Hail and Damaging Winds in Alabama, March 9 to 10, 2017

Area Forecast Discussion
National Weather Service Birmingham AL
224 PM CST Thu Mar 9 2017

.DISCUSSION...

Temperatures are soaring this afternoon with deep-layer westerly
flow and a dry low-level airmass in place. However, moisture is
beginning to increase especially across West AL and into MS due to
the onset of WSW flow at 850mb. This is occurring in advance of
an approaching subtle shortwave embedded within WNW flow at 500mb.
As a cold front sharpens to our north tonight, thunderstorms are
expected to develop upstream near the MS river and grow upscale.
Wind fields should strengthen in response to the approaching
shortwave with a 45kt low-level jet across our North at 06z. A
tongue of 500-800 J/kg MLCAPE and fairly steep mid-level lapse
rates combined with a mostly unidirectional wind profile could
lead to isolated damaging winds mainly along and north of I-20 in
association with a QLCS.

Our next chance of rain will come Saturday night into Sunday
morning with another shortwave in the WNW flow pattern. A cool/dry
antecedent airmass will be in place, leading to evaporational
cooling and temperatures falling into the 30s and 40s. Any impacts
from a wintry mix should stay just north of our forecast area,
though some ice pellets appear possible across the very northern
part of our northernmost counties.

Models are in good agreement that another shortwave will rotate
through on Monday with a strong reinforcing shot of cold air
lasting through Thursday. The trailing airmass may be the coldest
in several weeks, and a widespread significant freeze cannot be
ruled out in the Wednesday/Thursday timeframe.

87/Grantham

&&

.AVIATION...
18Z TAF Discussion.

Pretty quiet for the next 12 to 15 hours as a cold front will
begin to slide into the region. Looks like most of it will hold
off until after 3Z north and 9Z south. VFR until the rain starts
then MVFR with brief rounds of IFR. Included VCTS but not
positive on exact timing as the front moves through. Conditions
remain MVFR through 18Z with backside clouds.

16

&&

.FIRE WEATHER...

A moistening will continue this afternoon into tonight with a line
of showers and storms expected to affect much of the area. A
second system will bring widespread rainfall to the area Saturday
night and Sunday morning. There are no fire weather concerns.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     57  66  35  60  38 /  80  10   0  20  90
Anniston    57  69  38  63  39 /  80  20   0  20  90
Birmingham  60  68  38  61  38 /  80  20   0  30  90
Tuscaloosa  61  72  40  65  40 /  70  20   0  30  80
Calera      60  70  40  64  40 /  70  30   0  30  90
Auburn      58  73  42  66  46 /  60  50   0  10  90
Montgomery  59  77  44  70  46 /  50  50   0  20  90
Troy        57  77  44  71  50 /  40  50   0  10  90

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
239 PM CST Thu Mar 9 2017

ALZ011>015-017>050-102345-
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee-
Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega-
Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa-
Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon-
Bullock-Lee-Russell-Pike-Barbour-
239 PM CST Thu Mar 9 2017

This Hazardous Weather Outlook is for the counties served by the
National Weather Service office in Birmingham.

.DAY ONE...This Afternoon and Tonight.

There is a risk of isolated severe thunderstorms tonight across
northern Alabama, mainly near and north of a line from Carrollton to
Birmingham to Anniston from midnight to 4 AM. A few of the strongest
storms may produce damaging winds up to 60 MPH.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management may be needed
late tonight.