Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 304
The Storm Prediction Center issued this mesoscale discussion at Mar 30, 2021, 5:46 PM CDT for 4 states. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Mar 30, 2021, 5:46 PM CDT (22:46 UTC)
- Expired
- Mar 30, 2021, 7:45 PM CDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
All 73 counties
Washington County, AL, Ashley County, AR, Bradley County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, Union County, AR, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Bolivar County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wayne County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 82 km from the middle of the area, began a volume at 22:48 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
Jackson, MS (KJAN), launched 12:00Z, 10.8 hours before the alert went out and 75 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
- 1615 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 67 m²/s²
- 0-3 km storm-relative helicity
- 124 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
747
ACUS11 KWNS 302246
SWOMCD
SPC MCD 302246
ALZ000-MSZ000-LAZ000-ARZ000-310045-
Mesoscale Discussion 0304
NWS Storm Prediction Center Norman OK
0546 PM CDT Tue Mar 30 2021
Areas affected...The Ark-La-Miss region into southeastern
Mississippi
Concerning...Severe potential...Watch unlikely
Valid 302246Z - 310045Z
Probability of Watch Issuance...5 percent
SUMMARY...A few strong to severe storms may evolve within a broad
warm advection regime across Louisiana, southern Mississippi, and
southern Arkansas. Hail and damaging winds will be the primary
concerns, though a low-end tornado threat is noted.
DISCUSSION...Recent GOES IR imagery and lightning data show deeper
convection has begun to develop within a broad, but modest, warm
advection regime in place over the northern Gulf states. These
deeper updrafts are beginning to mature in a supportive environment
with 500-1000 J/kg MLCAPE and 35-45 knots of effective bulk shear.
Additionally, the low-level warm advection regime has resulted in
substantial directional shear in the lowest 2-3 km per regional
VWPs. Little to no surface-based inhibition has allowed earlier
scattered convection to develop in close proximity to neighboring
storms, resulting in numerous storm interactions and storm clusters.
This trend may continue with the more recent, deeper convection and
limit the overall severe threat.
However, a few discrete storms may evolve over the next few hours
and pose a risk for severe hail and damaging wind. Effective SRH on
the order of 100-200 m2/s2 across the region appears sufficient to
support a low-end tornado threat, but mitigating factors, such as
downdraft/precipitation distribution ahead of the storm path, may
limit this potential. That being said, the tornado potential may be
slightly higher along a weak surface warm front noted from southern
AR into far southeast LA/southwest MS where surface winds are backed
to the south/southeast and low-level SRH may be enhanced. But given
the conditional/isolated nature of this threat, a watch is not
expected.
..Moore/Edwards.. 03/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MOB...JAN...LIX...LZK...LCH...SHV...
LAT...LON 33839050 33418990 32688910 32028865 31368806 30758815
30488864 30508921 30918986 31059050 31189123 31139227
31149302 31469341 32059355 32819315 33309280 33849220
34059193 33839050SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 30, 6:47 PM CDT | Mesoscale Discussion | SPC | Calhoun, Clark, Columbia, Dallas, Hempstead, Howard and 8 more | 2 hr |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Arkansas, 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.