April 27, 2011: And 7 Hours 24 Minutes, 380 Miles That Redefined Tornado History

Radar Composite of the one, single  MegaTornadic Supercell Thunderstorm that originated in Mississippi at 3:40pm EDT and lasted until 10:40pm  (at least) on April 27, 2011. Note that it had a 'hook' shape (indicative of a tornado or the high potential to contain one) almost from birth.  Nearly every thunderstorm that erupted this day was rotating.

Swath of Rotating Storms this Day, nearly all of which produced a tornado, some extremely long tracking. If you live in Florida, can you imagine a tornado producing thunderstorm to be in  South Carolina while enjoying your morning coffee, only to have it cross Orlando near bed time the same day, same storm? Not unlike anticipating the approach of a very small but very violent Hurricane Charley, only smaller, but much stronger.

THE EPIC TORNADO EVENT OF APRIL 27th 2011 HAS OR WILL GO DOWN IN METEOROLOGICAL HISTORY, ALONG WITH THE TRI-STATE TORNADO, THE SUPER OUTBREAK, AND A NUMBER OF SMALLER OUTBREAKS BUT OF NO LESS INTENSITY (some of them were actually STRONGER if that's possible).   No point to go into the details of this event, the information is aplenty...beyond what we may even want or need to hear or know.


It should also be pointed out that BEFORE the day in the Deep South, there was two to three previous days while this system was still evolving that produced tornadoes and large hail back torward Abilene, Texas and east and north into Oklahoma, Arkansas, Missouri, and Illinois.


The point is, we have lived during a period in history now with not only this event, but just recently those of the Tsunami/Earthquake in Japan and Haiti, Hurricanes Andrew and Katrina, the dubbed Moore, Oklahoma EF5 Tornado with the strongest recorded tornado wind yet measured (305 mph). Further information, videos, and stories will be coming across the air waves for many more days to come. 


Many lives have been lost, and the number continues to rise with reportedly those still unaccounted for (which may or may not equate to fatalities).  I watched the entire event unfold on the internet 'as it happened', beginning back in Mississippi...by the time this one storm only had passed Birmingham, AL there was no doubt how fully epically extraordinary the day had become. Realize, that during the time of the 'big one' making news, there were many other tornadoes occurring as well, of no less significance. The  Smithville, Mississippi tornado, for instance, has already been confirmed as being of  EF-5 intensity. That is strong enough to wipe a two story structure to the foundation, pull pavement from the ground, and as I heard recently, it pulled a fire hydrant out of the ground! 


I suspect that at some point the Tuscaloosa to Birmingham storm will be found to have exhibited EF5 strength at some point during its grind across the state, most certainly EF-4.

BEFORE AERIAL VIEW: What appears to be a common Strip Mall and surrounding community

AFTER: Same Location. Note the Strip Mall area. Almost looks like the pavement was scoured. In fact, there is not even debris laying around. It is simply GONE! Imagine those huge projectiles flying through the air for the next area down the line and the impacts those would have on the human skin....that's one way of 'imaging' it to be, uh, conservatively. (I do not believe this was from Tuscaloosa)

BEFORE/AFTER within the same track, same tornado. Your common, everyday neighborhood
If you were to stand in the middle of this, it would almost cover an area as far as the eye can see, 360 degrees of it.

THIS IS A RADAR IMAGE OF THE TORNADIC STORM RIGHT AFTER PASSING
OVER TUSCALOOSA. NOTE THE PURPLE RADAR RETURN IN THE LOWER LEFT/CENTRAL PORTION OF THE IMAGE. THIS IS DEBRIS BEING PICKED UP BY RADAR (the term being thrown around lately as if common knowledge is "Debris Ball". IT WAS NOT AS EVIDENT BEFORE PASSING OVER THE CITY.


I had never heard the term, "Debris Ball" until this year. I don't know if it is something new, or if these events are just so rare that the term was not used widely enough to be easily heard (by myself).  


Below is an image captured during live coverage on the internet. We can see the tornado on a building mounted video cam, and  radar at the same time.

The following day Florida experienced some severe, non tornado producing weather as well. However, had the conditions that evolved during the early evening over East Central Florida been only a bit different, a weak tornado or strong waterspout could have occurred near Port Canaveral. This would have been if the surface winds had been just a bit more from the SE rather than the SSE and the storm had made a harder turn toward the right than it did into  Titusville/Port St. John instead where it produced pea to golf ball sized hail. This storm was mean, inhaling 35mph easily strong SSE winds from the coast and across both intracoastal waterways. The moisture at low levels was so  dense, and the atmosphere so unstable away from the coast that the beaches appeared to be in a dark fog bank under subsidence (settling) behind the East Coast Sea-breeze when seen from Merritt Island. The view into this storm was quite different.

Near the top we see the normal shelf cloud that precedes a strong storm; meanwhile, the storm acquired an attendant inflow band close to the ground near Frontenac. You can see how moisture was feeding into the storm from left to right just above the ground. Hail was falling toward the right side of this photo. That's water vapor in action. Lighting was quite frequent in this storm, even where it originated back in Osceola County.

FORECAST:
TODAY: Chance of showers far SE Florida and possibly thunder western portions of Dade/Broward Counties, evolving more into an isolated strong storm or two into Collier, Hendry, or Lee Counties. Very late toward dark a storm could evolve as far north as Sarasota. Otherwise, further north into Central and North Florida it will be quite pleasant with hardly a cloud in the sky. ENE-E winds at 10-15mph with a high near 80F at the coast and mid-80Fs inland.


TONIGHT/SUNDAY: Chance of a coastal shower or two beginning near daybreak Sunday over Indian River to St. Lucie Counties...perhaps crossing into far South Brevard before 11AM. If these materialize they will be low topped showers. Any activity will progress a bit inland and diminish by mid- afternoon. Perhaps some rejuvenation toward the west side of the state in the early evening.


During Sunday North Brevard near the Beachline will be on a 'gradient' of greater atmospheric moisture with more moist air to the south and much drier air toward the north, those areas from there to the south will see more clouds and maybe the showers...whereas the area just to the north into Georgia will be under full subsidence and much less moisture and may see another clear day altogether.


