I BELIEVE THE AIRMASS OVER SOUTH EAST FLORIDA WILL HAVE BEEN TOO STABILIZED EARLY THIS MORNING FOR ANY ADDITIONAL RAIN CHANCES, ALTHOUGH THEY COULD DEVELOP LATE THIS AFTERNOON. THE BEST CHANCE OF THUNDER IT  APPEARS COULD OCCUR EITHER NORTH OR SOUTH OF A LAKE SHADOW, WITH SOME LIGHT SHOWERS JUST AHEAD OF THE FRONT AFTER NOON TO 7PM.
FORECAST FOR TODAY: Florida is still embedded within an unseasonably deep 500 mb trough; the configuration of the trough axis is now no longer negatively tilted as was the case yesterday and the day befre, but is becoming more oriented North / South..or will be by Monday while the front gets alinged with the flow aloft  and sinks off South Florida by later Tuesday


There is a chance of a shower or two very close to the front, mainly on the east side of the state after noon time near Daytona toward North Brevard. As the afternoon wears on toward peak heating, it is possible a thunderstorm could occur very close toward the east coast, but more than likely any thunderstorm to occur over North Central Florida will only be a rain shower until moving offshore. The best time for that to occur today will be as the boundary enters North Brevard between 4-7 pm from Orange County toward Port St John to Cocoa Beach just ahead of the boundary. Otherwise, there is no boundaries to 'play' with today in the absence of the Sea Breeze. Should the C-Breeze Develop the chance of thunder along the very immediate coast increases, but that would still be within the given time frame and locations. There is no chance of rain once the front has cleared, and for the most part, the chance of the sea breeze today is very very low. Highs today will be in the low 80Fs, with the air beginning to dry out some.


Elsewhere, there is a chance of a thunderstorm, which would be stronger, in Palm Beach County after 2pm due to the Lake Okeechobee and perhaps far SW -SE Florida around the Lake Shadow and warmer temperatures. It does not appear there will be a sea breeze there either, but the chance does exist, and is the most likely candidate.


BEYOND: A secondary front accompanied by very strong winds aloft will cross Central and South Florida during Monday and Tuesday. However, like today...despite how strong the wind aloft is with impulses and vorticity passing over head..moisture is very limited and low level forcing with what moisture there is would likely only result in clouds below the stronger winds above them. Some showers, at this time, are possible at almost any time. The best chance of thunder would be over far South Florida, but that chance looks very low as well due to limited, although more that north or south central, moisture.


THE REMAINDER OF NEXT WEEK will be dry with very cool mornings for this time of year.  for two morning. Could see some mid-upper 50Fs on Wednesday morning when the second front has cleared with one day or two of highs just below 80F to 82F.  The air over Florida will begin to moderate from South to North ahead of another approaching front for next weekend. Some showers and thunder might occur this this front...but we'll leave it as partly cloudy until the writing is on the wall and the timing of its arrival, assuming it even does, draws closer.

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Saturday, May 14, 2011

Potent Storms From West To East Possible Today - Isolated Hail Would be Likely

LATEST INSTABILITY INDEX VALUES: HIGHEST ACROSS CENTRAL, LOWER SOUTHEAST BUT STILL VERY UNSTABLE THERE. STORMS MOST PROBABLE IN THE BLACK LINES. LEAST LIKELY FAR SOUTHEAST FLORIDA INTO A PORTION OF PALM BEACH COUNTY. STRONGER STORMS POSSIBLE IN PURPLE. WITHIN WHITE, COULD GET CHAOTIC FOR A BRIEF SPELL IN ISOLATED POCKETS. SEE BELOW FOR WHY.

SYNOPSIS: A large upper level low pressure system over the Eastern U.S. is slow to move out due to a blocking pattern. A cold front has cleared the western Panhandle, but might not clear the peninsula fully until late Tuesday. Until that time, periods of unsettled weather in the form of showers and thunderstorms can occur..separated by periods of pleasant weather and less hot temperatures than days past.

TODAY: THE FRONT IS THE BLUE LINE. A COMBINATION THERMAL/PREFRONTAL TROUGH IS ANTICIPATED TO BE FORMING AS A TYPE. WEAK SURFACE LOW SEEMS TO BE FORMING NEAR WEST PALM, OR IS ANTICIPATED. IF SO, THIS TROUGH WOULD ALLOW A SEABREEZE TO FORM NORTH OF THE LOW.

 NET RESULT...CLASH OF THE EAST AND WEST COAST SEA BREEZES CLOSE TO OR EAST OF I-95 UNDER VERY COLD AIR ALOFT


TODAY: As shown in the above image, a cold front is still far away from North Central to South Florida. Unlike the winter months when they blast through, this one will take at least 60-72 hours to push through. Another impulse (upper level disturbance) is expected to cross the Peninsula Early tomorrow, potentially bearing a 'pre-disturbance' trough as well..


Meanwhile...


The west coast sea breeze will be dominant today within the synoptic scale pattern of west to east motion. Only far South Florida is not within this pattern...with the weather down in Broward, Dade, and Southern Palm Beach County being dictated by more of a sub-tropical nature. 


A disturbance is FORECAST to move across the state today. Within it could be isolated to possible scattered thunderstorm activity. If so, (still tapping my fingers and waiting)...storms will strengthen with time as the develop after 2-3pm as the cross the trough shown above. Some of these storms in isolated fashion could contain small coin sized hail. Unlike yesterday, the sea breeze IF IT DEVELOPS would be East of  Orlando Metro and the Airport, but I see that the NWS might be putting that area on somewhat of a 'Heads Up" mode for hail and/or stronger wind gusts due to the passage of proximity of storms in both MLB and MCO. JAX has some severe storms approaching already...this was indicated to occur my most (but not all) model guidance).


