Area Forecast Discussion
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590
FXUS62 KTAE 130218
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
918 PM EST Mon Nov 12 2018

.NEAR TERM [Through Tonight]...

The threat for severe weather has essentially come to an end
across the region this evening as the area of greatest instability
has retreated back over the Gulf. The emerging consensus is that
the intensity and overall coverage of rain will diminish through
the overnight hours before filling in along and ahead of the cold
front tomorrow. Expect fog to be a concern overnight with the
soupy airmass that`s in place along and east of a line from Destin
through Albany. Overnight lows will generally settle into the 60s
region-wide.

&&

.PREV DISCUSSION [657 PM EST]...

.SHORT TERM [Through Wednesday Night]...

The complicated forecast pattern continues through Wednesday night.
18Z regional surface analysis showed a low in coastal central LA
with a cold front extending southwestward offshore and a warm front
extending east-northeastward along coastal eastern LA, MS, and AL.
The warm front reaches across the FL Panhandle to just into western
Walton county, FL before diving south along the Panhandle coastline.
As the low moves eastward slowly tonight, the warm front will
continue to work its way into the area. A stable environment with
socked in low clouds north of the front has prevented severe storms
offshore from making it inland, but as the warm front pushes
northward, the environment will become increasingly unstable until
around sunset. The low level (0-1km) shear is 30-40 kts west of the
Chatahoochee/Apalachicola rivers. When combined with the forcing
from the warm front and decreasing instability, tornadoes will be
possible in this region. A tornado watch is in effect through 8 PM
ET. The heaviest rainfall has remained offshore so far today as well
and so far the zones in the flash flood watch have received around
2" or less. As the warm front continues northward, however, the
threat for heavy rainfall will also increase and will continue
through the night.

Instability will wind down again this evening and the front will
stall for the night. At this time, it`s looking like the cold front
will stall near New Orleans to Birmingham. As a result, rounds of on
and off showers will likely continue through the night in our
western zones, but the severe threat will lower. The front will
again make some eastward progress on Tuesday and stall again Tuesday
night as the upper level disturbance driving it becomes cut off in
the southeastern Plains. Light to moderate rainfall is expected on
and off through the day Tuesday, with isolated thunderstorms
possible, followed by a brief break in rainfall overnight,
particularly east of Tallahassee/Valdosta.

On Wednesday, the low pressure system will deepen as the cut off
upper level low moves into the lower Mississippi Valley. Deep layer
southerly flow will drive another plume of moisture into our area
with PW values rising back to 2+" over the area. Another round of
heavy rainfall appears likely Wednesday through Wednesday night, as
the front pushes through most of the forecast area. Additional
rainfall accumulations tonight through Wednesday night are expected
to be around 3-5". At this time, the flash flood watch remains in
effect through Tuesday evening west of the Flint and Apalachicola
Rivers, but may need to be extended into Wednesday depending on how
much rainfall we get tonight.


.LONG TERM [Thursday Through Monday]...

Relatively quiet weather is expected through the long term period
beginning on Thursday as a trough of low pressure finally swings
through the southeast. Much cooler conditions expected behind the
front with high temperatures on Thursday and Friday dropping into
the mid 50s to low 60s. We could also see our first instance of
nighttime temps dropping into the 30s on Friday and Saturday
morning. Temps moderate slowly over the weekend with the upper 60s
and low 70s returning by Monday.

Conditions should remain dry through the period.


.AVIATION...
[Through 00Z Wednesday]

Rain with some embedded thunder will persist overnight. Visibility
will be MVFR or better outside of the heavier rain. IFR and possibly
even LIFR CIGs are expected overnight and in the morning hours. Late
tomorrow morning another round of thunderstorms will likely develop
ahead of the cold front. The best chance for storms will be at TLH
and VLD. Elsewhere a steady rain with isolated embedded thunder is
likely tomorrow. Winds will be northwesterly and a bit gusty behind
the front tomorrow afternoon.


.MARINE...

Winds and seas have lowered, but will increase again, possibly up to
advisory levels Tuesday afternoon through Wednesday morning.
Widespread showers and some thunderstorms will persist through
Wednesday night and exit Thursday morning as a slow moving cold
front pushes through. A tornado watch is in effect for our western
coastal waters through 7 PM CT.


.FIRE WEATHER...

Aside from low dispersion indices, hazardous fire weather conditions
are not expected. A wet pattern will continue through mid to late
week.


.HYDROLOGY...

Rainfall accumulations so far today have received around 2" or less.
As the warm front continues northward, however, the threat for heavy
rainfall will also increase and will continue through the night. The
slow moving front is not forecast to exit the area until late
Wednesday night/early Thursday morning, so periods of on and off
moderate to heavy rainfall will continue for the next few days.
Additional rainfall accumulations tonight through Wednesday night
are expected to be around 3-5". Flash flooding remains a concern. At
this time, the flash flood watch remains in effect through Tuesday
evening west of the Flint and Apalachicola Rivers, but may need to
be extended into Wednesday depending on how much rainfall we get
tonight.


.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   67  75  55  63  50 /  50  80  40  70  80
Panama City   68  71  52  60  49 /  80  80  50  70  80
Dothan        61  62  48  55  44 /  90  80  50  80  80
Albany        63  67  53  56  47 /  80  80  50  80  90
Valdosta      65  78  57  63  51 /  20  80  40  60  70
Cross City    69  81  63  73  58 /  20  40  40  50  60
Apalachicola  68  76  57  66  52 /  60  70  40  70  80

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Flash Flood Watch through Tuesday evening for Calhoun-Central
     Walton-Coastal Bay-Holmes-Inland Bay-Jackson-North Walton-
     South Walton-Washington.

GA...Flash Flood Watch through Tuesday evening for Baker-Calhoun-Clay-
     Dougherty-Early-Lee-Miller-Quitman-Randolph-Seminole-
     Terrell.

AL...Flash Flood Watch through Tuesday afternoon for Coffee-Dale-
     Geneva-Henry-Houston.

GM...None.
&&

$$

NEAR TERM...Harrigan
SHORT TERM...Nguyen
LONG TERM...Dobbs
AVIATION...McD
MARINE...Nguyen
FIRE WEATHER...Harrigan
HYDROLOGY...Nguyen



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