Special Weather Statement, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
651 PM CDT Mon May 3 2021

.UPDATE...
For 00Z Aviation.

&&

.SHORT TERM...
/Updated at 0100 PM CDT Mon May 03 2021/
Through Tuesday.

Showers and storms have blossomed on radar over the past couple of
hours in response to destabilizing conditions at the surface,
along with steep lapse rates aloft. A persistent low-level jet of
45 to 50 knots at 850mb along with 3000-3500 J/kg of SBCAPE are
more than sufficient ingredients to sustain storm updrafts this
afternoon. Large hail and damaging straight-line winds will be the
primary threat but a tornado can't be ruled out, especially in
regards to storms that may interact with mesoscale boundaries.
With the summer-like atmospheric conditions at the surface and
pulse-type storms this afternoon, an updraft could get just enough
additional shear from an old outflow boundary for a tornado to
form. That will certainly bear watching as we go through the
afternoon. The forecast includes likely rain chances through the
early evening hours, then gradually decreasing in coverage. High-
res guidance is hinting at the possibility of some storms lasting
a bit longer toward midnight, so I wouldn't be surprised if an
update may be needed at some point to keep rain chances going a
bit longer.

The more significant severe weather threat will materialize during
the day on Tuesday. Confidence in terms of the severe weather
parameters available for severe storms remains fairly high, but
uncertainties remain in terms of where the severe storms will
develop and propagate as we go through the day. Mesoscale factors
will remain in play, and some high res guidance is hinting at
widespread shower and storm activity during the morning hours. As
is the case with any QLCS or MCS activity, we'll have to closely
monitor the radar trends through the overnight hours in order to
better determine timing of the severe storms as they move through
the area. If we don't get as much morning convection,
destabilization should easily occur and we could get cellular
severe storm development out ahead of what may become our QLCS
that is expected to move across Alabama during the day on Tuesday.
Stay tuned for subsequent mesoscale updates as we go throughout
the evening and overnight hours. Storms should move south of
Central Alabama by late evening, followed by cooler and drier air
moving southward behind the warm front.

56/GDG

.LONG TERM...
/Updated at 0100 AM CDT Mon May 03 2021/

Wednesday through Sunday.

The main trough axis continues to move east of our area early
Wednesday morning. The frontal boundary takes its time getting out
of the area, however, so expect lingering showers across the
southeast through the day, though any thunderstorm chance will be
dwindling as we transition to more of a zonal flow aloft and see
slight amplification of the 850mb ridge int he wake of the trough.

The zonal flow becomes more of a northwesterly flow aloft Thursday
into Friday as another impulse digs out a trough across the Eastern
CONUS. Model guidance still varies somewhat on if this trough will
reach far enough south to bring any chance of rain Thursday night.
For now, will stick closer to the Euro solution, which has better
ensemble agreement, keeping the area dry through Saturday with low
level ridging building across the Gulf States.

A weak upper level shortwave trough slides across the Central Plains
and develops a surface low Saturday night. This low is expected
to slide quickly eastward across the Ohio Valley Sunday morning
through the afternoon, draping a frontal boundary through the MS
Valley. Model guidance varies on the strength of the ridge and
just how far south the frontal boundary reaches by Sunday, so I've
kept rain/thunderstorm chances around 30-40% for Sunday afternoon
across the northern half of Central AL for now. This forecast
will likely change in coming days as we hopefully start to see
more model agreement.

25/Owen

&&

.AVIATION...
00Z TAF Discussion.

A few areas of thunderstorms are ongoing at the beginning of the
forecast period, with impacts possible at MGM and TOI this
evening. Will need to watch the northern edge of activity, as it
is possible it could impact EET before weakening. Stronger storms
could produce heavy rainfall and vis reductions, along with
frequent lightning and hail. Cannot rule out a strong wind gust.

Elsewhere, skies are clearing with winds out of the south to
southwest at 5-10kts. This activity will continue to diminish and
shift eastward, leading to a lull in rain activity for much of the
area overnight. Moist low level southerly flow will continue, and
expect low cigs to develop overnight, with MVFR/IFR heights. The
next round of showers and storms could arrive as early sunrise
Tuesday morning, and will include a prob30 for this activity.

Through the day, the chances for TSRA increase, along with severe
storm potential. Winds will remain from the south to southwest,
with wind gusts up to 22kts, with high-end MVFR/VFR cigs.

Note: AMD NOT SKED until further notice at KASN due to ongoing
equipment issues.

14

&&

.FIRE WEATHER...

Another round of scattered to numerous showers and storms are
expected today, and again on Tuesday before a cold front moves
through the day. Winds will increase from the south and become
southwesterly today. Speeds of 10-12mph are possible today. Drier
air arrives for Thursday and Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     68  82  60  75  48 /  40 100  90  20   0
Anniston    68  82  63  77  51 /  30 100 100  30   0
Birmingham  71  82  63  76  52 /  40 100  90  20   0
Tuscaloosa  72  83  61  77  52 /  40 100  70  10   0
Calera      70  81  64  76  53 /  30 100  90  20   0
Auburn      68  81  66  77  56 /  40  90  90  50  10
Montgomery  72  85  69  80  57 /  40  80 100  50  10
Troy        72  85  69  80  58 /  40  70  90  70  10

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
620 PM CDT Mon May 3 2021

ALZ011>015-017>050-050230-
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-
620 PM CDT Mon May 3 2021

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

.DAY ONE...Outlook through Tonight.