As we see in the first image, I've somewhat 'color coded' where storms might become stronger and then strongest mainly along and east of I-95. CAVEAT: Much better news if the east coast sea breeze does NOT develop. It is almost hard to envision that it will not though, given that on the beach in Cape Canaveral the west wind is only about 4 mph. My initial line of thinking is that at least a weak sea-breeze would form after 1-2pm..if not sooner given the current conditions. 


Dew Point temperatures across Central Florida are running in the low to nearing mid-70Fs in pockets. It is a bit cooler so far today, but it's still early. Some of this moisture will hold in the normally warmer afternoon heat, and reserve it for release today in the form of Convective Available Potential Energy (CAPE). The higher the CAPE..the bigger the release. Vertical Atmospheric Upward Velocities (VVs) are being forecast to be strong..and in one instance..were forecast to continue upward right up to nearly the jet stream level. This would keep downward descending parcels, i.e. rain drops)..from falling to the ground until they are heavy enough to do so. Morning soundings are showing a dry mid-level layer..adding to the mid-level buoyancy (lifting mechanism).  


1) If the sea breeze does indeed form..and that is questionable...storms could become severe in some areas as they begin to the most western impingement of the sea breeze front. One model indicates very high precipitation totals just east of Central Florida in the very late afternoon hours...indicating the activity will collapse quickly and possible drop a lot of hail in the process and gusty winds out at sea. However, should the collapse occur sooner, the would translate on the coastal communities.


2). If the sea breeze does not develop..storms would not be nearly as strong with all potential negative factors greatly reduced by a very wide margin. 


3). Third..the obligatory worst case scenario. As long as there is a glimmer of doom, might as well capitalize on it. It's only a blog post anyway. If you've read this far, you'll be intrigued if nothing else: 


The sea breeze does form and is magnified around the crook of the Cape area..or Cape Bight which runs from Port Canaveral out past the lighthouse. Mesoscale (small scale) circulations would form  (like they always do in such cases) within that zone and west into Titusville, Mims or even Oak Hill toward Sanford depending on the strength of that sea breeze. This would be a concern for the region in North Brevard toward Sanford and Southern Volusia Counties. Namely because the further north one goes the stronger the winds aloft area as well, which would support even yet bigger storms capable of dropping golf ball sized hail at least. I do not think that will happen, but it is something to passively watch consider there is a Shuttle Sitting on the Launch Pad.


In general, the strongest of storms, if they form, could run within the bounds noted above, or from Jacksonville to West Palm Beach. As of this time (and that could change), the Miami Metro area and Ft. Lauderdale do not in any way seem to be in a threat zone...not for today that is. This will possibly change with time in the next two days, contingent upon how much further South that big upper level trough digs south. We'll know on Tuesday.


And finally, I do have second thoughts about how virtually ever single model portrays this afternoons events. Perhaps something even more 'squirrelly" will occur near the coast, if so, most likely near the Cape area within 10 miles.


SUNDAY: Could be a stormy day over Central Florida again, but very isolated. Or, simply a bit showery with some afternoon thunder. Worst case scenario is that the storms move offshore tonight (if they even form as noted in length above) and collapse, sending an outflow boundary back to the coast. This would provide better impedance for a sea breeze to develop once again on Sunday...very sketchy though. Things have changed since last night's model runs, and I FULLY expect things to change at least two more times before the next post is made.


With that said, it would behoove "High Speed Dirt" to continue ad nauseum before today is even yet through. Much of what happens today might provide a hint as to what would occur on Sunday.


MONDAY: Between disturbances. Looks very quiet although an isolated shower or thunderstorm could occur, but only isolated and remote.


TUESDAY: South Half of Florida could have the better chance of showers and thunder, but it is very very sketchy what form the precipitation will take. Could it snow there?! (just checking to see if you read this far). 


 Best chance of thunder appears to be far South Florida despite the fact that the strongest winds aloft, which are pretty impressive for this time of year, will be over Central and South Florida. If the precipitation shown in guidance is thunder storms..they could easily be severe. Time will tell..I'm on the cusp of very uncertain about Tuesday. Beyond Tuesday...the coast is clear, literally...SE Florida? Maybe Miami Metro.

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Friday, May 13, 2011

Low Confidence (Location/Chances) Of Late Afternoon/Early Evening Storms In Florida Today

ALL CONDITIONAL STORM CHANCE AREAS: Chance of rain showers or thunderstorms within the green bounds, most likely area is within the light blue and lavender, with the peak conditional chance along the east coast in the yellow highlight/dark green areas (see below). Another area not shown is along the West Coast from near Brooksville and south toward Naples. Also not seen here is an area extending toward Miami in SE Florida.

OBLIGATORY DISCLAIMER: As is always the case and as printed on the web page at 
http://www.highspeeddirt-steve.blogspot.com  all thoughts are of the author's own. Please refer to local official outlets (my most preferred is the National Weather Service until an 'event' (storm) develops), then your local televised news channel,  for the latest officially released information for where storms are located and expected to move toward.


TODAY: First of most importance there are three items to consider: 


(1) Nearly every forecast model is in disagreement with where rain/thunderstorms will develop today. It does appear that there will be an isolated  very strong storm or two or 3 today within the 'green' today, which is almost the entire state. The most likely area appears to be in the center of the state.  Even timing is an issue. One chain of thought calls for early afternoon activity which I had dismissed since sunrise, yet they are still showing the possibility. As of now it is supposed to be raining where I sit (for example) based on the short term local WRF model. Yet there is not a storm building anywhere in the state, with some cumulus along/over SE Florida and some that tried around the Big Bend but were snuffed out by high cirrus clouds.


