Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 573
The Storm Prediction Center issued this mesoscale discussion at May 9, 2021, 3:53 PM CDT for Madison Parish, Tensas Parish, Louisiana; 16 counties in Mississippi. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 9, 2021, 3:53 PM CDT (20:53 UTC)
- Expired
- May 9, 2021, 6:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Madison Parish, LA, Tensas Parish, LA, Claiborne County, MS, Copiah County, MS, Covington County, MS, Hinds County, MS, Jasper County, MS, Jefferson County, MS, Leake County, MS, Madison County, MS, Neshoba County, MS, Newton County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Warren County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 41 km from the middle of the area, began a volume at 20:57 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
Jackson, MS (KJAN), launched 12:00Z, 8.9 hours before the alert went out and 34 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
- 34 J/kg
- Mixed-layer CIN
- -569 J/kg
- Mixed-layer LCL
- 741 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 100 m²/s²
- 0-3 km storm-relative helicity
- 281 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
083
ACUS11 KWNS 092053
SWOMCD
SPC MCD 092053
MSZ000-LAZ000-092300-
Mesoscale Discussion 0573
NWS Storm Prediction Center Norman OK
0353 PM CDT Sun May 09 2021
Areas affected...Southwest to southern Mississippi
Concerning...Severe potential...Watch unlikely
Valid 092053Z - 092300Z
Probability of Watch Issuance...5 percent
SUMMARY...Ongoing thunderstorms moving into southwest Mississippi
may be capable of isolated damaging winds, especially if an
organized cold pool can develop. However, the overall potential
remains low and a watch is not expected.
DISCUSSION...A cluster of thunderstorms moving into southwest MS has
a history of transient stronger updraft pulses within the cluster
over the past 30 minutes per GOES IR imagery. Although this cluster
is currently unorganized, reflectivity trends from KDGX suggest weak
cold pool propagation is occurring on the eastern periphery of the
cluster in line with the mean wind vector. The environment across
southern MS is generally supportive of organized convection with
nearly 2000 J/kg SBCAPE and around 30 knots of effective bulk shear
analyzed in recent RAP mesoanalysis. Additionally, the KDGX VWP
recently observed 30 knots of 0-3 km bulk shear, which is adequate
to support further cold pool organization. As such, a damaging wind
threat may evolve from this cluster as it moves into south-central
MS, though confidence is this scenario is low. Marginally severe
hail will also be possible in the near term with any stronger
updraft pulses, but given the unfavorable storm mode and weak
forcing for ascent, a persistent hail threat does not appear likely.
This potential may persist for the next few hours, but a watch is
not expected.
..Moore/Thompson.. 05/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...JAN...
LAT...LON 31799160 32469119 32989062 33058986 32988893 32018912
31598941 31569029 31579142 31799160SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 9, 12:14 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 13 more | 91 min |
| May 9, 1:14 PM CDT | Severe Thunderstorm Watch | SPC | Bienville, Bossier, Caddo, Claiborne, De Soto, East Carroll and 9 more | 8 hr |
| May 9, 3:42 PM CDT | Mesoscale Discussion | SPC | Bossier, Caddo, Claiborne, Webster | 93 min |
| May 9, 5:41 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 22 more | 2 hr |
| May 9, 5:45 PM CDT | Severe Thunderstorm Watch | SPC | Allen, Avoyelles, Beauregard, Caldwell, Evangeline, Grant and 7 more | 7 hr |
| May 9, 2:27 PM CDT | Severe Thunderstorm Watch | SPC | Alcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more | 7 hr |
| May 9, 5:48 PM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Coahoma, DeSoto, Itawamba, Lafayette and 11 more | 87 min |
| May 9, 6:40 PM CDT | Mesoscale Discussion | SPC | Calhoun, Chickasaw, Itawamba, Lafayette, Lee, Monroe and 3 more | 65 min |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Louisiana, 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.