TUESDAY-FRIDAY: I'm leaving this open ended at this point, other than it will be getting much warmer once again as a frontal boundary approaches late Tuesday through Thursday. The latest European Model was almost a full 18 hours faster than the GFS, but in either case I'm not expecting any stormy weather impacts from this front as it approaches. Rain chances appear will mainly exist during the first few hours after the front moves by in a more stable environment. This boundary will wash out to be replaced by possibly another within 48-72 hours. Again, the details are even more sketchy as model discrepancies are now compounded.  


THUNDERSTORM SEASON WILL SOON BE HERE:
One thing does seem to be in the process though, as I write...if fact, as of yesterday.
Florida is in a transitional phase. Fronts can barely clear the state, and when forecast to do so, could start to actually hang up over South Florida instead..oops. This trend will continue into the first week of June, with the fronts stalling further and further north toward Central and then North Florida. Where ever the fronts stall, chances of thunderstorm activity (some strong) will be possible going into the first two weeks of June, during which time the bona-fide Thunderstorm season will also be evolving. First over the Southern Portion of the state, possibly as soon as within the next 10-20 days..and spreading north with time. Some years, the evolution occurs almost everywhere all at once or nearly so...other years the trend is more 'classic'.

Slight Chance of Strong to Marginally Severe Storms Today - With Caveats

This is the official thunderstorm outlook issued by the Storm Prediction Center (SPC) this morning.
Severe Storms are Possible Roughly north of I-4. Additional images are included further down in this post with a slight variation to this outlook of the authors own  only.

WEB PAGE UPDATES: If you haven't visited the web page recently, you will now find the current, running  conditions for Cocoa Beach just south of SR 520 reflected on the page. This information is not available via mail distribution. The page has been reformatted to hold larger images and the Post History (archives) is now only available view a pull down menu so that the day's post (only) will load faster. 

RECAP: If you are not already aware, an EPIC TORNADO OUTBREAK has occurred over the past 24 hours in the Deep South from Mississippi, Alabama, North Georgia, parts of North Carolina, Tennessee, South Carolina and Virginia just to name a few. The fatality count when I woke was 174 and is now over 217. The huge piles of twisted debris (including vehicles) is still being dug through, so it seems probable that more fatalities will be accounted for before the day is through.  The shear number of tornadoes and the path length of a few of them, one (or many) of which were generated from one single storm that tracked over 300 miles from Mississippi to nearly Virginia, is astoundingly record breaking or nearly so.  Yesterday is going down in weather history to match that of the infamous Tri-State Tornado of March 18, 1925 and the Super Outbreak of April 1974.  Interestingly, another infamous outbreak occurred in Kansas on nearly the same date  (April 26, 1991).  In fact, one of the tornadoes yesterday, the worst so far known of which hit a part of Tuscaloosa, Alabama closely resembled the Andover Tornado from certain angles with the appropriate lighting.


 This day is already going down in Meteorological History as an Epic Event of unmatched or nearly so proportions due to the number and intensity of tornadoes. In fact, there was more tornadoes reports or nearly so that of hail.  Aerial and ground assessments are being made today to determine the strength, width, and length of tornado paths. I have not seen any indications of EF5 intensity yet, but certainly EF3/EF4 strength tornadoes will be determined (on a scale of 0-5).  I am not going to go into the finer details, images, and video links that are widely available on the Internet concerning this event in assumption that anyone who desires to hunt this information out can easily do so at will with minimal effort via a Google or YouTube Search. There is a LOT of video out there that is quite astounding and shocking, but this is one is a astounding for starters. Once you reach this link, you will see others as well. This tornado resembles the Andover, KS Tornado of April 26, 1991:


http://www.youtube.com/watch?v=9M_mcOL99qA


RECAP LOCALLY: A few storms finally materialized after dark yesterday which impacted mainly Okeechobee and Osceola Counties. The storms made it as far east as the Brevard County line. Lightning was beautifully visible from the beaches of Brevard and surrounding areas as the activity peaked, but as it reached Brevard it ran into a stout, strong sea breeze 'wall' and collapsed.


TODAY: The Storm Prediction Center has issued a severe thunderstorm watch box this morning for most of the area in the outlined Slight Risk area shown above. 


Refer to http://www.spc.noaa.gov for details.


Otherwise, they have  'generously' placed the entire peninsula in a chance of thunderstorms today; however, most of this area will not receive rain today. Therefore, I introduce the self annotated images  below:

The first image shows the current location of an approaching cold front with my own slight risk area overlayed on the current (high) dewpoints. Note  that really the only difference in my self assessed slight risk for severe  is that it is a bit further south than that of the official outlook.


To the right is the SPC outlook for General Thunderstorms which shows all of the state in a chance of thunder after 4pm with a higher chance of coverage within the bounds of the blue line. I have added two items here. First, the extension south of a chance of severe level thunderstorms (green line)  and second, the chance of strong thunderstorms within the orange/brown area.


Note that these areas do NOT mean that everyone within either of these regions will even receive rain today. Storms will be isolated, with a greater coverage or chance (more appropriately) of coverage within the two areas. No guarantees. Odds are there will be less coverage rather than more than current thinking. 


TODAY: Cold front will move only slowly South and East today through sunset. The strongest activity will be located closer to the front where the more favorable wind fields exist to support severe level type storms combined with colder air aloft  for  stronger surface thunderstorm winds and possibly hail, although it  does not seem severe sized category hail is possible south of a St. Augustine to Cedar Key line.


FURTHER SOUTH: First off, be aware that the activity over most of North Central Florida to South Florida will be in no way related to the Epic Event that occurred yesterday over parts of the Deep South into the Mid-Atlantic and Mississippi River Valley Basin area. Today will be more like a summer day over Central and South Central Florida that would favor stronger storms due to 1) a dry mid layer, and 2) somewhat cold air aloft, but not impressively so.
This activity will be most enhanced near Lake Okeechobee Boundaries and/or both west and east coast sea breeze convergence boundaries just inland from either coast or a combination thereof.


