Alert archive / Alabama / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 81, NWS Birmingham, AL

April 12, 2020Blount County, Jefferson County, Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Apr 12, 2020, 8:36 PM CDT for Blount County, Jefferson County, Alabama. It was in force for 54 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 12, 2020, 8:36 PM CDT (01:36 UTC)
Expired: Apr 12, 2020, 9:30 PM CDT
In force: 54 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 70.0 mph

Counties Blount County, AL, Jefferson County, AL

The radar

The Birmingham radar (KBMX), 82 km from the middle of the area, began a volume at 01:37 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Apr 12, 9:22 PM CDT	TSTM WND DMG	Fultondale, AL	SEVERAL TREES DOWN AND MANY LANDED ON HOMES BETWEEN FULTONDALE AND GARDENDALE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 46 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 12, 3:20 PM CDT	Tornado Watch	SPC	8 hr
Apr 12, 4:38 PM CDT	Tornado Watch PDS	SPC	7 hr

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 1.6 hours before the alert went out and 81 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 533 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 847 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 401 m²/s²
0-3 km storm-relative helicity: 509 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 8.4

Open this sounding in Storm Lab

The text

As transmitted.

340 
WUUS54 KBMX 130136
SVRBMX
ALC009-073-130230-
/O.NEW.KBMX.SV.W.0081.200413T0136Z-200413T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Birmingham AL
836 PM CDT Sun Apr 12 2020

The National Weather Service in Birmingham has issued a

* Severe Thunderstorm Warning for...
  Blount County in central Alabama...
  Northern Jefferson County in central Alabama...

* Until 930 PM CDT.

* At 835 PM CDT, severe thunderstorms were located along a line
  extending from Smith Dam to near Sumiton to 6 miles south of Gorgas
  Steam Plant, moving east at 65 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Northern Birmingham, Trussville, Gardendale, Leeds, Fultondale,
  Oneonta, Sumiton, Blountsville, Cleveland, Dallas, Center Point,
  Clay, Pinson, Tarrant, Adamsville, Warrior, Kimberly, Graysville,
  Morris and Brookside.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1000 PM CDT for central
Alabama. A Tornado Watch also remains in effect until midnight CDT
for central Alabama.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3411 8631 3394 8637 3393 8633 3391 8635
      3389 8634 3380 8658 3355 8655 3358 8720
      3366 8706 3377 8702 3380 8695 3387 8696
      3387 8692 3391 8692 3394 8688 3397 8677
      3403 8670 3409 8669 3408 8669 3417 8637
TIME...MOT...LOC 0135Z 270DEG 58KT 3394 8712 3378 8703 3355 8721 

HAIL...<.75IN
WIND...70MPH
 
$$

17/KLAWS

1 follow-up statement

837 
WWUS54 KBMX 130215
SVSBMX

Severe Weather Statement
National Weather Service Birmingham AL
915 PM CDT Sun Apr 12 2020

ALC009-073-130230-
/O.CON.KBMX.SV.W.0081.000000T0000Z-200413T0230Z/
Blount AL-Jefferson AL-
915 PM CDT Sun Apr 12 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM CDT
FOR BLOUNT AND NORTHERN JEFFERSON COUNTIES...

At 914 PM CDT, severe thunderstorms were located along a line
extending from 6 miles south of Altoona to near Ashville to near Bald
Rock, moving east at 65 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Northern Birmingham, Trussville, Gardendale, Leeds, Fultondale,
Oneonta, Sumiton, Blountsville, Cleveland, Dallas, Center Point,
Clay, Pinson, Tarrant, Adamsville, Warrior, Kimberly, Graysville,
Morris and Brookside.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1000 PM CDT for central
Alabama. A Tornado Watch also remains in effect until midnight CDT
for central Alabama.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3411 8631 3394 8637 3393 8633 3391 8635
      3389 8634 3380 8658 3355 8655 3358 8720
      3366 8706 3377 8702 3380 8695 3387 8696
      3387 8692 3391 8692 3394 8688 3397 8677
      3403 8670 3409 8669 3408 8669 3417 8637
TIME...MOT...LOC 0214Z 270DEG 58KT 3394 8636 3378 8627 3355 8645 

HAIL...<.75IN
WIND...60MPH
 
$$

17/KLAWS

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Birmingham, AL wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 12, 7:19 PM CDT, 1 hour 17 minutes earlier.

Area forecast discussion, Apr 12, 7:19 PM CDT, 1 hour 17 minutes before

Area Forecast Discussion
National Weather Service Birmingham AL
719 PM CDT Sun Apr 12 2020

.UPDATE...
For 00Z Aviation.

