Special Weather Statement, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
900 AM CDT Fri Apr 9 2021

.UPDATE...
MESOSCALE UPDATE.

&&

.SHORT TERM...
/Updated at 0853 AM CDT Fri Apr 09 2021/

Local mesoscale discussion valid through 11 am.

Continuing to monitor showers and thunderstorms across portions of
our southern counties. Mesoanalysis data indicates sufficient
instability resides along and roughly south of a diffuse warm
front extending from west to east generally near the U.S. Highway
80 corridor. Environmental shear continues to increase from the
southwest and this setup is supportive of splitting storms which
will be capable of producing large hail and damaging winds. The
wind damage risk remains relatively low at this time but is
expected to increase as we head through late morning into the
afternoon hours. Hail threat is the most concerning and will
persist through the rest of the day. KBMX 12z sounding shows steep
lapse rates generally above 750 mb due to cold air aloft. Some dry
air aloft will also encourage the hail and damaging wind threat
later today. As the surface destabilizes due to increasing
thermal/moisture advection along with solar heating, expect large
amounts of convective energy to be realized that will support at
least isolated severe convective development and sustainment with
time.

Expect the risk for strong to severe storms to persist across our
southern counties through late morning, expanding further north
toward the Interstate 20 corridor closer to the midday into early
afternoon time frame.

05

Previous short-term discussion:
/Updated at 0338 AM CDT Fri Apr 09 2021/

Today through Saturday.

Southerly low level flow has increased overnight with radar based
winds estimated at 30-40 mph around 2000 feet agl. Low clouds have
also pushed northward into south central Alabama with convection
developing along the Alabama and NW Florida coast. Expect showers
and thunderstorms to quickly increase in areal coverage across the
southern counties this morning and spread northward to the I-20
corridor by early afternoon. Convection will be primarily driven by
diurnal heating, more like a summertime pattern. Better coverage of
storms today should be east of I-65 and south of I-20, where deeper
moisture will exist. Strong low and mid-level lapse rates will favor
storms with damaging winds and large hail. Main limiting factor will
be 0-6km bulk shear, which is forecast to remain around 30 knots, so
storms may struggle to maintain updraft strength for long duration.
Tornado threat remains low today due to unfavorable low level
helicity. Storms should decrease in intensity after sunset, but
still capable of producing damaging winds and large hail. Models are
hinting at better coverage of storms shifting into west Alabama this
evening, as forcing increases ahead of approaching short wave trof.
Model consensus is for several clusters of ongoing convection across
Arkansas, Mississippi, and west Alabama overnight merging into a
QLCS by 3 AM Saturday. The fast moving QLCS will favor a damaging
straight line wind event, but 0-3km SRH values of 300-350 will also
result in an associated tornado threat. The QLCS should be near or
just east of I-65 by sunrise Saturday, and exiting the southeast
counties by 10 AM. The highest threat for damaging winds and
tornadoes with the QLCS should be along and south of line from
Carrollton, to Tuscaloosa, to Centreville, to Wetumpka, to Hurtsboro.

58/rose

.LONG TERM...
/Updated at 0338 AM CDT Fri Apr 09 2021/

Saturday night through Thursday.

Lingering thunderstorms are possible across the southeastern
counties late Saturday night through early Sunday morning as the
main frontal boundary finally pushes through Central AL. The low
pressure system itself is expected to lift northward into the Great
Lakes region, leading to height rises across the Deep South Sunday
through Monday. With the ridging developing in the lower levels, we
should remain rain-free. We transition to more of a quasi-zonal flow
aloft Monday afternoon through Thursday. However, this doesn't mean
we'll stay rain-free as model guidance picks up on at least two
quick shortwave impulses that slide across the southern half of the
CONUS Tuesday through Thursday. Each of these will increase
rain/thunderstorm chances for our area, though specific timings
remain uncertain this far in advance. Therefore, I've trended PoPs
up around mid-week, but will keep chances in the 40-50% range.

25/Owen

&&

.AVIATION...
12Z TAF Discussion.

A very active pattern through the period with several rounds of
thunderstorms. Southerly winds 7-10 kts today will spread gulf
moisture and low clouds northward today. The storms have already
developed near the I-85 corridor, and this activity will spread
northward throughout the day. Locally heavy, wind gusts up to 35
kts, and large hail could accompany any storm that develops
through the evening hours. IFR cigs across south Alabama early in
the period could reach the I-20 corridor this morning, and added
a tempo for IFR cigs at KEET and KTCL thru 15z. Cigs will improve
by this afternoon with mostly VFR cigs between 18z and 03z. MVFR
cigs will develop across central Alabama by 03z with widespread
IFR cigs after 06Z. A QLCS will spread from west to east across
Alabama between 06Z and 12z. The line of storms will likely
contain damaging winds, with a threat of isolated tornadoes. Ahead
of the QLCS, south surface winds will become gusty with peak
values arnd 20 kts.

58/rose

&&

.FIRE WEATHER...

Scattered showers and thunderstorms expected today across much of
the area. This could cause erratic gusty winds in locations
nearest to any thunderstorm development. More widespread rain and
thunderstorms move in overnight tonight into Saturday.