 Note the two areas along the east coast: Those are outliers, but important. Important because if storms do develop and/or move into those locations, they could be severe, along I-95 toward US-1 late today after 6pm if conditions exist for such at that time. How/why? Temperatures aloft at 700mb are expected by one model to drop by several degrees after 4 or 5pm. Will that happen? Time will tell. But at least we have been forewarned of this possibility.


(2) Will there be many storms at all today in fact?  The atmosphere looked very unstable since sunrise, observed by the cloud types (did not need a model to see that).  However, the approaching disturbance to affect the state tomorrow is shielding cirrus clouds across the state, limiting  the atmosphere's instability, and in some model portrayals, by a big margin..significantly so.  I do believe that even still,at least sea breeze storms will form in the interior after 5pm.


The reason for the bigger threat along the East Side is caused by coastal low level helicity (sort of like little whirl pools or eddies that form along the sea breeze, which is closely paralleling the coast today. It is the near parallel motion that sets the eddies going. When a storm approaches them..they tend to 'jack up'..especially just east of I-95. If this situation does develop, it would not be until after 5:30 or even 6:30pm...and in full force east of I-95 around 6-7pm.   


(3) Lastly, there is a chance that mid-evening post thunderstorms could develop (or continue) in the favored inland location  as well as closer to the coast in South Central Florida (toward South Brevard/Indian River Counties). This is very remote but still possible. This storm would for after the sea breeze has relaxed.


(4) There is a big change to occur sometime after 4pm with wind fields as well as some lowering in mid-level temperatures. This might be throwing a lot of models of, and will affect (if this is real)..where the heaviest activity will occur).  It may also be why the weather is so benign this early afternoon. Nothing to happen until that time it occurs (if it does).  Since that time has not arrived yet...it's a waiting game. Waiting to see how long the high clouds stick around (which looks almost certain)....and if those mid-level wind fields indeed to change so quickly.


LASTLY: In Looking at the latest hourly information availabe which included (the mental analysis/picture) a vast variety of parameters, the most likely area as of 1pm for activity today is toward the center of the state, with a slight lean toward the east coast in  Volusia/North Brevard (South Florida is a different story altogether, and beyond the scope for one post). It is down there though that the first signs of an approaching rain chance are manifesting this hour.  Should the high clouds persist or thicken with time, the chance of rain diminishes significantly everywhere, other than perhaps toward South Florida, with maybe just some showers and a thunderstorm or two inland of non-strong character. Note though. No model shows a 'dead late day'...yet.


SATURDAY: The Storm Prediction Center already has the Panhandle and North Florida in a "Slight Risk" for severe weather tomorrow. In Florida, that would be mainly for hail. There is uncertainty though even there since persistent cloud cover would limit instability if it is there from early morning toward noon. It may be that Central and South Florida will end up with the stronger weather when all is said and done. I'm inclined to lean in that direction.


SUNDAY-TUESDAY: More chances for showers and some strong to severe storms will exist on 1, 2, or all days, depending where in the state one is located. After tomorrow, the Panhandle is 'out' since that area will be behind a cold front in more stable air.  The most favored area on Sunday appears to be for a portion of South Central to South Florida. But that too may change. Earlier guidance indicated the showers would begin over night into Sunday morning, and could be 'in the area' all day. Along and South of the BeachLine to Miami. 


That, plus we might not have a sea-breeze. If this indeed is the case, Sunday could just be mostly cloudy with showers ...and some thunderstorms from early afternoon to evening possible (perhaps). A lot of what occurs Sunday - Early Tuesday is contingent upon a combination of the surface winds and timing/passage of embedded disturbances aloft. All wet chances abate by late Tuesday in South Florida.

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Wednesday, May 11, 2011

Rains Chances Slowly Increase For Florida...But When?

The BIGGEST Player for much of North America Today through Friday seems to be that big Double Whammy System in the Atlantic Off New England. It is barely moving if at all this morning. We can see in this image the third of three small MCS (Mesoscale Convective Complexes) that moved off the Coast of South Carolina since this morning. These are narrowly missing Florida, and the storms associated with them can be seen on The Weather Channel here in East Central Florida.
CLOSE UP OF THE SYSTEM OFF NEW ENGLAND.
THESE TWO AREAS ARE STAYING IN PLACE...ROTATING
IN PLACE DISCRETELY, WITH THE SOUTHERN ONE ROTATING NORTHWARD AROUND THE LARGER, NORTHERN ONE. NO MODEL SHOWS THESE AS SEPARATE ENTITIES!!

THE THREE MCS COMPLEXES EARLY THIS MORNING. THE MOST SOUTHERN ONE WAS VERY ACTIVE SHORTLY BEFORE I SAVED THIS IMAGE. HIGH PRESSURE JUST TO THE WEST AND OVER WEST FLORIDA IS BLOCKING THESE FROM REACHING THE STATE
TODAY'S VERY SMALL CHANCE OF AN ISOLATED RAIN SHOWER OR MAYBE THUNDER. EAST CENTRAL WOULD BE AFTER 6PM. THE ZIG ZAG LINE IS SUBSIDENCE TO THE WEST OF THE DISTURBANCE THAT IS OFF TO THE EAST, WHICH CAN BE SEEN IN THE FIRST  IMAGE ABOVE BUT NOT IN THIS ONE. LOW PRESSURE NEAR ORLANDO IS THERMALLY INDUCED (FROM HEAT)

SYNOPSIS: Big blocking low pressure system (s) off the New England/Mid-Atlantic Coast and high pressure over the NE Gulf at time, as has been the case the past 48 hours. Little has changed other than that the low pressure area is enlarging. This system is proving to be quite the forecaster's quandary for not only Florida but the Central Plains states today. This will continue to be the case until it moves..somewhere..which should be a bit more south..then east to northeast beginning later Friday as a system in the Central Plains today  finally gives it the boot.  The Central Plains states system will be forced to 'dig' toward the ESE-SE in days ahead, and in turn force the high pressure area near Florida that is creating all of the hot, dry afternoons to move south and east with time. At time, it appears fairly safe to say this process will begin on Friday but that to could change given the now unforecast/unanalyzed strength of the Atlantic System by the models. This system is indirectly affecting forecasts in the Plains as well, making what looked initially to be a very active severe weather day there not 'quite so bad'...but still 'bad'.


TODAY/THURSDAY: Until that time, the best chance of any showers or thunder will be in the areas drawn above, with an outlier on the South Side of Lake Okeechobee.


It is interesting that a lot of the reason we have not had rain is due to warm air in the mid -levels. Per the latest short term model, in disagreement with the other models run this morning, this warm 'cap' is to disappear this afternoon; however, moisture is too meager in general (PWAT too  low) to produce rain. I can tell by looking outside that the warm air aloft hasn't broken down yet over Brevard due to the haze. Perhaps even the short term model was a bit too hasty in removing this 'cap' of warm air.


Would like to add at this point, the for several days now the high pressure was supposed to break down, with some models (all of them) showing increased rain chances starting yesterday or Tuesday. But that low of the NE U.S. Coast is stronger and more stubborn than any model or person for that matter could foresee. Remember in the post two days ago, this possibility was alluded to? It was mentioned in could even end up drifting right over the state. That too, can still happen going into Friday, thus..the chance of no rain is always there until proven otherwise.


How much of glitch in any forecast going into the weekend will this have? Not too much, but the timing will be an issue. Timing, that is, of when the Atlantic System makes a move.


Two boundaries today. 1) a bit of a trough axis will lay across far N. Brevard County today until mid-late afternoon. We'll know when it breaks over East Central at the coast when we gain an on-shore wind component. In the upper levels moisture is slowly working south from far NE Florida and will build up behind this boundary. Another spoke, or boundary, lies further north toward JAX which will move little. Both of these boundaries could act as focal points for a small precipitation  'chance' later today...but the southern one near Brevard will rely on the wind shift..and that would have to happen at just the right time. If it happens too soon the area will be scoured out by subsidence behind the boundary with the land/sea breeze meeting each other over an area further to the NW where the air is too dry after day time heating removes the low level moisture in that area...caveat..with that boundary in place near North Brevard..just enough moisture could accumulate near it. Thus, the rain chance. Anything to form, if the timing is just right, would probably only be a rain shower though unless something very magical occurs beyond the scope of the laws of physics.


The same scenario will likely play out tomorrow as well, but a change will be in progress.


FRIDAY: Based on guidance, Saturday would be a transition time when the Plains system works far enough east to dislodge the high pressure over the NE Gulf. This would allow more moisture to work in, and with cold air aloft and late afternoon seabreeze / land breeze collision to occur along the east coast of the state late in the day. Better chance of thunderstorms on Friday...but isolated. However, forward motion...and more importantly to Florida, the direction of that forward motion owing to whatever the Atlantic System does..will make a big difference for the state down the road to 'recovery'.


SATURDAY/SUNDAY: Given the blocking pattern and it's evil history (for forecasters), the weekend will be interesting to see how it unfolds. COULD be that there will be rounds of rain/thunder chances at just about anytime, favoring the east side but not always. It gets more difficult when it is forecast that the sea breeze on the east coast will no longer develop. There will be cold air aloft and no capping, but lack of a trigger and any low level boundary collisions as well, in the presence of no forecast upper level disturbance could result in just lots of clouds and some showers. On the other hand, any unforeseen disturbance embedded in this "yet to develop pattern' could contain all kinds of little disturbances to generate very strong thunderstorms. At this time, it appears either Saturday or Sunday would be that day. ...keeping in mind that often any kind of blocking pattern is often hastened foreword too quickly by models..so that time frame could very well end up being Monday/Tuesday...or anywhere in between.

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Tuesday, May 10, 2011

Isolated Shower and Remote Thunder Chances Begin Wednesday -Increase Sunday

Water Vapor Imagery This Morning: We have a large low pressure gyro off the  Mid-Atlantic Coast slowly dropping SSE this morning. Noted is where strong storms could occur today over South Carolina, Eastern Tennessee, and western North Carolina this afternoon into the Evening. Those storms could be important for NE Florida and perhaps a portion of the East Coast Wednesday as they push into the Atlantic tonight.


TODAY: Just looked at the morning sample taken by a weather balloon (in essence) of the atmosphere from the Kennedy Space Center. It is showing an increase in atmospheric moisture, but most of this is either at the lowest levels or highest. A dry layer remains above cumulus cloud level as has been the case for a while now,  and little change is expected from that through today into tonight. The most instability is just near and off both coasts which developed relative to the cooler air above the land mass over night. There was much more there this morning then in the past, and even more is expected to be there tomorrow morning. Daytime heating will dry out the interior, whereas afternoon sea breezes will create sinking motion near the coast to clear out any remaining cumulus clouds near the coast before noon...although they might linger longer toward coastal SE Florida. Highs will be in the low 90s inland and closer to the mid-80s at the beach. Not expecting any showers today, although a shower could pop up on the western portion of Tampa Bay late this afternoon into the early evening. Maybe they will eke out thunder due to low level forcing of local bay boundaries, but at this time it does not look like the moisture will be deep enough, nor will any 'forcing' be strong enough, in the absence of any upper level energy, to generate thunder there later today as of this hour.


