Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 132022
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
Issued by National Weather Service Peachtree City GA
222 PM CST Fri Dec 13 2019

.SHORT TERM...
/Updated at 0230 PM CST Fri Dec 13 2019/

This afternoon into this evening, a broad longwave trough will
continue digging into the Mississippi River Valley, bringing another
round of showers that are beginning to move into the western portions
of the forecast area. Convection overall looks relatively benign,
but a slight chance for thunderstorms will still exist for
southeastern and portions of east central Alabama going into the
overnight hours, the final line of showers and storms expected to
exit the forecast area around midnight.

By Saturday morning, the axis of the upper-level trough will have
swept through into Georgia. Providing enough subsidence to reduce
precip chances, but not enough to completely dissolve the low-level
shield of stratus, but we should expect some it to begin breaking up
by the late morning with some sunlight peaking through. Highs will
increase slightly but remain in the mid- to upper-50s.


Thiem


.LONG TERM...
/Updated at 0230 PM CST Fri Dec 13 2019/

No major changes to the long term portion of the forecast were
made. See previous discussion.

NLIST

Previous Discussion...
Saturday night through Thursday.

Overall an active pattern will continue through the extended.
Severe weather possible on Monday afternoon/evening. Best chances
for sunshine will be on Sunday and again on Wednesday.

High pressure will be in place on Sunday but will not last long as
the next system will begin to work into the area overnight Sunday
and push through the area on Monday. Rain will linger through
Tuesday morning in the northwest to Tuesday afternoon in the
southeast. This system will be another potential beneficial rain for
the extended period. Highs will warm into the mid 60s to low/mid 70s
degrees in the south in Monday ahead of the front that will move
through sometime overnight Monday night into Tuesday afternoon.

Model consensus continues to agree that there is a severe chance
during the day on Monday into Monday night. There will be a good
window for a moist and unstable environment across the Southeast.
Strong vertical shear will be available across the area with the
best locations across the northwest. Here we could see 0 to 6 shear
around 60 kts, 0 to 1 km helicity around 300, bulk shear of 50 to 55
kts. Mid-level lapse rates will support the threat as well along
with a strong LLJ working into the area. Forecast soundings and
hodographs support supercell environments during the day as well.
Will continue with the severe weather threat on Monday/Monday night,
including the threat for tornadoes. Adjusted the timing only a touch
to be a little later. Much more on this over the next few runs. Dry
weather returns on Wednesday behind the cold front, with highs in
the upper 40s and low 50s.

16

&&

.AVIATION...
18Z TAF Discussion.

Currently SHRA is focused near MGM, with model progs indicating
another possible wave of SHRA later tonight between 21-06Z. CIGS
will continue to waffle between IFR and LIFR with VSBYs possibly
getting down to 1-2 SM at times. Thunder probability is not zero,
but it is too low to mention in terminals at this time.

Thiem


&&



.PRELIMINARY POINT TEMPS/POPS...
Gadsden     41  55  37  57  50 /  60  20   0  10  20
Anniston    42  55  38  59  51 /  70  20   0  10  10
Birmingham  42  55  39  58  54 /  40  20   0   0  20
Tuscaloosa  42  58  39  61  56 /  20  10   0   0  20
Calera      41  55  38  59  53 /  40  10   0  10  10
Auburn      44  55  39  58  50 /  80  10   0   0  10
Montgomery  45  59  39  61  54 /  70  10   0   0  10
Troy        46  59  40  62  53 /  80  10   0   0  10

&&

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

&&

$$


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