"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"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 26, 2011

Numerous Showers and Isolated Thunder Possible Today from Noon through 9pm

TUTT low continues east of the Bahamas with a high to its north. This blocking pattern is one factor that is preventing the low over N. Illinois from moving through the past few days until  at least the first 1/2 of Wednesday. Weak boundary from the Gulf to the panhandle is washing out this morning. Cold front/trough over Ohio Valley will press east to the north but its southern tail end will only sag south slowly with time.

SYNOPSIS: Upper low remains in place as expected awaiting a 'kicker'. Blocking pattern over the western Atlantic continues to stagnate the upper level pattern from progressing. More active stormy areas over the Ohio and Mississippi River Valleys in a few areas today, while Florida and the East coast to North Carolina continue to bathe in a high moisture content atmosphere. This same pattern, with a little drying in the atmosphere will continue on Tuesday with much less activity, although isolated storms are still possible over Florida.

TODAY: Latest SPC MesoAnal shows surface vorticity running up and near the SE coast and  the Gulf Stream. Flow aloft at the steering level remains weak, but latest KSC sounding and area profiles show a steady SSE-S Flow at 10-18kts from 2000 - 7000ft running up the east coast...nearly parallel to the coast to just a bit of an offshore component north of Ft Pierce. Otherwise, abumdant cloud cover exists across the South Half of the state under divergent flow aloft at the jet stream level. Abundant moisture and moderately unstable mid-level air might serve to continue cloud cover over the southern 1/3 to 1/2 of the state as opposed to rain/storms with some heating, OR..heating might serve to break the cloud cover up. However, thunderstorm activity along the SW coast is spreading anvil debris across the region south of Lake Okeechobee, so thunder might be hard to come by in that area except toward the East Coast where it will be last to arrive. Either way, convergence near the coast in SE Florida could generate some good rainfall totals. That area is also first to become less inundated with convective inhibition as seems to always be the case, but the remainder of the state should follow suit by 11am to noon. The least cloud cover will be north of the Beach line toward Sarasota and up toward Jax.

Sea breezes might be a bit delayed due to the cloud cover, but are more definitely expected by 2 pm from the SSE or nearly 'upriver', with winds just above that level almost due south and weak steering above that under divergent flow aloft. The atmosohere will become most unstable where there is less cloud cover, namely from Brevard County and west toward Sarasota and north toward Ocala/Jax/Gainesville.

Showers could form along the Treasure Coast, and if the pattern which was set in place very late yesterday holds, which seems to be the case this morning, activity could move right up the intracoastal to just offshore into Brevard County and the interior.

Once the sea breeze is more solidly set, the stronger storms should end up north of the Beachline along convergence of that wind with the prevalent South wind just above the surface along and west of US1 and amass in the most unstable atmosphere over North Central toward NE Florida, with strongest storms toward Ocala/Gainesville/Jax areas with other storms closer to the coast of Flagler and Central to northern Volusia Counties later in the day toward 5-6pm and beyond.  All of the above might be able to occur regardless of cloud cover. That will be 'the bugger' for today regarding coverage amount, location, and intensity, but still believe it will be the northern more areas with the stronger storms.

Further south toward Central, other most isolated storms west of US1 or I-95 could also develop late, after 4-5pm with the sea breeze merger and be advected and propagated toward the NNE. Showers and thunder might be able to generate late as well toward South Florida given there might be time for this area to clear out, assuming the activity along the SW coast dies out and allows some clearing, although by later this area might be either completely worked over or too cloudy for storms to generate. 


TUESDAY/THURSDAY: It appears as of early this morning that moisture will begin to wane on Tuesday, but only to the degree to limit extensive cloud coverage but not enough to prevent rain and storm formation. There might be a brief 'drying out' period across Central on Tuesday, but as we work toward the Wednesday through Friday time frame that secondary frontal boundary, albeit washed out, will move into Central Florida where it is then possible it will wash out during Friday toward South Florida by Friday. During this time, sea breeze convergence and much colder upper level temperatures could result in more isolated but stonger thunderstorms, most likely somewhere across Central portions. This is a new outcome portrayed by the 2AM run of the GFS, of which reliability out toward Thursday starts to become more uncertain, but is worth monitoring.

No comments: