Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 182046
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
346 PM CDT Fri Aug 18 2017

.SHORT TERM...
Through Tonight.

Weak upper level trough pushing southeastward through the area
this afternoon, allowing drier air to spread southward. This has
prevented any shower or storm activity today across Central
Alabama. Cannot rule out a stray shower across the far southeast
this afternoon, but chances are small and activity will be short
lived. Cumulus clouds will diminish with sunset this evening with
winds becoming calm. Overnight lows will be in the upper 60s in
the northeast, and low to mid 70s elsewhere.

14

.LONG TERM...
Saturday through Friday.

An upper trough moves eastward through the Midwestern states on
Saturday as a broad upper-level low retrogrades westward through the
Gulf of Mexico. Low-level ridging is in place across the
Southeastern US with northerly flow making its way into Central AL.
This dry northerly flow will keep us mostly dry Saturday and Sunday.
I`ll keep mention of slight chances for rain/thunderstorms across
the southern half of Central AL both days as I can`t rule out some
afternoon development with peak heating.

Upper level ridging builds in Monday and southerly flow returns.
Expect Monday and Tuesday to be typical summer days with diurnal
thunderstorm development. PWATs increase to near 2" with lower
values in the northwestern counties Monday. Have therefore kept 30-
40% PoPs in the forecast for areas south and east of the I20/59
corridor Monday, becoming area-wide on Tuesday.

Another surface low pressure system develops in the Upper Midwest on
Tuesday and moves eastward with the base of a synoptic scale trough
Wednesday. A cold front stretches through the Ohio River Valley and
pushes southward into the Tennessee Valley Wednesday night into
Thursday. Expect increased chances of showers/storms towards this
end of next week as the front passes through. Exact coverage of
storms along the frontal boundary is still uncertain, so will keep
30-40% in the forecast at this time.

25/Owen

&&

.AVIATION...
18Z TAF Discussion.

Fair weather cu across the area today, with west to northwesterly
surface winds. Do not expect convective development today given the
dry and warm air aloft. Winds will diminish this evening, become
calm. Drier air tonight should inhibit significant fog formation and
vis reductions. Given the terrain characteristics near many of
Central Alabama terminals and good radiational cooling conditions,
have added light fog at most terminals overnight.

14


&&

.FIRE WEATHER...

Drier weather through the weekend, with RH values remaining above
40 percent. Isolated to scattered afternoon showers possible for
portions of the Central Alabama both Saturday and Sunday
afternoons. There are no fire weather concerns at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     68  91  71  93  72 /   0  10  10  10  10
Anniston    70  91  71  93  72 /   0  10  10  20  10
Birmingham  72  93  74  94  75 /   0  10  10  10  10
Tuscaloosa  72  94  74  96  74 /   0  20  20  20  10
Calera      72  92  73  94  74 /   0  10  10  20  10
Auburn      72  91  73  92  74 /  10  10  10  20  10
Montgomery  74  94  74  95  75 /   0  20  20  20  10
Troy        72  93  74  94  74 /  10  20  20  20  10

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
None.

&&

$$


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