Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 121504
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1104 AM EDT Wed Jun 12 2013
The 13 UTC regional surface analysis showed an area of high
pressure across much of the Gulf Coast, and a weak trough from the
GA coast through the FL Big Bend. Vapor imagery and upper air data
showed very dry air above 700mb, as our forecast area remains
under the dry, sinking northwest flow under the eastern periphery
of the central CONUS ridge.
The relatively warm, dry air aloft and large scale subsidence will
make it difficult for significant cumulus growth today, and the
MOS consensus PoP and Convection Allowing Models (CAM) PoP are 20%
or less for this afternoon. However, as was the case 24 hours ago,
the HRRR and 11 UTC local WRF are much more bullish in developing
deep moist convection. We`re discounting the local WRF, as its
boundary conditions (from the RAP) resulted in unrealistically high
surface moisture (i.e. dewpoints of around 80 deg). The HRRR, on
the other hand, did an outstanding job yesterday, so we have
subjectively blended in its solution with the other, drier NWP
guidance. The resulting PoP is nearly identical to what we had
yesterday, 20-30% from I-10 to the coast. While most updrafts
struggled to get any depth yesterday, a few storms did manage to
develop impressive hail cores. We think that will be case today,
as some of the CAM solutions have updraft speeds exceeding 20 m/s.
Of course the limited cloud cover will result in above-average
temperatures, with highs in the mid to upper 90s. Deep vertical
mixing will allow surface moisture to decrease a bit this
afternoon, so maximum heat index values will be around 105 deg.
.AVIATION [through 12 UTC Thursday]...
Prevailing VFR conditions are expected through this TAF cycle.
Widely scattered TSRA will develop between 18 UTC and 00 UTC,
mainly between I-10 and the coast. Thus there is a slight chance
of TSRA at KTLH and KECP.
After the recent heavy rainfall across the area, two river points
are at or expected to reach Action Stage. The Ochlockonee River near
Thomasville is at Action stage, and will crest early Friday morning
then start to recede. The Little River near Hahira is expected to
reach Action Stage early Monday morning. With little precipitation
expected over the next couple of days, impacts to area rivers will
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 95 72 96 74 / 20 10 20 20
Panama City 90 76 91 78 / 30 10 20 20
Dothan 97 74 99 74 / 10 10 10 20
Albany 97 74 99 74 / 10 20 10 30
Valdosta 97 72 99 73 / 10 10 20 30
Cross City 93 72 93 74 / 20 10 20 10
Apalachicola 89 75 89 77 / 30 10 10 10
REST OF DISCUSSION...Fournier