FURTHER NORTH: A disturbance will drop SE and across the area above noted in RED  much later today (in general)...and create strong to marginally severe thunder later this afternoon into early evening. Another impulse may very well  make a repeat performance in the same area early Wednesday morning. Those could lay the frame work for some stronger storms over the Jacksonville area later on Wednesday if they manifest. However, it does look likely that they will.


WEDNESDAY: Chance of storms toward Jacksonville and over the St. John River Valley Basin in general. These, if they can form in the still somewhat questionable situation at hand, could end up being rather strong as a result of the cold air aloft combined with boundaries created by that activity moving off the South Carolina Coast.  There was some unstable air near the coasts of Central Florida this morning, and there is expected to be even more of it there tomorrow morning. Additional atmospheric moisture combined with strong winds aloft  should work in tomorrow to support a chance of an isolated shower early in the morning near the Cape and further south toward Ft. Pierce, with redevelopment of a possible thunderstorm from near Sebastian to just south of Vero Beach/Ft Pierce  in the afternoon, to possible into a portion of Osceola County later in the afternoon . An additional storm or two could form later in the afternoon around convergence of the sea breeze/lake breeze frontal boundaries off the Gulf/East Coast, and and Lake O '. Most likely on the NW-W side of the lake.
Any showers to form will be very isolated, with the best chance near Lake O.


THURSDAY: Isolated late afternoon sea -breeze front convergence thunder storms are possible down the spine of the state. See image below for these two days (Wednesday/Thursday). This is a first order 'best guess' based on what was available early this morning and will very likely have changed by later this afternoon or tonight. Just to serve as a heads up that there could be some thunder around the state Wednesday/Thursday. The GFS and now NAM are supporting the activity for Wednesday in a various forms though. The GFS for 36 hours now. Last night, in fact, the NAM was showing the potential for bombastic storms from JAX-N. Brevard late afternoon to mid-evening, but completely dismissed this chance only 6 hours later. Just to make a point how things can change fairly rapidly when using a model as a basis for where rain will occur.

IF YOU LOOK CLOSELY YOU CAN SEE A THIN VEIL DOWN THE SPINE OF THE STATE THIS MORNING. THAT IS SMOKE FROM A FIRE IN GEORGIA ,  ENTRAPPED IN THE MID LEVEL INVERSION, BEING FORCED TOWARD THE SSW-SW THIS MORNING. CIRCLED AREAS ARE "GREEN: WEDNESDAY, and BLUE: THURSDAY" PRELIMINARY RAIN CHANCES

BEYOND: The chance for isolated showers and thunderstorms will continue into Friday and Saturday, with a possible up tick toward Sunday or Monday. Models are varying in timing and strength of what could be one or two afternoons of strong thunderstorms from Jacksonville to Miami beginning Friday or Saturday...isolated. The bigger increase in coverage arrives on Sunday or Monday. Theres days favor the East Side of the state. There has been indications this activity will be quite potent; however, given the time of day (earlier than normal), and lack of a weak cap indicated, it could end up that these days will end up with general, wide spread thunder rather than stronger and more isolated activity.


Chances of afternoon thunderstorms outside of an inherent pre-noon time coastal shower activity could continue off and on for another week if the current longer range forecasts verify. However, I have very little faith in them at this point. But a pretty big change for most of North America is in the works heading toward next Monday and beyond once that low off the Mid-Atlantic Coast is out of the picture.


AND FINALLY: Way out in time the GFS is showing the first signs of a Summer Like Wet Season Pattern Developing going into the last week of May with much higher moisture content air in the tropics and a low level ridge axis across the state.  This will change though, and more than likely be pushed further out in time rather than sooner. The GFS seems to have a built in clock, perhaps 'climatology' as a part of its inheritance from the model developers/scientists/climatologists/meteorologists. Interesting to see this appear though. 


See the deep moisture down in the Caribbean approaching the Gulf by the lavender and deep red heading toward the last week in May? This would lay the foundation for more typical South/Central Plains Severe Weather, and eventually that for the Florida Wet /Thunderstorm Season. Also note all of the moisture over much of the Eastern and Southeastern States. This would be the indicator of continued thunderstorm chances in the Southeast and Deep South even as far out as May 25th. However, both of these depictions cannot be relied upon truth as much as in theory.

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Sunday, May 8, 2011

Showers Far SE-S Florida Today, Showers/Thunderstorms Possible Further North Beginning Monday

OLD BOUNDARY FROM DECAYED FRONT STILL OVER SOUTH FLORIDA FOR THE 3RD STRAIGHT DAY. IT IS ON IT'S LAST LEG TODAY, BUT SHOWERS ARE POSSIBLE IN THE AREAS IN GREEN, INTO THE KEYS.
NOTE THE HIGH PRESSURE OVER THE EASTERN GULF. THIS WILL BE ONE OF THE MAIN FACTORS IN DETERMINING PENINSULAR FLORIDA WEATHER DURING THE UPCOMING WEEK. AREAS IN PURPLE AND ORANGE INDICATE SHOWER./THUNDER CHANCES ON MONDAY AND/OR TUESDAY

TODAY: Old frontal boundary is about done with South Florida today. Whatever moisture remains will begin to lift north along the immediate east coast to Central Brevard Today with little to no notice. High pressure is over the Eastern Gulf at the surface and the mid-levels. Dry northerly flow today and a weak surface pressure gradient will allow the coasts to have a cool breeze while inland temperatures from either coast rise into the upper 80Fs to near 90F in a few spots.


