Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 947
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2021, 12:51 PM CDT for Mobile County, Alabama; 10 parishes in Louisiana; 24 counties in Mississippi. It was in force for 114 min.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2021, 12:51 PM CDT (17:51 UTC)
- Expired
- Jun 13, 2021, 2:45 PM CDT
- In force
- 114 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 265
All 35 counties
Mobile County, AL, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Helena Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Wilkinson County, MS
The nearest sounding before it
Slidell Radar S, LA (KSIL), launched 12:00Z, 5.9 hours before the alert went out and 66 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
- 2482 J/kg
- Mixed-layer CIN
- -20 J/kg
- Mixed-layer LCL
- 802 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 43 m²/s²
- 0-3 km storm-relative helicity
- 52 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 1.3
The text
As transmitted.
231
ACUS11 KWNS 131751
SWOMCD
SPC MCD 131751
ALZ000-MSZ000-LAZ000-131945-
Mesoscale Discussion 0947
NWS Storm Prediction Center Norman OK
1251 PM CDT Sun Jun 13 2021
Areas affected...southern MS...southwest AL...southeast LA
Concerning...Severe Thunderstorm Watch 265...
Valid 131751Z - 131945Z
The severe weather threat for Severe Thunderstorm Watch 265
continues.
SUMMARY...A weak mid-level disturbance evident in water-vapor
imagery will likely focus storm development and severe potential
across southern MS and eventually northern parts of southeast LA
later this afternoon.
DISCUSSION...Visible-satellite imagery shows an agitated cumulus
field over southern MS ahead of a weak mid-level vorticity maximum
located near Hattiesburg, MS early this afternoon. Surface
conditions over southern MS and northeast LA have warmed into the
lower 90s deg F with mid to upper 70s dewpoints. Steep surface to
1.5 km lapse rates were noted on the 18z Jackson, MS raob with 25-30
kt north-northeasterly flow in the 500-400 mb layer. The
high-PW/very unstable environment will favor water-loaded downdrafts
with the more intense cores. Strong to severe gusts ranging 50-70
mph are possible with the most intense storms. Expecting initially
isolated storm coverage early this afternoon to further increase
into scattered coverage by late afternoon. The wind damage hazard
will likely concentrate around a couple of linear clusters.
..Smith.. 06/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MOB...JAN...LIX...
LAT...LON 29848987 30439118 31459149 32189098 31748947 31008805
30058823 29848987SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 13, 10:45 AM CDT | Mesoscale Discussion | SPC | Choctaw, Colbert, Cullman, Fayette, Franklin, Greene and 10 more | 60 min |
| Jun 13, 12:22 PM CDT | Severe Thunderstorm Watch | SPC | Choctaw, Clarke, Fayette, Greene, Hale, Lamar and 9 more | 9 hr |
| Jun 13, 1:25 PM CDT | Mesoscale Discussion | SPC | Choctaw, Greene, Marengo, Sumter | 2 hr |
| Jun 13, 3:43 PM CDT | Mesoscale Discussion | SPC | Covington, Jasper, Jones, Leake, Newton, Scott and 1 more | 2 hr |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Alabama, 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.