Strong Lightning Storms Possible Southeast Florida Later This Afternoon

Graphic of Severe Storm Reports Thursday -Saturday
(0.25" - 0.75" is not severe)
See third image down for much finder details

Breaking it down into Tornado Clusters/Families

An epic severe weather event started Thursday afternoon as a warm front/cold front/surface low/dry line collaborated to join forces all embedded with the periphary of a deep 500mb trough aloft. Net effect - tornadoes/hail/high winds, especially along the dryline in Oklahoma.


The parent 500mb trough continued to dig SSE-ward into the Deep South overnight and things calmed down a bit but not entirely for the state of Arkansas. Shortly after the first light of day on Friday the system rejuvenated. Closer proximity to a moisture source (the Gulf of Mexico), storms formed in SE Louisiana and all through Mississippi and moved into Alabama during the early -mid afternoon as upper level divergence in a split jet stream pattern developed, adding an 'upward vacuum' from the upper atmosphere.  Most of the reports are actually from a few long-lived/long tracking supercell thunderstorms as you can see by the 'tracks' in the next image.  A repeat performance ensued on Saturday, particularly over North Carolina where it is possible they experienced an all time record tornado event. Note the tracks of 'red tornado dots' in the image below over North Carolina. These might be all one tornado, or one that lifted with another to set down shortly thereafter from the same long-lived supercell thunderstorm. Radial velocity imagery on the Raleigh storm was clearly picking up debris within the knob of the hook echo. This 'hook' persisted for a remarkable amount of time. Warnings were issued well in advance of the storm's approach.

Here we can see the tornado reports in red. Note the storm tracks of red dots in North Carolina , Mississippi, and Alabama as well as in South Central Oklahoma. Last I heard it is possible that up to 47 deaths can be attributed to this 3 Day event, at least half of which were in North Carolina

Countless videos and photos streamed in across the Internet through all the big social media outlets such as Twitter, Facebook, and YouTube. New images and photos were coming in as fast as the next event was already occurring. This had to have been one of the most epic performances made by modern times for the United States, as equally made throughout the world during and after the earthquake/tsunami in Japan not too long ago. Perhaps some 'newly found' tornado video will eventually show up to surprise us all further in the next few days.

TODAY: A frontal system has passed through the North Half of Florida overnight. It appears the boundary will get about as far as West Palm Beach this afternoon before washing out while a thermal heat low forms over all of South Florida this afternoon. Given the synoptic scale wind pattern during the afternoon south of the washed out boundary combined with a localized east coast sea breeze strong lightning storms are possible over SE Florida beginning mid-afternoon and lasting until about sunset. There are a variety of other 'enhancing' features popping up on various models at various times...but they are never absolutely constant. 


The only factor that is to prevent the weather in South Florida from being most assuredly notable will be the weakness in the low level convergence of the sea breezes and deeper atmospheric moisture, but only as it appears now. However, it seems given that the best likelihood of said activity with those limiting factors aside will exist from somewhere to near Boynton Beach into all of  Broward County and down to near Miami Metro. It appears activity will push toward the east coast from the WNW-NW.  Temperatures aloft will be cold enough to support hail...and as is the case with any storm in Florida when hail can reach the ground rather than melt, lightning I'd think will be quite active in any storm. This has been my personal observation on numerous occasions over the years. Storms are not expected to be numerous (probably because of the limited atmospheric moisture content)..but rather the energy is expected to be 'savored' by a few select storms, wherever that may be.  There is a sharp demarcation to the northward extent as to where storms can manifest today. Latest run of one model showed a delayed onset of storms near West Palm very late in the period prior to 8pm, but not of the strength possible further south, as the old frontal boundary weakens further and the thermal low acts to break it down, pushing various parameters back northward a bit.

This image shows the 0-3KM Helicity that could be advected south and east during the afternoon

This is the RUC 1000mb (near surface) vorticity this afternoon clustered on the SE Coast. I've drawn in the expected afternoon sea breeze and noted that in another graphic a weak 500mb lobe is shown on the west side of the state

MONDAY: Prolific Lightning Storms are possible over a broader expanse of Florida to include Central Florida, when similar upper level temperatures will exist. The washed out boundary will wash out overnight and southerly winds return to Central Florida in the process.  It is impossible to say with any guarantees this morning just exactly where they will/won't occur, but at time the SW side of South Florida and the east side of South Central/North Central seem to be the favored locations.  There are areas shown this morning where I stronger storm could not occur, whereas there are other areas they seem most likely; however, given that this is a recent chain of possibilities to unfold since late last night, the evolution and/or de-evolution of tomorrow's storm chances is yet to be fully resolved, flailing figures and parameters around all over the place. For now, it's a safe bet to say there could be some isolated strong storms tomorrow over a larger expanse than that which will possibly occur today. 


FLY IN OINTMENT: There's always one doing the backstroke it seems, and tomorrow may be no different. The one clincher for tomorrow will be the amount of moisture available at around the 10,000ft level. Last night's runs first hinted at some respectable storm possibilities for Tuesday, so my eyes were focused on that day..and in even more isolated fashion. The morning 06z runs were not only sooner with the activity, but covered a more vast expanse. The 12Z runs are coming out now (one already is, I just haven't looked at it)...there is still disagreement converning the amount of moisure available aloft, as well as whether or not there will be a 'warm cap' at around 5000 ft (850mb)..which would stunt cloud growth to nothing more than cumulus clouds, no matter how unstable the surface conditions are.

NO - Good Chance of Rain/Thunder, Especially Interior East Central Friday

Forecast highlights for 5pm Friday. Details are in the body of ths post.

In lieu of rewriting an entire post today it is easier to answer the question proposed yesterday. As you can see from the subject line, there is NOT a good chance of Rain /Thunder today...SEE "FRIDAY" further below in this post for details.