MONDAY-FRIDAY: The majority of the upcoming week is highlighted by a near blocking pattern. For Florida concerns, the contributor to the block is low pressure off the Mid-Atlantic and NE U.S. Coast which will move little. Storm systems are forecast to roll out of the North Plains and the Great Lakes and dive toward South Carolina beginning tonight, as 'faux backdoor cold fronts from the north". However, they will mostly wash out after reaching Central Florida. Won't be surprised to see some major storms move through South Carolina in a day to two though, for starters. Other areas to watch through Wednesday will be Nebraska (today) into Kansas/Oklahoma/and North Central Texas by Wednesday. The system on Wednesday will more directly (and most likely) be one that will affect most of the state going into Friday and the weekend.


MONDAY: First off, I want to point out the source of moisture next week for any rain chance will not come from the south, but rather from the North. Days will be characterized by very little surface gradient flow, and groudn level winds will nearly solely be dictated by coastal sea breezes. Inland temperatures could approach record levels or if not, just be plain old hot approaching the low-mid 90Fs on various days, with the coast in the mid-upper 80Fs before onset of the sea breeze. Perhaps by Friday the  east coast will see 90F degrees readings as well.


The first storm system to dive south from interior positions of the mid-Atlantic Coast states  is forecast to bring moisture into all of North Central Florida tomorrow from north to south, reaching the Beachline by sunset or shortly thereafter, mainly on the east side. Afternoon sea breeze should keep the moisture convergence, and hence showers and possible thunderstorms along and west of I-95...but this bears watching. Storm motions would be from the NNW, which will struggle with the sea breeze and likely avoid the cooling subsidence behind the sea breeze front.


TUESDAY/FRIDAY: Pretty much the same scenario everyday. Whether or not rain/thunder will be realized, and if it is , where..is contingent upon the strength and breadth of the oscillating area of high pressure to our West. If it is weaker, each impulse from the north (carrying moisture with it)...will affect more of the north half of the state than on days when it is stronger or when the impulses are too weak or are not transporting enough moisture with them.  Everyday will not be carbon copy of the day before. Some days could favor further to the west..whereas other days could favor the immediate  east coast.


Temperatures will be quite warm in this regime. It is possible both from this synoptic scale regime  as well as from a climatologically perspective, that Central and North Florida will encounter some of the highest temperatures of 2011 during the next week if not beyond into next week, with highs in the mid-90Fs. Far to soon to say for sure, especially since these 'warm to hot events' are seldom foreseen and not well handled by guidance. The chance of abnormally warm temperatures can also occur as late as early-mid June to keep things in check.


It does not look like far South Florida will get into the 'rain game' initially, but should the pattern shift to even a stronger blocking pattern as indicated by the GFS by Friday..they too will be pawn for the rainstorms.


SIDE NOTE: Long range guidance has been implying that a big blocking weather pattern (one that changes little for over a week at least) could be in the making. This has been implied to occur for several days now, and this morning's model run of the GFS is no different. Most favored has been a classic "Omega Block"..I wrote about that type of pattern several months ago, and will re-introduce that type of pattern should it emerge. The other blocking pattern shown last night was a strong "REX BLOCK" on the East Coast of the U.S. In either case though, the pattern over Florida is nearly the same as an end results (and as described in the earlier paragraphs).


FINAL NOTE: Should thunderstorms be able to develop in the next week, they will be isolated to possibly scattered, but also restricted to a particular 'favored zone' for that particular day . They could also be quite strong to marginally severe at times with both modes of strong storm characters involved (small hail/strong wind gusts).  Would not be surprised to see some sort of 'mesoscale accidents' on a day or two, with a storm somewhere between Jacksonville to Orlando being especially feisty, especially if a storm can impinge through the East Coast sea breeze front...in which case a coastal community could get a good rain.


Should high pressure over the Gulf shove just a bit further east toward the state, all rain chances most everywhere will go to zero..and the heat would be "On" with little relief.

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Saturday, May 7, 2011

IN The Mood For Clouds, A Shower, A Storm? Let's go PWAT CHASING!!!

WHAT WAS THE "TOTAL" PWAT THIS DAY? HOW WAS IT DISTRIBUTED VERTICALLY AND HORIZONTALLY ACROSS CENTRAL FLORIDA THIS DAY? WHAT WERE THE WINDS AND TEMPERATURES ALOFT?~
IMAGE: LEADING EDGE OF A SHELF CLOUDY ABOUT TO TURN "OUT FLOW GUST FRONT", CAPE CANAVERAL




Throughout previous posts, and in the current Convective/Wet Season in Florida in progress, I've used this term, PWAT. But what is that, and why is precipitable water value expressed in these discussions?  


Namely, because it is important in a variety of ways. It can define days that will have clouds (or none) and at what level(s) of the atmosphere they will be for starters. It also determines if there will be showers or storms. But it does not stand alone. Other parameters include the vertical thermal profile of the atmosphere (temperatures near the ground and aloft), the amount of instability in the lower levels and conversely, the amount of stability above the lower levels.


Technical precipitable water (PWAT)—(Or precipitable water vapor.) The total atmospheric water vapor contained in a vertical column of unit cross-sectional area extending between any two specified levels, commonly expressed in terms of the height to which that water substance would stand if completely condensed and collected in a vessel of the same unit cross section.


