Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 121537
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1137 AM EDT Fri Sep 12 2014
.Near Term [Through Tonight]...
Our morning analysis reveals that the forecast area is situated
squarely underneath deep layer ridging. The GOES blended PWAT
product, as well as 12Z soundings from TAE and JAX, shows a pocket
of drier mid-level air over north Florida and south Georgia. The
Tallahassee sounding also indicated a relatively warm layer aloft
from about 650-400mb. The poor lapse rates could negatively affect
updraft strength today. Given the combination of drier mid-level
air, deep layer ridging, and poor lapse rates, we expect
convection to be relatively suppressed for much of the day. The
previous forecast indicated that already with mostly 20% PoPs, so
we have not made any significant changes. Meanwhile, the 850mb
temperature on the 12Z Tallahassee sounding has warmed from around
+17C yesterday morning to +19C today. With limited convective
coverage and slight boundary layer warming, today should be a
little warmer than yesterday, with highs in the mid-90s.
Convection that initiates this afternoon closer to a quasi-
stationary surface front in central Alabama and central Georgia
could drift south into parts of our Alabama and Georgia counties
either late this afternoon or into this evening. Therefore, the
best chances of rain through tonight could be in the northern half
of our area from 22-06Z.
.Prev Discussion [637 AM EDT]...
.Short Term [Saturday Through Sunday]...
Although weak upper ridging will continue locally, we will see a
gradual increase in deep local moisture through the weekend. The
stalled front to our north will get slowly nudged to the south on
Saturday becoming quasi-stationary across our CWA on Sunday.
Meanwhile, a tropical wave well south of our coastal waters is
forecast to stay on a westward coarse heading toward Texas. Our
position with respect to this system, the frontal boundary, and
return of deep moisture, all lead to increasing PoPs into the
chance/good chance range the next few days. Max temps will be in
the lower 90s inland areas Saturday and then around 90 for Sunday.
.Long Term [Sunday Night Through Friday]...
The elongated east-west oriented ridge axis will still be in place
at the start of the period. However, it will begin to break down
early in the work week as a long wave trough begins to amplify into
the Southeast. This trough will help push the front currently draped
across the Ohio Valley toward the Gulf Coast. It is still uncertain
just how far south the front will make it before stalling. There
appears to be model consensus that there will be enough energy
upstream in the long wave trough to induce weak waves on the front
that will help inhibit its southward progress. The proximity of the
boundary through much of the period will result in unsettled
conditions with above normal PoPs for the most part. Max temps will
correspondingly be generally below normal from Monday onward.
[Through 12Z Saturday] We expect generally VFR conditions today,
outside of isolated to scattered SHRA/TSRA this afternoon and
evening. Winds will be light and rather variable (6 KT or less),
except for a south wind near 10 KT developing this afternoon at
KECP. The PoP is rather low this afternoon (generally 20-40%), so no
TSRA is currently forecast at any of the terminals, but adjustments
to this may be made on the 18z TAF package when daytime convective
trends can become better established.
A very weak pressure gradient is forecast to remain in place. This
will keep winds and seas well below any headline criteria.
Red Flag conditions are not expected through at least this
Rainfall totals over the next few days are expected to be below
normal and not have an impact on area rivers. However, QPF is
expected to increase next work week.
.Preliminary Point Temps/PoPs...
Tallahassee 96 73 93 72 91 / 20 20 40 30 50
Panama City 91 77 90 76 87 / 20 20 40 30 50
Dothan 94 73 92 72 90 / 20 30 50 30 50
Albany 95 73 92 72 91 / 20 30 50 30 50
Valdosta 95 72 92 71 90 / 30 20 40 30 50
Cross City 94 71 93 70 89 / 20 20 40 30 40
Apalachicola 92 76 89 77 87 / 20 20 30 30 40