Area Forecast Discussion
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061
FXUS62 KTAE 191917
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
317 PM EDT Sat Jul 19 2014

.Near Term [Through Tonight]...
Moisture-rich environment combined with diffluent flow aloft and
isentropic ascent to generate widespread rains today with scattered
embedded thunderstorms. Lapse rates have been anemic and shear is
gradually weakening, so stronger storms are no longer anticipated,
except perhaps over the Gulf of Mexico. The abundant cloud cover and
precipitation have kept temps in the 70s for much of the area, with
80s over our eastern and westernmost zones. Some recovery is
anticipated late in the day once the large rain shield over the FL
Big Bend pushes east. It will be replaced by more cellular
convection moving in from the west. PoPs are likely to categorical.
Overnight, PoPs drop back to the chance (scattered) category after
sunset. However, most CAMs show another area of convection
developing over the Gulf and moving ashore into the FL Panhandle. We
bring likely PoPs back to that area after midnight.

.Short Term [Sunday Through Monday Night]...
A generally stagnant upper level pattern will lead to unsettled
weather and elevated chances for showers and thunderstorms during.
the short term period. Locally, this will be highlighted aloft by a
very strong upper ridge over Rockies and another weaker ridge over
Wrn Atlc. In between, an amplified trough dominates Ern states.
Shortwave energy diving into base of trough amplifies axis ESE
thru at least Monday before beginning to weaken. At surface,
shortwave pushes surface low to across SE AL on Sun, Srn GA at
night and extending into adjacent waters on Mon with stationary
front W-E. All this yields SSW flow sfc to at least H5 with PWATs
generally 2.2 to 2.3 inches thru the period.

This upper/lower scenario will favor deep layer inflow, upper
forcing and outflow boundary/seabreeze clashes producing locally
heavy rain and will still have to keep an eye on Storm Total
Rainfall for some potential minor/nuisance flooding in any low lying
and poor drainage areas. Cannot discount strong storms with ample
lightning and gusty winds especially with boundary clashes. Will go
W-E POP gradient thru the period with 50-70% W-E POP gradient each
day, 30-50% Sun night and 20-40% Mon night. High temps tricky and
will depend on the amount of cloud cover and rainfall, with any
areas that do not see any/many breaks in the overcast remaining in
the upper 80s. A few areas that do see a couple hours of
insolation could break the 90 degree mark. Lows in the low 70s.

.Long Term [Tuesday Through Saturday]...
The first two days of the longterm will be near or above climatology
in terms of rain chances while temperatures are expected to be below
climatology. The increased chances for rain will be due to general
longwave troughing over the Eastern CONUS and an upper low that is
forecast to cut off from the mean 250mb flow and move southwest. As
this low rotates around a fairly anomalous ridge over the Western
US, rain chances will remain high through Wednesday. After Wednesday
afternoon, models diverge slightly but both the Euro/GFS suggest a
return to near normal climatological rain chances. For the end of
the long term took an equal blend of HPC, Euro, and GFS guidance.

&&

.Aviation...
[Through 18Z Sunday]  This forecast is more pessimistic than the
last. Numerous showers and isolated thunderstorms will impact the
aerodrome through much of the forecast period with a lull during
part of the night. We no longer expect VFR conditions overnight. The
latest model data indicates that IFR ceilings will be likely at most
TAF sites. An early start to convection is indicated for Sunday
morning.

&&

.Marine...
A low pressure system off to our west will increase onshore winds
slightly to the west of Apalachicola thru tonight, and a long
fetch of southerly winds deep into the Gulf of Mexico will
increase seas over our western coastal waters into the 2 to 4 foot
range. However, this will be below any headline levels, and
further to the east, winds and seas will remain significantly
lower. By Sunday and beyond, a weaker pressure pattern more
typical for summertime will return, resulting in light winds and
low seas for the rest of the period.

&&

.Fire Weather...
A moist pattern is expected to persist for the next several days
with increased rain chances each afternoon and evening.

&&

.Hydrology...
Rain chances will be quite a bit higher than recently through the
weekend and into early next week. Isolated rainfall totals in
excess of 2 to 4 inches are possible across the western half of
the forecast area with lesser amounts of 1.5 to 2 inches to the
east through Monday. These rainfall amounts should not be
widespread enough to cause any river flooding, although some
localized minor flooding in the usual flood prone areas will be
possible.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   73  89  73  89  72 /  30  60  40  60  50
Panama City   77  87  77  88  74 /  40  60  40  50  40
Dothan        72  88  72  91  71 /  40  60  30  40  20
Albany        72  88  71  88  72 /  40  60  40  50  30
Valdosta      71  90  72  89  71 /  30  70  50  60  50
Cross City    72  90  72  88  71 /  20  60  40  60  50
Apalachicola  77  87  75  87  75 /  30  50  40  50  50

&&

.TAE Watches/Warnings/Advisories...

FL...High Rip Current Risk through late tonight for Coastal Bay-
     Coastal Gulf-South Walton.

GA...None.
AL...None.
GM...None.

&&

$$

NEAR TERM...WOOL
SHORT TERM...BLOCK
LONG TERM...BLOCK/DOBBS
AVIATION...WOOL
MARINE...BLOCK
FIRE WEATHER...WOOL
HYDROLOGY...GODSEY






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