Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 221805
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
205 PM EDT Tue Apr 22 2014
.Near Term [Through Tonight]...
The local pattern shows that mid/upper low amplitude shortwave
trough over local area this eve moves SEWD and offshore overnight to
be replaced by upstream shortwave ridging thru overnight hours.
At the surface...this will push cold front to S/Cntrl AL/GA by
sundown with assocd shwrs and thunderstorms ahead of front reaching
our Nrn tier counties and increasing west winds. With mid/upper
trough and support exiting...The front and assocd precip will
continue to weaken and likely stall across extreme N FL and become
oriented east to west.
The deepest moisture and best lift with this system will stay well
to our north. Locally...poor mid level lapse rates...meager CAPE and
loss of sun translates to marginal instability and deep layer shear
so chance for strong storms not high. Still...evening guidance shows
vorticity axis from SC across FL Panhandle into NW Gulf. H5 temps
will be cool enough i.e. -14C combined with aftn temps in the low
80s and dew points approaching 60 degrees...enough ingredients
lingering into eve for isold Tstms.
Our local CAM forecasts best chances of preccip will be closest to
upper support...NE tier GA counties with increasingly limited POPs
NE-SW. All of the MOS and dynamical guidance forecast a strong
weakening/drying trend after midnight so divided POPs into 3hr
GRIDS. Sharp 50-0% NW-SE evening POP gradient. With loss of sun
and dynamics....NIL POPs after midnight. Good chance for low
stratus and at least patchy fog ahead of front.
.Short Term [Wednesday Through Thursday Night]...
The mid/upper level local pattern begins with shortwave trough well
into Atlc replaced by amplified ridging...rising heights and
subsidence. At surface...remnants of Tuesday`s cold front limps
into our SE Big Bend Swwd into our Nrn marine area. In its
wake...area model soundings show flow sfc-upper levels NWLY
however with proximity of front...PWATS remain around 1 inch.
During the rest of the period...local ridge amplifies into Thurs
ahead of upstream trough/low developing over Wrn states. By
aftn... this low pivots Newd resulting in Ern ridge flattening
yielding near zonal flow. At surface...increasingly diffuse front
lingers in place before likely lifting Nwd late Wed into Thurs as
high develops over NE Gulf and...along with ridge across Nrn Gulf
Coast...remains established into Thurs night. The combination of
strong mid/upper subsidence and weakening front south will yield
partly to mostly sunny skies. The lifting front will shift local
winds to onshore on Thurs with rising humidity as reflected in
model PWATS which remain around 1 inch. So it will feel muggy.
With very dry mid/upper levels...at best isold POPs near the
front. Temperatures will be near climatology through the period,
with lows in the 50s and highs in the lower to mid 80s.
.Long Term [Friday Through Tuesday]...
On Friday, a weak surface trough will extend down from the Great
Lakes. This trough will become oriented SW to NE as the parent low
moves off to the northeast and the trough weakens. Southerly flow
off the Gulf and weak forcing will cause a slight chance of
thunderstorms over the the northern half of our area Friday through
Saturday. Ridging will settle in on Sunday with southerly surface
flow which will bring highs in the mid to upper 80s during the day.
At the end of the period both the GFS and EURO show a very amplified
pattern emerging with a deep upper-level trough digging down over
the southern Plains. While these models differ some in timing and
structure, they both show a blocking pattern emerging with a strong
upper ridge in the west and an amplified deep trough in the east.
This system should be our best chance of seeing showers and
thunderstorms in the extended period.
[Through 18Z Wednesday] VFR cigs and vsbys will prevail today
before another round of fog tomorrow morning. Around 20Z,
thunderstorms will move in to the northern terminals (DHN, ABY)
from west to east, exiting the area by around 03Z. Around 09Z,
area BR and FG will set in again across the area. The lowest
cigs/vsbys will be at TLH and VLD with LIFR conditions possible.
Guidance hinted at low vsbys along with low cigs at ECP, but left
out since winds are expected to remain around 5 kts overnight.
Despite the front approaching from the north into tonight, then
stalling across extreme North FL through Thursday, winds and seas on
the whole will remain quite low. The exception will be a moderate
increase in onshore winds and chop near the coast each afternoon
because of the daily sea breeze.
Red Flag conditions are not expected through the remainder of the
Most of our area rivers are above normal stage with many in flood
stage. The Choctawhatchee at Bruce is at major flood stage, several
others are in moderate. Most area rivers will crest soon or have
already crested. The exception is the Suwannee River chich will rise
slowly for the remainder of the week. Rainfall amounts are expected
to be less than 0.25 inch and will have little impact on area river
The most up-to-date river forecast information can always be found
on our AHPS page (below).
.Preliminary Point Temps/PoPs...
Tallahassee 62 82 58 82 62 / 10 0 0 10 0
Panama City 65 77 63 75 65 / 10 0 0 10 0
Dothan 61 82 57 83 62 / 30 0 0 10 10
Albany 60 82 56 83 61 / 40 0 0 20 10
Valdosta 61 83 59 83 61 / 20 10 10 20 0
Cross City 61 82 59 82 60 / 10 10 10 20 0
Apalachicola 63 75 63 74 64 / 10 0 0 10 0