Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 212143
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
343 PM CST Sat Jan 21 2017

.DISCUSSION...

We will focus on the short term, particularly tonight and the
potential for severe storms across the area. A discussion focusing
on the extended forecast will be issued later today.

This morning storms moved out quickly, with clearing skies and
warm temperatures in their wake. A stalled frontal boundary
stretches from the Gulf Coast near New Orleans to Mobile and then
angles to the northeast and cross far southeastern Central Alabama
and into Georgia. This front will be key in the potential for
severe storms tonight. A strong upper level impulse ahead of the
main trough will rotate into the area tonight, with both a low
level jet intensifying across the area and the upper level jet
nosing into the area from west. This will push the stalled front
back to the north, with the airmass south of the front becoming
increasingly unstable. Bulk shear values support updrafts and
thunderstorm development, while low level shear is supportive of
tornadoes, some of which could be strong.

The highest threat area will be across south Central Alabama,
generally near and south of the US Highway 80/I-85 corridor, but
will also be contingent on how far north the warm front lifts. To
the north of the front, storms will likely be elevated, but pose
a risk of damaging winds and large hail. Heavy rainfall is also
possible, and with saturated ground conditions, if and where
storms train over the same area, localized flooding in urban areas
and small streams will be possible. See the HWO and graphics on
our website for additional details concerning the severe threat
overnight.

This wave of storms will be end from southwest to northeast,
moving out of the area around 6AM. There is a low chance of
another wave of storms across the southeast tomorrow afternoon,
but that is dependent on how storms evolve overnight and how/if
the airmass can recover ahead of another upper level jet expected
to move across that area in advance of the approaching upper level
trough. Confidence is very low in whether this threat
materializes.

14

&&

.AVIATION...
18Z TAF Discussion.

This morning`s storms have moved out of the area, with only
lingering light rain at TOI, that should clear within the next 20
minutes. Winds will be somewhat variable through the afternoon, as
Central Alabama sits between two weather systems. Winds will become
southeasterly late this afternoon, increasing to 8-10kts this
evening as wind fields strengthen ahead of the next round of TSRA.
Expect a MVFR cloud deck to also spread northward across the area in
advance of the approaching storms.

Storms will move generally from southwest to northeast late tonight,
beginning to affect terminals around 05Z tonight. This timing will
need to be adjusted as storms develop to our southwest. Some of
these storms will be strong to severe.

14


&&

.FIRE WEATHER...

Strong to severe storms can be expected tonight, along with
periods of heavy rainfall. Rainfall amounts through Sunday will
average 1 to 2 inches. Drier conditions return through the
beginning of next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     55  63  45  53  35 /  70  80  70  20   0
Anniston    57  65  46  53  37 /  70  80  70  20   0
Birmingham  57  64  46  54  36 /  70  80  60  20   0
Tuscaloosa  56  65  46  56  37 /  70  80  50  20   0
Calera      57  64  46  55  38 /  70  80  60  20   0
Auburn      60  67  48  56  40 /  70  80  50  20   0
Montgomery  59  68  47  58  39 /  70  80  50  20   0
Troy        58  69  47  59  39 /  70  70  40  20   0

&&

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

&&

$$



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