Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 220606
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1206 AM CST Sun Jan 22 2017

.UPDATE...
For 06Z Aviation.

&&

.DISCUSSION...

As of 0435Z, a 40-50 knot low-level jet was overspreading the
Florida panhandle and into far southern Alabama, while 15-20 knots
of flow was in place across our area/central Alabama. Breezier
surface winds of 15-20 MPH/gusts to 30 MPH were being observed in
association with the low-level jet wind field, overall much
lighter toward the north. Increased low-level flow arcs back into
central Mississippi in association with the western perimeter of
the overall 850mb surge. This feature will be key in the
manifestation of the tornado threat tonight.

With strong 500-300mb flow and swaths of recovering dew points,
resulting bulk shear and CAPE/steep lapse rates will support
severe thunderstorms as they spread into central Alabama in the
coming hours. Large hail and damaging winds are on the table, with
a developing tornado risk as well once the low-level jet advances
into the area. The highest tornado concern is across the
southeastern counties where jet shear will be the highest, with
supporting higher-value dew points advecting farther north with
time.

-----

Also, we have updated our forecast to include a third round of
severe thunderstorms, focused on southeastern portions of the area
Sunday morning through the afternoon as a meso-low moves through.
The same parent weather maker is forecast to send another corridor
of enhanced low-level winds across the area, while strong southwest
upper-level flow continues. This in tandem with modeled moderate SB-
and ML-CAPE, and steep lapse rates, will promote an additional
threat of tornadoes, large hail, and damaging straight-line winds.
Refer to our webpage for the threat graphic associated with this
period.

89^GSatterwhite

&&

.AVIATION...
06Z TAF Discussion.

Extensive showers and thunderstorms are present across Central
Alabama affecting most TAF sites. TS will continue off and on
through much of the night and into Sunday. There may be a little
break in between rounds but do not have that reflected at this
time with boundary still to the south that it is expected to push
northward later tonight. Will have reduced visibility and lower
cigs with TS. Also, if break occurs before daybreak could end up
with some lower cigs and fog to deal with and will monitor for
these changes.

08

&&

.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     63  45  53  35  59 /  90  70  20   0   0
Anniston    65  46  53  37  60 /  90  70  20   0   0
Birmingham  64  46  54  36  61 /  80  60  20   0   0
Tuscaloosa  65  46  56  37  63 /  80  50  20   0   0
Calera      64  46  55  38  62 /  80  60  20   0   0
Auburn      67  48  56  40  61 /  80  50  20   0   0
Montgomery  68  47  58  39  64 /  80  40  20   0   0
Troy        69  47  59  39  64 /  80  40  20   0   0

&&

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

&&

$$

89/08


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