A Few Isolate Stronger Storms Possible Today - Big Rain Totals West Central Late??

Early A.M. First Guess within the Storm Prediction Center's 10% area for Thunderstorms today over Florida.
Green areas: Early activity prior to 4pm, Red -Shortly thereafter but stronger. I would extend the red area a bit further north to include all of Lake County though...oops.  Black- possible accumulations over 1.5"???

There was some isolated strong storms yesterday over Far SW Brevard County into SE Osceola County, but the strongest by far was over and near the Everglades/Lake Okeechobee late in the afternoon. A Special Weather Statement was issued by the NWS in Melbourne for the early in the afternoon activity for small hail being possible, as was one issued by Miami for the South Florida activity. Indeed, the culprit storm which instigated the statement by MLB exhibited an overshooting top easily visible from the backside. This indicates a strong up draft poking higher than what would normally expect to see. Wish I could have seen what radar looked like at this time What cannot be seen is the anvil of the storm at the same time which was stretched well out into the Atlantic downstream of the upper level 30,000ft winds. That is certifiable based on the satellite imagery I saw upon returning home.

Overshooting top to the right of the telephone pole. A thunderstorm anvil was stretched far down stream of this storm but is not visible upstream (from my location) . Photos were taken at the I-95/SR520 exit looking SE into far SW Brevard County

TODAY: Another day of some stronger, isolated storms is possible. At this hour there is moderately- high atmospheric instability mounting over the far East Central Brevard County area. This is analyzed by local data integration and also forecast by both short and mid-range models. For this hour of the day..the values shown are unusually high.  


Model guidance (the same ones) show there to be a zone of almost zero convective inhibition encompassed within an area of  fairly low Precipitable Water (PWAT) values (only 1.16")  over the Space Coast as I write just waiting to be activated (in the summer PWAT can be over 1.80") upon reaching the Convective Temperature of only 83F.  This tells me that the PWAT is averaged over a layer of the atmosphere of which parts of it are dry...but if we cut out the mid levels there is more there than meets the eye.  The Level of Free Convection is rather low today, so despite how dry the mid-levels are (and cold)...activity should be able to initiate once the East Coast Sea-breeze gets moving inland as the earth heats up. The low level moisture will be free to penetrate the drier, surrounding air. Perfect for pretty "Storm From A Distance" photographs without a lot of other low level clouds obscuring the view as is the case in the summer a lot of the time.  


The areas for early initiation are show in light green along the East Coast Seabreeze. Other activity is expected to start near Miami and SW Florida very early..but that should be early and brief. In fact, some is already near SW Florida. There's seems to be a weak upper level perturbation over far south Florida this morning which could be the culprit.


THIS AFTERNOON: After some POSSIBLE (not guaranteed) activity along the west bound east coast sea breeze (eastern Osceola County/Western Volusia) other activity could start near Ft. Myers - Punta Gorda along the west coast sea breeze, but not expecting this activity too be as strong as that further north. The two breezes should meet just west of Orlando late after 4:30pm.  over Lake, Polk Counties and south toward Ft Myers. Strongest storms should be along Rte 27  over Lake and Polk Counties later this afternoon under near nil steering currents. If this does occur, could see some bigger rainfall totals shown in the area in black.


LATE AFTERNOON: Lots of assumptions here already, but 'assuming'  the above does occur, much of the east side of the state after 5pm could be overcast with "Anvil Overflow" from storms on the west half of the state with jet stream level winds from the WNW-NW.


At this hour, The Weather Channel is not mentioning rain at all...but some of the model guidance definitely begs to differ. Local WRF model runs from the Storm Prediction Center in Norman, OK have shown a bib, black nasty bulls eye in the general area I have one drawn for rainfall just under 2" this afternoon in two consecutive runs, whereas other model guidance is not so generous...in fact, some of them show NOTHING..(can I write "LOL" or is that too informal?).


INTERESTING ITEM: What is interesting is that the models that are showing the most rain/storms today are also showing an north/south strip of no convective inhibition and low liftng condensation levels migrating west across the state this afternoon, originating from Brevard/Indian River/St Lucie Counties this morning. The North Half of Brevard County right now is unstable with no atmospheric lid. Problem is..we have yet to reach the temperature to stir the pot.  The ingredients are in place to bake a cake, but the oven has to be turned on. In other words, North Brevard looks to be raw batter...the supplier...the "Source Region" for areas to the west later today. Once anvil debris spreads east and cuts of the sunlight the source region will shut down as will convective precipitation. Rains could linger over the Orlando area until 8-9pm with the far east side never seeing a drop.


