Alert archive / Alabama / Mesoscale Discussions in 2021
Mesoscale Discussion 416
The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2021, 1:00 AM CDT for 8 counties in Alabama; 6 counties in Florida; 8 counties in Mississippi. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 24, 2021, 1:00 AM CDT (06:00 UTC)
- Expired
- Apr 24, 2021, 3:30 AM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 22 counties
Baldwin County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Escambia County, AL, Geneva County, AL, Mobile County, AL, Washington County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Perry County, MS, Stone County, MS
The radar
The Mobile radar (KMOB), 61 km from the middle of the area, began a volume at 06:04 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.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Slidell Radar S, LA (KSIL), launched 00:00Z, 6.0 hours before the alert went out and 208 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 873 m above ground
- 0-6 km bulk shear
- 62 kt
- 0-1 km storm-relative helicity
- 156 m²/s²
- 0-3 km storm-relative helicity
- 263 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
767
ACUS11 KWNS 240600
SWOMCD
SPC MCD 240600
FLZ000-ALZ000-MSZ000-LAZ000-240830-
Mesoscale Discussion 0416
NWS Storm Prediction Center Norman OK
0100 AM CDT Sat Apr 24 2021
Areas affected...southern Mississippi and Alabama into the Florida
Panhandle
Concerning...Severe potential...Watch likely
Valid 240600Z - 240830Z
Probability of Watch Issuance...80 percent
SUMMARY...Storms will evolve eastward out of Louisiana into southern
Mississippi next few hours, with a severe threat developing into
Alabama and the Florida Panhandle later tonight. Damaging gusts and
a couple tornadoes will be possible.
DISCUSSION...Numerous thunderstorms currently exist from southern LA
into southern MS, with a few cells now extending east of WW 104 near
the MS/AL border. This zone is near a convectively enhanced warm
front which is expected to lift north across far southern AL and the
FL Panhandle after 08-09Z.
Subtle midlevel height falls will occur tonight across the region,
as a shortwave trough continues east across the Arklatex. Ahead of
this feature, southerly 850 mb winds in excess of 50 kt will
persist, aiding theta-e advection and possibly stalling the
southward progress of the rain-cooled air. This may setup a
favorable zone for storms to ride along the front, as Bunkers
motions veer to 240 or 250 degrees tonight. As dewpoints rise into
the 68-70 F range, effective SRH will also increase, providing a
favorable environment for supercells, and/or organized bows capable
of damaging winds with 65 kt effective deep-layer shear.
..Jewell/Edwards.. 04/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...MOB...JAN...LIX...
LAT...LON 30188857 30118945 30388968 30648955 30888930 31358931
31478930 31578782 31618608 31508578 31308560 30898549
30478559 30178592 30238628 30298677 30218731 30168807
30188857SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 24, 1:00 AM CDT | Mesoscale Discussion | SPC | Baldwin, Coffee, Conecuh, Covington, Escambia, Geneva and 2 more | 3 hr |
| Apr 24, 1:23 AM CDT | Tornado Watch | SPC | Baldwin, Clarke, Conecuh, Covington, Escambia, Mobile and 2 more | 8 hr |
| Apr 24, 3:04 AM CDT | Mesoscale Discussion | SPC | Baldwin, Mobile, Washington | 116 min |
| Apr 24, 4:26 AM CDT | Mesoscale Discussion | SPC | Conecuh, Covington, Escambia, Monroe, Washington | 2 hr |
| Apr 24, 5:22 AM CDT | Tornado Watch | SPC | Coffee, Dale, Geneva, Henry, Houston | 9 hr |
| Apr 24, 7:29 AM CDT | Mesoscale Discussion | SPC | Coffee, Dale, Geneva, Henry, Houston | 91 min |
| Apr 24, 12:29 PM CDT | Mesoscale Discussion | SPC | Baldwin, Choctaw, Clarke, Conecuh, Escambia, Marengo and 4 more | 2 hr |
| Apr 24, 1:17 PM CDT | Severe Thunderstorm Watch | SPC | Autauga, Baldwin, Barbour, Bullock, Butler, Choctaw and 23 more | 8 hr |
| Apr 24, 1:22 PM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Clay, Cleburne, Colbert and 22 more | 113 min |
| Apr 24, 3:40 PM CDT | Mesoscale Discussion | SPC | Autauga, Barbour, Bullock, Butler, Clarke, Coffee and 19 more | 95 min |
| Apr 24, 4:52 PM CDT | Severe Thunderstorm Watch | SPC | Bibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 15 more | 4 hr |
| Apr 24, 5:56 PM CDT | Mesoscale Discussion | SPC | Barbour, Bullock, Coffee, Dale, Henry, Houston and 1 more | 94 min |
| Apr 24, 6:13 PM CDT | Mesoscale Discussion | SPC | Calhoun, Chambers, Cherokee, Clay, Cleburne, Coosa and 6 more | 2 hr |
| Apr 24, 9:10 AM CDT | Mesoscale Discussion | SPC | Nassau | 95 min |
| Apr 24, 9:35 AM CDT | Tornado Watch | SPC | Baker, Columbia, Duval, Hamilton, Nassau, Suwannee | 7 hr |
| Apr 24, 11:05 AM CDT | Mesoscale Discussion | SPC | Calhoun, Gadsden, Holmes, Jackson, Jefferson, Leon and 4 more | 85 min |
| Apr 24, 3:35 PM CDT | Mesoscale Discussion | SPC | Duval, Nassau | 85 min |
| Apr 23, 8:30 PM CDT | Tornado Watch | SPC | Adams, Amite, Claiborne, Copiah, Covington, Forrest and 15 more | 8 hr |
| Apr 23, 10:29 PM CDT | Mesoscale Discussion | SPC | Amite, Forrest, George, Hancock, Lamar, Marion and 6 more | 2 hr |
Nearby
Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Florida, 2021Every mesoscale discussion 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.