Alert archive / Georgia / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 71

March 31, 20219 counties in Alabama; 5 counties in Florida; 10 counties in Georgia

The Storm Prediction Center issued this severe thunderstorm watch at Mar 31, 2021, 3:12 PM CDT for 9 counties in Alabama; 5 counties in Florida; 10 counties in Georgia. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Mar 31, 2021, 3:12 PM CDT (20:12 UTC)
Expired
Mar 31, 2021, 7:00 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
55 kt
All 24 counties

Baldwin County, AL, Coffee County, AL, Covington County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Mobile County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Baker County, GA, Calhoun County, GA, Clay County, GA, Dougherty County, GA, Early County, GA, Lee County, GA, Miller County, GA, Quitman County, GA, Randolph County, GA, Terrell County, GA

The radar

The Eglin Afb radar (KEVX), 99 km from the middle of the area, began a volume at 20:13 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
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Mar 31, 4:07 PM CDTSevere Thunderstorm WarningTAECoffee, Dale53 min
Mar 31, 4:13 PM CDTSevere Thunderstorm WarningMOBCovington47 min
Mar 31, 4:37 PM CDTSevere Thunderstorm WarningTAECoffee, Dale, Geneva38 min
Mar 31, 4:40 PM CDTSevere Thunderstorm WarningMOBCovington44 min
Mar 31, 4:42 PM CDTTornado WarningTAECoffee, Dale17 min
Mar 31, 4:52 PM CDTSevere Thunderstorm WarningTAECoffee, Dale, Henry, Houston49 min
Mar 31, 5:03 PM CDTTornado Warning Tornado observedTAEDale, Henry9 min
Mar 31, 5:29 PM CDTSevere Thunderstorm WarningMOBOkaloosa, Santa Rosa46 min
Mar 31, 5:30 PM CDTSevere Thunderstorm WarningTAEHenry, Houston45 min
Mar 31, 5:39 PM CDTSevere Thunderstorm WarningTAEGeneva66 min
Mar 31, 5:54 PM CDTSevere Thunderstorm WarningTAEHouston51 min
Mar 31, 6:39 PM CDTSevere Thunderstorm WarningTAEBay, Holmes, Walton, Washington36 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 12:00Z, 8.2 hours before the alert went out and 229 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-pSkew-T log-p diagram, Birmingham, AL at 12:00Z on 2021-03-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 455 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2021-03-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 273 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
455 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
527 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
273 m²/s²
0-3 km storm-relative helicity
283 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.5

Open this sounding in Storm Lab

The text

As transmitted.

316 
WWUS20 KWNS 312010
SEL1  
SPC WW 312010
ALZ000-FLZ000-GAZ000-CWZ000-010000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 71
NWS Storm Prediction Center Norman OK
315 PM CDT Wed Mar 31 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Southern Alabama
  Western Florida Panhandle
  Southwest Georgia
  Coastal Waters

* Effective this Wednesday afternoon and evening from 315 PM
  until 700 PM CDT.

* Primary threats include...
  Scattered damaging wind gusts to 65 mph possible

SUMMARY...QLCS with an embedded bowing segment should spread
east-southeast across the rest of southern Alabama into a portion of
southwest Georgia and the western Florida Panhandle before
weakening.

The severe thunderstorm watch area is approximately along and 30
statute miles north and south of a line from 10 miles southwest of
Mobile AL to 75 miles east northeast of Dothan AL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU1).

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 70...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few
cumulonimbi with maximum tops to 450. Mean storm motion vector
28030.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 31, 1:55 AM CDTMesoscale DiscussionSPCBlount, Cullman, Fayette, Franklin, Lamar, Lawrence and 5 more2 hr
Mar 31, 10:57 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bullock, Butler, Chambers, Choctaw and 17 more93 min
Mar 31, 11:19 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bibb, Bullock, Butler, Chambers and 23 more6 hr
Mar 31, 2:15 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Butler, Clarke, Conecuh, Crenshaw and 4 more90 min
Mar 31, 2:52 PM CDTMesoscale DiscussionSPCBaldwin, Coffee, Covington, Dale, Escambia, Geneva and 2 more53 min
Mar 31, 4:50 PM CDTMesoscale DiscussionSPCCoffee, Dale, Houston115 min
Mar 31, 5:24 PM CDTMesoscale DiscussionSPCBryan, Bulloch, Burke, Candler, Chatham, Effingham and 11 more2 hr

Nearby

Severe Thunderstorm Watches in Georgia, 2021Severe Thunderstorm Watches in Alabama, 2021Severe Thunderstorm Watches in Florida, 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.