The total precipitable water is that contained in a column of unit cross section extending all of the way from the earth's surface to the “top” of the atmosphere. Mathematically, if x(p) is the mixing ratio at the pressure level, p, then the precipitable water vapor, W, contained in a layer bounded by pressures p1 and p2is given by

where g is the acceleration of gravity. In actual rainstorms, particularly thunderstorms, amounts of rain very often exceed the total precipitable water vapor of the overlying atmosphere. This results from the action of convergencethat brings into the rainstorm the water vapor from a surrounding area that is often quite large. Nevertheless, there is general correlation between precipitation amounts in given storms and the precipitable water vapor of the air massesinvolved in those storms.




AUTHOR'S NOTE: So what if you're not so hot at, or are even familiar with, the mathematical principles of "Integration" as shown in the example above by that vertical squirrelly line running up and down with p1 and p2 shown?  All that means in the equation, is that they are using the moisture content from one pressure level (p1) to the next higher level in the atmosphere (p2)..of whatever chosen levels desired. For instance, to even have rain  in Florida I'd look at the surface to 700mb (10000 ft, the standard height/level) for starters, and to simplify it. There has to be 'some' moisture at 700mb, but it doesn't have to be a lot...in fact, lower moisture at or near that level will ENHANCE storm strength because the more moist (and more buoyant) air below that level will rise faster into the drier and colder air above the warm/moist air below, inducing rising air currents/lift/convective type clouds/showers/thunderstorms. The 'w= 1/g' portion of the equation is the upward component (g being gravity)...so 1/g is the inverse of the downward pull of gravity.  In sum, we are looking at the mixing ratio (which involves moisture( integrated from one level of the atmosphere to another.


1.  A little easier now (I never say, "simply" because nothing is ever THAT simple). 

What is PW?

PW stands for Precipitable Water. It is a parameter which gives the amount of moisture in the troposphere (which is the part of the atmosphere that contains weather as we know it).

2. How is PW determined?

PW is determined by taking all the mass of water vapor in the troposphere and depositing it on the earth's surface (or as shown in that equation up to, 'integrating' the moisture content through two chosen levels of the atmoshere).

The depth of moisture that would be on the earth's surface is the PW value. The mass of water vapor is determined by the dewpoint (saturation mixing ratio) of the air integrated over the troposphere. Higher dewpoints lead to higher PW values, especially if the relatively high dewpoints extend through a significant vertical depth. The scale below gives an indication of the moisture content of the troposphere via PW. Note, these are TOTAL precipiciptable water values in the 'weather region' which can be quite high up there. 

*****Author's Note: THIS is where I think some folks mistake a lower PWAT value as meaning it will not rain. It is NOT the total PWAT that matters nearly so much as how and where that moisture is distributed vertically, as well as how much square footage on the ground it encompasses, as well as what type of conditions surround the area of concern!!! 

Conversely, a very HIGH PWAT does not guarantee rain if the entire atmosphere is a big soupy mess. It just means it will be very cloudy and in the case of a Florida summer, very humid and sticky. I've seen this over and over again when frontal boundaries go stationary over the Central Peninsula. Almost a guaranteed Forecast Bust if one is calling for big rain chances area wide. Often on these days, the forecast calls for a good chance of rain that never materializes (not always though). These days can be very 'conditional' though, since we can never know all the time what is going on in the atmosphere aloft in regards to the atmospheric profile. THAT is a problem.

0.50 inches or less = very low moisture content
0.50 to 1.25 inches = low moisture content
1.25 to 1.75 inches = moderate moisture content
1.75 to 2.00 inches = high moisture content
2.00 inches or above = very high moisture content

3. (Operational) significance of PW:

Flooding potential: A forecast area has a climatological normal PW for a certain time of year. In cases where the PW value is 2 to 3 or greater times more than the climatological value, flooding becomes more likely when (I'll add, "IF") a heavy precipitation event occurs.

!*****Lightning: In a high CAPE environment, high PW will lead to storms that produce an abundant amount of lightning.

PERSONAL NOTE: In Florida, not necessarily true. Our highest lightning days can be when PW is 'moderate'. But again, it depends on how the moisture is distributed. We need an area in the mid-levels that is NOT saturated, odd as it may sound. Additionally, when air aloft is colder then 'normal' (that is another discussion FOR SURE)...this produces more ice particles (hail) aloft which, in theory, when they clash well aloft, generate more lightning whether or not the hail reaches the ground does not matter. NOTE: In the full bore summer time, the most prolific lightning makers will produce  small pea or smaller hail mixed in with the rain. Originally, that hail was likely much larger before reaching your noggin.  The statement about the 'clashing hail...causing friction' is also very much in question in my mind. There is a lot more to it than that). Also, I think the hail does not only go up and down until falling, but also moves horizontally in and out of swirling currents. Still a lot to be researched.

Updraft velocity: PW is the most significant contribution to water loading. ****Water loading reduces updraft strength since gravity tries to push the precipitation mass downwards-- against the momentum of the updraft. High PW also produces a heavier downdraft. The updraft being reduced is especially evident in a weak shear environment where the downdraft locates very near the updraft, thus destroying the updraft.*****

***This was my point previously. Water loading, TOO MUCH PWAT kills updrafts and makes it cloudy and clammy, with some showers storms around which are of short duration and do not lend will for active lightning as well.****

Hail: High PW tends to reduce hail size since the updraft velocity is reduced. Again, we need a drier level to induce the moist, buoyant air below to RISE through the dry layer.  Moisture content even higher does not have to be very much, in fact..but 'some' is needed. Bone dry won't work in other words.  The most active storms will have several thin drier layers distributed throughout the vertical column (the troposphere/boundary layer)...to promote more rising, the moistening, then more rising again into cold cold cold air way up there.