Yesterday, the sea breeze boundary started up not only earlier than thought  by several hours, but was also stronger. Even as I type the same trend seems to be getting underway. Winds at Melbourne are SSW though still,  whereas at the beach in Cocoa Beach the winds are SE-SSE so perhaps the sea breeze is holding off just a bit more today.


The first image above is an overlay with dew point temperatures. We see very high dew point air at the surface embedded within the prevailing SSW Flow off of the Gulf. However, not shown is a pronounced tongue of warm, dry air in the mid levels.  


Therefore, the atmosphere south of the Slight risk area (especially on the east side) will remain capped and non-conducive for even a shower well into the early afternoon.  A weak surface, thermal type low pressure circulation could develop over the interior through early afternoon which might enhance the east coast sea breeze south of Daytona Beach, but I do not think that low level moisture will be completely scoured. 


What happened yesterday to prevent daytime storms, as I see it, was that the winds at the lower levels over came the winds in the mid-levels and essentially 'cut-off' any otherwise potential convection. This very will could be the case once again today; however, given that nearly every single model is breaking out precipitation this morning I will not differ far from this solution. However, I think it will be only isolated in nature rather than the great coverage that is shown by model guidance. Assuming it can manifest at all.


The capping environment is forecast to break down from west to east beginning around 1-2pm..with activity spreading west and south from North and Northwest Florida...and possibly up from the SW near Lake Okeechobee after 2:30pm. 


Showers/storms appear will enter Central Florida proper (such as Orlando/Daytona/Lake County between the hours of 3pm- 6pm with the strongest storms just west of how far inland the East Coast Sea-breeze penetrates. Expecting it to penetrate inland more the further south one goes, thus the slanted nature of my "Possible Strong" area.


It is possible that no thunder will be revealed east of I-95 south of Titusville/Mims area...but this is not set in stone.


**For Official short term graphic casts and hazardous weather potentials please consult the NWS web page/blog at. This page is normally updated by them as conditions warrant for either the good or bad. (Central Florida Interests).


http://www.srh.noaa.gov/mlb/blog.php


OTHERWISE: Activity will dwindle after dark, although some nocturnal activity once again cannot be fully discounted anywhere over South Central Florida toward the east side.


OVERNIGHT: The cold front itself will move south into Central Florida with the best chance of rain showers just ahead to just behind the boundary along the east side of the state from Daytona Beach to Ft Pierce. The front will be located approximately near South Brevard shortly after day break.


FRIDAY: The front will progress in a much weakened state with virtually no upper level support remaining as it continues south toward Southern Palm Beach county by peak heating hours. South Florida can expect another day of diurnally driven thunder and showers until it progresses to the Keys or Florida Straits after dark.


WEEKEND: Onshore winds of 10-18 mph over the weekend. Much drier to start the weekend with only a gradual moistening of the atmosphere through Monday morning...with a bigger rebound into Tuesday afternoon. Another front will approach the state on Tuesday into Wednesday, but just exactly where it will get hung up to the north, if it does, is TBD. It might not reach the state at all. 

Strong/Marginally Severe Storm or Two Possible East Central/South Florida Late Today

IMAGE: The Outlook area for General Thunderstorm Activity today issued by the Storm Prediction Center  (SPC) for late this afternoon through early evening.  Please consult the SPC website at spc.noaa.gov for all official information. Note: you can also click on the title of this post to go to the NWS MLB latest forecast update and graphic:  http://www.srh.noaa.gov/images/fxc/mlb/Latest.gif

RECAP: A strong storm materialized late afternoon through early evening along a moisture/wind convergence boundary that had materialized along the Lake Okeechobee "Shadow"/East Coast Sea Breeze boundary.  Hail to nickel size and a funnel cloud were photographed and submitted to a local news channel out of West Palm Beach of the funnel near Ft. Pierce in St. Lucie County. Details are sketchy as to whether it actually reached the surface, but either way, the storm was well structured / organized and visible even as far north as North Brevard County with a bit of a back-sheared anvil look and solid updraft. Other photographs were taken by others closer to the activity  of the hail/funnel/storm structure...but you know the drill, "All Rights Reserved".

These images show the storm as it appeared
from Cape Canaveral which was well
to the South over St. Lucie County, Fl. The
backshearing of the anvil (against the upper level winds) is seen behind the telephone pole in this first photograph captured from my camcorder. Rain showers and some thunder had also occurred from Mims/Titusville/ KSC/Cape Canaveral earlier in the afternoon.











TODAY: The first image shows the area most likely to get a thunderstorm (s) outlined by the Storm Prediction Center based in  Norman, Oklahoma. This area is not annotated (yet) with a "See Text" refrain for strong storms, likely because any strong activity will be very isolated, if it can manifest at all. I've generated an image from the OFFICIAL latest post from the NWS in Melbourne, which will likely be updated later in the day after this post is complete. I'll check it before posting today. Otherwise, expecting a strong/marginally severe storm is POSSIBLE in one of three areas as annotated and numbered below. Each area is squared off, then circled for a better location/chance per only the morning model guidance (which will change with every hour!), with annotations. They are also numbered, but the number does not necessarily reflect a greater likelihood of a strong storm, or even rain at all for that matter in any of these locations. The purple text of my own doing highlights the main reason for the green circled areas (based on morning guidance).

EXPLANATION OF EACH AREA FOLLOWS: Firstly, strong day time heating will occur today as noted by the NWS.  There is a big glitch here though, and that is upper level, thin high cirrus clouds. This could put a big damper on late day activity anywhere over the North half of the state.


