FXUS64 KBMX 230011
Area Forecast Discussion
National Weather Service Birmingham AL
711 PM CDT Sat Sep 22 2018
For 00Z Aviation.
A weakening upper level ridge axis extends into the area from the
northeast, making for a split flow pattern over Central Alabama.
For the southeast, flow around an upper level low in the Gulf is
slowly advecting moisture northwestward. Weak impulses around the
northern edge of this feature are allowing for isolated showers
near and south of the I-85 corridor. Winds become more southerly
and then southwesterly across the west, due to the influence of an
approaching upper level trough and stalled front to our
northwest. Weak convergence and uplift south of that front has
resulted in scattered showers across the west.
Most of this activity will diminish this evening, and will trim
rain chances back gradually to the northwest. With the front
nearby cannot rule out isolated to scattered coverage north of
I-20 overnight. Expect lows in the upper 60s to lower 70s.
Sunday through Friday.
The overall setup for Sunday should not change much from Saturday,
with a patch of residual drier air indicated in model guidance
east of I-59. This is where isolated showers and storms are
expected, and greater coverage should be confined to our
A transition to deep-layer southerly flow on Monday will usher in
an abundance of moisture and widespread PWAT values around 2
inches. Remnant boundaries and small shortwaves generated by
convection to our west on Sunday may play a role in enhancing
activity on Monday. Rain chances have been increased into the
50-60 percent range across the entire area.
A similar regime of 850-500mb southwesterly flow should continue
for Tuesday through Friday. This will be supported by a nearly
steady-state upper-level pattern, characterized by broad trough
over the central and northern CONUS and a strong ridge centered
just southwest of Bermuda. Relatively high rain chances are
expected especially each afternoon and evening. The approach of a
cold front on Wednesday and Thursday should contribute to even
higher rain chances (60-70 percent) northwest of I-85.
With the ridge holding firm to our south and east on Friday, there
is no evidence of a significant frontal passage in the foreseeable
future. For those who are looking for fall-like conditions,
unfortunately you'll probably be waiting until at least the first
week of October.
00Z TAF Discussion.
Kept the trend of VFR going through the period. A cold front was
located north of all the terminals early this evening, across the
far reaches of northwest Alabama. This front will not make much
more headway into the state and will meander around the northwest.
An area of relatively dry air will remain over much of Central
Alabama limiting rain chances into Sunday. A few showers/storms
are possible overnight, but most should remain north of the
terminals. On Sunday, showers.storms are possible again but the
highest chances are south of MGM/TOI and west and north of the
northern sites. Therefore, will not mention anything at this time.
Winds will be calm to light east southeast overnight and only
increasing to around 5-6kts south southeast on Sunday. The low
level atmosphere looks to stay dry enough that fog or low clouds
should not be a problem.
Showers and storms should generally remain isolated to scattered
through tomorrow, with the best rain chances across the northwest
each period. Rain chances will increase significantly for the
upcoming week. Morning patchy fog and/or low clouds appears
unlikely tomorrow but will become more likely beginning Monday.
There are no fire weather concerns at this time.
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 68 90 68 84 70 / 30 20 30 60 30
Anniston 68 91 69 85 70 / 20 20 20 50 30
Birmingham 71 90 71 85 71 / 30 20 30 60 40
Tuscaloosa 71 91 71 87 72 / 30 20 20 60 30
Calera 69 89 70 85 70 / 20 20 20 60 30
Auburn 69 89 70 85 70 / 20 20 20 50 30
Montgomery 69 92 71 88 72 / 20 20 20 60 30
Troy 68 90 70 88 70 / 20 30 20 50 30
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