"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, June 28, 2010

Greater Storm Coverage Again Today

What a change a few days can bring. That has been the case the past two days and this trend will ever so slowly continue as a number of unrelated features attempt to come together in a somewhat ambiguous, if not questionnable, fashion during the next 48-96 hours.

To start the day its seemingly no different than any other normal summer day across the area. I noticed a few scrappy attempts at cumuliform development as early as 8am this morning and although they seem to be dissipating already at this time it is still a sign of things to come (like yesterday) as we work into the afternoon hours. Latest KSC sounding indicates that moisture in the upper levels of the atmosphere has increased quite a bit and temperatures at this level have dropped a degree or two. That's a good thing. On the other hand, at the mid levels is where the greatest drying has occurred in parallel with a slight warming at that level, which is not a good thing (as for as precipitation prospects are concerned). Otherwise, the infamous ridge axis remains parked across Central Florida in general, just a tad further to the north at the surface but more directly overhead to just a tad further south aloft.

Elsewhere, but of possible significance to our local environment in the upcoming 48-72 hours, is what is happening in other regions far from home. Three things stand out right away. (1) Of course, there's TS Alex..(2) then the cold front and associated upper level trough just now beginning a dig from Canada which in the near future will impact the east coast in various ways from New York to at least Central Florida.. (3) and finally another item I had inadvertently failed to mention yesterday is a TUTT low east of the Bahamas which has been circulating out that way for a number of days now and has been slowly creeping just north of due west. It's fun to watch on satellite and water vapor loops but has little active weather associated with it.

Keeping those items in mind we can briefly shift gears to the local area and today's weather makers. As noted earlier, the morning XMR sounding was warmer and driest in the mid-levels. This indicates to me that earlier day convection will essentially be held at bay to nearly non-existent. Steering winds at this level are nil...that is until we get up to the 20,000 to 25,000 foot level where they are about 10 kts from the west. PWAT values throughout the column are about the same as yesterday...but as noted earlier most of this is found either very close to the surface or way up there in the heavens.

There really is no reason why thunderstorms cannot once again erupt by mid-afternoon once sea breeze and lake breezes boundaries begin to interact under a generally light SSE surface flow regime. Like yesterday, storms will erupt along or just west of I-95 and move little to none. About the only difference I see the potential for today from yesterday is that the east coast could see some storms anywhere from Daytona Beach north to JAX under a weak west to east steering flow...but as one works further south toward Brevard areas east of I-95 will be hard pressed to see the wet stuff since any steering currents that exist (or will exist) will essentially be from south toward the north for any convection that gets going in earnest. Since the atmosphere is very moist very high aloft, expect that the storm tops (anvil blow-off) will hold together and spread toward the east and over the coastal communities. This means that by late afternoon into the early evening many of the beach side cities will be under a cirrus umbrella with a dark look to the sky as one looks least this would put a damper on uncomfortably hot late afternoon temperatures when combined with the sea breeze. Any storm(s) that get going well enough to make a serious punch through the mid-levels could produce some small hail or close to severe wind gusts as they collapse, but for now it appears that any such storm will only manifest itself along I-4 in the interior away from either coast...not discounting the DAB reporting station however.

Expect to see other storm activity, although maybe not quite as potentially vigorous across interior Osceola County, almost anywhere in Orange County and Seminole, then further east and north the closer to Daytona one gets.

As we progress through tomorrow and into Wednesday things become even more interesting with regards to storm coverage / location potentials. It still appears that the trough along the U.S. east coast will dig at least as far south as the Deep fact the evening GFS run was even more vigorous than any run yet over the past 4 days! Whether that comes to fruition in quite that fashion of aggressiveness or not, the combination of "a trough of sorts" along with that 'passive' TUTT low east of the Bahamas will at least erode the ridge at the upper levels that has loomed overhead almost entirely by Wednesday. This is important in that this would result in the upper level temperatures to cool by at least a few more degrees resulting in an unstable environment juiced enough to induce storms with a greater punch and lasting power...and with an increased number of them other than just the one or two Central Florida has seen the past several days. The GFS is STILL continuing to form at least a closed low circulation along the Florida-Georgia border by Saturday then strengthening that low as it moves off the southeast U.S. coast. Circulation behind this low in combination with high pressure building south along the Appalachian Chain pushes the trailing wind shift line (frontal boundary) through Central Florida by early NEXT week. Although the GFS has followed this train of thought for several days now...just as aggressively as ever...the timing of all these factors to come together has been pushed out be nearly 48 hours since it initially portrayed these implications.

The low down if we look at the very broad, unfinished picture is that storm coverage will increase most notably across all of Central Florida by Wednesday through Friday...there is no indication that the area from Brevard County and points south will see a strong push for storms to assuredly penetrate eastward right to the coast at that time...but on the other hand these are no pointers out there stating this couldn't happen either. That will be contingent more on daily if not hourly localized circumstances which can be fine tuned as we get closer to that time frame.

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