Area Forecast Discussion
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FXUS62 KTAE 300019
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
819 PM EDT Sat Apr 29 2017

.UPDATE...

The forecast through tonight looks to be on track, only minor
updates were applied to temperature/wind based on latest
guidance.

Some adjustments were made to thunderstorm chances for tomorrow
afternoon and night. For tomorrow afternoon, instability will rise
above 2000 J/kg across some inland areas; sea breeze forcing
could spark a few showers or possibly an isolated thunderstorm
across the FL Big Bend or southern GA, so added slight chance PoPs
to these areas. During Sunday evening through the overnight
hours, slightly higher chances of thunderstorms were added across
our western zones since some hi-res models are hinting at a
stronger/faster moving squall line pushing across the Gulf Coast
region during this time. The HRRR has been one of the most
aggressive models with the forward motion of this feature,
although it only extends out through 16Z Sunday at this time.
Other models have been much slower with the front/squall line, so
there is considerable uncertainty regarding possible thunderstorm
timing. As a result, additional adjustments to thunderstorm
chances will likely be needed through tomorrow.

&&

.PREV DISCUSSION [718 PM EDT]...

.NEAR TERM [Through Tonight]...

A light shower is possible for the remainder of the afternoon into
early evening across the region. Otherwise, it will be mostly cloudy
with only patchy fog expected overnight. Lows will be in the upper
60s to around 70.


.SHORT TERM [Sunday Through Monday Night]...

The upper low centered over the Four Corners region this morning
will be centered just north of the Great Lakes Monday morning. The
attendant surface cold front will translate eastward across our
forecast area on Monday, which is 6 hours or so slower than the NWP
model runs from 24 hours ago. There is still good agreement among
the various model runs that much of our region will receive some
needed rain on Monday.

The severe weather threat for Monday still appears marginal. We
expect a rather vigorous QLCS to approach our forecast area from the
west Sunday night, but to begin weakening as it enters southeast AL
and the FL Panhandle in the pre-dawn hours of Monday, as the parent
surface cyclone begins occluding over the Great Lakes. Significant
pre-frontal cloud cover is likely to limit MLCAPE values to 1000
J/kg or less, and weakening wind fields aloft with time will lessen
the potential for significant storm organization. Still, there may
be enough surface cold pool organization, especially early Monday
while vertical wind shear is stronger, to support isolated damaging
wind gusts. The main threat area will be for the region north
and west of Tallahassee.


.LONG TERM [Tuesday Through Saturday]...

We expect generally fair and warm weather Tuesday and Wednesday.
There is a good chance of rain Thursday as an upper-level trough
develops over the central Gulf Coast states. However, the global
models diverge considerably in their handling of this system by
week`s end, with the ECMWF and CMC models taking the trough axis
(and associated surface cold front) east of our forecast area
Thursday night, and the GFS closing off an occluded low over the
Deep South and having it meander through Saturday. The GFS solution
would keep rain chances for our region into Saturday, while the
other solutions would mean clearing by Thursday night. Temperatures
will be near average during this period, but could be below average
of the CMC/ECMWF solutions verified, with cooler, drier air entering
the area sooner.


.AVIATION [Through 00Z Monday]...

Southerly winds will become light during the next couple hours
with the loss of mixing as the sun sets. Expect winds to drop
below 10 kts by 01Z and winds will become southeasterly
overnight. Low clouds with MVFR cigs could develop at all
terminals early Sunday morning, and cigs are expected to return
to VFR levels by the early afternoon on Sunday. Winds will become
south-southeasterly during the mid-late morning hours and
increase to around 15 kts, with gusts to 20-25 kts possible at
ECP, DHN and TLH.


.MARINE...

Moderate to strong SE-S winds will continue across the coastal
waters through Monday, ahead of an approaching cold front. Advisory
conditions are possible at times, mainly west of Apalachicola. This
will lead to high surf, strong rip currents, and slightly above-
normal tides. Much lower winds and seas are expected mid week.


.FIRE WEATHER...


.HYDROLOGY...

Local rivers will remain below flood stage through at least Monday
morning. QPF values will generally be in the 0.50 to 1 inch range
from Tallahassee north and westward, and not enough to cause
significant river rises. QPF values in north FL will likely be much
less. More rain is expected later next week, but model differences
make it unclear as to how much of, if any a flood threat there will
be.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   69  86  70  81  58 /  10  10  20  60  30
Panama City   73  81  72  76  62 /   0  10  60  80  10
Dothan        69  87  69  79  56 /  10  20  70  80  10
Albany        69  89  70  80  55 /  10  10  30  70  10
Valdosta      67  89  69  84  60 /  10  20  20  50  40
Cross City    67  89  69  85  65 /  10  10  10  20  50
Apalachicola  72  81  73  79  63 /   0  10  30  50  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...

FL...High Rip Current Risk through late Sunday night for Coastal Bay-
     South Walton.

GA...None.
AL...None.
GM...Small Craft Advisory from 5 AM to 5 PM EDT Sunday for Apalachee
     Bay or Coastal Waters From Keaton Beach to Ochlockonee
     River Fl out to 20 Nm-Coastal Waters From Ochlockonee River
     to Apalachicola Fl out to 20 Nm-Coastal waters from
     Suwannee River to Keaton Beach out 20 NM-Coastal waters
     from Apalachicola to Destin FL out 20 NM-Waters from
     Suwannee River to Apalachicola FL from 20 to 60 NM-Waters
     from Apalachicola to Destin FL from 20 to 60 NM.


&&

$$

UPDATE...Lahr
NEAR TERM...Barry
SHORT TERM...Fournier
LONG TERM...Fournier
AVIATION...Lahr
MARINE...Fournier
FIRE WEATHER...Lahr
HYDROLOGY...Fournier


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