Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tallahassee Florida
931 PM EDT Tuesday Aug 23 2016
Near term [through tonight]...
Showers and storms continue west of a line from Apalachicola to
Cuthbert. Trimmed back pops east of the line for the rest of the
night and raised pops west of this line. Hi-res models continue to
show an overall weakening trend over the next several hours. Partly
to mostly cloudy skies can be expected overnight. Lows will be in
the mid 70s.
Previous discussion [833 PM edt]...
Short term [wednesday through Thursday night]...
Drier surface air will begin to advect into the area on Wednesday in
association with a shift to northeast flow. As a result of the drier
air, dewpoints are expected to drop to unseasonably low values,
around the upper 60s, across the northern portions of our area.
Dry conditions are to be expected in the northeastern part of the
area. Convection will then become focused in the western portions
of the area, with pops in the 30-40% range there on Wednesday
Dry air will continue to move into the area on Thursday, inhibiting
convection to pops less than 20% across the southeast Big Bend.
High temperatures in the period will be mainly in the low to mid
90s, and low temperatures will be in the low to mid 70s.
Long term [friday through tuesday]...
Dry air, at least for this time of year, will persist Friday and
Saturday. Precipitable water values around 1.0" or slightly lower are possible
during this time, which is 1 to 2 Standard deviations below normal
for our area. As a result, showers and thunderstorms will be
mainly confined to the Gulf during this time, with a few isolated
showers and storms possible near the coast.
For the remainder of the period, attention shifts to the potential
for tropical development in the Atlantic. A disturbance currently
just east of the northern Antilles will move west-northwest into
the Bahamas by Friday, and could approach Florida later in the
weekend through early next week. There is still a massive
discrepancy in the guidance; the GFS and some models keep the
system very weak, likely remaining a tropical wave or depression
in these outcomes, while the European model (ecmwf) and several other guidance
members develop a strong tropical cyclone. The track is also
uncertain at this time, but a strong deep-layer ridge developing
over the mid-Atlantic states could help force the disturbance
westward across the Florida Peninsula over the weekend and into the
eastern Gulf early next week. Upper level shear could be fairly
weak in these areas and water temperatures are very warm (mid-
upper 80s f), so the stronger scenarios remain plausible at this
time. We will continue monitoring this system, and will likely
have increased confidence in the track and intensity of this
system during the next few days.
Aviation [through 00z thursday]...
Thunderstorms and rain continues this hour along several outflow boundaries and
along and west of tlh to dhn line. These storms will continue to
move slowly southwestward and weaken over the next several hours.
Low MVFR has been observed underneath heavier storms this
afternoon. Outside of convection, VFR will rule. Overnight, vld
has the possibility of MVFR cig/vis around dawn. Other sites
should remain VFR. On Wednesday, very low probability for thunderstorms and rain
with drier air working into the area so left any mention out of
tafs. VFR should prevail.
Seas will generally remain under 2 feet through Wednesday due to light
winds, then increase to 2 to 3 feet through the next few days as
easterly winds will increase to 10-15 knots over the northeastern
Drier air will work into the area beginning Wednesday with
precipitation chances decreasing through the end of the work week.
Relative humidity values will remain above critical levels. There
are no fire weather concerns this period.
No widespread flooding concerns are expected for the next few
days, although brief heavy rainfall is possible with any slow-
moving thunderstorms. Early next week, potential for heavy
rainfall and localized flooding could exist depending on tropical
development, but it is too early to determine possible impacts.
Preliminary point temps/pops...
Tallahassee 76 93 73 93 74 / 20 20 10 10 10
Panama City 78 90 77 90 77 / 40 30 10 10 10
Dothan 74 92 71 92 72 / 30 30 10 10 10
Albany 74 93 71 94 72 / 10 20 10 10 10
Valdosta 74 92 71 92 72 / 10 20 10 10 10
Cross City 76 92 73 92 74 / 20 20 10 20 10
Apalachicola 79 89 77 89 78 / 30 20 10 10 10