Area Forecast Discussion
Issued by NWS Birmingham, AL

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896
FXUS64 KBMX 221720
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1120 AM CST Sun Jan 22 2017

.UPDATE...
For 18Z Aviation.

&&

.DISCUSSION...

Another round of showers and thunderstorms today as an upper low
over Texas tracks eastward across Alabama this evening. The closed
upper low will deepen and trigger a surface low development across
south Alabama later this morning. This surface low will also
deepen as it tracks northeast across east Alabama. The track of
the surface low is very critical to determining the highest
tornado threat area. The southeast counties, mainly along and
south of I-85 still look like the prime area for tornado
formation today, and have elevated this area in our threat area
graphics. The surface low will track quickly northeast and the
severe threat will end fairly quickly once the surface low crosses
over into Georgia, sometime around 3 pm. This is a very dynamic
system and widespread showers and elevated thunderstorms expected
on the north and west side of the upper low. Temperatures near the
center of the 500mb upper low will be near -25 celsius, and steep
lapse rates could produce some large hail across the southeast
counties in the more vigorous convection, with small hail as far
north as I-20.

Cooler and more stable air will overspread all of central Alabama
this evening. Scattered to numerous showers will continue across
central Alabama tonight as the upper low center moves across the
area. A very tight surface pressure gradient will develop later
tonight as the surface low deepens and moves east of Alabama.
Sustained west to northwest winds of 15 to 25 mph will likely
develop after midnight and last through Monday morning, and a wind
advisory may be issued later today. Monday will be a very chilly
day with brisk northwest winds and lingering clouds. Skies will
gradually clear from west to east Monday afternoon, and there may
be some lingering showers across east Alabama Monday morning.

Mostly clear and dry Monday night and Tuesday. A weak front will
pass through the area Wednesday and Wednesday night and bring some
scattered showers. Drier and slightly cooler conditions Thursday
through Saturday.

58/rose


&&

.AVIATION...
18Z TAF Discussion.

Today will be another difficult day to forecast for aviation. A
strong low pressure system will be moving through Central AL
today with storms and rain building along the warm front as it
lifts northward through the afternoon. Hi-Res models have not been
handling the timing overly well this morning, trying to move the
warm front and rain/storms through quicker than is actually
occurring. Therefore, have slowed the progress of TSRA and RA in
the terminal forecasts. Storms have begun moving into the TOI and
MGM areas around 17z, and should progress northward during the
afternoon, impacting all TAF sites by late afternoon. Behind the
warm front and low pressure system, winds will become
northwesterly as light rain showers will persist through midnight
for Central AL. Behind the rain shield, gusty northwesterly winds
will be likely. Have issued a Wind Advisory for all of Central AL
from midnight tonight through 6:00pm Monday. Sustained winds
15-20kts with gusts up to 30-35kts possible.

25/Owen

&&

.FIRE WEATHER...

Another round of showers and thunderstorms today, with heavy
rainfall at times. Much cooler and breezy tonight with showers
likely. Rain free conditions Monday and Tuesday. No fire weather
concerns.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     63  48  53  35  59 /  80  80  30   0   0
Anniston    64  50  55  37  60 /  80  80  30   0   0
Birmingham  64  49  56  36  61 /  80  80  20   0   0
Tuscaloosa  63  49  56  37  63 /  80  70  10   0   0
Calera      63  49  56  38  62 /  80  70  10   0   0
Auburn      64  51  57  40  61 /  70  60  20   0   0
Montgomery  66  51  60  39  64 /  70  50  10   0   0
Troy        68  50  59  39  64 /  70  50  10   0   0

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
Wind Advisory from midnight tonight to 6 PM CST Monday for the
following counties: Autauga...Barbour...Bibb...Blount...
Bullock...Calhoun...Chambers...Cherokee...Chilton...Clay...
Cleburne...Coosa...Dallas...Elmore...Etowah...Fayette...Greene...
Hale...Jefferson...Lamar...Lee...Lowndes...Macon...Marengo...
Marion...Montgomery...Perry...Pickens...Pike...Randolph...
Russell...Shelby...St. Clair...Sumter...Talladega...Tallapoosa...
Tuscaloosa...Walker...Winston.

&&

$$



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