Drier/rain-free conditions are expected Sunday into Monday, with
afternoon RH values in the 30-40 percent range.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     81  59  75  49  72 /  40  90 100  20  10
Anniston    81  62  75  53  74 /  40  90 100  20  10
Birmingham  80  62  75  51  74 /  40 100  90  10  10
Tuscaloosa  80  62  76  51  75 /  40 100  90  10  10
Calera      79  62  75  52  74 /  40 100 100  10  10
Auburn      75  62  72  57  74 /  50  50 100  30  10
Montgomery  80  64  77  57  77 /  50  70 100  20  10
Troy        80  63  75  59  77 /  50  50 100  30  20

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
512 AM CDT Fri Apr 9 2021

ALZ011>015-017>050-101315-
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-
512 AM CDT Fri Apr 9 2021

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

.DAY ONE...Outlook through Tonight.

Severe storms are possible late this morning through the evening
hours across all of Central Alabama. Threats include damaging winds
and large hail.

Another round of severe storms will move through late tonight
and into Saturday morning. Damaging winds and large hail are
possible along with an isolated tornado threat. Locally heavy
rainfall may also cause minor flooding.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Severe storms will continue through Saturday morning. Damaging winds
and large hail are possible along with an isolated tornado threat.
Locally heavy rainfall may also cause minor flooding.

Minor flooding along portions of the Tombigbee River Saturday night
through Tuesday.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management will likely be
needed this afternoon through Saturday.

Special Weather Statement
National Weather Service Birmingham AL
940 AM CDT Fri Apr 9 2021

ALZ035-041-043-091530-
Chilton AL-Autauga AL-Elmore AL-
940 AM CDT Fri Apr 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN AUTAUGA...
NORTHWESTERN ELMORE AND SOUTHEASTERN CHILTON COUNTIES UNTIL 1030 AM
CDT...

At 940 AM CDT, Doppler radar was tracking a strong thunderstorm over
Elmore, or 7 miles north of Millbrook, moving northeast at 20 mph.

Dime size hail will be possible with this storm.

Locations impacted include...
Millbrook, Wetumpka, Elmore, Coosada, Deatsville, Marbury, Santuck,
Titus, Weoka Mills, Jordan Lake, Welona, Ten Cedar Estates, Dexter,
Western Lake Martin, Holtville, Wetumpka Municipal Airport, Central,
Jordan Dam, Wallsboro and Speigner.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Birmingham.

&&

LAT...LON 3253 8658 3277 8649 3278 8641 3275 8637
      3275 8634 3277 8634 3277 8632 3275 8632
      3276 8606 3274 8597 3250 8627
TIME...MOT...LOC 1440Z 222DEG 19KT 3258 8633

40/Sizemore

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
953 AM CDT FRI APR 9 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0940 AM     HAIL             DEATSVILLE              32.61N 86.40W
04/09/2021  E0.70 INCH       ELMORE             AL   TRAINED SPOTTER

            DIME SIZED HAIL REPORTED IN DEATSVILLE. TIME
            ESTIMATED BY RADAR.

&&

JH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
955 AM CDT FRI APR 9 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0913 AM     HAIL             MILLBROOK               32.48N 86.36W
04/09/2021  E0.25 INCH       ELMORE             AL   PUBLIC

            PEA SIZED HAIL REPORTED IN MILLBROOK. TIME
            ESTIMATED BY RADAR.

&&

JH

Special Weather Statement
National Weather Service Birmingham AL
1021 AM CDT Fri Apr 9 2021

ALZ043-091600-
Elmore AL-
1021 AM CDT Fri Apr 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN ELMORE COUNTY UNTIL
1100 AM CDT...

At 1021 AM CDT, Doppler radar was tracking a strong thunderstorm near
Santuck, or near Wetumpka, moving east at 20 mph.

Dime size hail will be possible with this storm.

Locations impacted include...
Wetumpka, Tallassee, Eclectic, Santuck, Dexter, Southern Lake Martin,
Blue Ridge, Wallsboro, Claud, Yates Reservoir and Yates Dam.

LAT...LON 3252 8589 3252 8623 3263 8623 3275 8589
      3272 8589 3269 8591 3266 8591 3265 8589
TIME...MOT...LOC 1521Z 251DEG 18KT 3258 8612

40/Sizemore

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1044 AM CDT FRI APR 9 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1026 AM     HAIL             3 S SANTUCK             32.59N 86.14W
04/09/2021  E0.75 INCH       ELMORE             AL   PUBLIC

            REPORT FROM MPING: DIME (0.75 IN.).

&&

GGOGGINS

Special Weather Statement
National Weather Service Birmingham AL
1107 AM CDT Fri Apr 9 2021

ALZ037-045-047-091645-
Lee AL-Tallapoosa AL-Macon AL-
1107 AM CDT Fri Apr 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LEE...NORTHEASTERN
MACON AND SOUTH CENTRAL TALLAPOOSA COUNTIES UNTIL 1145 AM CDT...

At 1107 AM CDT, Doppler radar was tracking a strong thunderstorm near
Liberty City, or near Notasulga, moving east at 30 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Auburn, Opelika, Tuskegee, Tallassee, Notasulga, Franklin, Liberty
City, Auburn University, Tallapoosa City, Tuskegee National Forest,
Society Hill, Loachapoka, Robert G. Pitts Airport, I 85 Rest Area,
Uphapee Creek, Chewacla State Park, Reeltown and Moton Field
Municipal Airport.

LAT...LON 3242 8542 3246 8586 3248 8586 3248 8585
      3249 8586 3260 8585 3264 8541
TIME...MOT...LOC 1607Z 273DEG 26KT 3253 8578

40/Sizemore