Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 337
The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2021, 2:49 AM CDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 2:49 AM CDT (07:49 UTC)
- Expired
- Apr 9, 2021, 5:15 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Baldwin County, AL, Mobile County, AL, Bay County, FL, Calhoun County, FL, Escambia County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Liberty County, FL, Okaloosa County, FL, Santa Rosa County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Jefferson Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Hancock County, MS, Harrison County, MS, Jackson County, MS
The radar
The Mobile radar (KMOB), 126 km from the middle of the area, began a volume at 07:49 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
Slidell Radar S, LA (KSIL), launched 00:00Z, 7.8 hours before the alert went out and 227 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
- 44 J/kg
- Mixed-layer CIN
- -210 J/kg
- Mixed-layer LCL
- 1605 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 24 m²/s²
- 0-3 km storm-relative helicity
- 62 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.7
The text
As transmitted.
340
ACUS11 KWNS 090750
SWOMCD
SPC MCD 090749
FLZ000-ALZ000-MSZ000-LAZ000-091015-
Mesoscale Discussion 0337
NWS Storm Prediction Center Norman OK
0249 AM CDT Fri Apr 09 2021
Areas affected...Central Gulf Coast
Concerning...Severe potential...Watch unlikely
Valid 090749Z - 091015Z
Probability of Watch Issuance...5 percent
SUMMARY...A marginal hail threat is expected in the central Gulf
Coast area early this morning from far southeast Louisiana eastward
across the Florida Panhandle. Weather watch issuance is not
expected.
DISCUSSION...Water-vapor imagery shows an upper-level trough over
the Mississippi Valley with an east-to-west plume of mid-level
moisture located in the central Gulf Coast region. Thunderstorms are
ongoing along the southern edge of this plume from just off the
coast of far southeast Louisiana into far southern Mississippi.
Other storms are ongoing near the Florida Panhandle to the southeast
of Panama City, Florida. The storms in the central Gulf Coast are
supported by a warm advection regime that will continue through the
remainder of the night. Moderate deep-layer shear is present with
the Mobile WSR-88D VWP showing 0-6 km shear near 40 kt. This will
support both multicell and supercell development. The hodograph
suggests that left-moving storms will be possible. The shear
combined with 700-500 mb lapse rates of 7.0 to 7.5 C/km, according
to the RAP, will be favorable for hail with the stronger updrafts.
However, any hail threat is expected to be marginal through
daybreak.
..Broyles/Edwards.. 04/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...MOB...LIX...
LAT...LON 29158875 28808920 28808967 28988997 29339015 29829009
30378968 30628883 30778738 30798609 30738493 30518436
30068417 29668435 29458477 29508538 29848590 30068656
29988792 29568848 29158875SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 7:38 AM CDT | Mesoscale Discussion | SPC | Autauga, Barbour, Bullock, Butler, Chambers, Clarke and 17 more | 3 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 |
| Apr 9, 9:49 AM CDT | Mesoscale Discussion | SPC | Bossier, Caddo | 116 min |
| Apr 9, 12:07 PM CDT | Severe Thunderstorm Watch | SPC | Bienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 5 more | 6 hr |
| Apr 9, 1:25 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caldwell, Claiborne, De Soto, East Carroll and 12 more | 95 min |
| Apr 9, 3:10 PM CDT | Mesoscale Discussion | SPC | Claiborne, East Carroll, Lincoln, Morehouse, Ouachita, Richland and 2 more | 95 min |
| Apr 9, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | East Carroll, Franklin, Madison, Morehouse, Richland, Tensas and 1 more | 7 hr |
| Apr 9, 5:19 PM CDT | Mesoscale Discussion | SPC | Bienville, Caldwell, Claiborne, De Soto, Franklin, Grant and 10 more | 116 min |
| Apr 9, 5:32 PM CDT | Severe Thunderstorm Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more | 7 hr |
| Apr 9, 6:14 PM CDT | Mesoscale Discussion | SPC | Caldwell, East Carroll, Franklin, Madison, Morehouse, Ouachita and 2 more | 3 hr |
Nearby
Mesoscale Discussions in Florida, 2021Mesoscale Discussions in Louisiana, 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.