"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 28, 2011

Continued Cloudy With Rain Chance Today/Tonight

Image shows Depression Rina near the NE Tip of the Yucatan, which looks less than a depression this hour. The heavier rain and some thunder is well to the NNE of what was Rita. It looks more like that is what is left of the upper portions of Rita is this activity further north with only a surface circulation left behind further south. More on Rita below.
Otherwise, cold front is moving through the NW Gulf of Mexico. Area of inverted low pressure in the Central Gulf ahead of the front where sea surface temperatures are warmest with a tiny circulation on the north end well south of Mobile, AL.

TODAY: Considerable cloudiness across the peninsula especially all central portions, less so South Florida. The upper level portion of Rita has detached (or de-coupled) from the surface circulation and based on some of the 'other' tracking models, will cross Central or South Central tonight if it gets that far. Area of convection in the Gulf is occurring over the warmest Gulf waters in an area of better low level convergence..with Deep Layer Mean winds aloft steering the cloud tops across the Florida Peninsula into an area of upper level divergence. This activity has been slowly crawly  north and eastward, but not sure how long this will last before reaching land..but I suspect it will cease tonight. Otherwise, temperatures are in the mid-80Fs over South FLorida with mainly mid-upper 70Fs elsewhere.

Taking the optimistic 'less rain' slant today based on trends and disregarding all of the models as far as rain fields goes. Overall, South Florida is the most unstable from near Port Charolette to West Palm and South for storms. However, lapse rates in this area are horrible (some warmer air aloft) as well as a dry mid-layer region per the MIA sounding with no apparent triggers to set storms off. If that aspect of the atmosphere down in this region changes, thunder could easily occur. BUT, high clouds from the Gulf could stabilize the atmosphere here, so my line of thinking is that although thunder is possible here, it might not occur. Latest Meso analysis on the SPC website definitely would give cause to reason at least the chance though if it is correct.  

Rina is the lavender "L". Note the convergence is all to the north of the circulation shown by those light blue lines. This is where storms have been going up. All the divergence is over Florida though..perfect ingredients over the state for cirrus clouds. Rina has nothing going for it now, and would expect it will be close to gone by tonight unless it races toward the SSE, but even so, it still has a loft of upper level shear to contend with, so not expecting a rebirth.

Elsewhere, convective inhibition and a stable environment will yield mainly only elevated light rain fall in patches.  Note the area of low pressure in the Gulf. This will be forced eastward and become involved with the actual cold frontal boundary tonight which will press  across the Panhandle and into Central Florida by late morning on Saturday. Thus, at least a chance of rain remains across Central where the most northern extent of the deeper moisture managed to advect.  Best chance of rain between 6pm toinght through noon Saturday seems to be in the area in Green shown in the first  image (although, it might need to another 50 miles further north on the north side),  rain eneding from north to south from sunrise to noon,  reaching South Central portions solely by early afternoon. Rainfall tapering off the further south the front goes after 4pm, with the actual front clearing South Florida shortly after sunset Saturday.

Behind the front, temperatures will be in the mid-upper 60Fs for lows (cooler west of I-95), with highs in the 70Fs. Might not be much clearing over South Florida on Sunday, with a much better chance from Brevard County and north, although some strato cumulus clouds could advect in along the coast accompanied by some alto-cumulus along with breezy N-NNE winds by Sunday afternoon.

Sunday night, the next system in the gravy train of impulses will bottom out well north of the state, with the Southern Branch jet still across Central Florida. Net result will be to buckle north the low level flow bringing a return to moisture as far north as a line running from North Volusia toward Brooksville, with the deeper moisture running South of I-4 in Volusia to the north side of Orlando and toward North Tampa Bay.

It appears the best chance of rain with this moisture surge will be along a line running along the Beach line, through Orlando and on  to Tampa Bay because by this time upper level temperatures will have cooled with passage of the earlier cold front (the upper level heights will have lowered), yet surface temperatures will remain relatively warm. Moderate mid-level lift could induce some moderate rainfall here with some rumbles once the moisture works north and under the cooler air aloft toward sunset Sunday night through mid-afternoon Monday. Another impulse to the north will push this region southward but rain chances should decrease toward Lake Okeechobee due to continued warmer air aloft in this area.

BEYOND: N-NNE winds and breezy Monday becoming more NE-ENE Tuesday into Wednesday. Cooler inland temperatures in the 50Fs, but closer to the mid-upper 60Fs closer to the coast. Afternoon highs in the 70Fs possibly warming to the lower 80Fs late week. Mostly clear mornings with near shore stratocumulus clouds advecting into the coast at times, most likely by Wednesday morning through Thursday night. Perhaps a coastal sprinkle toward Thursday.

NEXT FRONT appears on the backdoor near next Friday. With the wind shift ahead of that boundary rain chances end as the front goes through dry..maybe yet another front after this one as well two days later, which goes through 'dry' as well. No big temperature departures with these fronts, as the Southern Branch jet which will merge with the northern branch at times..both remaining over far North Florida and Georgia.  Continued re-enforcing cold shots though in the NE states with some snows tomorrow then followed by cold rain later in the week, followed by more cold. Looks very negative NAO (North Atlantic Oscillation), being counter-acted by strong La Nina.        

No comments: