Alert archive / Alabama / Mesoscale Discussions in 2021
Mesoscale Discussion 338
The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2021, 7:38 AM CDT for 23 counties in Alabama; 12 counties in Georgia. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 7:38 AM CDT (12:38 UTC)
- Expired
- Apr 9, 2021, 10:15 AM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 35 counties
Autauga County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Chambers County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Tallapoosa County, AL, Wilcox County, AL, Chattahoochee County, GA, Harris County, GA, Marion County, GA, Muscogee County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taylor County, GA, Webster County, GA
The radar
The Maxwell AFB radar (KMXX), 69 km from the middle of the area, began a volume at 12:38 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 12:00Z, 0.6 hours before the alert went out and 154 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
- 89 J/kg
- Mixed-layer CIN
- -208 J/kg
- Mixed-layer LCL
- 1321 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 70 m²/s²
- 0-3 km storm-relative helicity
- 141 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted.
376
ACUS11 KWNS 091238
SWOMCD
SPC MCD 091238
GAZ000-ALZ000-091515-
Mesoscale Discussion 0338
NWS Storm Prediction Center Norman OK
0738 AM CDT Fri Apr 09 2021
Areas affected...Southern and Central Alabama...Western Georgia
Concerning...Severe potential...Watch possible
Valid 091238Z - 091515Z
Probability of Watch Issuance...40 percent
SUMMARY...An isolated large-hail and wind-damage threat will
continue to develop across parts of southern and central Alabama
this morning. Cells are expected to increase in coverage. Weather
watch issuance may need to be considered later this morning.
DISCUSSION...Latest surface analysis shows a warm front from
southern Mississippi eastward across southern Alabama. Thunderstorms
are forming in the vicinity of the front to the west-southwest of
Montgomery, Alabama. Additional storms are developing to the
southwest of Columbus, Georgia. RAP forecast soundings along the
front suggest that MUCAPE is near 2000 J/kg. Effective shear is
estimated in the 35 to 40 kt range according to regional WSR-88D
VWPs. This environment will support supercell development over the
next few hours. Cells that track east-northeastward near the front
may be associated with a wind-damage and brief tornado threat. The
storms will also produce isolated large hail. Cells that move to the
north of the warm front will predominately have a large hail threat.
..Broyles/Edwards.. 04/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FFC...TAE...BMX...MOB...
LAT...LON 31488546 31248615 31048687 31088761 31268808 31658818
32078796 32768679 32928598 32988517 32838413 32538403
32068411 31838444 31488546SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 2:49 AM CDT | Mesoscale Discussion | SPC | Baldwin, Mobile | 2 hr |
| Apr 9, 11:44 AM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Chambers, Chilton and 28 more | 2 hr |
| Apr 9, 12:54 PM CDT | Severe Thunderstorm Watch | SPC | Autauga, Bibb, Blount, Chilton, Coosa, Dallas and 19 more | 7 hr |
| Apr 9, 5:54 PM CDT | Mesoscale Discussion | SPC | Fayette, Greene, Lamar, Marion, Pickens, Sumter and 2 more | 96 min |
Nearby
Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Georgia, 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.