Hail is another story altogether. It is fairly common knowledge that hail rises and falls in the updrafts, gaining more and more layers of ice until it is too heavy for the storm's supporting updraft. This is SO over simplified.  Hail can fall far from the updraft in supercell thunderstorms where no rain exists...namely and mostly in the Plains. In Florida, when it starts to hail in the summer it is usually in the last stages of the storm. Lightning will be most prevalent just before we know it to be over our heads and through the falling of it..but shortly thereafter the storm will collapse under its own weight.

Convective wind gusts: A high PW often occurs when the troposphere is fairly saturated. This can reduce convective wind gusts since convective wind gusts require dry mid-level air to add to their significance. 

Get it? Big wet blobs (preferably very cold ones, colder than what one would expect based on morning sounding data) will accelerate DOWN ward through dry air, just as they will upward during storm formation. Convective wind gusts can be microbursts, wet microburts, and downdrafts. Extensive study has been made concerning these terms...I originally included a link to a study (of many) that was made and published, but not so sure the individual would like the paper mentioned in this post. If you would like the URL (web link)...flash and email or Facebook message this way.

FORECAST: No issues today. Sunny, but guess what..some riches low level PWAT air might move into Eastern Portions of North Central late today bringing in some late afternoon/early evening clouds. Let the PWAT FUN BEGIN!

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Friday, May 6, 2011

Caveat Change of Strong Thunderstorms Late Afternoon-Evening South Half of Florida

CONDITIONAL-CAST TODAY: EXPLANATION OF IMAGE BELOW

SOUTH OF BLUE LINES IS WHERE STRONG STORMS COULD OCCUR AFTER 4pm  unitl just after dark
RED ARROW SHOWS DIRECTION OF ANVIL BLOWOFF
PURPLE: SUSPECT SATELLITE IMAGE. Not sure what those clouds are yet
NOTE THE STORM NEAR TAMPA BAY RELATED TO TROUGH NUMBER 1

LASTLY: YELLOW ARROW: STRONG WINDS ALOFT OF 100-120kts AFTER  3PM to DARK

TODAY: Interesting day today that could amount to a whole lot of nothing. Model guidance continues to be very inconsistent in the precipitation fields. Then again, I used to NEVER use them, other than to see if they broke any out. Sometimes they are almost right on the mark, whereas other times you wonder if the model has the right day. Today, none of the models agree much on where or even IF rain will fall today. And when it does, it is at different times. Per once model, it should be raining right on my roof as I type. Not even remotely close.

This forecast discussion addresses the best case scenario for rain over much of the areas that really need it due to on going drought. However, if this does occur after 4-5pm, the storms could be very strong with 1/4-3/4" inch hail in the very strongest of storms (1 or 2 storms some where), with 'hefty, 'hefty' gusty winds.  I would not expect storms before 4pm to be very strong. Storms are not expected to be officially bonafide severe though due to lack of instability and stronger winds in the mid-levels even though higher up they are about as stronng as we ever see here, even in the winter! .NOW: What I'm calling 850mb trough number 1 moved  in on the west coast during the early morning ..and is now starting to lift off to the NNE. In its wake of showers and a decaying thunderstorm over South Tampa Bay.. is a lot of anvil debris  which is being caught up in the strong jet stream winds  overhead  and spreading to the east coast.










 However, these should thin out during the next few hours heading toward latter portions of the afternoon. Additionally, toward the west side of the state clearing is already in progress, and as such, so is increasing instability.  Meanwhile, on the east side of the state near the coast is where coastal helicities will continue until late afternoon as long as the wind remains from the SE-SSE. These winds penetrate about as far inland as I-95 (at most) with any strength.

IN TROUGH ONE THUNDER STORMS HAVE OCCURRED. ONE IS NEAR TAMPA BAY. THIS TROUGH IS FORECAST TO LIFT NNE QUICKLY AND BEGIN TO BE REPLACED BY TROUGH 2.
MEANWHILE, EAST OF THE TROUGH THE ENVIRONMENT IS CAPPED AT 700MB. THIS IS FOR NOON TIME. AS YOU CAN SEE, NO RAIN ON THE EAST SIDE OF THE STATE. See the placement of TROUGH 2 in the second image after 6pm. TROUGH 2 is way up there in Virgina, and will generate some strong storms there.


Here on the left is 6pm. Trough 1 is well to the north and Trough 2 has moved in. In thinking of the best chance for rain or storms, by this time the high clouds will be cleared, and more important, height falls at the 850 and 700mb levels will break the cap which would permit storms to form rapidly toward 5pm on the east half of the state where the clouds might have begun to clear. At this time is when winds aloft will be the strongest as it so happens..up to nearly 120 kts at 200 mb. 

Additionally, temperatures will begin to fall to meet the dew points and precipitable water values will rise and lift north a bit in response to height falls. Temperatures aloft are quite cold at 700mb and 500mb...cold enough to support hail and strong wind gusts of 40-50mph. If the mid level winds were any stronger we would be dealing with big time severe storms today. 

Strongest storms, if they form will be within 6 miles of the East Coast where the strongest onshore component wind is found and as such, low level coastal helicities that feed into the storm along the storm relative wind fields . Any storm that does form ,and strongly, is likely to move right on offshore to the east and into the Atlantic.

NOW FOR THE CAVEAT: The high clouds have to clear for the atmosphere to destabilize. At least on the west half of the state.  And that is just the beginning. All in all, confidence is low today of anything to materialize of note worthy record keeping, but the above is something to keep in mind. Wouldn't hurt to watch the 3pm  onward time frame...just to see what might be brewing in your neck of the woods. Could be that activity will start before that time if it does. Also expecting some frequent lightning with any strong storm.

BEYOND: Weekend is looking nice, with only a marginal chance of thunderstorms sometime well into next week. Become warm by Sunday or Monday.

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