Area Forecast Discussion
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564
FXUS62 KTAE 220205
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
905 PM EST Fri Nov 21 2014

.Near Term [Through Tonight]...

A quiet evening is in store for tonight as we begin the transition
from dry and stable conditions to an active pattern. Light E
and ENE winds will reign over the CWA through tonight and will begin
to increase early tomorrow afternoon. Winds should not go calm and
accounting for the slow addition of Atlantic moisture, expect lows
to be in the middle 40s for most of the CWA. Lows are forecast to be
near 40 in N and NW parts of the area near Dothan and Albany, and in
the upper 40s in SE parts near Cross City.

&&

.Aviation...
[Through 00Z Sunday]...

VFR Conditions are expected through most of the
TAF period. The  only uncertainty is how quickly VCSH and low cigs
move in from the S and SE. Skies will start out clear tonight but
cirrus will begin building in from SE to NW early this morning. By
19z, all terminals should at least see BKN cigs at or below 5000ft
with decreases first occurring at SE terminals (VLD and TLH) and then
moving NW through the afternoon. Expect near MVFR cigs (BKN035) and
VCSH to move into ECP, TLH, and VLD after 21z.

&&

.Prev Discussion [446 PM EST]...

.Short Term [Saturday Through Sunday Night]...

Nearly zonal upper-level flow locally will begin to amplify on
Saturday afternoon in response to a strong shortwave forecast to
be passing through Texas. A southern stream PV anomaly will
energize convection in the western to central Gulf on Saturday,
spreading into the northeast Gulf late Saturday night. The
developing warm front will lift into the Tri-State region very
early on Sunday morning. Anomalously high PWAT values will combine
with a strong southerly low-level jet and boundary parallel upper-
layer flow to present a threat for very heavy rainfall. Widespread
average rainfall amounts of 2.5"-3.5" will be possible over a
relatively short period of time. Due to the progressive nature of
the system, any sort of significant flooding is not expected at
this time. For further information on the heavy rain threat
reference the hydrology section below. Impressive wind shear
profiles suggest a non-zero threat for an isolated severe
thunderstorm during the overnight hours, though pretty much all
thunderstorms should be elevated during this period.

On the heels of the aforementioned system, the previously
mentioned strong northern stream shortwave will be moving into the
Tri-State region. Once again, very impressive shear profiles will
overspread the region from west to east through the late morning
and afternoon hours on Sunday. The main question will be just how
much instability will be present in the wake of the morning
rainfall. Early indications from some of our high resolution
modeling suggests a quicker progression of the morning rainfall
and thus a better chance for destabilization during the day on
Sunday, while the global-scale models indicate very little surface
destabilization and lingering rain through the day on Sunday. With
the event just starting to fall within the range of the higher
resolution models, there is quite a bit of uncertainty but given
the fact that the global-scale models tend to be a bit slow with
isentropic rain development, it is certainly possible that the
hires models may be on to something. Should the severe threat pan
out, the primary threats would be damaging winds and tornadoes
within discrete supercells.

The more dynamic shortwave will move out of the region by Sunday
evening, stalling a weak front across the region. Continued
southern stream support will keep the potential for showers and
isolated thunderstorms through the night on Sunday, but the severe
threat will have come to an end.


.Long Term [Monday Through Friday]...

The primary northern stream longwave trough will gradually
approach through Tuesday. Increased diffluence between the
northern stream and southern stream anomalies will continue to
support primarily showers across the eastern half of the region
until a stronger cold front clears out all of the rain by
Wednesday morning. Arctic high pressure will fill in across the
Southeast on Wednesday, capping afternoon highs in the 50s to
finish out the week. Overnight lows starting on Wednesday night
will fall back into, at least, the lower 30s.


.Marine...

Advisory level winds and seas should be expected through Sunday
associated with a complex frontal system. A temporary dip below
headline levels is expected on Monday before another strong cold
front re-introduces headline conditions on Tuesday, possibly
through the end of the week.


.Fire Weather...

With increasing low level moisture and rain chances, no Red Flag
concerns are expected through the weekend. In fact, Wet Flags are
expected on Sunday.


.Hydrology...

Storm total rainfall amounts Saturday through Tuesday will be on
the order of 2 to 4 inches, with most of the rainfall coming over
a 12 hour period late Saturday night through Sunday morning. Low
river levels will likely prevent any river flooding even with
these high totals. However, there is a concern for some localized
flooding in the more urbanized locations that receive the higher
totals over a short period of time. Any decisions about a Flash
Flood watch will likely come overnight tonight, or tomorrow
afternoon when more guidance becomes available.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   45  68  60  75  64 /   0  20 100  70  50
Panama City   49  67  63  75  66 /   0  30 100  80  50
Dothan        40  65  56  74  62 /   0  10 100  80  40
Albany        39  65  56  74  63 /   0  10 100  80  50
Valdosta      43  68  58  76  64 /   0  20 100  80  50
Cross City    49  72  63  77  64 /   0  20 100  60  40
Apalachicola  51  67  66  74  67 /   0  30 100  60  50

&&

.TAE Watches/Warnings/Advisories...

FL...None.
GA...None.
AL...None.
GM...Small Craft Advisory until 7 PM EST Sunday for Coastal waters
     From Ochlockonee River to Apalachicola FL out to 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.


&&

$$

NEAR TERM...CAMP/DOBBS
SHORT TERM...HARRIGAN
LONG TERM...HARRIGAN
AVIATION...CAMP/DOBBS
MARINE...HARRIGAN
FIRE WEATHER...GOULD
HYDROLOGY...HARRIGAN






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