Special Weather Statement, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
708 AM CDT Thu Mar 25 2021

.UPDATE...
For 12Z Aviation.

&&

.SHORT TERM...
/Updated at 450 AM CDT Thu Mar 25 2021/
Today through Friday.

So far this AM we have had widespread showers with embedded
thunderstorms as it spread NE across C AL. The activity has been
elevated and while we are watching for any rogue storms, severe
activity during the early morning hours should be marginal at
best until the warm front makes its way northward later today. We
have increased the severe threat in the NW half of C AL for this
afternoon and evening. This probably doesn't come as much of a
surprise as this system is ramping up to be significant there with
strong tornadoes a possibility. The SE half of C AL is a
different story. While we have a marginal threat this AM for
portions of C AL, for the rest of the afternoon and evening,
parameters are much lower in the SE counties with convection not
as likely there until later this evening. After the current
convection currently on the radar pushes N, we should have a
somewhat lull in activity in the SE.

In contrast, by around 11am, our warm front should be to the N of
the area. Models suggest some cellular activity will likely pop
up in the NW first. MUCAPE will not be lacking, but will be
highest in the west for this afternoon. 0-6km bulk shear will be
in ample supply across C AL. However, 0-1km shear will be
decidedly higher in the NW. Although amounts vary, guidance is in
agreement decreasing this low level shear significantly after 6z
as the bulk of the instability skirts to the NE. This will be not
only with the front moving across, but our negatively tilted upper
shortwave that is expected to be over the Arklatex ~18z today
expected to race off toward IL/IN by midnight tonight. With the
bulk of the activity in the SE counties expected for later this
evening, this greatly decreases the chance for severe weather for
them S of the I85 corridor. This is the reason for the sharp risk
gradient in our severe graphics. Timing is pretty similar to what
we had yesterday except possibly starting in the NW at 11am
instead of noon. The front is expected to make progress after
midnight with the risk for TS in the SE counties much lower for
the day on Friday with lower dew points moving in behind the
front.

08

.LONG TERM...
/Updated at 450 AM CDT Thu Mar 25 2021/
Friday night through Wednesday.

Rain chances should be minimal for Friday evening but increase
after midnight into the pre-dawn hours on Saturday with some
thunderstorms possible in the NW with shortwave activity. Rain
chances increase once again for Saturday into Sunday with the
approach of another frontal system number 2. However, the upper
dynamics still need to be worked out. The upper setup does not
show a negatively tilted system like front 1. However, we will
have warm and moist air waiting for this springtime front. While
some strong storms cannot be ruled out, will hold off adding
severe just yet with the weekend system. Extended guidance
diverges on timing and strength of the upper low/shortwave behind
the front for Mon/Tue time frame, so only going with low pops for
now. A third front approaches by end of the extended by Wednesday
with elevated shower and thunderstorm chances returning.

08

&&

.AVIATION...
12Z TAF Discussion.

The more widespread shower and thunderstorm activity will shift to
the north and then northwest this morning ahead of our next
frontal system. Conditions will continue to deteriorate from MVFR
to IFR over the next couple of hours for the NW and from VFR to
MVFR in the S and E. TSRA (some strong to severe at times during
the afternoon and evening closer to the I59/I20 corridors) will be
possible along and ahead of an approaching front. Most of the
activity early this morning will be elevated until a stalled
boundary moves NWD as a warm front across C AL toward midday into
the early afternoon. Gusty winds are also possible outside of
storms at terminals with tight surface pressure gradients. I do
have a brief mention of non-convective LLWS at TOI as they are in
a lull in the convective activity and before their surface winds
kick up.

08

&&

.FIRE WEATHER...

