Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 241032
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
632 AM EDT Thu Jul 24 2014
[Through 12z Friday] VFR conditions are expected to prevail for
most of the day with winds from the southwest around 8-10 kts in
the afternoon. The typical summertime scattered diurnal convection
will develop during the late morning and afternoon hours with VCTS
shown at the terminals. The earliest start is expected at ECP with
later start times farther to the north and east.
.Prev Discussion [253 AM EDT]...
.Near Term [Today]...
The overnight analysis shows a strong upper level ridge across the
Rockies and a seasonably strong subtropical ridge off the east coast
of Florida. In between the two, weak upper level troughing exists
just west of the local area. As we head through the day, the
1000-700 mb mean wind will be out of the southwest, yielding a type
4 or 5 sea breeze regime. This favors an early start to convection
across northwest Florida with convection spreading inland into
southeast Alabama and southern Georgia during the afternoon hours.
The ensemble of convection allowing models also shows this general
evolution, so the PoP forecast will favor a blend of the CAMs and
sea breeze climatology for today with seasonable high temperatures.
.Short Term [Tonight Through Saturday]...
The GFS and ECMWF are in good agreement in maintaining the base of
a weak 500 mb trough over GA through Saturday, while a surface cold
front stalls well to our north. The mean 1000-700 mb wind across
our regions will be out of the southwest, which is often
associated with above-climatology PoPs for portions of our
forecast area (especially in FL). Curiously, there is considerable
difference in the forecast PoP among the GFS, NAM, & ECMWF MOS
each day, but it`s not that obvious (looking at the synoptic
scale) why this is. We averaged the various PoPs together, as well
as our local sea breeze climatology, and our PoP forecast changes
very little between Friday and Saturday. Scattered evening
thunderstorms (mainly in GA and AL) will dissipate before midnight
tonight, but isolated showers/storms will begin to develop near the FL
coast by dawn on Friday. PoPs both Friday and Saturday are around
40%, which is near climatology. Highs will be in the mid 90s and
lows in the 70s.
The prospects for organized severe thunderstorms continues to be
low due primarily to weak winds aloft. However, the GFS, ECMWF,
and NAM all forecast some drying and steepening of the mid
tropospheric lapse rates Saturday afternoon. SBCAPE values will
likely exceed 2500 J/kg on Saturday, and delta theta-e values are
forecast to reach or exceed 30 K. Together, these factors suggest
a greater potential for strong/severe wet microbursts, albeit
disorganized and "pulsey" in nature, and we will continue to
monitor this threat.
.Long Term [Saturday Night Through Thursday]...
The region will be dominated by a typical summer pattern Sunday.
As a result, expect isolated afternoon/evening rain and
thunderstorms. Monday an upper level trough moves in and increases
afternoon/evening precip chances. A stationary boundary is
expected to linger over the area Tuesday and Wednesday bringing
increased rain chances in the Big Bend Region. In addition to the
increased rain chance expect abundant cloud cover. It will be
slightly cooler and less humid Tuesday and Wednesday...particularly
in the Alabama and Georgia counties.
An east-west oriented surface ridge will remain across South FL
and the southeast Gulf of Mexico through this weekend. Winds will
generally be from the southwest around 10 KT, except for an
increase to 10 to 15 KT near the coast during the late afternoon
and evening hours from strong daytime heating. Significant wave
heights will be mainly 2 ft or less.
Red flag conditions are not expected over the next several days,
although dispersion values will be high this afternoon across a
large portion of the area away from the immediate coast.
Any heavy rain that occurs is likely to be too localized to
significantly impact local rivers. The probability of Flash
Flooding is very low.
.Preliminary Point Temps/PoPs...
Tallahassee 92 73 93 73 94 / 50 10 40 20 40
Panama City 88 77 89 77 89 / 40 10 40 20 40
Dothan 92 73 92 74 94 / 50 30 40 20 40
Albany 93 73 93 74 94 / 40 40 30 20 30
Valdosta 96 72 96 71 96 / 50 20 40 20 40
Cross City 92 74 91 71 92 / 30 30 40 20 40
Apalachicola 89 77 89 77 89 / 40 10 40 20 40