Scientific Forecaster Discussion
fxus62 ktae 162336
Area forecast discussion
National Weather Service Tallahassee Florida
736 PM EDT Mon Sep 16 2019
[through 00z wednesday]
VFR conditions will persist for all terminals throughout the taf
period. Winds will remain light and variable at times.
Previous discussion [337 PM edt]...
Near term [through tonight]...
Dry air will remain in place over the near term limiting pops to
near 0%. Hurricane Humberto to our east will keep the surface
winds out of the north, however, an area of low pressure located
in the northwestern Gulf of Mexico will keep the pressure gradient
over the County Warning Area quite weak. Therefore, winds will remain light for
the near term. Low temperatures will dip down into the upper 60s
and lower 70s tomorrow morning.
Short term [tuesday through Wednesday night]...
The short term period will feature a couple of unseasonably warm
days. Aloft, the region is on the eastern periphery of a large
Continental U.S. Ridge. With effectively deep layer northerly flow and a
fairly dry atmosphere on Tuesday and Wednesday, afternoon high
temperatures will warm into the mid 90s, with a few spots taking a
shot at the upper 90s. This will be near records for Tallahassee
each afternoon (records 99 Tue and 98 on wed).
Big changes will begin to unfold on Wednesday evening as a
backdoor cold front surges through the area. Model guidance even
suggests that some showers could accompany this front at least
prior to midnight Wednesday evening. Behind the front, cooler air
will filter in with overnight lows across our NE zones dropping
into the mid 60s.
Long term [thursday through monday]...
The long term period is expected to be essentially rain-free and
will feature the first noticeable break in the summertime heat.
As a large surface ridge becomes established across the mid
Atlantic states, cool, dry NE flow will prevail through Friday
night across the forecast area. While moderate/strong NE flow
could advect in some Atlantic moisture and cloud cover during the
afternoon hours Thursday and Friday, pops will be extremely low in
the fla Big Bend and dry elsewhere. Model guidance does have some
fairly large ranges with respect to high temperatures thurs- Sat
with some ensembles still showing low 90s during this period.
Given the pattern, however, trended the forecast closer to the
cooler operational mex guidance, with highs ranging from the lower
80s across our northern zones to the mid to upper 80s in the
Overnight lows through Sunday will be cool as well, dropping into
the 60s over the entire area. With the high still pretty far to
the north on Thursday/Friday nights, should keep enough wind going
to prevent lows from crashing too far. Given a large range in the
ensemble members, will stay fairly close to the operational mean
for lows during this time frame. By Saturday night, the surface
high pressure area drops a little bit to the south and weakens,
resulting in a weaker pressure gradient over the region, and the
possibility of a period of calm winds overnight. With most of the
guidance indicating Saturday night could be a couple of degrees
colder than previous nights, trended the forecast that direction
as well, with lows from 60-64 across inland areas. It wouldn't be
surprising for a couple of spots to reach the upper 50s across
some of the south central Georgia counties.
By Sunday, the pattern will begin to shift as the high weakens and
the local flow picks up more of a southerly component beneath a
weak mid level ridge. This will favor gradually warming
temperatures into the end of the period.
Tranquil marine conditions are expected to prevail into Wednesday
afternoon. Thereafter, the pressure gradient will tighten as a
large ridge of high pressure builds across the mid Atlantic
states. This will create an extensive period of cautionary
conditions with advisory level winds possible overnight in
nocturnal easterly surges Thursday night through Saturday night.
Although red flag conditions are not expected for the next several
days, conditions are expected to remain dry with relative humidity
values dropping into the low to mid 30s at times this week. In
addition, northeast winds may get into the 10-15 mph range at times
by Thursday and Friday.
Little or no rainfall is expected over the next seven days, thus
there is no flood potential.
Spotter information statement...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting US @nwstallahassee.
Preliminary point temps/pops...
Tallahassee 71 98 72 98 70 / 0 0 0 20 20
Panama City 74 94 76 94 74 / 0 0 0 10 20
Dothan 70 97 71 97 69 / 0 0 0 10 10
Albany 69 96 73 95 69 / 0 0 0 10 20
Valdosta 69 96 71 92 67 / 0 0 0 20 20
Cross City 70 94 72 94 70 / 0 0 0 30 20
Apalachicola 74 92 76 92 74 / 0 0 10 10 20