&&

.SHORT TERM...
/Updated at 0700 PM CDT Sun Apr 12 2020/

Mesoscale Update.

An all-hazards severe weather threat continues across portions of
Central Alabama. Damaging winds up to 70 mph, large hail, and
tornadoes all remain possible into the overnight hours as a dynamic
shortwave trough (which is taking a more neutral tilt) and surface
low pressure eject eastward.

Recent surface observations depict a favorable warm sector now along
and north of the I-20/59 corridor, including SBCAPE 500-1,500 J/kg,
EBS 60-70 kts, and 0-1 km SRH 500-700 m2/s2. These values are also
supported by the 21Z BMX RAOB and various RADAR derived hodographs.
Lift will continue to be abundant across the region as pressure &
height falls accompany upper-level diffluence & quasigeostrophic
forcing, as well as a surface moisture convergence axis from
northeast AL into southwest MS. Thus, deep/moist convection will
continue to be problematic over the next several hours, even as
storm modes become less discrete. Threats also include flash
flooding as high rain rates train north of I-20, generally
along/near a 1.8-2.0" PW axis and confluent flow in the 925-850 mb
layer. Short-range guidance suggests favorable atmospheric
conditions for all-hazards will persist for the next several hours
as a more linear convective system with embedded supercells ejects
across Central AL. The effective layer significant tornado parameter
is progged to remain as high as 5 ahead of this system through that
time, suggesting an environment favorable for tornadogenesis and
strong tornadoes.

Residents of Central AL must remain diligent and weather aware into
the overnight period and have multiple ways to receive warnings so
that necessary action to protect life and property can be taken.

40/Sizemore

.LONG TERM...
/Updated at 0250 PM CDT Sun Apr 12 2020/

Monday through Saturday.

Cooler, clearing conditions are expected on Monday as the cold front
tracks towards the east coast. Lingering clouds may persist through
the morning across our north as an upstream reinforcing front moves
across the area, but a dry, northerly flow and increasing CAA will
support sunny skies during the afternoon with highs in the lower 60s
northwest to near 80F southeast. Guidance continues to indicate the
front stalling generally east to west across the Gulf Coast region
on Tuesday before lifting slightly into southern portions of Alabama
early Wednesday morning. This should focus highest PoPs over our
southeastern quadrant, but a flattened low-level ridge over the
Lower MS Valley may hinder much of the activity from entering our
forecast area, so PoPs may be lowered in future updates.

Otherwise, the remainder of the extended will remain dry and cool as
the weak low-level ridge slides eastward across the region with dry
zonal flow aloft persisting through the period. Northeasterly flow
Thursday morning should allow temps to lower into the 30s.
Therefore, I continued to mention localized patchy frost across our
northern counties. The latest round of data indicates lows may be a
couple degrees warmer than previously forecast, but leaned on the
cooler side since models are typically too warm under northeasterly
flow.

Rain chances will begin increasing at the end of the week as another
low propagates across the Desert SW towards the Tennessee Valley.
Kept PoPs around 40-50% since there is still plenty of uncertainty
regarding timing, moisture return, and the evolution of the system.

86

&&

.AVIATION...
00Z TAF Discussion.

Widespread showers and thunderstorms will impact all TAF sites
overnight. Some of the storms will be severe with damaging winds
and isolated tornadoes. Strong gradient flow will also produce
south winds sustained 15-20 kts with gusts to 35 kts. The winds
will relax at bhm/tcl/eet by 05z as the low level jet shifts
eastward, with the severe threat also ending at these sites. For
the remainder of the TAF sites, the severe threat will end between
05z and 08z. Sfc winds will gradually veer overnight becoming
westerly by 12z. VFR cigs at the start of the forecast period will
become MVFR at all sites by 03z. Some clearing possible between
09z and 12z behind the initial front, but cold air stratocumulus
could bring back MVFR cigs across the northern TAF sites between
12z and 18z, then become scattered.

58/rose

&&

.FIRE WEATHER...

Widespread rain and thunderstorms are expected tonight across
Central Alabama. Winds will be gusty through the evening hours
with south winds gusting to 35 MPH. Drier weather builds in
the area on Monday before rain chances return across south
Alabama Tuesday night and Wednesday morning. Dry weather
will prevail Thursday and Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     58  65  42  68  41 / 100   0   0   0  10
Anniston    60  69  44  70  44 / 100   0   0   0  10
Birmingham  59  67  45  69  43 / 100   0   0   0  20
Tuscaloosa  58  67  45  69  43 / 100   0   0   0  20
Calera      60  68  46  70  44 / 100   0   0   0  20
Auburn      64  76  49  76  49 / 100  10   0  10  40
Montgomery  65  77  51  78  50 / 100   0   0  10  40
Troy        66  80  52  81  52 / 100  10   0  10  50

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
Wind Advisory until 3 AM CDT 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.

