"But seeing they could not See; hearing they could not Hear"
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"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

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

Tuesday, April 19, 2011

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 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.

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