Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 190035
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
835 PM EDT Fri Jul 18 2014
.Near Term [Through Tonight]...
The 8 pm EDT regional surface analysis showed a 1012 mb low
pressure system centered near Jackson, MS, with a quasi-stationary
front extending southeast from this low across Southeast AL and
South GA. Vapor imagery and upper air data showed a long wave
trough (positively tilted) from Ohio to TX, with moist southwest
flow ahead of it over much of the Gulf Coast. The radar network
showed a QLCS approaching the western portions of our forecast
area, although it was moving into a region of progressively drier,
more stable air. The best initialized Convection Allowing Models
(mainly the latest HRRR and CONUS WRF ARW) bring this system into
primarily the western portions of our forecast area tonight,
though they do show a weakening trend. Our latest PoP/QPF reflect
these changes, which is quite a bit faster and farther east (with
the rain) than what we were thinking earlier.
[Through 00Z Sunday]...A few rounds of showers and thunderstorms
will be possible in the region during the TAF period. An initial
round of thunderstorms should approach ECP and DHN this evening
from the west around 02-06Z before diminishing. After that, the
timing and location of showers and storms becomes less certain,
but the current expectation is that additional rain and storms
will develop and spread into the area in the early morning hours -
beginning first at ECP (possibly as early as 12Z) and then pushing
north and east from there. Due to timing uncertainties, periods
with chances for showers and storms were indicated in the TAFs
with SHRA and VCTS but kept in the VFR flight category. However,
in heavier rain or storms, LIFR/IFR visibility will be possible
along with some gusty winds. When timing becomes more certain,
lower flight categories may be indicated explicitly at a later
.Prev Discussion [342 PM EDT]...
.Short Term [Saturday Through Sunday Night]...
The upper trough over the Mississippi Valley today will slide
eastward over the weekend bringing a return of unsettled weather to
the region. Low to mid level flow will be out of the WSW, a
favorable directly for higher coverage of sea breeze convection.
However, synoptic influences will also be in play with a remnant
front dissecting the CWA and impulses rotating through the mean
trough. Deep layer shear will be above typical summertime levels on
Saturday. However, mid level lapse rates will be poor and low level
instability will be limited by abundant cloud cover. Still, one or
two strong storms cannot be ruled out over our FL Panhandle coastal
zones and the marine area. A bigger concern will be locally heavy
rain. 48-hr QPF could be over 3 inches over our far northwestern
zones with a much larger area over 2 inches. PoPs will be in the
likely category for most of the area and max temps will mainly be
held in the 80s with 90s restricted to the eastern FL Big Bend.
Sunday will see more typical distribution of scattered storms and
.Long Term [Monday Through Friday]...
A wet pattern will be prevailing over our CWA through the long term
as we will be in the weakness between two large longwave ridges, one
over the Atlantic, and one over the Western CONUS. This weakness
will allow the area to be under the influence of deep layer
southerly flow which will give good rain chances for all parts of
the forecast region. Further adding to the weakness will be a cut
off upper low that the GFS and Euro indicate could drop down from
the mean 250mb flow Monday afternoon. As this rotates SW around the
ridge, it will further fortify our rain chances throughout the long
term especially Monday-Wednesday afternoons.
Low pressure west of the area will briefly increase winds and seas
over the waters west of Apalachicola through Saturday. By Sunday and
beyond, a weak pressure pattern more typical for the summer months
will return. This will result in light winds and low seas from
Sunday through Wednesday.
Hazardous fire weather conditions are not expected over the next
several days as moisture levels drastically increase along with
Rain chances will increase through the weekend. Isolated rainfall
totals in excess of 2 to 4 inches are expected across the western
half of the forecast area with lesser amounts of 1 to 2 inches
through Sunday night. Rainfall amounts should not be widespread
enough to cause any river flooding, though some localized issues
in flood prone areas are possible.
.Preliminary Point Temps/PoPs...
Tallahassee 72 89 72 91 73 / 10 70 30 50 40
Panama City 75 86 75 89 76 / 30 70 40 50 40
Dothan 72 87 72 90 72 / 40 70 40 50 30
Albany 73 87 71 91 72 / 20 70 40 50 40
Valdosta 71 89 70 91 72 / 20 50 40 50 40
Cross City 71 91 72 91 72 / 10 40 30 50 40
Apalachicola 75 86 74 90 75 / 10 70 40 50 40