Flash Flood Watch until midnight CDT tonight for the following
counties: Blount...Cherokee...Etowah...Fayette...Lamar...
Marion...Walker...Winston.

&&

Hazardous weather outlook, Apr 12, 6:39 PM CDT, 1 hour 57 minutes before

Hazardous Weather Outlook
National Weather Service Birmingham AL
639 PM CDT Sun Apr 12 2020

ALZ011>015-017>050-140245-
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-
639 PM CDT Sun Apr 12 2020

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

.DAY ONE...through Tonight.

Severe thunderstorms are likely across all of Central Alabama.
Threats include tornadoes, some of which could be strong, damaging
straight line winds up to 70 MPH, and hail up to golf ball size.
Localized flooding could also occur.

Winds will also be breezy outside of thunderstorms with gusts between
30 and 40 MPH.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Minor flooding is forecast along portions of the Tombigbee River and
Black Warrior River starting midweek.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management will be
necessary. Please follow all local, state, and CDC guidelines in
regards to travel.

In the hours before

Local storm report, Apr 12, 7:50 PM CDT, 46 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
750 PM CDT SUN APR 12 2020

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

0558 PM     TSTM WND DMG     4 SE HENDRIX            34.00N 86.40W
04/12/2020                   BLOUNT             AL   EMERGENCY MNGR

            TIME ESTIMATED. TREES DOWN ON SANDERS LANE
            BETWEEN CR 39 AND HALE CREEK ROAD.

&&

MAL

Local storm report, Apr 12, 7:51 PM CDT, 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
751 PM CDT SUN APR 12 2020

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

0643 PM     FLASH FLOOD      5 SSW BROOKSVILLE       34.12N 86.51W
04/12/2020                   BLOUNT             AL   EMERGENCY MNGR

            CORRECTS PREVIOUS FLASH FLOOD REPORT FROM 5
            SSW BROOKSVILLE. CORRECTS PREVIOUS FLASH
            FLOOD REPORT FROM 5 SSW BROOKSVILLE. WATER
            WASHED AWAY ROAD NEAR WHEELER RD AND CTY HWY
            49.

&&

AS

Local storm report, Apr 12, 8:13 PM CDT, 23 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
813 PM CDT SUN APR 12 2020

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

0705 PM     TSTM WND DMG     1 WNW GAINESVILLE       32.82N 88.17W
04/12/2020                   SUMTER             AL   PUBLIC

            SEVERAL TREES WERE BLOWN DOWN AROUND
            GAINESVILLE.

&&

MAL

Local storm report, Apr 12, 8:15 PM CDT, 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
815 PM CDT SUN APR 12 2020

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

0805 PM     NON-TSTM WND DMG 3 NE SELMA              32.44N 86.99W
04/12/2020                   DALLAS             AL   PUBLIC

            1-INCH TREE LIMBS BROKEN; SHINGLES BLOWN
            OFF. GRADIENT WINDS.

&&

MAL

Local storm report, Apr 12, 8:21 PM CDT, 15 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
821 PM CDT SUN APR 12 2020

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

0700 PM     TSTM WND DMG     1 S NEW MOON            34.38N 85.52W
04/12/2020                   CHEROKEE           AL   EMERGENCY MNGR

            SEVERAL TREES WERE BLOWN DOWN ALONG CR 99.
            TIME ESTIMATED.

&&

MAL

Local storm report, Apr 12, 8:27 PM CDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
827 PM CDT SUN APR 12 2020

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

0642 PM     TSTM WND DMG     2 N LEESBURG            34.21N 85.77W
04/12/2020                   CHEROKEE           AL   EMERGENCY MNGR

            A VEHICLE RAN INTO A DOWNED TREE BLOCKING
            THE ROADWAY ALONG CR 36 AND TURTLE CREEK
            LOOP.