A moist air mass with high relative humidity values will develop
today and continue through the weekend with multiple episodes of
showers and thunderstorms. A warm front will lift northward
today and produce numerous showers and a few thunderstorms.
Southerly winds will increase to 10 to 15 mph with higher gusts
today as a strong storm system approaches from the west. There is
risk of severe thunderstorms with tornadoes this afternoon and
evening. Rain chances are lower on Friday, but more showers and
thunderstorms are expected for over the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     75  52  75  54  79 /  80  80  10  40  70
Anniston    78  57  78  59  82 /  70  80  10  40  60
Birmingham  76  55  76  60  81 /  80  80  10  50  70
Tuscaloosa  77  54  78  62  82 /  80  80  10  40  60
Calera      76  57  76  62  82 /  70  80  10  40  60
Auburn      80  63  76  64  82 /  30  70  40  20  30
Montgomery  83  64  78  65  85 /  40  80  20  20  30
Troy        84  65  80  66  85 /  30  70  40  20  20

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
Wind Advisory from 11 AM this morning to 10 PM CDT this evening
for the following counties: Autauga...Bibb...Blount...Calhoun...
Chambers...Cherokee...Chilton...Clay...Cleburne...Coosa...
Dallas...Elmore...Etowah...Fayette...Greene...Hale...Jefferson...
Lamar...Lowndes...Marengo...Marion...Montgomery...Perry...
Pickens...Randolph...Shelby...St. Clair...Sumter...Talladega...
Tallapoosa...Tuscaloosa...Walker...Winston.

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
504 AM CDT Thu Mar 25 2021

ALZ011>015-017>050-261315-
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-
504 AM CDT Thu Mar 25 2021

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

.DAY ONE...Outlook through Tonight.

A couple severe storm may occur this morning with a threat of a
couple tornadoes, damaging winds, and hail up to quarter size. This
morning threat is mainly for areas near and west of Interstate 65
through around 11 am.

A significant severe weather event is expected across much of
Central Alabama from around 11 am through midnight. The greatest
threat will be along and northwest of Interstate 59, where strong
tornadoes, damaging winds, and large hail will be possible. The
overall threat gradually decreases to the southeast of there.

A Wind Advisory is in effect from 11 AM through 10 PM for most of
Central Alabama excluding areas generally south of Interstate 85.
Sustained winds will be out of the south around 10 to 20 mph with
occasional gusts up to 40 mph outside of any thunderstorm activity,
especially in higher terrain areas.

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

Minor flooding may occur along portions of the Tombigbee and Black
Warrior River Basins this weekend and into early next week.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management is expected
on today into this evening.

08

Special Weather Statement
National Weather Service Birmingham AL
454 AM CDT Thu Mar 25 2021

ALZ047-251030-
Lee AL-
454 AM CDT Thu Mar 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN LEE COUNTY UNTIL 530
AM CDT...

At 453 AM CDT, Doppler radar was tracking a strong thunderstorm over
Griffen Mill, or 8 miles west of Smiths, moving east at 40 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Smiths, Smiths Station, Bleecker, Griffen Mill, Monterey Heights and
Bartletts Ferry Dam.

LAT...LON 3251 8504 3251 8506 3250 8506 3247 8520
      3247 8525 3258 8531 3269 8512 3267 8509
      3265 8509 3265 8511 3263 8509 3263 8508
      3262 8509 3258 8507 3252 8500
TIME...MOT...LOC 0953Z 247DEG 36KT 3253 8523

86/Martin

Special Weather Statement
National Weather Service Birmingham AL
745 AM CDT Thu Mar 25 2021

ALZ030-039-251330-
Sumter AL-Marengo AL-
745 AM CDT Thu Mar 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL MARENGO AND SOUTHEASTERN
SUMTER COUNTIES UNTIL 830 AM CDT...

At 745 AM CDT, Doppler radar was tracking a strong thunderstorm near
Butler, moving northeast at 50 mph.

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

Locations impacted include...
Linden, Jefferson, Thomaston, Sweet Water, Myrtlewood, Dayton,
Freddie Jones Field, Pin Hook, Nanafalia, Miller, Chickasaw State
Park, Half Acre, U.S. 80 and AL 28, Old Spring Hill, Octagon,
Calvary, Demopolis Municipal Airport and Whitfield.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 3246 8802 3247 8767 3223 8759 3200 8811
      3205 8812 3208 8804 3211 8805 3214 8804
      3215 8802 3217 8801 3226 8801 3228 8802
      3230 8798 3230 8794 3228 8794 3229 8793
      3231 8793 3231 8813
TIME...MOT...LOC 1245Z 227DEG 45KT 3211 8813

40/Sizemore