Alert archive / Alabama / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 85
The Storm Prediction Center issued this severe thunderstorm watch at Apr 9, 2021, 9:15 PM CDT for 20 counties in Alabama. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 9:15 PM CDT (02:15 UTC)
- Expired
- Apr 10, 2021, 4:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 65 kt
Counties Bibb County, AL, Colbert County, AL, Cullman County, AL, Dallas County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Marengo County, AL, Marion County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL
The radar
The Columbus AFB radar (KGWX), 85 km from the middle of the area, began a volume at 02:17 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 SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 9:25 PM CDT | Severe Thunderstorm Warning | BMX | Lamar, Marion | 50 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Birmingham, AL (KBMX), launched 00:00Z, 2.3 hours before the alert went out and 94 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.
- Mixed-layer CAPE
- 53 J/kg
- Mixed-layer CIN
- -225 J/kg
- Mixed-layer LCL
- 744 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 182 m²/s²
- 0-3 km storm-relative helicity
- 294 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.2
The text
As transmitted.
343
WWUS20 KWNS 100212
SEL5
SPC WW 100212
ALZ000-100900-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 85
NWS Storm Prediction Center Norman OK
915 PM CDT Fri Apr 9 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Western Alabama
* Effective this Friday night and Saturday morning from 915 PM
until 400 AM CDT.
* Primary threats include...
Scattered damaging winds and isolated significant gusts to 75
mph possible
SUMMARY...Squall line should initially spread into northwest Alabama
before weakening in northeast Alabama. Trailing portion of the
squall should spread into west-central Alabama overnight. Damaging
winds will be the primary hazard.
The severe thunderstorm watch area is approximately along and 35
statute miles east and west of a line from 20 miles north northeast
of Muscle Shoals AL to 80 miles south of Tuscaloosa AL. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU5).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 78...WW 80...WW 81...WW
82...WW 83...WW 84...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 65 knots. A few
cumulonimbi with maximum tops to 450. Mean storm motion vector
26035.
...GramsSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 7:20 PM CDT | Mesoscale Discussion | SPC | Colbert, Lauderdale | 115 min |
| Apr 9, 10:25 PM CDT | Severe Thunderstorm Watch | SPC | Choctaw, Clarke, Washington, Wilcox | 6 hr |
| Apr 10, 1:52 AM CDT | Mesoscale Discussion | SPC | Baldwin, Butler, Clarke, Coffee, Conecuh, Covington and 8 more | 113 min |
| Apr 10, 2:30 AM CDT | Tornado Watch | SPC | Baldwin, Butler, Coffee, Conecuh, Covington, Crenshaw and 7 more | 8 hr |
| Apr 10, 4:06 AM CDT | Mesoscale Discussion | SPC | Baldwin, Butler, Clarke, Coffee, Conecuh, Covington and 8 more | 114 min |
| Apr 10, 7:10 AM CDT | Mesoscale Discussion | SPC | Dale, Geneva, Houston | 2 hr |
Nearby
Severe Thunderstorm Watches in Alabama, 2021Every severe thunderstorm watch in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.