Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 290116
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
916 PM EDT Mon Jul 28 2014
.Near Term [Through Tonight]...
During Monday evening, a large upper trough anchored itself over
the ERN most U.S. At the surface, cold front from low off New
England SSW across Srn most AL/GA. Earlier, ahead of front and
across local area, ample low level moisture aided by strong
heating combined with a relatively unstable airmass
(thermodynamics quite favorable but kinematics only moderately
favorable) but augmented by added forcing from upward vertical
motion and vertical shear on Srn periphery of upper trough. Add
forcing from ESE-WSW oriented cold front and some mid-level dry
air and we had the ingredients for local enhancement and the
development of severe storms in the form of cell mergers or linear
segments especially near seabreeze boundaries. With roughly WNW
uni-directional flow, storms moved ESE. Primary impacts were from
damaging winds/downbursts plus small hail and intense lightning.
By 9 PM EDT, the focus was across the Big Bend but overall storms
were weakening due to the sheared out pre-frontal dynamics and
nocturnal stabilization as the cold front pushed further Swd
leaving generally isolated convection north of FL border and sct-
nmrs convection over FL. A strong storm cant be ruled out there
but the severe threat appears to have ended.
HI RES guidance indicates that storms across Florida should diminish
and largely end after 04z. Front should reach coastal area before
sunrise. Will go with 0-60% POPs thru 03z highest across coastal
FL, then 10-40% thru 12z highest over waters. In its wake, cooler
and drier air will begin spreading SEWD into the region with
overnight lows north of the Florida border possibly dropping into
the upper 60s with clouds and some winds translating to low to mid
70s over N FL.
[Through 00Z Wednesday]...Thunderstorms with MVFR conditions
remain possible into 1030 PM EDT and around midnight EDT ahead of
a cold front over TLH and ECP respectively. Otherwise, in the
wake of cold front...expect VFR conditions rest of the perid.
.Prev Discussion [241 PM EDT]...
.Short Term [Tuesday Through Wednesday Night]...
By Tuesday morning the cold front will be south of a
Valdosta-Tallahassee-Apalachicola line and will continue to push
south of the FL Big Bend by late afternoon. This will result in a
chance of showers and thunderstorms south of the front through the
day, mainly in the Big Bend area, with dry conditions Tuesday night
through Wednesday night.
The front will usher in cooler and much drier air, resulting in
overnight lows that will come close to some long-standing records.
For Tuesday night expect low 60s in southern AL and southern GA with
mid to upper 60s elsewhere. Similar readings are expected for
Wednesday although some locations could be cooler by a degrees or
two as drier air continues to work into the area. Daytime highs will
range from the upper 80s to the lower and mid 90s.
Stayed close to current forecasts for next couple of days. For
example at Tallahassee going for lows around 66 Wednesday and
Thursday mornings. The record lows here for those dates are:
July 30 - 67 (1927) Tuesday night/Wednesday morning
July 31 - 63 (1896) Wednesday night/Thursday morning
.Long Term [Thursday Through Monday]...
There will be continued amplification of the meridional upper level
flow as a strong high remains entrenched across the western CONUS
with a deep trough across the east. This pattern may finally begin
to weaken into early next week. In the meantime our area will remain
at the base of the upper level trough under broad cyclonic flow
aloft. Any subtle disturbances moving through the trough will help
enhance diurnal convection.
Another reinforcing surface boundary will sag across the southeast
U.S. by Friday with an east-west surface trough setting up along the
Gulf coast. This will be the focus for increased convection as we
move into the weekend and moisture gradually returns to the area.
Friday will be the transition day from dry to increasing moisture
with the weekend and early next week looking unsettled with high
rain chances. Overnight lows will return to normals in the 70s.
Daytime high temperatures will be somewhat suppressed compared to
last week with an increase in convection, with readings in the upper
80s and lower 90s.
Westerly winds will continue at a solid 15-20kt in the exercise
caution range with the approach of a cold front from the north.
Winds will become offshore behind the front on Tuesday and gradually
diminish Tuesday night. Expect light to moderate offshore winds
Wednesday through the end of the week.
Drier conditions will move in on Tuesday in the wake of a front
and continue through Thursday, with minimum relative humidity
values dropping into the lower 30s. Red flag conditions are
possible if conditions get drier than currently anticipated.
Storms moving through the region today could produce isolated
rainfall totals around an inch or so, but widespread heavy totals
aren`t anticipated. Storm motions are also quick enough to lessen
any flood concerns.
.Preliminary Point Temps/PoPs...
Tallahassee 72 93 66 93 66 / 60 10 0 10 0
Panama City 75 92 72 90 72 / 60 10 0 10 0
Dothan 70 91 66 90 65 / 40 0 0 10 0
Albany 69 91 65 91 66 / 40 0 0 10 0
Valdosta 71 92 64 92 67 / 60 10 0 10 0
Cross City 75 93 68 94 69 / 50 30 10 10 0
Apalachicola 76 91 71 90 73 / 50 20 0 10 0
FL...High Rip Current Risk until 4 AM EDT /3 AM CDT/ Tuesday for
Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton.