Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 262308
Area Forecast Discussion
National Weather Service Tallahassee FL
708 PM EDT FRI AUG 26 2016
.AVIATION [Through 00Z Sunday]...
VFR conditions are expected through the TAF period. While isolated
TSRA is possible across the ECP to TLH to VLD areas tomorrow
afternoon, chances are only around 20 percent and thus too low to
mention in the TAF at this point.
.PREV DISCUSSION [332 PM EDT]...
.NEAR TERM [Through Tonight]...
Dry conditions will persist across most of our area through the rest
of today and tonight as mid-level dry air continues to funnel into
our area from the northeast. However, a surge of slightly increased
moisture more in line with seasonal averages (PWAT values above
1.5") is developing across the eastern FL Big Bend this afternoon,
and will push offshore into the northeastern Gulf tonight. Current
radar is also showing some widely scattered showers/storms across
northeastern FL moving toward the west-southwest. As a result, low
chance PoPs were maintained from Dixie County through much of our
marine zones through the rest of this period. Low temperatures
tonight will range from the upper 60s to lower 70s inland, with mid-
upper 70s expected along the coast.
.SHORT TERM [Saturday Through Sunday Night]...
Deep easterly flow will persist with a ridge to our north. There
will be a sharp gradient in deep layer moisture, with unusually dry
conditions across GA and AL, and increasingly moist air in FL and
especially offshore. While we don`t expect any large scale Q-G
forcing, there are likely to be mesoscale perturbations within the
easterlies which lead to localized increases in rain chances where
there is sufficient deep layer moisture. This is often difficult to
time, so our PoPs will just generally follow the moisture gradient,
with 20-30% PoPs in FL and south central GA (mainly during the
afternoon & evening hours), and 10% PoPs elsewhere. High
temperatures will remain above average in the mid 90s, but with
dewpoints in the mid 60s to lower 70s, heat index values are
unlikely to exceed 100. Lows will be in the 70s.
.LONG TERM [Monday Through Friday]...
Our focus continues to be on the evolution of notorious tropical
disturbance "99L", which was a tropical wave in the central Bahamas
this early afternoon. The system`s satellite and low level wind
field presentations were a little better than 24 hours ago, but it
was still in a sheared environment and appears rather unlikely to
become a tropical storm this weekend as it moves across South FL.
The latest GFS and ECMWF have come into better agreement, and now
show a weak system (strong tropical wave/depression/weak storm)
meandering in the northeast Gulf of Mexico by mid week as the
steering winds collapse. Regardless of development, people in our
forecast area, especially at the coast, should at least prepare for
the possibility of heavy rain and hazardous boating and beach
conditions next week.
With a surface ridge to our north, winds will continue from the east
at moderate levels during the overnight and early morning hours, but
become lighter (especially at the coast) during the afternoon and
early evening hours. By early next week the conditions will depend
greatly on the development and track of disturbance "99L", but for
now we are forecasting near-advisory conditions. This is more in
line with the GFS, as the ECMWF and CMC wind speeds were quite
High dispersion values are possible Sunday afternoon across the Big
Bend area. Otherwise, there are no fire weather concerns given RH
values remain above critical thresholds.
No organized heavy rain is expected through Monday. By Tuesday the
threat for heavy rain may begin to increase, though the global
models have the heaviest rain totals over the Gulf of Mexico and
across central FL.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 73 93 75 93 75 / 10 20 10 30 20
Panama City 76 89 77 89 77 / 10 20 10 30 20
Dothan 70 92 73 92 73 / 0 10 0 10 10
Albany 70 94 73 94 73 / 0 10 0 10 10
Valdosta 70 93 74 93 73 / 0 20 0 30 0
Cross City 73 93 75 92 74 / 20 30 10 40 10
Apalachicola 77 88 78 89 77 / 20 20 20 20 20