Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 151427
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1027 AM EDT Tue Jul 15 2014
.Near Term [Through Today]...
A fairly active day of convection is expected with a tropical
airmass in place and a cold front approaching. Modifying the 12z
KTAE sounding for the 14z observed T/Td at the airport already
shows SBCAPE values near 3000 j/kg, and this is in close agreement
with the SPC mesoanalysis. Expect to see a few stronger storms
with gusty winds this afternoon, and an isolated severe storm or
two remains possible. The only changes to the previous forecast
were to add a mention of gusty winds and to tweak PoPs slightly to
account for the latest radar trends and add some temporal detail.
Expect one batch of storms to move along the coast and across the
Florida zones through the early to mid afternoon, and then a
second batch to develop closer to the front and affect southeast
Alabama and southwest Georgia later this afternoon. This is in
agreement with the CAM Ensemble.
[Through 12z Wednesday] The coverage of rain and storms should be
high today with most of the terminals likely to be affected. MVFR
CIGS and IFR VIS and gusty winds will be possible with
thunderstorms. After 07z, areas of MVFR CIGS/VSBYS are expected
especially where residual moisture lingers due to Tuesday`s rain.
.Prev Discussion [608 AM EDT]...
.Short Term [Tonight Through Thursday]...
The approaching cold front will continue to cross our area through
Thursday. Tonight, model MLCAPE values will still be in the
2000-2500 J/kg range for the early hours of the evening, keeping a
potential threat for damaging winds through midnight, when
instability will decrease. By Wednesday, the front is expected to
bisect the area roughly from ECP to FZG, keeping chances for
thunderstorms highest south and east of this line. With 1500-2000
J/kg MLCAPE Wednesday, there will still be chances for damaging
winds with these storms, although less so than today/tonight. The
front will continue its eastward progression Wednesday night and
is forecast to lie roughly from CTY to JAX on Thursday, giving the
southeastern Big Bend the highest chances for storms on Thursday.
Highs will be in the low 90s Wednesday and Thursday. Lows tonight
will be in the low 70s. With some of the cooler air working its
way into the area by Wednesday night, lows will be in the mid 60s
in SE AL, upper 60s to around 70 elsewhere.
.Long Term [Thursday Night Through Tuesday]...
The frontal boundary will stall over the southeastern Big Bend by
early Thursday as the upper trough weakens and the axis lifts
northeast. With drier air in place, expect only isolated
thunderstorms for most of the region. Moisture will begin to
increase once again on Friday as a shortwave trough approaches
from the west. This feature will help to enhance convection by
early Saturday through the weekend.
Westerly winds will peak around 15 knots during a cold front passage
Tuesday through Wednesday night, approaching cautionary conditions.
After the frontal passage late Wednesday night, winds will weaken
and remain below headline criteria through the rest of the period.
Red flag conditions are not expected thru the work week with
relative humidity values above critical levels.
Widespread rain is expected today, and some of it may be heavy. The
greatest potential for heavy rain appears to be in South AL & GA,
where a few of the Convection Allowing Models forecast rainfall
amounts to exceed local Flash Flood Guidance. Sometimes these values
tend to be too high, but this will be monitored as several of these
models forecast at least 3 inches of rain in this general area. As
for the effect on local rivers- everything will depend on whether or
not this rain occurs right over one of the basins or not.
.Preliminary Point Temps/PoPs...
Tallahassee 89 73 90 69 94 / 80 40 30 10 10
Panama City 88 75 89 73 89 / 80 40 30 10 10
Dothan 90 70 90 66 90 / 80 50 20 10 10
Albany 90 71 90 66 92 / 80 50 20 10 10
Valdosta 91 71 90 68 93 / 80 40 30 10 10
Cross City 91 73 87 70 92 / 60 50 50 20 20
Apalachicola 87 76 89 73 89 / 80 40 30 10 10