Strong to severe thunderstorms are possible through 10 pm for the
southeastern half of Central Alabama. Threats include damaging winds
up to 60 mph and large hail. An isolated tornado cannot be ruled
out.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Strong to severe thunderstorms are possible Tuesday and Tuesday
evening across the all of Central Alabama. Threats include damaging
winds up to 70 mph, large hail and isolated tornadoes.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management may be
needed this evening and again on Tuesday.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
738 PM CDT MON MAY 3 2021

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

0653 PM     TSTM WND DMG     COOSADA                 32.50N 86.33W
05/03/2021                   ELMORE             AL   EMERGENCY MNGR

            SEVERAL TREES WERE BLOWN DOWN AROUND
            COOSADA.

&&

MAL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
739 PM CDT MON MAY 3 2021

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

0647 PM     TSTM WND DMG     1 WSW WETUMPKA          32.54N 86.22W
05/03/2021                   ELMORE             AL   EMERGENCY MNGR

            SEVERAL TREES WERE BLOWN DOWN AROUND
            WETUMPKA.

&&

MAL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
740 PM CDT MON MAY 3 2021

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

0648 PM     TSTM WND DMG     1 SE OPELIKA SPORTSPLEX 32.66N 85.34W
05/03/2021                   LEE                AL   PUBLIC

            A FEW TREES WERE BLOWN DOWN AROUND OPELIKA.

&&

MAL

Special Weather Statement
National Weather Service Birmingham AL
746 PM CDT Mon May 3 2021

ALZ034-035-040130-
Chilton AL-Bibb AL-
746 PM CDT Mon May 3 2021

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN CHILTON AND SOUTHEASTERN
BIBB COUNTIES UNTIL 830 PM CDT...

At 746 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles east of Centreville to Maplesville.
Movement was northeast at 25 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Clanton, Centreville, Jemison, Thorsby, Maplesville, Lawley, Ashby,
Brierfield Ironworks Park, Talladega National Forest, Chilton County
Motor Sports Park, Randolph, Lomax, Trio, Six Mile and Isabella.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
central Alabama.

LAT...LON 3277 8702 3284 8702 3284 8705 3295 8709
      3310 8695 3308 8695 3308 8693 3306 8693
      3306 8690 3305 8690 3305 8688 3289 8664
      3275 8685 3271 8700
TIME...MOT...LOC 0046Z 220DEG 20KT 3298 8702 3280 8690

32/Davis

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE BIRMINGHAM AL
801 PM CDT MON MAY 3 2021

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

0248 PM     HAIL             ETHELSVILLE             33.42N 88.22W
05/03/2021  E0.70 INCH       PICKENS            AL   PUBLIC

            DIME SIZE HAIL WAS REPORTED IN ETHELSVILLE.

0406 PM     HAIL             4 SW TALLADEGA          33.40N 86.16W
05/03/2021  E0.70 INCH       TALLADEGA          AL   PUBLIC

            DIME SIZE HAIL AT THE INTERSECTION OF
            HIGHWAY 275 AND HIGHWAY 77.

0524 PM     HAIL             ALEXANDER CITY          32.94N 85.95W
05/03/2021  E0.70 INCH       TALLAPOOSA         AL   PUBLIC

0630 PM     HAIL             3 NNE PRATTVILLE        32.50N 86.44W
05/03/2021  E1.00 INCH       AUTAUGA            AL   PUBLIC

            QUARTER SIZE HAIL WAS REPORTED ON OLD RIDGE
            ROAD NORTH OF PRATTVILLE.

0646 PM     TSTM WND DMG     1 W WETUMPKA            32.54N 86.22W
05/03/2021                   ELMORE             AL   EMERGENCY MNGR

            TREE BLOWN DOWN ON OSCEOLA ST.

0647 PM     TSTM WND DMG     1 SSW WETUMPKA MUNI AIR 32.52N 86.34W
05/03/2021                   ELMORE             AL   EMERGENCY MNGR

            TREE BLOWN DOWN AT INTERSECTION OF MEADOW
            LANE DR AND AIRPORT ROAD.

0647 PM     TSTM WND DMG     1 WSW WETUMPKA          32.54N 86.22W
05/03/2021                   ELMORE             AL   EMERGENCY MNGR

            SEVERAL TREES WERE BLOWN DOWN AROUND
            WETUMPKA.

0648 PM     TSTM WND DMG     1 SE OPELIKA SPORTSPLEX 32.66N 85.34W
05/03/2021                   LEE                AL   EMERGENCY MNGR

            SEVERAL TREES AND WERE BLOWN DOWN AROUND
            OPELIKA.

0653 PM     TSTM WND DMG     COOSADA                 32.50N 86.33W
05/03/2021                   ELMORE             AL   EMERGENCY MNGR

            SEVERAL TREES WERE BLOWN DOWN AROUND
            COOSADA.

&&

Special Weather Statement
National Weather Service Birmingham AL
830 PM CDT Mon May 3 2021

ALZ045-047-048-040215-
Lee AL-Macon AL-Russell AL-
830 PM CDT Mon May 3 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL LEE...CENTRAL MACON AND
NORTHWESTERN RUSSELL COUNTIES UNTIL 915 PM CDT...

At 830 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Shorter to near Lake Tuskegee to near
Beauregard. Movement was southeast at 10 mph.

Pea size hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Auburn, Opelika, Tuskegee, Shorter, Franklin, Liverpool, Uchee, Lake
Tuskegee, Hardaway, Tuskegee National Forest, Beauregard,
Victoryland, Davisville, Society Hill, Griffen Mill, Robert G. Pitts
Airport, I 85 Rest Area, Cross Keys, Chewacla State Park and Marvyn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southeastern and east central Alabama.

LAT...LON 3235 8532 3227 8587 3229 8588 3230 8590
      3241 8600 3245 8570 3267 8536 3262 8522
TIME...MOT...LOC 0130Z 295DEG 10KT 3237 8591 3242 8563 3260 8532

32/Davis