Area Forecast Discussion
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FXUS62 KTAE 221352
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
952 AM EDT Sun Oct 22 2017

.NEAR TERM [Through Today]...

Then upper level pattern has become more amplified across the
CONUS as a trough deepens across the Great Plains and a ridge hold
firm off the Southeast U.S. Coast. Surface high pressure centered
northeast of the area is gradually retreating. A cold front
bisects the nation from Lake Superior to Texas. Regional radars
show scattered storms developing across the Central Gulf Coast as
far east as Mobile Bay. This activity should continue to gradually
developed eastward. We inched PoPs upward a bit, 30-50% in most
areas. Any severe threat in our area should hold off until late
tonight.

&&

.PREV DISCUSSION [651 AM EDT]...

.SHORT TERM [Tonight Through Tuesday]...

A mean upper-level long wave trough will become established over
much of the eastern CONUS by Tuesday as potent short wave troughs
in the northern and southern streams become phased. This phasing
will mark the beginning of a cool spell with fair weather across
our forecast area. Before this occurs we will have a rainy Monday
as an initial southern stream trough, currently over the TX
Panhandle, translates quickly eastward across our region. A narrow
plume of strong south winds will develop across our forecast area
tonight and Monday, advecting ample moisture from the tropics.
This deep moisture, coupled with strong Q-G forcing, will lead to
numerous showers and thunderstorms tonight through Monday.

The forecast threat of severe thunderstorms is still problematic.
Forecast 0-6km bulk shear values of 30 to 40 knots could support
some storm organization, but the broad region of fairly strong
Q-G forcing suggests widespread clouds and rain by morning, which
would limit both low level and mid level lapse rates, and perhaps
even prevent much of the convection from being rooted in the
surface layer. We think the expected marginal buoyancy will
prevent a more widespread severe storm event, but there are enough
favorable environmental parameters to warrant a low-end threat,
with marginally damaging winds (40-60 MPH) and perhaps even an
isolated tornado being the main threats.

Intense drying aloft will spell a quick end to the rain from west to
east Monday afternoon and evening. Forcing for ascent will develop
once again on Tuesday as a rather strong 850-700 mb cold front
moves quickly southeast across our region. However, the lack of
deep- layer moisture will keep rain chances below 20%. After a
summer-like night (with lows in the 70s), temperatures will return
to average to close out the forecast period.


.LONG TERM [Tuesday Night Through Sunday]...

The 500 mb height pattern will remain amplified, as a mean long wave
trough will oscillate between the eastern and central CONUS. Fair
and cool weather is expected mid to late in the work week, followed
by increasing rain chances next weekend. (However, the global models
differ in the details on next weekend`s system). High temperatures
will struggle to reach 70 on Wednesday (despite ample sun), and will
remain in the 70s for the remainder of the week. Lows will generally
be in the 40s Tuesday night through Thursday night, then in the 50s.
Rain chances will average around 30% next weekend, mainly due to the
uncertainty between the models.


.AVIATION [Through 12Z Monday]...

A brief period of MVFR cigs this morning at DHN. Otherwise, VFR
will prevail until at least this evening. After that, expect
showers/TSTMs to spread across the area from west to east ahead of
a strong cold front. Convection may be accompanied with gusty
winds and MVFR/IFR conditions, mainly late this evening and
into daybreak Monday.


.MARINE...

Winds and seas will remain elevated through mid week, initially due
to a strong high pressure system centered over the Mid Atlantic
region today, and then to a cold front moving east across the
coastal waters on Monday. Winds and seas will gradually subside
later this week.


.FIRE WEATHER...

Hazardous fire weather conditions are not expected over the next
several days.


.HYDROLOGY...

The greatest chance for heavy rain will be Monday, especially
along and west of a line from Albany to Tallahassee, where
widespread QPF amounts of 1 to 3 inches are expected. Isolated
amounts of 4 to 6 inches are possible, but the expected coverage
of these higher amounts is so low that a Flood Watch is not
needed. While the widespread QPF currently forecast will cause
some sharp rises on some of the rivers, most of the local rivers
were running very low to begin with, and river flooding is
unlikely.


.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   87  73  80  58  77 /  40  60 100  20   0
Panama City   83  73  80  60  75 /  50  80 100  10   0
Dothan        86  71  77  54  73 /  40  80 100  10   0
Albany        87  72  78  55  74 /  20  50 100  10  10
Valdosta      87  71  79  59  75 /  30  40  90  50  10
Cross City    87  72  81  61  78 /  50  30  90  70  10
Apalachicola  82  74  81  60  78 /  40  70 100  10   0

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late Monday night for Coastal Bay-
     Coastal Franklin-Coastal Gulf-South Walton.

GA...None.
AL...None.
GM...None.
&&

$$

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



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