============================PAST INFO============================

THURSDAY: Big time storm maker in the South Central Plains states with nearly all the values required for a strong tornado and supercell thunderstorms was in place, or at least there's a very good chance of them. I've marked an area that I was watching at 7AM this morning as shown below, although would probably extend that a bit further north now.  I'm expecting that initially there will be some discrete cells that will spread east near the surface low in Kansas as well as further south along the dry line into far NE Texas with time, eventually evolving into a severe QLCS (Quasi-Linear Convective System) of mini-bows, loops, and sups (supercells) which will become more linear with time but with continued strong mechanical lift into the night where winds and hail will become the primary threat, although there could be some misocyclones (mini-spin up tornadoes) along the line to produce a tornado or two as it presses into far Eastern OK , Arkansas, and Southern Missouri.  

CENTRAL/SOUTH TODAY: Splendid day Central/North, but some pesky showers and perhaps some thunder along the SE Coast from Boyton Beach and south. This activity will not become strong, but they could use the rain. This afternoon may become partly cloudy to almost cloudy later, but this will all be from high clouds and might not even be noticeable for the most part, although around sunset ..maybe more so. The activity over Southeast Florida today is along and near the old surface boundary that passed through North and Central the other day and will wimper at sunset or thereabouts. This boundary will lift north late today and cross Central in the middle of the night. It is not impossible that Brevard could see a rain shower or two as the boundary lifts north sometime after 3AM.


===============================FRIDAY - TODAY =======================


TODAY: High clouds will have cleared the area. and they did just shortly before surise Winds SE-SSE  behind (south of the boundary) and a bit breezy near the coast . A 500mb pocket of cold air will be passing to the north of Central..but will be close enough to provide an added boost of cold air aloft.  (TRUE) The east coast sea breeze will dominate on Friday, but will struggle against the developing WSW-SW winds which will be moving in during the late morning in advance of the big squall line over Alabama (for starters) in the mid-levels.  (TRUE AGAIN)  With those in place, the west coast sea breeze could conceivably be stronger than model guidance portrays which might prove to be of great significance later in the day in regards to rain chances. (BUT ONLY CONCEIVABLY)...


DISCLAIMER TIME: This forecast for tomorrow HIGHLY Diverges from official forecasts and is based mostly on the NAM model. It is quite possible that this discussion below will fail to materialize is written. You might say...this is l "Wishful Thinking on the part of HSD (HighSpeedDirt)." Official outlets are not calling for much if any activity over the East Side of the state tomorrow. But onward we'll push now for some science fiction to those who bother reading my posts and care to be entertained.
=============================IT WAS WISHFUL THINKING=================
Actually, the NAM wasn't far off, and it is more likely it was wishful thinking by not further looking into EVERY detail. That being the moisture content of the atmosphere around 700mb.  The NAM continues to show the same conditions for today, but it is too dry above 10,000 ft to support little more than a rain shower...However,


Per that same model and two others, there is a window of opportunity for 1 thundershower over far SW Brevard into SE Osceola County late this afternoon as the lower level winds start to transition from a SSE direction later this afternoon paralleling the coast to South around 4-5pm. Should the 700mb level respond for a time to the shift with a boost in moisture from below through the column..a small thunderstorm is possible somewhere near I-96. Rainshowers will become more possible up toward Ocala or just north of there...and some widely scattered small showers can skirt or impact the coastal areas after 12-1pm as far north as Cape Canaveral to Titusville. The west side of the state will be dry today and Orlando might get into the act with some showers but it's extremely conditional. It is possible a larger storm will manifest near Indiantown later this afternoon.  Otherwise, breezy this afternoon and partly cloudy.


NOW: Contnue to the bottom of this post to see Saturday......
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THE IMAGE -- The ANNOTATIONS. Precipitable water values tomorrow in the atmosphere will be about the highest I've seen since the last big rain in September 2010. Not as high as that day, but you get the picture.... written in blue. The bright reddish colors are the Energy Helicity Index (EHI) forecast values. This value is basically a comination of thermalwind energies spit out as a number and put in pretty colors. You do not want to be within eye shot of the very pretty colors!


 Note that the colors over Florida are nearly as astounding as those with the severe squall line that will be moving east tomorrow over the Mississippi River Valley portion of the Deep South tomorrow! Don't panic.  I believe most of the EHI is contributed by CAPE/moisture rather than spin which will be there as a function of the sea-breeze rather than of synoptic scale organization through the deeper layers of the atmosphere...but the spin does give upward motions boost and combine that with the sea breeze convergence boost, I'd think there would be thunderstorms late tomorrow afternoon right at rush hour over Metro Orlando and vicinity lasting into the late evening.


Rain chances begin around 5 pm over the spine of the state probably just west of Orlando, but will fill in rapidly between 4-6pm, struggling to spread east. Expect there could be some strong storms, with small hail under the strongest core especially near Clermont to Altamonte Springs. Overall, it looks like the area just NW-N of MCO might bear the brunt of this activity (near Clermont) as the steering currents  pushing toward the East struggle against the  frisky late afternoon east coast sea breeze (which always peaks an hour or two after peak heat and lasts about 2 hours).  


The activity will spread toward the east coast from mainly Wilbur-by-the Sea south to Sebastian Inlet after 6:00pm and exit the coast while fizzling and be over with by 11pm at the latest. Another stronger storm could develop close to the coast from Mims to Cocoa as well around 7pm while isolated activity with lightning just possibly might be near Lake Okeechobee into western Palm Beach County at the same time as further north, perhaps sooner,
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THIS IS WHAT SATURDAY WILL BE LIKE: Have a nice weekend.
SATURDAY: Still waiting for some agreement between model guidance, the NWS, and The Weather Channel  (?). They are calling for severe for a portion of North Central tomorrow. Don't see it at all.... For now though, believe that Saturday is going to be warm and breezy like the other day before the cool front passed through. But rain chances look even less with this upcoming system due to lack of moisture that the Friday activity will take with it. In other words, Saturday looks dry and warm. That description for the day  doesn't sound Severe to me.

Dick McGowan

Dick McGowan

Strong Storms Possible North Central Today...Or Are They?!

INSTABILITY INDEX: Convective Available Potential Energy and the surface based Lifted Index.
Note the high CAPE values and low LIs over Volusia and North Brevard County at Noon
Theoretically this would mean big thunder today...but...?

TODAY: A weakening frontal boundary is moving down the Florida peninsula early this afternoon from the NNW. Ahead of the front the air mass over Eastern Portions of North Central Florida is growing increasingly unstable as noted in the image above. Also note the dry pocket over KSC which was previously the most moist area.