Highs appear will reach the low 90Fs inland otherwise, with perhaps a few near mid-90Fs. Breezy all locations, especially over the causeways where the wind will run right up the intracoastal. A bit cooler beach-sides.  Some showers could occur in the absence of the sea breeze from North of Daytona and down the coast to Broward County, with the first activity south and working north with time, but currently the cirrus clouds are putting the big snuff on this possiblity. Some lightning could occur with this activity almost in any location...but I'm favoring far SE Florida primarily for the early afternoon activity. Showers further north will be generated purely through horizontally stretched moisture convergence rather than vertically...so not expecting much thunder further north. Further south the geography alone combined with the gradient flow will add in better but not great convergence there. Later today: 


(1) East Central Florida - Local geography could play a role this late afternoon/early evening as was the case yesterday. Expecting a late afternoon sea breeze close to the coast. The past hour or so winds have been between South and SSE. This is forecast to change to a solid SE-ESE after 4:30pm (but just noticed that MLB is now ESE) as is a local station from Weather Underground in Cocoa Beach. Meanwhile, winds just above the surface will remain from the SSW at 15-20mph.  The 200-300mb jet stream will be nosing into North Central Florida late afternoon about the same time the sea breeze 'could' set up (appears it already has begun). Moisture convergence would be the main initiating factor late in the day aided by stronger winds aloft late, and a possible cool mid-level "pool" within a dry mid layer. Thus, stronger wind gusts and small hail are possible. Any sustained updraft near devoid of rain or nearby rain-cooled air could generate a funnel cloud as was the case yesterday over St. Lucie County. 


This occurs most likely when the sea breeze/gradient flow converges with the moisture/thermal gradient all in delicate unison over the Intracoastal or near shore Atlantic waters as the storm is about to peak or just peaks in height. Again, this is assuming there even IS a storm here. I have annoted this as #1 based on the notion that the NAM and GFS have targeted this area with higher precipitation between 5-9pm. Interestingly, the NAM even shows a light precipitation 'backwards hook' field going across the Mims/Titusville area with a pin prick precip core to the SW near Cocoa. This could be a flanking updraft field, but such a notion is purely conjecture/day dreaming on my part. This model, nor any really, can pick up on such storm development. Big con for this area is early afternoon cirrus clouds which will be in place through mid-afternoon, at least. Model guidance is also showing a lowering of the lifted condensation level east Central over Eastern Central Brevard after 6-7pm time frame in the absence of a precipitation field. This would aid in storms becoming fully surface based.  This is sketchy/questionable. Should this be where the model should be showing the rain in reality as opposed to further to the W-NW over the Mims area south to Cocoa? Will anything form here at all due to the current presence of cirrus clouds? They seem to be on the verge of thinning out.


(2) Further north from near Daytona/Ormond Beach to St. Augustine. This area is being watched for stronger synoptic scale winds and the tip of better moisture convergence from the South. This area does not seem as likely to generate a strong storm due to lack of convergence or a trigger, but it gets more iffy the further south one goes in that area going toward Daytona/New Smyrna. Con for this area is also cirrus clouds. The West Coast Sea Breeze does not play in today and the cirrus here also appears to be thinning as of 1:30pm.


(3) South Brevard/St. Lucie/Martin/North 1/2 of Palm Beach County: Very sketchy. Only one model shows a precip bullseye down there. One which later took that chance out. But I'm looking to differ. The best onshore/sea breeze flow should be down in SE /South Central Florida (coastal) beginning after 4:30pm and maximized after 6:30pm (as is the case in the other locations). Dew-points inland will be allowed to rise after peak heating has subsided, thus moisture convergence will increase in all areas. This area could get an additional boost from the Lake Okeechobee "Shadow Affect"  from South Brevard to Martin County. Oddly, one model showed that something to generate down there would latch on to upper level jet stream winds and take a deviant right turn down the sea breeze boundary toward SE Palm Beach County before exiting off shore and dying. VERY odd ball, but 'odd events' have occurred in the past in all 3 of these locations, even on a normal summer day. They are normally lmited though to when the gradient flow winds are much weaker than they are today. Less cirrus clouds in this area...at least for now, favors this area.


All activity, assuming it can be generated, will be on the East Side of the state, with initiation contingent upon how far inland the Sea Breeze can penetrate...but it's hard to imagine that despite that fact I'm sitting here typing with an ESE wind to my back. that not far away to the west toward I-95 there is likely no sea breeze. So far, it seems to be not much further than I-95...additionally, the Big Lake Shadow is showing up with a vector toward North East Brevard along I-95 near Titusville along its Eastern Flank. Far South Florida seems to getting scoured out by the combined gradient flow with the Sea breeze so the Miami Metro area/ Dade and most of Broward can likely be tagged' out' for storms today.


*As of 12:45pm the Hazard outlook from the MLB NWS has not changed. See this link for the latest update or click on the title of this post to be steered there:


http://www.srh.noaa.gov/images/fxc/mlb/Latest.gif


THURSDAY: Different type of day and much to cumbersome to go into detail with. Best chance of strong/severe storms is over North and far North Central Florida with a secondary area over Eastern Portions of North Central to Dead Central (near the Beach line to Eau Gallie Cswy corridor) late afternoon as noted yesterday.  All activity will occur along a pre-frontal boundary over North Central to Central rather than on the front proper. South Florida may also see another round of thunder/showers in the afternoon due to different circumstances altogether, favoring SE Florida.


FRIDAY: South Florida and portions of South Central will be favored during the noon time to Early Evening as the front moves further south and goes stationary over the Keys area by late Friday through Sunday. Over the weekend the Keys and extreme South Florida might have a chance of showers and thunder, especially far SW Florida over the weekend.


MONDAY-TUESDAY: Moisture inches back northward into Central and then all of the peninsula, by late Tuesday in response/ advance of another approaching frontal boundary. This boundary might not penetrate as far south and could get hooked up across North Central or North Florida beyond next Tuesday...so later next week week is still up for grabs over the peninsula as to whether rain chances COULD remain for much of the second half of next week. It appears that if this does occur that showers would be caused by a long fetched/duration onshore moisture/flow component, with thunder favoring SW to West Central Florida. Way too soon to say.

A Few Showers Until Noon, Thunder Possible Late Afternoon-Early Evening

SUMMARY: Somewhat of a 'tropical warm front' went up the state this morning from South Florida and is now beginning to clear North Central Florida while washing out. The boundary brought higher dew-point air to mostly the coast considering it is loosely associated with the old Invest 91L's upper level features, which are well off to the east. Respectable rain showers were on the way very early this morning for the coastal communities, but only made it as far north as the Melbourne Beach area before collapsing, sending a 'cooling' outflow out in all directions and smuffing out all surrounding activity that was on the approach to the areas further north.


At sunrise, the atmosphere is recovering now with some large lightning storms well off the coast from Miami to East of Daytona and a few rainshowers reaching the the Space and Treasure Coasts.  A few renegade showers can still impact the east coast about anywhere until noon time until a more pronounced East Coast sea-breeze can develop after 1pm.


This afternoon:  Believe the East Coast Sea breeze will begin to kick in earnest at 10-15mph from the SSE-SE, whereas the west coast sea breeze will be slow at getting started until the prevailing SE winds and thier land breeze of the past 2 days begin to wane.  By mid-afternoon a diffuse west coast sea breeze under the prevailing westerly flow at the mid-upper levels will push toward the spine of the state, where it will be warming into the upper 80Fs to near 90F.  Rain showers and clouds will begin to clear the coast while cumulus form further west of the coast.

It appears a weak 500mb disturbance will approach the state from the NW by early afternoon today, reaching NW -far N Central Florida by mid-afternoon. As a result, some thunderstorms may begin to arise near the east side of the state from St. Augustine into Seminole Counties.  Meanwhile, mid-afternoon activity will be at hand from West of Miami Metro, Lake Okeechobee, to very close to West Palm Beach.  The storms over South Florida will form within a broad area of low pressure covering the South half of the state.  This activity could begin to collapse and send outflow into South Central Florida into the by then much heated and modestly unstable environment of Osceola and Orange Counties, as well ..or almost anywhere West of I-95 toward Southern Volusia County.

Net affect, the disturbance triggering off activity to the North of Central moving SE combined with the outlfow from the south might ignite the strongest storms of the day very close to Orlando Metro, the North Half of Osceola County, Seminole County, and SW Volusia.  This activity should move slowly east toward the coast after 6pm with the heaviest of impacts along I-95 to maybe US1 in Brevard and Indian River Counties from Titusville to Vero Beach.

Shown in green  is where there is the best chance of showers and thunder today. The area in South Florida should be thunder during the early-mid afternoon, whereas the area in red 'should' be later in the afternoon to early evening as moisture converges from the west with that already in place along the East Coast which will push inland afternoon noon time under a moderately unstable atomospheric environment

STORM NATURE TODAY: A lot of presumptions already, but it is possible some 1.5" rain amounts could accumulate in an isolated area over South Florida as well as near the Orlando Area by the time the day is through where rains linger the longest.  It is also possible that the immediate coastal areas will be heralded of the rains' approach by a cooling outflow, or gust front from the west, followed shortly by the rains, although at time it is questionable as to whether folks east of US1 in much of Brevard will truly experience the heaviest impact of the storms, assuming (again) that they do materialize. I'm faily sure that about 60% of the folks in East Central Florida will get some rain today though.  Rains could linger with the slow east ward push aloft toward the east coast until 9-10pm in a location or two along US-1 to A1A.


WEDNESDAY:  A totally different scenario tomorrow but one which at time seems to favor another chance of storms along the East Coast from North Central to South Central Florida (interior).  Doesn't look like we'll have any early morning shower activity, and the day will heat up very well. Expecting a broad corridor to heat up to the low to near mid 90Fs far interior tomorrow with coasts in the mid-upper 80Fs.  Since temperatures aloft tomorrow are not forecast to be as cold, I'm not expecting as strong as storms that COULD manifest today, but there are indications some stronger activity could be closer to the East Coast particularly from Brevard-St. Lucie Counties.  Much of the day the atmosphere will be capped with warmer air aloft, and it would take strong updrafts to break through. Could be more lightning tomorrow than what we will see today...but let's get today over worth and see what happens.


THURSDAY: Still on schedule for a  front to enter North Central Florida during the early-mid afternoon to reach Dead Central by early Friday.  Also, watching again as noted yesterday for some sort of 'pre-frontal' activity to form over Central/South Central which will be much stronger than the front itself, with potent thunderstorms mainly along and north of the Beach Line/Melbourne Cswy area. Would not be surprised to see a "Slight Risk' for Severe issued by the Storm Prediction Center for as far south as St. Augustine, or perhaps Daytona due to the dominant synoptic set up; however, if taking local affects and the timing of day into consideration  should the prefrontal boundary form over Central Florida, I'd throw in an additional slight risk for a  Melbourne to Orlando Line and north.


The  front is not forecast to reach Central until after sunrise Friday, so some early-mid morning showers are still possible near the coast before it completely washes out to nothing more than a wind shift until it reaches to near Boynton Beach-Ft. Lauderdale by early afternoon where some thunder could occur.


WEEKEND: Still looks nice with on shore flow.


Moisture looks to return from the South by late Monday, which might be 'activate-able" by Tuesday afternoon over the interior for showers and perhaps an isolated thunderstorm Central and South Florida.


(Disclaimer: All forecasts, graphic annotations, notions and musings are of the writer and not official. Consult official NWS Outlets if so desired).

Possible l Thunder West Side, Perhaps Isolated Interior Late Afternoon

Visible Satellite Image at 12:35pm EDT shows cumulus fields forming across the state.
Early - late morning rain showers have moved on shore Martin/St. Lucie/Indian River /and parts of Brevard County.
In this image it is noticed that no sea breeze boundaries have yet to form under the prevalent SE-ESE low level flow by the lack of 'clearing' along the coasts behind these boundaries once they form.However, there are some glitches to today's discussion to point out....

TODAY: There is no doubt the today the weather over the peninsula is being dictated by low level and to some degree mid-level flow/wind from the ESE-SE, becoming more predominately SE-SSE by sunset.  However, in the mid-upper portions of the atmosphere above 10,000ft the winds come to near calm under a 500mb ridge axis shown in the image below late today. There is some cold air in the mid-upper levels today, which most likely could induce the highest concentration of stronger storms on the west side of the state once again late this afternoon until dark under the assumption the west coast sea breeze forms and works against the prevalent easterly surface winds, otherwise noted. These storms will be very close to the coast today.

This image isn't as complicated as it may look. The black box shows where the best chance of thunderstorm activity will exists today, with the red areas (same as yesterday) highlighted.

 The area near Brooksville looks to hold a better potential today. The blue line is the approximate position of the cold 500mb trough axis late this afternoon. The latest RUC model dared to show a tiny circle over Western Orange County late today to denote the center of a closed circulation there. Not really feasible, but the point is winds way up there today will be near calm/temperatures cold.