NOTE: Mid-levels dry, mid-upper levels cold, but a cap at 5000 ft would limit early day activity...and could almost entirely...but anything to go, especially before 6PM, could drop some small hail (0.25") and wind gusts near 45mph in and near down-drafts, thus the "strong' wording.


DISCLAIMER: All things aside, I have discussed the most active possible solution today. The other is for just some isolated pockets of storms. In either case, it will be interesting to see what, if anything, transpires this afternoon.

Some Respectable Storms Possible Today South Central/South Florida??

Some possible areas to watch today. Note the question marks (?)!!
See the text below for more details

RECAP: There  was a strong storm or two down in far SE Florida yesterday which quickly gasped along the SE Coast over Key Biscayne/Virginia Key area when all was said and done. Some small hail was observed and stronger winds gusts were reported. Nothing too unusual for a strong near summer like thunderstorm in Florida. The season in South Florida is arriving in the next few weeks.


TODAY: Today is different from the get go from yesterday. The old frontal boundary seems to be decaying as a mid level ridge builds in from the east as shown by the yellow lightning bolts drawn in the figure above.  The area that gets rain north of the ridge will see rains hardly moving, as will the area further north.  The area to the south should push east and fizzle over Eastern Collier County with the setting sun.


Highest instability is forecast to exist from near Fr Lauderdale northward and up to Cape Canaveral by sunset is one factor to consider.  The highest CAPE is actually near Indian River County by early afternoon...I think this is because the area further south 'should' get an earlier start. An area of mid-level helicity over far Southern Osceola County near YeeHaw Juncton is being shown by Local Data Integration, but I do not have much faith in this.  


The other is associated with what appears could be a disturbance in the 250mb jet stream level winds per water vapor and infrared satellite imagery animations over the SE Gulf of Mexico progressing east.

It looks like the situation for far SE Florida will be a bit different today. Activity should build very close to the Metro Area of Miami and begin to push west south of the ridge axis shown above into the Everglades. Believe this will occur later in the afternoon toward 4pm. This activity could be enhanced much more west of Miami over the Everglades, particularly if that anomaly in the Gulf  continues east. Timing places it south of Lake Okeechobee between 4:30-6pm.


Further north, the area near the Martin County/Palm Beach County has the greatest overall lapse rates as depicted in the image above...and is also the most moist throughout the atmosphere. Believe this area will be the first to go today...and could send an outflow boundary south to that area in the Everglades which would enhance that activity. 


Further north toward Okeechobee/South Osceola County will be closest to the High Convective Available Potenial Energy, or rather just downstream of it.  I'm expecting that...should activity get started sooner over the area mentioned above (Martin/Palm Beach), it's also possible an outflow boundary will eject into this area and stack up against the inhibition further to the west.  This area is highly questionable as noted above. All these areas are also forecast to be closes to lowest lifting condensation levels which will reside east of I-95 from Brevard - Broward County. The area over the ever Glades is never forecast to have low LCLs like those other areas, so it will be interesting to see what happens there.  This could merely aid in late development..


The LCL is a good approximation of the height of the cloud base which will be observed  when air is lifted mechanically from the surface to the cloud base (e.g., due to convergence of airmasses), which in this case in the area north of Lake O would be the east coast / west coast sea breezes...albeit, weak.


In order of appearances would be 1) Martin/Palm Beach ; 2) S. Osceola/O County 3) Miami show after 5pm, with earlier activity in limbo...tooling around until late in the day for the real activity there. Possible lots of 'false alerts'.


NOTE: Our local forecast is not calling for activity today in Martin County or S. Osceola County, but I did notice that MIA is referring to more strong storms today.  


CONCERNS: Warm air capping just about cumulus cloud tops especially north of Lake Okeechoibee toward Ft. Pierce Will it be able to break through?  


So far I think it will, but this is not a given...but latest RUC guidance at 8am is breaking out precipitation in all of these areas, which by the way are not set in stone and could shift around. It does not look as if activity today will be as isolated today ...so instead of the 20% of what I'd call yesterday it could be 30-35%.  Strongest activity could drop more small hail, with some gusty sub-severe strength winds later in the afternoon over the Glades. Activity could creep in to the far South Brevard County area as well prior to 4pm but will be struggling with the eastward steering currents against the SE Seabreeze in a narrow corridor...likely getting strangled.

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......
==================================================================


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,
==================================================================


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