RECAP OF THE MORNING: During the mid morning hours the air mass over Florida was very moist at the low levels; however, during the course of the past 2 hours the dewpoints have been steadily dropping off from near 70F to the mid-60Fs if not less, This line is currently moving into the unstable environment as I write...but the air is also drier, mostly WEST of Volusia and thus limiting both the intensity and coverage of rainfall. This is not expected to change during the course of the afternoon. However, some 70F dew points still reside over Volusia and into North Brevard. There is a dry pocket very close to Port Canaveral, but that seems to be on the eroding trend as the boundary approaches and moisture convergence is increased.


FORECAST PRELUDE: In the absence of any low level upward forcing mechanisms or stronger upper level energy streaks other than what is supporting the line at this time...believe the best location for lightning today will be over Volusia County and south toward Port Canaveral as a last gasp tail end charlie of non-descript worthiness nature.


There is an odd moisture divergence circulation of note going on in Southern Brevard of which the Port of Canaveral  is on it's outer fringes. This circulation has been in place since before sunrise, and I have no understanding as to why it is there and what it means..if anything.


Other than the frontal boundary, and in the absence of a sea breeze boundary..what we have is what we got. At least as of this hour.


FORECAST:  The front is forecast to gradually slow in its southward progression today and eventually reach my house...that's what the RUC and NAM models told me. Beyond Melbourne the front is non-existent losing all identity at the surface level...thus..the upward forcing mechanism is shut down..and likewise, the rain other than lingering pockets where ever operation 'breakdown' commences. This could happen over Central Brevard.


Showers and very isolated thunder will continue south  while pusing east through Volusia today. Watch out for renegade lightning strikes! Precipitation will not be excessive no matter how one slices the pie...but lightning could still occur from a select storm cell or two as the boundary proceeds to South of the Border (of Volusia/Brevard).

However, it is highly uncertain in regards to the activity in Volusia. I seem to see a few ingredients at play that could bring a respectable lightning generator into Volusia..which would be in the 2:30-4:00pm time frame. An additional enhanced area could from as well further south from Titusville to the Port. Believe these will be at their strongest once they reach the higher dew point air along the West Border of Volusia as the move east...as well as with N. Brevard after 5-6pm time frame.


Strong wind gusts in the 40-50mph range seem possible..given the winds and cold air aloft, but they will first have to reach great heights of which I have yet to see on radar imagery. The afternoon is still young though...so be advised...watch the western horizon for towering clouds of convective nature.


IN SHORT: The best chances for lightning today are all of North Central Florida ...including a part of the Orlando area to Cocoa Beach, but the strongest of activity will be anywhere over Volusia and possibly as an outlier South of the Border toward Titusville/Cape Canaveral at the North Central/South Central line...The Great Divide I have referred to how many times now in the past few months?! My goodness.


The most likely areas to receive a potentially stronger storm are near Daytona Beach and Titusville/Cape Canaveral as an  outlier considering a secondary impulse is implied by model guidance to cross that area sometime later in the afternoon as it rides along the near stationary frontal boundary by that time. It would be interesting if this were to occur, because that might allow the sea breeze to develop. I am also  interested to see what will happen when the more southern impulse reaches the coast of Brevard where that seeming circulation is residing and helicities right at the coast have been forecast to increase. Could be nothing at all..might, not even rain for that matter..but it seems set in stone that it will at least rain near the Port as well based on the past 3 model runs of 3 separate models. Remembering my post of yesterday where I questioned that area. However, none of the high values are portrayed as they were yesterday..sort of a weaker version of possibly nothing anyway. Maybe you can tell that I WANT A STORM!  Near DAB seems a given.


NEXT RAIN CHANCE: Perhaps Friday and / or Saturday. The GFS is all over the place with these two days. But note...today's system is an introduction to a new season for all of North Central to South Florida with more systems to either directly impact or graze the region through the end of the month..PERHAPS.


Either that, or we'll be entering the dreaded dry spell before Thunderstorm season begins. That too, has varied on a 12 hourly basis. But I'm opting that the last GFS run was a  fluke' bustcast'.


The front is expect to stationarialize (new word)...over or near the 520 Cswy and wash out. with rains not expected much further south than that location on the east coast or anywhere else over the state to the south where mid level warming is capping the region.

A Strong Storm Near East Central Coast is Possible on Tuesday (Perhaps Unfounded)

Brief  Post For Today:
IN GENERAL: Based upon the 12z GFS/NAM model runs only.

Storm system sweeping SE toward Florida this afternoon will sink south into Central Florida shortly after peak heating hours. The front is forecast to come in alignment with the Beach Line and fall stationary between the hours of 2-8pm.  It is possible that frontal boundary could be accompanied by a thunderstorm or two, which would be strong considering the cold temperatures aloft and steep low level lapse rates. There are indications that some sort of 'significantly interesting event' may transpire very near the Kennedy Space Center within this time frame. Possibly a strong waterspout or tornado.


HOWEVER - Please note: The likelihood of said is highly unlikely as waterspouts are not synoptic scale events but rather a very localized event that can happen on even only a fair day with virtually no snyoptic scale features present (of apparent significance). So just exactly what these values portrayed, and the gradient values mean just exactly, is uncertain on my part.
Addtionally, conditions are not favorable for development of a rotating, supercell thunderstorm..at least not as normally potrayed in text books.


But worth noting in the images are: A strong 100o mb vorticity bulls eye just offshore (very odd!!) with moderately strong vorticity riding up the east coast which intersects the more outstanding bulls-eye feature, ample all day sunshine to increase instability even at the coast since most of the day there will be a land breeze which will swing toward paralleling the coast sometime during the mid afternoon, very high 700mb RH values in a highly confined / tight area, and a very strange forecast vertical sounding...during the time of this sounding surface winds are forecast to be calm on the ground,. 

Some select images from the NAM and one from the GFS are included below: 

SIDE NOTE: In the great beyond, it is looking more like the above average rainfall totals going into next week that were referred to in the past two posts and as forecast by the big wheels who specialize in such matters is heading toward fruition. High instability will be mounting over the Gulf of Mexico waters during upcoming days under neath a strong capping environment of near clear skies. As a result, this heat energy will not be permitted to be released ..being shunted toward "Somewhere" in the SE and Gulf Coast states. 


