Alert archive / Alabama / Mesoscale Discussions in 2021
Mesoscale Discussion 358
The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2021, 4:06 AM CDT for 14 counties in Alabama; 6 counties in Florida; George County, Greene County, Jackson County, Mississippi. It was in force for 114 min.
The area
The outline as issued.
The facts
- Issued
- Apr 10, 2021, 4:06 AM CDT (09:06 UTC)
- Expired
- Apr 10, 2021, 6:00 AM CDT
- In force
- 114 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 09:10 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 nearest sounding before it
Birmingham, AL (KBMX), launched 00:00Z, 9.1 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.
934
ACUS11 KWNS 100907
SWOMCD
SPC MCD 100906
FLZ000-ALZ000-MSZ000-101100-
Mesoscale Discussion 0358
NWS Storm Prediction Center Norman OK
0406 AM CDT Sat Apr 10 2021
Areas affected...Southern Louisiana...Southern Mississippi
Concerning...Tornado Watch 87...
Valid 100906Z - 101100Z
The severe weather threat for Tornado Watch 87 continues.
SUMMARY...A severe threat will continue across WW 87 over the next
few hours. A tornado will be possible, along with wind damage and
hail.
DISCUSSION...The latest radar imagery shows several
southwest-to-northeast bands of strong to severe convection ongoing
from just northwest of Lake Pontchartrain eastward into far southern
Mississippi. The storms are located along the northern edge of a
very moist airmass with surface dewpoints in southeast Louisiana in
the lower 70s F. This is contributing to moderate instability with
the RAP estimating MLCAPE in the southern part of WW 87 to be as
high as 2500 J/kg. The instability will help maintain storm
intensity over the few hours. In addition, the WSR-88D VWPs at New
Orleans and Mobile have 0-6 km shear in the 50 to 55 kt range. 0-3
km storm relative helicities are estimated to be near 450 m2/s2
suggesting that the environment will be favorable for supercells
with tornado potential. Wind damage will be likely along the leading
edge of the faster moving line segments. The severe threat should be
increasingly isolated across the western half of WW 87 as the storms
with more severe threat coverage move into the eastern part of the
watch.
..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, 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, 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.