Area Forecast Discussion
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FXUS62 KTAE 201900

Area Forecast Discussion
National Weather Service Tallahassee FL
300 PM EDT Tue Apr 20 2021

.NEAR TERM [Tonight Through Wednesday]...

Mid-level clouds and lingering sprinkles are beginning to move out
this afternoon, as the responsible shortwave exits the region. The
remainder of the evening and overnight period will be benign ahead
of a dry cold front on Wednesday. This front will cross the area
during the morning hours, followed by increased northwesterly winds.
No precip is expected with the front, but cooler high temperatures
are expected across the northwestern half of the area, where the
front will cross earlier in the day.

.SHORT TERM [Wednesday Night Through Thursday Night]...

In the wake of Wednesday`s cold frontal passage, a 1024 hPa high
pressure system will build into the region. Clear and dry weather
is expected. Low temperatures Thursday and Friday morning`s will
be in the 40s away from the gulf coast, with highs on Thursday in
the low to mid-70s. Daily averages several degrees below normal.

.LONG TERM [Friday Through Tuesday]...
The main concern continues to be the potential for severe weather
Friday Night through Saturday Night. Prior to that, fair weather
is expected on Friday as 1024 hPa high pressure moves off the mid-
Atlantic coast. A mid-level trough ejects out of the plains into
the Ohio Valley this weekend. The ECMWF and its ensemble continue
to be more robust with this system, while the GFS and GEFS are
weaker, and also place more emphasis on the development of a wave
of low pressure along the cold front, slowing its progress thru
our region. This forecast package leaned more toward the ECMWF.

There is increasing potential for at least one round of severe
weather Friday Night through Saturday Night. A warm front is
progged to lift northeast through the area late Friday Night/Sat
Morning. Ensemble means indicate instability rapidly increasing
with this feature as a 40+ knot low-level jet advects mid-60s
dew points northward. Meanwhile, bulk shear (0-6 km) is 50+ kts.
There is a favorable interface of instability and clock-wise
low-level hodographs near this boundary, with the potential for
discrete supercells to develop, which may be capable of a brief
tornado, damaging winds, and hail. There is lower confidence in
this first potential round of severe weather occuring (depends
on where the warm front/activity sets up). The next potential
round of severe weather would be associated with the pre-frontal
trough/cold front on Saturday into early Saturday Night, and
there is greater confidence in this. The pattern is favorable
for a squall line (QLCS) and the intersection of parameters
would also be favorable for damaging winds and brief spin-ups
along the line. Stay tuned to the latest developments as we draw
nearer to this potential severe weather event over the weekend.

There is uncertainty on Sunday`s forecast, which is dependent
on how quickly the front exits the region. For now, we show dry
weather, which is expected to continue through Tuesday. Daily
average temperatures are expected to be above normal through
the period.


[Through 18Z Wednesday]

Lingering sprinkles and mid-level cloudiness should diminish by
late in the afternoon. A dry cold front will push across the
region Wednesday morning, followed by gusty northwesterly winds.
Otherwise, VFR conditions are expected to prevail through the
forecast period.



Elevated winds and seas returning Wednesday and continuing into
the weekend. A period of 15 to 20 knot winds is likely with a dry
cold frontal passage Wednesday afternoon into Thursday. Another
cold frontal passage this weekend will likely lead to advisory
level conditions and may sweep a line of strong thunderstorms
across the waters.



Light winds and mostly cloudy skies will persist through the
afternoon into the overnight hours. Northwesterly winds will
increase Wednesday morning in the wake of a cold front. The stronger
winds and elevated mixing heights will lead to very high dispersion
values from late in the morning through the afternoon. Humidity
values will drop into the lower to mid 30s on Wednesday.



Most local rivers are steady or falling. Drier weather is expected
through Friday. The next system will move in Friday night. Forecast
rainfall totals over the next seven days are 0.5 to 2.00 inches with
the highest totals forecast for the Florida Panhandle, Southeast
Alabama and Southwest Georgia.



Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur (while following all local, state, and CDC guidelines) by
calling the office or tweeting us @NWSTallahassee.



Tallahassee   79  56  81  45  72 /  20   0   0   0   0
Panama City   77  60  77  47  72 /  20   0   0   0   0
Dothan        78  52  73  42  70 /  10   0   0   0   0
Albany        81  54  79  41  71 /  10   0   0   0   0
Valdosta      78  56  80  44  71 /  20  10   0   0   0
Cross City    79  58  81  46  75 /  30  10   0   0   0
Apalachicola  76  60  77  48  70 /  20   0   0   0   0




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