Should this be the case (it is just now beginning to get underway today), the Gulf  waters will have ample and perhaps accelerated time to warm up (read into that statment as you will).


 A closed 500mb low is forecast to reside well to the north of the state, with ripples of energy passing primarily north of the state, but even still, the forecast situation portrays an enviroment that would be ripe for afternoon thunder from time to time - favoring the east side of the state-, and perhaps an all out rainy day here or there. The most of the rainfall would be just to the north of the state as current depicted by the GFS run of 06z last night going out toward the 20th and beyond:
Forecast rainfall by the extended GFS :

TOMMORROW'S PARAMETERS: These can easily change by the next run. and likely will to favor another location. However, I do not believe it will change significantly in regard to where an amplified boundary of some sort will be located across East Central Florida, favoring the coast and inland along a narrow corridor. It's best not to necessarily focus on the center of these values in some of these portrayed, but rather areas that lie along the sharp edges that define them. (the gradient).

Tornadoes/Hail/ Past 2 Days - 2 More Days To Go With This Sytem

The Cat Eyes NW Iowa Before The Tornado
Event Even Began - The Cat's Sixth Sense
at work

RECAP: Clear and warm in Florida yesterday and more for today. Just a quick recap of the events that have transpired that past two days elsewhere. A few days ago I mentioned that the upcoming event, (which is now the current one) might not have quite as big of a number of storm reports as the record breaking last one, but I'm not so sure now. Already, we have had more tornadoes than the last one; this was expected. But it is not over yet.

We see in the second image that yesterday alone there was 27 (not official yet) tornado reports. Some of those might be duplicates, or some more might be revealed. I've included some radar images below of one of them. There was also 3 tornadoes the day before in Oklahoma . This go around, there are more hail reports than wind ones, with a running total so far of 610 reports total . Still nearly 800 more to tie the last event. I think we will break it by Tuesday morning.  We can see there was two significant areas yesterday responsible for the reports by the image above. Siblings of the same parent storm system.

Lola, my cat, was eyeing the Border crossing from Nebraska into Iowa for storms that initiated in Nebraska to become more surface based as they crossed into Iowa beyond the Missouri River, possibly generating tornadoes as a result...in the image above where all the red dots are ... those are tornado reports. Good eye, Kitty! She even nailed the track of part of one right there with a yellow highlighter to prove her point as shown in the image above.

Here is some radar imagery. The first image was the storm that started the whole. thing. It cross the Missouri River into Iowa and crossed right over Sloan, Iowa as a developing supercell.  from that point on the storm reports began to filter in. Shortly thereafter, it entered a region of lower lifting condensation levels and immediately became fully rooted in the boundary layer and tornado'd...for quite a while in fact!. This tornado was a large, wedge tornado that directly hit the city of Mapleton. There is already You Tube videos out there you can see by doing the search in You Tube's search engine. There are some other very small townships that appear to have been in the path as well, but they are so small we'll probably never hear about it.   The second image is the supercell storm on radar in full birth mode with the hook clearly apparent. We might even be able to see the debris field by the darker red colors curling around the hook's appendage. This was a monster tornado reportedly 1/2 -3/4 mile wide...the video I've seen back this up.

Lastly, this final image is taken from the Des Moines, NWS radar. The arrows I've drawn in  point to SIX storms lined up. all of them rotating. This is a radial velocity image at Tilt 2. It depicts in bound and out bound winds toward and away from the radar's location by the color schemie noted on the right hand column of the image. In bound  directly next to outbound indicates rotation. Makes sense.
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FORECAST: Really not much of anything other than what we've seen the past few days until possibly Tuesday. Therefore:


TODAY: Pretty much instant replay today.  High pressure was suppressed a bit to the west of the state last night as the storm system that generated all the storm reports over the East Side of the country and its associated trough moved SE and offshore over night. Therefore, winds will be NW and light, becoming more north with time..but nearly calm at times... expecting a delayed sea breeze this afternoon with inland highs in the upper 80S and a few low 90s; closer to the low-mid 80Fs right at the beach before the sea breeze kicks in.


Another big day for the upper Mid-West and Great Lakes region will commence around 1pm their time and be ongoing well into the night. A squall line will eventually form that will cover vast amounts of landscape going into later tonight and tomorrow which will be on going all day tomorrow. Hence, imagine all the storm reports that will filter in. Today looks like another big day for tornadoes..or at least the potential is certainly there, especially over the North Half of Wisconsin down into NW Illinois perhaps...parts of South Minnesota as well. Others could occur into NW Illinois. The squall line won't materialize yet today.


MONDAY: Possibly warmer than today, especially east side where there may not be a sea breeze. Dry otherwise.  The squall line will be passing through the Deep South and into the Mid-Atlantic Region. More storms reports ad naseum will be flooding the SPC Data banks.


TUESDAY: The remaining last gasp of the frontal system reaches Florida, with the last possible chance of severe gone in general.  I will go into the details regarding this day either tomorrow or on Monday, since the situation that MIGHT occur over a small portion (s) of Florida has been changing with every model run. So far, there's been just enough to keep things 'interesting'.


But for now, it's safe to say that the information coming in has been latching on favoring all of North Florida for rain, with a Southeast Slant toward the East Half of North Central Florida during the course of the afternoon.  For several runs now the front to the north weakens..but appears to send an outflow boundary further south toward North Brevard later in the afternoon as sort of a "Faux Front"..the actual front never really makes it south of St. Augustine.  If this occurs, there might be some sort of Mesoscale Accident somewhere over Southern Volusia County southward into the North Half of Brevard. It would include some lightning I suppose. Hard to tell for sure. But it looks like some folks could get a swat at some small rain fall totals less than 1/4".


The last gasp of the "Faux Front" dies and pulls off shore Brevard after dark. South Florida might also have some thunder, but the chances down there look pretty meager. But who knows, it may be that the area from Boyton Beach to Miami will end up with the thunder for an entirely different reason not associated with the front before Central Florida does right where the front is supposed to dissolve. Temperatures aloft even that far south will be cold enough.  But north of Central Brevard and north of that is where the even colder air and winds aloft will reside. Some of the storms at this point by all appearances could be efficient lightning producers. In either location with the cold 500mb temperatures at play.


NOTE: The Storm Prediction Center has most of the state under a "See Text", meaning weather worth noting could occur on Tuesday. But if I were a betting man I'd whittle it down to NE Florida from St. Augustine north...and the East Side of the State from Southern Volusia County south  to Southern Brevard..mainly east of I-95.  The other area would be the east half of South Florida South of West Palm Beach, especially close to the coast.


BEYOND: Table turning here and there. Two consecutive runs showed the state would be almost dry ...totally blowing away the long range forecast of above average rainfall for most of the state. However, after seeing the 06Z runs, I'm not so sure this will be the case. In other words, more rainfall looks to be back in the picture for more of the month for a wide variety of reasons from time to time. Should be interesting...Time will tell.

Nearly Hot (Inland) Sunday - 'Capping' Warm Layer Aloft To Break Down By Mid-Week

LATEST EXTENDED PRECIPITATION FORECAST VALID: 4/16 -4/22
NO CHANGE FOR FLORIDA SINCE PREVIOUS EXAMPLE WAS POSTED WITH AN INCREASE
UP THE U.S. EAST COAST  (PREVIOUS POST END TIME WAS 2 DAYS EARLIER

TODAY: High pressure prevails over Florida, much like yesterday, although the surface ridge axis may have sunk south a bit today. In turn, chances of a shower far SW Florida look very slim...in fact..that is the case state wide. Land breeze over night along the coasts  will be over come by diurnal afternoon sea-breezes with a collision near the spine of the state near sunset with no affect. Temperatures aloft remain to warm and sufficient moisture is lacking as well. 


Meanwhile, a very significant severe weather situation is setting up for the Central Plains states later today where severe weather/tornadoes/large, damaging hail is a given.  Even as I write I'm seeing the values of various atmospheric parameters needed for the "Severe Weather Cake Batter Recipe" being revealed on an hourly basis. Additionally, severe weather has been ongoing in part of the Ohio River Valley as I write such as in Kentucky and West Virgina.

2PM EDT RADAR WITH TORNADO /SEVERE THUNDERSTORM WARNING OVERLAYS.
A LARGE AREA HAS BEEN UPGRADE FROM A SEVERE THUNDERSTORM
TO TORNADO WATCH BOX, WHICH GENERALLY ENCASES THE ENTIRE REGION
WITHIN WHICH THESE STORMS RESIDE

SEVERE STORMS/TORNADOES/SQUALL Beginning late this afternoon through Early Tuesday to impact a large portion of the country. Believe this storm system will be more significant that the one of last week in regards to tornado potential (and some could be quite strong) as well as a large hail threat; as opposed to mostly a marginal wind threat that impacted the eastern U.S. last week. NOTE: The bigger area of concern it not the area shown above. It will be over portions of Nebraska, Iowa, and South into Oklahoma to NE Texas..spreading east and expanding east , north and south through Sunday.


SUNDAY: Close to nearly HOT inland. Near classic inverted trough up the spine of the state form South to North  as temperatures reach the lower 90Fs over a broad expanse. All coasts are clear though with highs in the mid-80Fs , peaking early in the day.  But note the saving grace; dewpoint temperatures aren't going to be as high as would be the case in the summer, so tomorrow ill be like a 'taste' of summer without the salt. Coasts are 'clear' that is, except from 'Beach Flockers". Yes, "Meet the Flockers" is more than a movie.   This will be like the polar opposite to the "spine of the state" cold spells Florida experiences in the winter when a ridge extends from north to south.


Expect to see the hordes pouring out of the urban inland areas like ants fleeing the mound for sugar neatly posing as a line of sand along the coast. The severe weather will continue tomorrow far from home base as well, as the responsible upper level system moves East toward the Western Great Lakes region and an appendant cold frontal extension of this systems slices south through the Southern Plains into Texas.  All forms of severe weather are possible within these regions tomorrow.


MONDAY: Similar to Sunday, although perhaps not quite as HOT inland due to less than perfect conditions for a maxed out heating event. However, the East Coast will bear more of the brunt because the high pressure ridge axis that will have been stretched East to West across the state  at the mid-levels will start to drop south in response to the large storm system pushing across the Mississippi and Ohio Valleys, with the front pushing through the Deep South as well. 


In turn, not sure we'll get a sea breeze on Monday  north of West Palm Beach which will be closer to the ridge axis with less synoptic scale gradient WSW - SW supporting flow further south.  A late seabreeze is always possible though, just later than normal. Otherwise, dry.


TUESDAY: The dog tail end of the major storm system will pass through Georgia and cross the I-1O of North Florida Tuesday morning, and sink only slowly south toward St. Augustine trough noon time...with possibly additionally inching further south through late afternoon.  The last of the upper level winds with this system will pull out and away by early afternoon. There will be a chance of strong/marginally severe storms north of St. Augustine between 11am -3pm as is being made known by the NWS there and The Weather Channel, although I don't really see it to be a very big deal.


*** INSERT: There is the possibility that, although not reflected in any forecast and only ONE model, that as the system over North  Florida starts to collapse an Outflow boundary will push south into South Central Florida and meet a  region of greater instability further south over South Central Florida.  This would actually be the leading edge of cooler air aloft (and hence, a portion of the Subject Line of this post necessitating explanation). That being, erosion of the mid-level cap of warm air. This will be a very subtle event,, yet will be just the beginning of a new weather regime for the state.


 The GFS Model has shown for three consecutive runs that this sort of boundary which aloft will be simply a fall in heights of the standard 700mb level (and cooler air)...will be enough to establish a zone for thunderstorms or rain showers to form somewhere over South Central Florida after 5pm.  This activity would drift slowly toward the NE but weaken before reaching the coast. Again, this is merely a possibility. But the more significant thing to come out of Tuesday as 'boldly put' above will be the loss of the strong thermal 850mb lid over Central and parts of South Florida that has been in place.