By early evening winds become more SSE-S over the interior and a secondary area shower/storms could from west of the purple line to the blue line..most likely over Central Osceola County into Orlando, after 4:30-8pm time frame.

 MEANWHILE AT THE COAST: Things look to be quiet at the coast today with brisk SE - SSE winds late toward early evening, especially once the sea breeze settles in and skies clear for a time until near/after sunset.


TONIGHT: The little circulation of Invest 91L is STILL VISIBLE on satellite imagery about to cross into the SW Bahamas Islands south of Grand.  Believe it will get caught up somewhere east of the Gulf stream..or split with one portion running toward the Keys with another portion to run up to the west side of the Gulf Stream overnight tonight.  There is a chance that the immediate coast from Fort Pierce to Titusville/Oakhill could see rain showers tonight accompanied by strong wind gusts with the cold air still aloft at the coast (as the 500mb axis drawn in blue above starts to pivot out of the state).  This would be after midnight to near sunrise if this occurs.  Interesting from this writer's perspective that the GFS favors the Cape area with the flow in the lowest levels of the atmosphere and highest land bound PWAT (precipitable water) values only passing over the Cape Extension but otherwise remaining all off shore. Fat chance, but will be interesting to see what comes out of it. Best bet is that any over night activity will latch on to the Gulf Stream, but overnight hours seem to have a mind of their own at the coast and don't always obey the rules.


TUESDAY: There is some agreement that conditions would favor the East Side of the state for showers and storms; however, this area, despite having the most available moisture and instability  might also be capped by warm air aloft...resulting in showers further to the west with nothing to show for it over the otherwise more favored area for showers or a thunderstorm or two on the East Side. 3 more model runs to resolve the discrepancy. Those West Side 'Boyz' have had their fun.


WEDNESDAY: All models agree that for the most part it will be warm and breezy under a capped environment. The GFS is hinting that showers could go up over far South to South Central Florida late in the afternoon that will form during a transition period as a cold front approaches. I love transition periods so I'm starting to hedge in this notion. Showers would be picked up by the now developing SSW to NNE Flow aloft and be carried off the East Central Florida coast by early evening from the Southern Interior.


THURSDAY: Front to approach with the best chance of strong/severe storms over NW-:Panhandle of Florida toward Jacksonville. Hot up and down the spine of the state with highs in the low-near mid 90Fs. 


Front is forecast to enter Central between the hours of 2pm -8pm.  Interesting evolution in the GFS for several runs for some sort of 5-6pm convective magic along the coast of East Central Florida from near Volusia south to Central Brevard County at different times as the boundary pushes in. 


Most interestingly, the latest GFS has come out with a prefontal boundary to form over East Central Florida as the front itself is much further to the north during the mid-afternoon with a little 500mb cold pool aloft...net result is a good storm(s) to move off the coast of Brevard sometime after 4-5pm as well as  one off Volusia


THURSDAY NIGHT: The front is forecast to wash out over Brevard County then drop into South Florida Friday with virtually all of the dynamics associated with it long gone.  Moisture having pooled ahead of it could still generate some showers and thunder though over far South Florida/Keys at almost anytime on Friday as winds become NE-ENE during the day.


WEEKEND: So far so good for rain freed-ness, although some showers and possible thunder could occur near the Keys on into Saturday.  Moisture returns north to Central by late Monday.

Happy Easter! Strong Lightning Storms Possible West of I-75 in Florida Today

A personalized outlook for stronger lightning and small hail activity for later today over the west side of Florida, with a somewhat enhance threat from near Sarasota to just north of Tampa Bay, although anywhere within the light green bounds on the west side has a chance at seeing lightning today. Further east is where some light, quickly moving rain showers could occur with the East Side mostly clearing out to the north, whereas over South Florida some additional showers could occur.

RECAP: Some light showers occurred during the evening along the East Coast from near Port Canaveral south to Miami with totals less than 1/4" is the swiftly moving showers last night through this morning, although some moments of heavier rain were briefly observed. 


TODAY: While a significant round of severe weather will ensue today over parts of the South Central U.S. from Central Texas east and North into Arkansas/ Oklahoma (to name only a few locations), Florida will enjoy a mostly uneventful Easter Sunday, with breezy conditions along the East Coast (watch the rip current threat) and late afternoon lightning storms along the West Coast.  Temperatures aloft today are quite cool/cold today, with forecast soundings looking a bit unusual where the bulk of the moisture will be concentrated in the mid-levels. Therefore, I would not expect that without a dry layer in that area that strong downburst winds would be an issue, although I am considering the potential for a wet microburst given the drier air closer to the surface through which the hail/rain cooled air could accelerate and spread out at ground level.  Otherwise, winds aloft are weak and steering is almost non-existent, so I'd expect the storms to pretty much die out in nearly in place. Could bring in some bigger rainfall totals though where storms decay over.


Afternoon sea breeze winds along the East Coast could pick up a bit during the late afternoon, so despite the comfortable beach side temperatures and partly cloudy to near clear skies and alluring waters which are now warming into the mid-upper 70Fs, rip currents will be a big threat today.  Meanwhile, expect that the thunderstorms will get going in earnest between the hours of 4-5pm off to the west. Anvil debris from these storms could spread out as far as the East Coast after 6:30 - 7:30pm resulting in a thin high overcast near the coast becoming more dense the further west one goes.  As drawn in, expect most of the big storms today to remain west of I-75 North of Tampa but a bit to the East of I-75 toward Ft Meyers.  I am watching the potential for some stronger activity (although not highlighted) in that area further south should the West Coast Sea-breeze manage to penetrate a bit further east and inland from the coast than currently depicted.


MONDAY: Looks at bit like an instant replay with activity perhaps shifting a little more Eastward by 25 miles or so.  A better chance of rainshowers over all of  South Florida into portions of South Central Florida, but believe the thunder will again be late in the day favoring the west side and portions of the interior of South and South Central Florida.


