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Area Forecast Discussion
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439
FXUS62 KTAE 191848
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
248 PM EDT Sun May 19 2013

.NEAR TERM [Remainder of this afternoon and tonight]...
-- Changed Discussion --
The 16 UTC regional surface analysis showed an outflow boundary
across central GA, associated with a fairly vigorous thunderstorm
complex. It appears that there will be enough of an interaction
between the cold pool associated with this storm complex and the
moderately unstable airmass in its path for scattered thunderstorms
to reach our forecast area later this afternoon and early evening.
The lower to mid tropospheric flow was weak, which would argue
against significant storm organization and/or updraft rotation.
However, sometime cold pools interacting with warm & humid boundary
layers can be more organized than the large scale environment might
suggest. Because the lower and mid tropospheric lapse rates were
relatively steep, marginally severe hail and/or damaging wind gusts
are possible, mainly in our GA zones.

Thunderstorms will gradually diminish after sunset, followed by
generally fair weather later tonight. Once again there may be areas
of low clouds and fog, especially west of the Apalachicola River and
in areas that get rain.-- End Changed Discussion --

.SHORT TERM [Monday through Tuesday Night]...
-- Changed Discussion --The consensus of numerical model guidance portrays an average mid-
upper level shortwave ridge over much of our area in the Monday
and Tuesday time frame, with a west-to-east gradient in PWAT. The
lowest values will be situated over the western part of our area,
with the highest values in the east - closer to the influence of
the Atlantic Ocean. The overall flow pattern through the depth of
the troposphere should be fairly weak, so there shouldn`t be a
larger-scale forcing mechanism for widespread convection. PoPs
were concentrated in our Georgia and Florida Big Bend zones where
deeper moisture will reside, with a diurnal trend to be maximized
in the late afternoon. Highs away from the coast will be around 90
degrees in general.-- End Changed Discussion --

.LONG TERM [Wednesday through Sunday]...
-- Changed Discussion --Chances for showers and thunderstorms are expected to be a little
more widespread in our area on Wednesday and Thursday as a low
amplitude mid-upper level trough ejects east from the Plains. On
Wednesday, our area will be situated right underneath highly
divergent flow aloft, and by Thursday a weak surface front should
be developing into our area; both situations favor at least a bit
of a focus for larger scale vertical motion. Therefore, PoPs on
Wednesday and Thursday were increased into the 30-40% range. After
that, a strong surface high builds south into the eastern US, and
the weak surface front shifts south into the Florida Peninsula.
This should allow for some drier air to arrive and slightly lower
PoPs closer to climatological normals. The temperature forecast is
one of persistence, with highs maintaining close to 90.-- End Changed Discussion --

.AVIATION [through 18 UTC Monday]...
-- Changed Discussion --Clusters of thunderstorms have developed in north and central GA,
and appeared to be headed toward KABY (mid-late afternoon) and KVLD
(late afternoon-early evening). Wind gusts of 35 KT and IFR Vis are
possible with these storms as they translate quickly southeastward.
It`s unlikely that these storms will affect the other terminals. Fog
and low CIGS are possible early Monday morning, especially at KECP
and KDHN.-- End Changed Discussion --

.MARINE...
-- Changed Discussion --
Winds and seas should remain relatively calm through the work
week. Winds will be generally 10 knots or less, and seas 2 feet or
less. There will be a chance for a few showers or storms, and
winds could be briefly higher near storms. Storms would be most
likely near the coast and in the late afternoon or evening hours.-- End Changed Discussion --

.FIRE WEATHER...
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Relative humidity values will remain above critical levels through
Tuesday with relatively light transport winds and deep mixing
heights especially over Florida. The airmass should remain
sufficiently moist to preclude red flag conditions into the upcoming
weekend.-- End Changed Discussion --

.HYDROLOGY...
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Any rain through Friday would likely arrive in the form of
scattered showers and thunderstorms, and average rainfall totals
should be low enough to prevent any widespread flooding concerns
or issues on mainstem rivers across the area.-- End Changed Discussion --

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --Tallahassee 66 90 66 90 69 / 20 20 10 20 20
Panama City 70 85 69 85 71 / 10 10 10 10 10
Dothan 68 91 67 91 71 / 10 10 10 10 10
Albany 68 90 67 91 69 / 30 20 20 20 20
Valdosta 67 89 65 90 68 / 30 40 20 30 20
Cross City 66 88 64 89 67 / 20 30 20 30 20
Apalachicola 69 83 68 82 71 / 0 10 10 20 10-- End Changed Discussion --

.TAE WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --FL...None.
GA...None.
AL...None.
GM...None.-- End Changed Discussion --

NEAR TERM...Fournier
SHORT TERM...Lamers
LONG TERM...Lamers
AVIATION...Fournier
MARINE...Lamers
FIRE WEATHER...Block
HYDROLOGY...Lamers

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