WEDNESDAY: With virtually all upper level support far removed after sunset and the ridge axis now even further south..it looks like the front will slide through the remainder of Central Florida overnight and into far South Florida by daybreak where it will remain.  Temperatures will be back to normal but the atmosphere will be a bit like a lady in waiting at this point with nothing to do  other than to generate some showers and perhaps thunder over South Florida ..favoring the SW side with a prevailing ENE-E wind most of the day.


THURSDAY: It appears the boundary will lift back north on Thursday as the displaced ridge attempts to reassert itself by building back toward the N from the SW...but will get hung up along a  line nearly paralleling the Turnpike up and down the state. This boundary may act to instigate some thunderstorms, some locally strong if this even materializes at all, due to cold air now aloft. Mainly west of I-95 for portions of South Florida and all of Central. There would be a convergence zone set up with the boundary where it meets  the east coast sea breeze. Would be very interesting to have this materialize...could make for quite a show west of I-95 from Volusia South to Okeechobee County, becoming less defined over South Florida where warmer air aloft remains.


FRIDAY: Have already bitten off more than I should chew, but I'm hungry for some thunder.  Next big storm system will already have been approaching the state on Thursday..and in response the boundary lifts north and east to Central Florida before washing out.  Could be another day of thunder favoring the East side of all of Central and South Florida, although The Weather Channel is showing "Sunny" on TV right now. Okay, so maybe that won't be the case.  But here's hoping for some drought relief.


CONCLUDING COMMENTS: Please note the image included in this post and the valid time. I believe they are seeing what I am (most of which I have not written about and is too lengthy an explanation to go into dissertation mode). But it does look like a  good chance of strong/severe storms going into Late Friday or Saturday (n that time frame, more likely Saturday) and a following short-lived respite, the extended out look is showing many days of possible thunderstorms off and on. 


NOTE: The above average precipitation depicted, it must be understood, is because this is normally considered our dry season before the summer thunderstorm season commences. So ABOVE AVERAGE  needs to be interpreted with that in mind. It does not mean insane heavy rains all the time or all day soaks. But who knows, maybe we'll have one or two of those somewhere along the line.

TODAY- COWS in Iowa!!

Past big events
in Oklahoma

A Quick Comparison Of the NAM Forecast DSM 21z Hodograph With Past Big Tornado Events in Oklahoma

Consider other hodographs today as well because although it might appear at first glance that tornadic storms would be most likely only when the

hodograph shows vertical shear that veers strongly with height, such storms are also possible when

Fsct 12z DSM Hodograph

the hodograph is relatively straight. Considerable streamwise voracity may be present with a

straight hodograph if storm motions lie significantly to the right of the hodograph. Such deviant

right motion is commonly observed with severe storms, especially isolated supercells. In straight

hodograph environments, the effect of vertical shear is to shift the storm's precipitation core onto

the downshear side of the storm, where it then tends to suppress and eventually split the updraft

(B E. W. McCaul. Jr.. Steve Lazarus. Fred Carr)

See the Crazy COWS grazing (Cross Over Winds) from 850mb –700 mb  level winds over Western Iowa, NE Nebraska, and SE South Dakota at 21Z? And the extreme high Energy Helicity Index values along the upstream backed winds axis running over and to the east of DSM (Des Moines).

FCST EHI 21z

The North Atlantic Oscillation

NAO: "The North Atlantic Oscillation Impact on Temperatures, Precipitation, Snowfall, and Snow Depth"

Latest guidance from the ECMWF Model, commonly referred to as "The Euro", indicates for several days/runs that we will be entering a period of a moderate to strong positive phase of the NAO. What 'could' that mean? Here's some information. Lsimple click on the Title of this post.

"High" and Dry Through The Weekend With Sunshine Abundant

HIGH PRESSURE AT THE SURFACE AND ALOFT
THIS IMAGE IS SURFACE TEMPERATURE ACTUALS FOR 2PM THIS AFTERNOON

Weather for today through Monday at least will be dictated by high pressure at the surface and aloft over the state of Florida. With light land breezes at night and sea breezes during the late morning through late late night, but like in the summer. Afternoon highs will vary from the low 80Fs along the coast to the mid-upper 80Fs inland. Temperatures all locales will warm a bit more on by Sunday.  A shower of two could develop on an day from far SW Florida to Naples, perhaps far NE Florida as well but the number of showers and strengthen is not worth mention.

FOR EXAMPLE: HERE IS THE AVERAGED WINDS ALOFT. NOTE THE LOCATION FO THE HIGHT AND SOME MOISTURES OVER SW FLORIDA AND NORTH FLORIDA

NOT MUCH ELSE TO MENTION WORTH MONDAY: During the weekend and into the early part of next weak a very strong, well devised system will move across the county juch like the once of the other day. However, this system is not directly thought to affect the state other than near I-10 on Monday


TUESDAY AND BEYOND: As noted, there is strong high pressure over the state. Strong systems approaching from the west will eventually suppress this high south and east with time..but just exactly when is too soon say say. The only consistency between models is that one of the systems will eventually erode the trough enough to allow strong winds aloft and more moisture  in as well. The first sign of this chance will be Monday.


RAIN WHEN? Rain chances pick up a bit more around 4/15, with a few meager chances haere and there but not worth mention

Florida Might Be Able To Break The Drought by Month's End !

An Example of Possible Precipitation Totals Over a 4 Day Period Ending Next Friday Night (April 15th)

TODAY THROUGH MONDAY: Florida will be under affect of a high pressure ridge at times centered directly over the state today through Monday. During this time some strong/severe weather producing storm systems will ride up and over the high pressure north of Florida, which will feed  moisture and heat into much of the Eastern United States as far north as Minnesota.  The weather will be dictated over the state by warmer afternoons working into the weekend (actually before that time in some locations) which will expand in coverage into much of the Eastern States as far north as Minnesota. Very cool morning low temperatures will be a thing of the past for all but NW Florida (at times). 

This COULD be significant further in time as this latent heat will eventually accumulate as energy to be transported...somewhere.  As we can see in the image above that energy could translate as storms and rain with time as upper level parameters become more favorable for its release (colder air aloft). First will likely be a squall line to develop into the weekend and/or two separate regions of severe weather north of the state.  This image is one example of what could be the net affect for the period of April 11-15 over the Southeast United States as these systems erode the ridge, finally affecting the state. 

