"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".

Monday, September 5, 2011

Un-Named "Lee" Now a Bigger Threat -"The 'Tropical Connection" Remains, Floridaekend"

Area in Blue Should have an Enhanced Tornado Threat as Old Storm Lee Opens Up a Bit..taking a course as shown in Black. The Official Track from the NHS is shown in White just to the left. Either way, makes little Difference. The area in Green will be prone to Heavy Rain and a Tornado Threat Throughout Today. The chance of Tornadoes today looks higher than yesterday as Lee begins to interact with approaching frontal boundary. Note the DRY AIR behind that front. Also note there is a Lagging Trough into the Gulf with active thunderstorms associated with it. This area could approach Florida beginning Wednesday and Be In Place (at play) over Central Florida by Wednesday/Thursday. The heavy rain area shown could shift around and is not meant to be exclusive of areas 50-100 miles to the east or west of that shown

TROPICS/SUB TROPICAL BLEND CAST: Lee was downgraded, but even so, the system now Un-named as a former storm likely poses MORE of a threat than it did while it was named. Reason being two fold: (1) Entering a more mountainous area with deep moisture and interacting with a frontal boundary/plenty of wind/energy dynamics ..the combination makes for a lethal rain making machine.  (2) The system , now having opened up a bit, will continue to do so through the day, and with that, wind fields will become less unidirectional with height. The area in Blue is the best area for a tornado chance today, but even along the Gulf Coast of Alabama, The Florida Panhandle, and Mississippi, the smaller threat will continue.  I would not be surprised to see the risk area extended further to the east and south a bit later today toward the Jax/St. Augustine area..more likely toward Gainesville...very late...but...

FLORIDA ELSEWHERE: Skies have cleared today as opposed to yesterday. As such, very warm today with highs in the 90Fs everywhere. Thunderstorms most likely almost anywhere Central Florida after mid afternoon through mid-evening. There seems to be a potential for 'enhanced' activity from Brevard County and North along and east of I-95 as instability has been building up offshore Brevard since yesterday. In deed, last night an area of thunderstorms developed well off shore the county and persisted for nearly 5-6 hours. This CAPE (instability) has increased even over night.  Thermal profiles for lapse rates (changes in temperature with height in certain levels between two altitudes) aren't all so great. but moisture is high...and sufficient. Do not expect wide spread activity at any one time..but they could line up and move on through inland areas any time after 2-3pm, perhaps a bit earlier further south. The only area that does not look all so great for storms is far South Florida (Dade/Southern Monroe). Most of this activity might only be is too early in the day to say for sure, but that currently appears to be the more prevalent mode except for near the east coast and interior. 

BEYOND: Tuesday looks similar as the remnant low moves slowly toward the ENE-NE toward the Southern Appalachians and weakens. Moisture and some dynamics might remain for part of the day..but the rains will continue for quite some time as it by then will be interacting fully with the approaching cold frontal boundary.  This moisture/front combination will stretch further north and east toward the NE states. Thus, more rains for the Appalachians of the Deep South and Mid-Atlantic, with run off of creeks, rivers, streams running into the lower land areas. Downstream communities should be on high alert for Flash Flooding.

For Florida, Tuesday looks like a variant of today, with perhaps a tornado threat emerging toward the NW Coast as the lagging boundary approaches the west coast. A tornado watch MIGHT be needed for an area around Brooskville/Cedar Key/Gainesville/ and maybe toward Ocala and west to far NW Volusia and western Flagler County late.  Areas further south might actually dry out just a bit, with a dry slot of air possibly remaining just ahead of that trough..this will have to be re-evaluated on this day. The trend has been for that dry slot to fill in with moisture a bit with time.

WEDNESDAY/THURSDAY: Potentially interesting day for Central Florida. The latest model forecasts are showing CAPE/CIN fields VERY similar to that which appeared when Squall Lines went through Florida in the late winter and early spring. With perhaps a very shallow sea breeze along the east coast of South Central to Central, these storms if this scenario unfolds could be very 'active' in some form. TBD on Wednesday/Thursday.  

BEYOND: The tropical connection continues as of Lee's Demise across the state. The trough so far is not forecast to get beyond Brevard as far as Southern Passage...not for a long time. Recent trends have shown it not to get quite as far south...never barely clearing Volusia before retrograding and weakening by  Friday and through the weekend.  

It is interesting that in the meantime that same boundary will extend the entire way to the Bay of Campeche.

Tropical Development is again anticipated along that boundary anywhere between that location toward the north side of the Yucatan. This activity will likely interact with the decaying boundary for a time..and if it becomes more organized and closes off, then rain chances would go down for a time. However, the trend has been for this 'low' to cross Florida going into the weekend later on down the line, but never getting very far beyond the state. This in turn sets the stage for further development. Bear in mind, that while this is all going on over and near the state and the Gulf, another tropical entity will be on the approach from the western Atlantic and/or the central Caribbean.  Thus, for the rest of the month (or at least the next 3 weeks), watching the Caribbean/Southern and Eastern Gulf/and SW Atlantic for future storm formation.

Katia is now the best looking storm of the season, but it appears will hold very little U.S. threat. Even the outliers like the Navy NOGAPS has trended the system just far enough off the coast than to be nothing more than a marine and near shore/rip-current interest.

1 comment:

Jason Weingart said...

Thank you Stephen. Very upfront, easy to understand, and informing as always.