Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 191406
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1006 AM EDT Tue Aug 19 2014
...Isolated Severe Storms Possible This Afternoon and Evening...
.Near Term [Through Today]...
The morning analysis depicts an upper level shortwave moving
east-southeast through northern Alabama currently with the axis
stretching southwestward back to east-central Mississippi. The low
level airmass across the area is very soupy this morning with
dewpoints hitting the 80 degree mark around Marianna and far
southern Georgia. Modifying the 12z KTAE sounding for an afternoon
T/Td of 95/70 yields SBCAPE values around 2800 j/kg. There is
some mid-level dry air present in the sounding so expect dewpoints
to mix out some this afternoon and drop from the very high values
this morning. Taking a peek farther to the west where the air will
be advecting from this afternoon, the 12z New Orleans sounding is
pretty impressive with steeper mid-level lapse rates and strong
instability. Given the presence of the upper level shortwave
passing near the area this afternoon, expect storms to ignite this
afternoon and the potential is there for some of them to become
severe with damaging wind being the main threat. In fact, the 06z
NAM depicts 850 mb winds of 30-35 knots across our northern
counties this afternoon which is unusually high for August. Our
locally run CAM ensemble utilizing 8 members is also on the
bullish side with the severe weather threat this afternoon. Given
all of this information along with the SPC outlook showing some
severe probabilities across the area, went ahead and added an
explicit mention of severe storms to the point and click forecast
across most areas except for the southeast big bend for this
The previous forecast already went with the higher guidance in
terms of PoPs for this afternoon, so no significant changes were
[Through 12Z Wednesday] Look for another active day with numerous
showers and thunderstorms by this afternoon. A few of the storms
could be strong to severe with most of the impacts occurring
sometime between 18z-00z.
.Prev Discussion [321 AM EDT]...
.Short Term [Tonight Through Thursday]...
Mid-level heights will be on the rise for Wednesday and Thursday
as the eastern U.S. trough slides offshore and a ridge builds over
the Central Gulf Coast. As the low/mid-level ridge builds west of
the forecast area, the low-level flow will become west-
northwesterly for Wednesday and northerly for Thursday. With
weakening upper support and less favorable flow for seabreeze
convection, expect decreasing PoPs through Thursday, especially for
The building ridge will also lead to some hot temperatures. Expect
highs to reach the mid 90s on Wednesday, with upper 90s to near
100 degrees possible on Thursday. Heat indices may rise above 105
in a few areas by Thursday.
.Long Term [Thursday Night Through Tuesday]...
An upper level ridge is expected to build northward from the Gulf
across the southeast states through the period. With deep layer
ridging acting to suppress afternoon convection, PoPs are forecast
to be slightly below average through the period with temperatures
above average. The main driver for convection will be the sea
breeze with isolated to scattered coverage expected.
Light to moderate west-southwest flow will continue through
Wednesday before high pressure builds over the waters and winds
and seas diminish through the end of the week. Conditions are
forecast to remain below headline criteria through the period.
Normal summer conditions through the week will mean plentiful
moisture, preventing red flag criteria from being met.
Significant flooding is not expected over the next several days.
.Preliminary Point Temps/PoPs...
Tallahassee 95 75 96 75 99 / 60 30 40 20 30
Panama City 94 78 93 78 93 / 50 20 30 20 30
Dothan 94 74 95 74 98 / 70 30 30 30 10
Albany 95 73 97 75 99 / 70 30 30 20 10
Valdosta 96 73 96 74 98 / 70 30 30 20 20
Cross City 94 75 94 74 96 / 20 10 40 20 20
Apalachicola 92 77 93 76 93 / 50 10 30 10 20