Per this same model, this is only but half the story!

Temperatures will be coolest near the coasts with highs 80F- low 80Fs where inland and SW Florida as well as portions of the state's spine could break the big  9-0 but mostly mid-upper 80Fs will be the rule.  Although sea-breeze collisions will occur on several afternoons, warm air aloft will preclude the formation of nothing more than clouds and perhaps a sprinkle or shower toward the favored west side of the state south of Tampa during this time frame with the east coast sea breeze being the most dominant, at least going into Monday.


TUESDAY: The first of possibly 2..and dare say..maybe 3 storm systems will cross the Western tier of states, gradually working to erode the ridge's influence. It will be a long, drawn out affair...but with time the warm air aloft in the mid-upper levels will be eroded from north to south over the next week, but here on the ground our temperatures will remain warm.  The first of these systems will make a gradual sink into the Panhandle area on Monday...by Tuesday there could be showers and thunderstorms over North Central Florida, working south with time into South Florida through Wednesday. If this does even occur, severe weather is not anticipated.


BEYOND: All things hinge on the long range forecast in regard to the image shown above. At this point in time perhaps it's wishful drought breaking thinking...in fact, it is. But at least there it is in print. After writing that sentence, I thought to myself, "hey , I wonder what the folks at HPC are thinking? I could get their image for comparisons sake, whether or not it is in agreement"

NOTE THE EXTENDED FORECAST ISSUED BY THE HYDROLOGICAL PREDICTION CENTER FOR APRIL 14-20, 2011:

The extended calls for Above average precipitation April 14-20th right during the normally driest time of the spring drought season...bizarre!

IN ESSENCE: To go out on the first limb of many (which I will not do)..the first limb will be one which could be a severe weather event beginning sometime around the 14th-15th time frame as noted yesterday (another possible event jumps out in guidance in an even later period). The ECMWF and GFS last night varied SIGNIFICANTLY with the handling of this time frame...but they seem to be falling in line in regard to the eventual outcome going into Tuesday through the 15th, and clearly from the image above the folks at HPC are willing to lay some bets on this.  ALL of Florida has a 'chance' to wipe the slate nearly clean of drought, or at least put a good dent in it, by the end of April if the GFS run of 8AM this morning comes anywhere close to fruition, considering that if it is correct (which it almost never is that far out in time)...the rains would continue until about the 23rd.  Please note, this is a Big "If".

Very Pleasant North/Central, Clouds South Today - Unsettled Later Next Week

Squall Line Lightning Over the Banana River south of Kelly Park

RECAP: Squall line cleared all of Central Florida by early afternoon, continuing through South Florida and the Keys by 4pm.  This organized line of storms originated from near the Ohio River Valley region 36-48 hours earlier...and has left it's dying energy, mostly moisture over far South Florida and the keys. A waterspout was sited about 7 miles offshore the Cape, and another was seen about 1 mile east of Patrick Air Force Base as well. There was some severe category level storm reports from wind in Florida, but not of the intensity or coverage as those observed last week. This was expected to be the case, since winds aloft were not as strong and temperatures up there were not as cold either. 

Here is the radar image as the system crossed along "The Great Dividing Line". It was at this time the squall encountered the richest dew point temperatures of 70F and above and the more unstable air over the South half of the state which had developed after sunrise. Also note the rotating single celled storms CLEARLY outlining the Gulf Stream. Kind of neat! Multiple waterspouts were supposedly reported from those offshore storms. I'm not surprised at all. It would have been fun to paddle out there with a long board equipped with a GoPro Video Camera to go "Storm Chasing, Doggie Paddle Style

AND HERE ARE THOSE DEW-POINTS. NOTE THE  NORTHWARD"NOTCH"  OVER NORTH BREVARD. THIS IMAGE WAS ACQUIRED 45 MINUTES PRIOR TO THE ARRIVAL OF THE SQUALL LINE AS SHOWN IN THE ABOVE IMAGE.

There was some weak subsidence in the air mass immediately preceding the line which precluding the southbound system from efficiently "inhaling" the juicy air mass immediately ahead of it over Central and South Florida. This, in fact, seemed to be a factor with this line during it's entire journey from the mid Country. My personal observation of this fact could confirm that, at least over Central Florida. As the system approached, the atmosphere acquired a 'hazy. muffled' appearance  10-20 miles in advance of the squall within the sinking air. 


Additionally, the sound of thunder seemed to be 'ducted'...only close to the ground. Thunder did not roll and roll..did you notice that if you are a reader and were in an area that had lightning? I did not see any cloud to cloud or in-cloud lightning. Only cloud to ground...and most of the lightning preceded the rain or occurred as the rain began. Might have been just where I was at though.


 An enhanced section of the line popped just a mile or so to the north over the Air Force station at the Cape, passing just east and north of Port Canaveral. That can be seen if you look closely at the above radar image. This occurred as the line met the higher dewpoints, cross sectioned with the higher low level helicities off shore.


NOT SURPRISED: Low level helicities were being analyzed and forecast for the coast and just offshore for 24 hours prior to the line's approach.

THIS IS THE NAM FORECAST FOR 11AM..1 HOUR SLOWER THAN WHAT OCCURRED.. However, this shown was a 33 HOUR forecast. NOT BAD!! We can see the gradients of Cape being pointed out over South Florida by the black arrow's text. Whereas this image (red arrow) portrays the low level helicities in the bright colors. NOTE the area off shore and over the Gulf Stream in faded orange...which eventually MET the south bound values east of Brevard County. They met and POOF...waterspouts and lightning, which the Port area had the benefit of experiencing as can be seen by the image at the top of this post.

TODAY: Front has cleared all but extreme South Florida..mainly the Keys. Ample low level and some mid level moisture remains, enough to generate clouds which thin and lessen the further north one gets where the air is drier at those levels. Just enough over Central to generate some flat topped stratocumulus clouds.  Could be a rain shower by the time the day is through over far SW Florida near the coast.  High pressure is located just East and North of the area this afternoon. This will sink south through the weekend, and as such clockwise flow around it will become SE overnight tonight which will advect higher dew point temperature air into all of Central Florida over night and through tomorrow. Over night lows will be a good 8 degrees warmer tonight than last night over Central and even warmer than that along the coast. Clear skies overnight Central and North.