&&

MAL

The office that day

Everything else NWS Birmingham, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 7:10 PM CDT	Tornado Warning	BMX	Greene	22 min
Apr 12, 7:14 PM CDT	Tornado Warning	BMX	Sumter	26 min
Apr 12, 7:16 PM CDT	Areal Flood Advisory	BMX	Cherokee, Etowah, St. Clair	6 hr
Apr 12, 8:08 PM CDT	Severe Thunderstorm Warning	BMX	Fayette, Walker	55 min
Apr 12, 8:14 PM CDT	Areal Flood Advisory	BMX	Fayette, Lamar, Marion, Walker, Winston	5 hr
Apr 12, 8:15 PM CDT	Tornado Warning	BMX	Walker, Winston	15 min
Apr 12, 8:25 PM CDT	Severe Thunderstorm Warning	BMX	Tuscaloosa	38 min
Apr 12, 8:29 PM CDT	Flash Flood Warning	BMX	Fayette, Greene, Jefferson, Pickens, Sumter, Tuscaloosa and 1 more	5 hr
Apr 12, 8:32 PM CDT	Tornado Warning	BMX	Jefferson, Tuscaloosa	21 min
Apr 12, 8:36 PM CDT	Tornado Warning Tornado observed	BMX	Jefferson, Tuscaloosa	17 min
Apr 12, 8:49 PM CDT	River Flood Warning	BMX	Greene, Hale, Marengo, Sumter	5 days
Apr 12, 8:51 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson	39 min
Apr 12, 8:52 PM CDT	River Flood Warning	BMX	Jefferson, Tuscaloosa, Walker	66 hr
Apr 12, 8:58 PM CDT	River Flood Warning	BMX	Greene, Hale, Marengo, Tuscaloosa	52 hr
Apr 12, 8:58 PM CDT	River Flood Warning	BMX	Greene, Hale, Marengo, Sumter, Tuscaloosa	61 hr
Apr 12, 9:12 PM CDT	Tornado Warning	BMX	Blount	20 min
Apr 12, 9:19 PM CDT	Severe Thunderstorm Warning	BMX	Blount, Etowah, Jefferson, St. Clair, Shelby	71 min
Apr 12, 9:33 PM CDT	Tornado Warning	BMX	Marengo	27 min
Apr 12, 10:02 PM CDT	Severe Thunderstorm Warning	BMX	Dallas	27 min
Apr 12, 10:22 PM CDT	Flash Flood Warning	BMX	Blount, Calhoun, Cherokee, Etowah, St. Clair	4 hr
Apr 12, 10:24 PM CDT	Tornado Warning	BMX	Cherokee	36 min
Apr 12, 10:37 PM CDT	Severe Thunderstorm Warning	BMX	Lowndes, Montgomery	53 min
Apr 12, 10:47 PM CDT	Severe Thunderstorm Warning	BMX	Calhoun, Cherokee, Cleburne, Etowah	58 min
Apr 12, 10:53 PM CDT	Severe Thunderstorm Warning	BMX	Autauga, Elmore	43 min
Apr 12, 10:59 PM CDT	Severe Thunderstorm Warning	BMX	Chilton, Clay, Coosa, Shelby, Talladega, Tallapoosa	43 min
Apr 12, 11:01 PM CDT	Areal Flood Advisory	BMX	Greene, Hale, Pickens, Sumter	3 hr
Apr 12, 11:15 PM CDT	Severe Thunderstorm Warning	BMX	Bullock, Macon, Montgomery, Tallapoosa	60 min
Apr 12, 11:16 PM CDT	Special Weather Statement	BMX	Fayette, Lamar, Marion	74 min
Apr 12, 11:24 PM CDT	Areal Flood Warning	BMX	Fayette, Tuscaloosa, Walker	6 hr
Apr 12, 11:30 PM CDT	Severe Thunderstorm Warning	BMX	Lee, Russell	75 min
Apr 13, 12:08 AM CDT	Special Weather Statement	BMX	Barbour, Bullock, Pike	82 min
Apr 13, 12:11 AM CDT	Severe Thunderstorm Warning	BMX	Pike	64 min
Apr 13, 12:13 AM CDT	Areal Flood Advisory	BMX	Lowndes, Montgomery	3 hr
Apr 13, 12:18 AM CDT	Severe Thunderstorm Warning	BMX	Chambers	16 min
Apr 13, 12:43 AM CDT	Severe Thunderstorm Warning	BMX	Barbour, Bullock	53 min
Apr 13, 1:04 AM CDT	Areal Flood Advisory	BMX	Barbour, Bullock, Pike, Russell	3 hr
Apr 13, 1:29 AM CDT	High Wind Warning	BMX	Autauga, Calhoun, Chambers, Cherokee, Chilton, Clay and 10 more	3 hr
Apr 13, 1:29 AM CDT	Wind Advisory	BMX	Autauga, Calhoun, Chambers, Cherokee, Chilton, Clay and 10 more	7 hr
Apr 13, 2:25 AM CDT	River Flood Warning	BMX	Bibb, Jefferson, Shelby	18 hr
Apr 13, 4:08 AM CDT	Areal Flood Warning	BMX	Cherokee	12 hr
Apr 13, 7:43 AM CDT	Areal Flood Warning	BMX	Cherokee	3 days

Nearby

Severe Thunderstorm Warnings in Alabama, 2020 Every severe thunderstorm warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.