TUESDAY: High pressure which will be generating the stronger onshore winds along the east coast the past few days now will relax eastward a bit in response to the naughty, nasty severe weather maker further West from the Southern Plains through the Ohio River Valley  (an upper level trough and associated co-hortial atmospheric parameters).  In doing so, the surface flow over Florida will become much more SSE and allow moisture from the old sub-tropical system (91L) to run up the spine and east side of the state of Florida beginning overnight Monday (first  South Florida) into the morning hours. There could be some early morning coastal showers as the moisture works at the coast.  By early-mid afternoon through early evening expecting thunderstorms (isolated) to form over South Central to North Central Florida, favoring interior portions of the East Side of the State from Southern Osceola County north toward West Volusia.  The activity will remain west of I-95, but during the period of sunset hours some of the rain/storm activity could reach the East Coast from Brevard County and South in a much weakened state. Too soon to say for sure, but that has been the going trend in guidance the past 24 hours. In either case, it will likely be a cloudy late afternoon into sunset for the East Coast.


WEDNESDAY: Perhaps a very early predawn/dawn time  east coast shower, but more likely the chance will remain just offshore as the upper level system moves further east into the Mississippi River Valley Basin and portions of the Deep South. Much of Alabama looks to be under the gun for severe storms this day as Florida could dry out for a day most everywhere. Could be a warm one too with lack of a seabreeze from near North Brevard northward due to increasing SW flow ahead of the trough and associated mid-spring cold front.

SOMEBODY WILL GET TO GO OUT AND PLAY WEDNESDAY AFTERNOON, SHE HOPES
Shes laying on the 'sweet looks' hard and heavy!

THURSDAY: Frontal boundary will be pushing through the Panhandle reaching NW Florida and portions of North Central Florida from mid-afternoon through early evening. Thunderstorms (some strong and maybe isolated severe) will be possible along and just ahead of the front, whereas some more isolated late afternoon storms are possible further south along the East Side of the state, mainly north of Lake Okeechobee.  The cold front now appears it will cross into Central Florida during the mid- late night hours, when perhaps a secondary round of storms will be possible (assuming there is even a first one) over a portion of East Central Florida.  As of this morning, believe that any possible chance of severe weather with and before the actual front will be limited to NW Florida and northern portions of North Central Florida.


FRIDAY: Thunderstorm/rain chances just about anytime over portions of South Central and all of South Florida from early morning through afternoon before the front clears the majority if not all of the state by late Friday afternoon. Winds will shift almost immediately behind the boundary to ENE, and lingering moisture might ensure a continued chance of showers of Southern portions of the state .


NEXT WEEKEND: Looks nice. Another frontal boundary could be on the approach early next week. This would be the final system to shut the severe weather ravaged portions of the country down for good for a while...and bring our last chance of rainfall to the state of Florida as well for a while. But this is still way out and beyond the world of reality to make such a determination. South Florida could really use the rain though, with the worst of the drought conditions now existing over that portion of the state.

IT MUST BE EASTER !

Review of Electrified Yesterday NW Florida - Much More Quiet Today

Areas of most active weather on Wednesday. Rainfall of up to 2.20" and numerous reports of pea to 1.00" hail received. Very little in wind reports which is not completely surprising. I've seen nothing written concerning this area of activity, but it looks to qualify as a Mesoscale Convective Complex (MCC). See next image.

In these images above we see that the activity in Florida was not the only weather maker. It was actually one of four other complexes that were ongoing during the late afternoon and early evening. None of these systems moved very much at all during their lifespans except for those over Mississippi and Arkansas. The ones in Texas and Florida were nearly stationary. Lightning in the Florida Complex was just as, if not more so, prolific than the other systems at one point in time. Due to the developmental nature of the system in Florida, this might have been a mesoscale convective complex (MCC) since it did not seem to be related to sea breezes and was mostly focused in the mid-upper levels by colder air and fairly steep mid-level lapse rates. Surface parameters would not have warranted such an active day as was experienced in this area. However, I've seen no mention out of any of the official weather services alluding to this possibility so perhaps the notion is pure conjecture. Either way, it was organized, strong, and never exhibited outflow boundaries on the south end as would be seen with generic summer like thunderstorms.

Now we see the graphic, hand-paint from yesterday's post:

We see the area circled in black. Almost matches the actual area in the images above doesn't it? Note the other areas that were in question at the time this was created. I had added verbiage to include Thunder in SW Florida with  sea-breeze convergence down there. The areas in the Central portions were too dry as peak heating came into play and never recovered. Additionally, the sea breezes never met until dark if ever. The higher dew points never reached much further west from the east coast as is depicted they were located in this image during the afternoon; therefore, there was not an active sea-breeze front. Cold air aloft over NW Florida with a feed of heat from the south kept the system further north alive and well, with the only outflow boundary from the entire complex evident while I watched to occur to the Northwest of the system in the early evening (which prompted a severe warning) and up toward Jacksonville (also severe warning).
No outflow boundaries were ever evident to plunge southward, which might have also been additionally 'causative' to preclude any chance of thunderstorms/showers over Central Florida altogether.

TODAY: Much less active day today appears at first glance to be at hand. Best chance for showers /thunder appears to be near the Tallahassee area to just east of there,so not going to go into any details regarding an other wise pleasant day.


FRIDAY: Could be active again tomorrow in nearly the same area as yesterday. A chance of thunderstorms will exist primarily west of I-95 and north of I-4, with the axis running along I-75 to the Florida Turnpike. Activity could begin over Western or even Central Volusia County as showers and perhaps some thunder and converge with the west coast sea breeze further west during the late afternoon. Colder air aloft could again warrant some big lightning makers. Activity it appears will move off the west coast near Cedar Key only slowly. Slow movers again over the Jungles. The NAM and GFS wildly diverge on this forecast though, with the NAM showing nothing but a rain shower/thunder near Tampa Bay. I'm hedging more toward the GFS solution.


SATURDAY: More model divergence. On this day the NAM favors the Jungle Region down to Sarasota, whereas the GFS shows nothing. I'm favoring the NAM this time. (Note that favoring toward an area of storms everyday somewhere? .  


SUNDAY/BEYOND THRU THURSDAY: Too great of disparity between the ECMWF/GFS/last leg of the NAM. There are indications by the GFS that morning shower activity could begin as soon as Sunday morning along the east coast, translating to thunder over NE Florida into Daytona, NAM shows nothing. 