TOMORROW: A warmer start to the day...and a warmer day overall everywhere in the afternoon. Winds along the East Coast will be SE-SSE at times and breezy at 12-18mph during the late afternoon especially as mid -upper 60F degree dewpoint air rides up the East Coast along and east of the Gulf Stream toward Sun Glow Fishing Pier. This will be the theme of tomorrow, with partly cloudy skies...of more puffy cumulus nature. 


There is a very small chance of some showers or even a thunderstorm from near Lake Okeechobee to just west of Orlando along Route 27 (Clermont/Bok Tower area) and/or over toward Central Osceola County and into Central Brevard very late afternoon to late evening due to a sea breeze collision.  The chance is close to zero; however, one model suggests this to occur 'somewhere' within ONE of those areas (not all of them), whereas another model shows zip.  That same model has shown it to occur on 4 consecutive runs, whereas the other consecutively shows nothing. The reason for this lies in the forecast of the mid-level temperatures. One of them is too warm aloft and 'caps' the atmosphere for upward moisture transport, and shows increased convective inhibition, which totally jives. However, the other is quite generous in comparison with a thunderstorm somewhere with air aloft just a few degrees cooler. My bet is it will rain somewhere with the upper trough in place and upward warming slow to occur as opposed to that at the surface, but this will be reassessed in future models with plenty of time for an official forecast made public should conditions warrant. Probably way before the next blog post of tomorrow morning we will see or hear a rain chance from the National Weather Service or on the news...but so far all is mute regarding a rain chance..


SATURDAY-MONDAY: Continued muggy and warmer with highs in the mid-upper 80Fs, and some low 90Fs far SW Florida. Winds SSE initially becoming S-SSW late Monday or Monday night. During this time frame warm air aloft over runs the peninsula as continuing warmth of the peninsula rises without impedance to the mid levels...this would be due to the fact we will have another system approaching from the west later next week..and the flow ahead of it will 'buckle'..or rather..Ridge/. So ,do not foresee a chance of showers. But plenty of moderate cumulus away from the east coast during the afternoons (inland) and most of all South Florida, with post sea breeze subsidence behind the east coast sea breeze each afternoon to further squelch the chance significant cloud coverage east of I-95 north of Ft. Pierce.


MONDAY NIGHT/TUESDAY: A storm system highly worth noting  for a small area of the Central/South Central Plains will be that area beginning tonight and into tomorrow and beyond will move east across the Mississippi River Valley Basin and toward the Mid-Atlantic by late Monday. The high pressure will sink south even more and allow winds to become more SSW. The associated cold front as it is so portrayed both all models will move into Central Florida on Tuesday around noon time or shortly thereafter. This front could be accompanied by some thunderstorms or showers, mostly along ...you got it.."The Great Dividing Line of Central Florida" which runs from Tampa to the Port. Other showers and storms could occur futher north, but due to the timing of this boundary passing through North Florida overnight and early morning instablity for thunder will be somewhat, but not entirely limited. The front could stall and pull out to the east during Tuesday. Leaving the South Half of East Central and South Florida in a rain chance through Wednesday.


 Chance of showers and thunderstorms on Tuesday as noted above, decaying shortly after nightfall as the boundary moves into South Florida or goes stationary very close to the location the boundary of today now lies over South Florida where rain shower chances will continue the following day.


***NOTE: Timing of this front will likely change as the time approaches. Therefore, the above stated is purely theoretical at this time. The front might never even reach South Florida at all.


GOING INTO LATE WEEK/THURSDAY: It's becoming close to the point that we can safely say that a very unsettled weather pattern over all of the state at various times will be the wild card in regard to rain and storms.So far, especially the South Half of the state, but initially all of NW Florida and the Panhandle. Another major storm system is going to affect much of the country working into next week. Wide spread severe weather is anticipated from the Gulf to the Great Lakes and parts of the NE States...and I expect there will be a higher number of tornado reports with this system than with the squall line of the past 2 days. Most of the exact same areas will be impacted by this system as well, including Florida.


However, the nature of this system, as it now appears, will manifest itself in an entirely different manner...at least for a portion of the time, as it crosses the states North of Florida. It probably will not be preceded by a shallow layer of subsidence and a squall line...at least not for the early to mid-time portions of its 'existence'.


The impacts on the state of Florida, and the timing of when exactly these will be sketched in stone remains a bit fuzzy as of the latest model runs, but all models are agreeing that a big change is in store sometime around April 14th for at least a three day period.  There is an indications that a large upper level 500mb low pressure area  (rather than a swiftly moving east bound trough) will cut off over or just west of Florida  resulting in very cold air aloft, yet warm air at the surface until there is a frontal passage. This could end up just being a cloudy/ rainy series of day (s) or very stormy ones. There does appear to be a least one window of opportunity for severe weather over Florida as much as a full day before the actual system moves in (or around April 14th).  


It is not shown yet, but what I will be watching is the area over the Loop Current. Should a surface low form here...things get very interesting. But as of now, there is hardly but one minute hint of something 'fishy in the waters of the loop current other than tarpon and Sailor's Choice".


Low and mid-level wind fields with this system as it appears now will be very weak...so it does not look like a tornado threat will be in the making at this time; however, there is still much to be determined at this point in time. The configuration this far out in time concerning this "POTENTIAL" system leaves a lot to be desired in regard to the low level features this far out in time. Something doesn't look quite right. Perhaps a secondary surface low will from in the Deep South near Florida..,seems possible. That would change everything.


For instance. at no time during its 3-5 day visit is a cold front portrayed to pass through the state by the time all is said and done once the upper low lifts out. In fact, we do not know how long it could linger, or if it even will. If it does not cut off, as only the latest GFS model portrays this morning, the impacts will be more significant, but the chances of rain fall and/or storms will be of short during. Could be a two day event...or a 5 day event.  


" Round and Round and Round "she" goes, where "she' stops...Nobody Knows"...Knowbody.