"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".

Friday, October 14, 2011

Skies Clear Sky Most of Florida, But Forecast Remains Murky

Thursday Late Afternoon. A Storm moved up the A1A Corridor from near Patrick AFB to the tip of the Cape, buidling northward along what appeared to be a weak sea breeze boundary combined with a forward flanking line of towering clouds and a separate updraft. The area in the center is what remains of a gust front that was absorbed by the newer updraft. To the left of this low cloud 'blob' is what appeared to be a shear funnel, not created by rotation within any part of the storm but by conflicted stirring behind the gust front and ahead of the heavy rain shaft's (barely visible to the left in this image) ouflow.

TODAY: Cold front moved through dead central sometime between 530AM-6:30AM, but it is not exactly clear. Based on a thin line of lower clouds it might have been closer to 8:00AM. These clouds seem to be more closely associated with the frontal trough at 925mb (2000 ft) rather than at the surface...and that is lagging ever so slightly behind. The mid and upper level troughs are even further behind. The prefrontal trough of yesterday over North Florida now traces the northern part of the Florida Straits.

8:15AM and estimated front position or zone. The boundary is now stretching from Fort Pierce to Port Charolette. Note the higher clouds over South Florida. They could be in an out of these clouds the remainder of the day, with some lower clouds over the Keys at this time. As of last hour they seemed to be thinning out a bit.

Little fanfare with the front except blue sky, ever so slightly drier air, and a wind shift which could be considered something to celebrate for those north of the front. Temperatures tonight are not expected to make much of a drop, and folks at the beaches might not be able to even tell the front went through by morning, if ever other than that there is no chance of rain.

The front is expected to make it as far south as the current position of the pre-frontal trough along the Florida Straits where it will remain through the first half of Saturday at least.

SATURDAY: Very pleasant Day for most of the state, but high clouds could move in for much of the peninsula. This will be about the only driving factor to make the weekend less than perfect. South Florida could have the most cloud cover, way South Florida. The Keys areas seems most likely to get in on the rain chances through Saturday and early Sunday, with the slight chance working slowly north with time as the frontal boundary relaxes, nearly washing out, and lifts back north uniformly across an even latitude .

SUNDAY: Looks very similar to Saturday with the ever present chance of High Clouds but otherwise pleasant with an ENE-NE breeze at the beaches shortly after sunrise.

MONDAY: Boundary slowly working north now, with a rain chance emerging along with it. It is a bit hard to say whether high clouds would reduce that chance, but in consistency with the matching GFS and NAM this far out in time, it could rain near the coast as far north as Sebastian Inlet prior to sunset and further north toward Southern Volusia by sunrise Tuesday. The remainder of the state is in on the rain chances by day's end as another frontal boundary approaches.

BEYOND TUESDAY: Here's where we enter the murky waters in the forecast from how I see it. Models are fairly similar but there are some differences that are significant. Based on the GFS and somewhat the ECMWF, tropical moisture will be drawn northward and across all of the state ahead of the next front.

The latest GFS is showing a potential rain event setting up toward Apalachicola (the Big Bend), but other heavy rain areas could amount almost anywhere working toward Wednesday/Thursday time frame, while other areas could be bone dry.

The big question comes: What will happen with this front? The GFS has more often than not had the surface front clear to the Florida straits, but leaves the mid-level trough behind across Dead Central which sets up for an isentropic lifting mini-rain event across Central. The GFS has been most consistent with having this mid level trough hang up across is what happens below that level that will make the difference of when/where/how any potential rain event can or will occur heading toward the end of next week. On the other hand, the last 2 of 4 runs has hand the front blast through with a quick burst of the coldest air this fall season, but it only lasts 18 hours. This looks very suspicious. Models over played this cold front of today, so I'm inclined to think they are over playing the next one as well.

Either way, there could be a slippery, wet road ahead for almost anywhere in the state between next Tuesday through the following Tuesday.

TROPICS: So far, only the NAM is showing any significant tropical development. It has been going a bit 'over board' in the tropical development realm all season beyond 24-36 hours, so disregarding for now.

But there is a part of it that may need closer consideration. If the low pressure area over and near the Yucatan Peninsula expands as shown by this model (but does not organize a concentrated center), this would be the impetus to prevent the next front mid next week from cleanly clearing the state at all levels of the atmosphere. 

 The other option per the latest ECMWF is that much of this area of low pressure is ejected northward ahead of the next front, soaking the Big Bend and likely putting a big 'squash' on any chance of tropical development in this area toward the Yucatan for quite some time to come. It would also mean a big reduction in the rain chances heading toward next weekend. Based on a loosely consistent GFS, I'm more prone to side with its trend, and to ignore any big chance of a substantially long term ,drying frontal passage in the later portions of next week.

Much to be determined still and to be on alert for. Either way, the GFS is now showing rainfall totals up to 9" inches once again, only in a different location than the event of late last week, with other areas across the state varying from 1" to as much as 6" over a one week period. If there is one thing we can learn, if it is showing 9" somewhere (and within 72 hours no less) , chances are it could be much more than that. Or, there could be a major 'event' to unfold, the origins of which or why remaining unknown. 

 It is interesting that the model run of last night showed a low pressure bubble just off the Space Coast in 192 hours, that looked identical to the event of last Sunday evening, but with much less wind/impacts.  In other words, we could be dealing with a mid-level trough, resulting in sub-tropical parameters mixed with completely non-tropical factors resulting in rains wide spread for quite some time...or, we could be looking at a big cold down.  

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