Alert archive / Alabama / Mesoscale Discussions in 2021
Mesoscale Discussion 357
The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2021, 1:52 AM CDT for 14 counties in Alabama; 6 counties in Florida; George County, Greene County, Jackson County, Mississippi. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Apr 10, 2021, 1:52 AM CDT (06:52 UTC)
- Expired
- Apr 10, 2021, 3:45 AM CDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 87
All 23 counties
Baldwin County, AL, Butler County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Mobile County, AL, Monroe County, AL, Pike County, AL, Washington County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, George County, MS, Greene County, MS, Jackson County, MS
The radar
The Mobile radar (KMOB), 100 km from the middle of the area, began a volume at 06:56 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
Birmingham, AL (KBMX), launched 00:00Z, 6.9 hours before the alert went out and 245 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.
832
ACUS11 KWNS 100653
SWOMCD
SPC MCD 100652
FLZ000-ALZ000-MSZ000-100845-
Mesoscale Discussion 0357
NWS Storm Prediction Center Norman OK
0152 AM CDT Sat Apr 10 2021
Areas affected...Southern Mississippi...Southern Alabama...Western
Florida Panhandle
Concerning...Tornado Watch 87...
Valid 100652Z - 100845Z
The severe weather threat for Tornado Watch 87 continues.
SUMMARY...A severe threat is expected to develop across southern
Alabama and the western Florida Panhandle later tonight. Wind
damage, a few tornadoes and isolated large hail will be possible.
Weather watch issuance will likely be needed.
DISCUSSION...The latest radar imagery shows a linear MCS across
southeastern Mississippi extending into north-central Alabama. The
line is being supported by a 40 to 50 kt low-level jet. Ahead of
this line of severe storms, surface dewpoints are in the mid to
upper 60s F across southwest Alabama and the far western Florida
Panhandle, where the RAP is analyzing moderate instability. The line
should be maintained as the low-level jet strengthens, and as the
storms move eastward along the northern edge of moderate
instability. Discrete thunderstorms are also expected to move from
the northern Gulf of Mexico into the coastal areas of Alabama and
the far western Florida Panhandle over the next couple of hours.
The Mobile, Alabama WSR-88D VWP shows 0-6 km near 65 kt with storm
relative helicity just above 400 m2/s2. This will be favorable for
supercells with a tornado threat. Tornadoes will be possible with
discrete cells that move onshore ahead of the line, and with
rotating elements with the squall line itself. Widespread wind
damage will also be possible along the leading edge of the squall
line. Weather watch issuance will likely be needed to the east of WW
87 in the next 1 to 2 hours.
..Broyles.. 04/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...BMX...MOB...LIX...
LAT...LON 31908769 31738847 31498886 30888903 30338906 30128841
30138763 30188612 30138560 30528532 31258531 31788569
31918690 31908769SPC 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, 9:15 PM CDT | Severe Thunderstorm Watch | SPC | Bibb, Colbert, Cullman, Dallas, Fayette, Franklin and 14 more | 7 hr |
| Apr 9, 10:25 PM CDT | Severe Thunderstorm Watch | SPC | Choctaw, Clarke, Washington, Wilcox | 6 hr |
| 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 |
| Apr 10, 8:58 AM CDT | Mesoscale Discussion | SPC | Bay, Calhoun, Dixie, Franklin, Gadsden, Gulf and 9 more | 92 min |
| Apr 10, 9:20 AM CDT | Tornado Watch | SPC | Dixie, Franklin, Gadsden, Jefferson, Lafayette, Leon and 4 more | 4 hr |
| Apr 10, 10:49 AM CDT | Mesoscale Discussion | SPC | Jefferson, Lafayette, Leon, Madison, Taylor, Wakulla | 116 min |
| Apr 10, 2:13 PM CDT | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Citrus, Clay, Columbia and 8 more | 2 hr |
| Apr 9, 11:00 PM CDT | Mesoscale Discussion | SPC | Adams, Amite, Copiah, Covington, Franklin, Jefferson and 10 more | 2 hr |
| Apr 10, 12:16 AM CDT | Tornado Watch | SPC | Amite, Covington, Forrest, George, Greene, Hancock and 15 more | 7 hr |
Nearby
Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Florida, 2021Mesoscale Discussions in Mississippi, 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.