By Monday/Tuesday time frame moisture from the sub-tropical system north of Puerto Rico is expected to reach Florida in near underhanded fashion Central and North, more directly South Florida/Keys, ahead of an approaching continental frontal system.  Wednesday is depicted to be a showery day everywhere, with thunder focused on East Central Florida (the GFS already has a CAPE bull's-eye over East Brevard during the afternoon.  The front is depicted to cross the peninsula during the afternoon - early evening on Thursday.


Temperatures aloft during this time frame are not forecast to be cold at all, so it looks like generic thunder and showers, but too soon to say for sure. Given that the moisture would originate from the Atlantic, for it to reach the state I'm inclined to believe this would be more of a sub-tropical/near tropical set up, very pre-early-season type scenario, so just exactly how it would manifest over the state is somewhat up in the air to myself.  Most activity on Tuesday would be the South Half of Florida with late day thunder further north.


THURSDAY: Too far out in time for even the official offices to mention, especially considering the great uncertainties involved two days prior. For now, just to throw it out there (and that is all), Thursday per the GFS is a slight risk for Severe Thunderstorms and possible eye toward a tornado threat for North Central and North Florida from Central Brevard -Tampa and North with very cold air aloft as well as many other features we look for in a late winter/early spring set up such as Bulk Shear (stronger winds aloft in layers), combined with some low level thermal instability.  South Florida looks to get in the game too, but I'd leave it a "See Text" for strong, organized storms (if the exact same set up were shown in the GFS, say..tomorrow..they'd probably stick the whole state in a "Slight Risk" though). It does look like something 'organized' could be in the making though. Given the time of year , it is all so very questionable, but the GFS has been consistent with this to occur now for nearly 3 full days of model runs in various forms.

A Strong Popcorn Storm or Two Possible Interior Central Late Afternoon

Initial Guess for a thunderstorm today is shown in the image above. Note all areas are north of the Beach line. Now See Figure 2.

Figure 2: Note the additional area in Dark Green. This area is a little more questionable but of more importance for later this afternoon in regard to stronger storms. Not shown is an slightly better chance to change the area in SW Florida to a Lightning Icon.

RECAP: A few strong storms yesterday, with dangerous lightning (isn't it always?), and a report of nickel sized hail in the Narcoosee area around prime time (6 pm).  Orange and Lake County (after dark) and a portion of Polk seemed to bear the brunt of the active weather, although Okeechobee had a whopper down there too. I could see the overshooting top from way up in Brevard...time lapse would have shown it to go up and collapse within 6 minutes. After that point, I saw radar shortly thereafter and the storm had nearly already dissipated in rapid fashion. A true pulse, strong storm.


Out flow from that storm triggered more activity northward as it road NNW up the east coast sea breeze and while other activity was getting started further north on its own accord. Lightning lingered in Lake County to near Ocala until late in the evening that disappeared quite quickly by 10:30pm. The atmosphere yesterday was quite unstable prior to onset of the storms.


TODAY: Different day altogether today, but it may end up that we'll end up with activity in much the same locations as yesterday as is often the case when steering currents are weak and not much has changed in the synoptic (larger ) scale pattern.  Rainfall from the previous day's rainfall aids in speeding up the atmosphere's instability  above during the trans-evaporation process unless dry air is being advected into the area. Such is the case over South Florida today, not so sure about far SW Florida though in regards to thunder, but I'd think that anything that can generate rain today will also generate lightning. It seems there could be a little bubble of moisture to move in during the late afternoon. The more focused area today though will be further north, at least that's how it looks now as a few models are depicing upper level energy to sweep from East to west across the North Half of the state today.


THIS AFTERNOON: Note the second image. A lot of this area highlighted is based on GUT FEELING...with little to back it up other than 1) unusual cloud lines through late morning along both the intracoastal waterways. Haven't seen that since last summer!  This means that higher dew-points just off shore and higher instability could be there ; 2)  High 70F+ dewpoint air (and CAPE) aligning the coast  (now analyzed as I write) almost on the coast just waiting for the sea breeze to come in.  Therefore, at this time instability is not high at all except for over North Central-North Florida at noon time...and not over South Central Florida, but the air mass further south is very warm (just not as moist/buoyant) . I'm very skeptical about the area South of the Beach Line today but will monitor since if it goes up, it would be the strongest of activity today.


Otherwise, the winds aloft are almost non-existent , so expect storm motion will be dictated by outflow boundaries and/or propagation along the sea breeze/lake breezes...with over-all-encompassing globular mass appeal toward the west slowly toward sunset while anvil debris has a mind of it's own and heads ESE/SE ward.   The east coast from Indian River and Brevard County into Southern Volusia  might again be overrun with high cirrus anvil debris after 5pm into sunset from activity further to the NW-W.


Expect mid-afternoon activity to being  in the first area in the light triangle into Western Volusia...ending by 5pm.


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The second area further south would be from 4:30pm -7:00pm (note I wrote Would or Could) , as would something that might go up over far SW Florida.  Both of these two areas are wild cards though, so keep in mind. Should the second area in dark green go up this afternoon, I believe this is where the strong storms would occur, if they do. Do not expect strong storms further north, but still could be lightning producers (and as such, dangerous).


A good thernal gradient down in this area (South)  might set up should activity further north spread anvils east ward..not affecting the area to the south like the West Half of Osceola County into Okeechobee County (where again a Lake Shadow will aid in moisture convergence). These areas will have all afternoon to heat up.
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 I'm only talking 1 -3 storms that might produce a few wind gusts of 40-48mph and pea-dime hail for a very brief time as they pulse or pop upward into the very cold air aloft still in place.  Showers will be widely dispersed as was the case the past two days due to the overall low atmospheric moisture content.  But at least they won't be competing with each other.


Therefore, more people will not see rain than will in those areas as has been the case the past two days. Keep in mind, these storms could be big lightning makers once again, and are capable of sparking fires when the lightning strikes in rain free areas which has occurred the past two days down in the Glades region along the Lake Okeechobee Shadow.