Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 418
The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2012, 5:36 PM CDT for Choctaw County, Sumter County, Washington County, Alabama; Orleans Parish, Saint Bernard Parish, Saint Tammany Parish, Louisiana; 48 counties in Mississippi. It was in force for 54 min.
The area
The outline as issued.
The facts
- Issued
- Apr 2, 2012, 5:36 PM CDT (22:36 UTC)
- Expired
- Apr 2, 2012, 6:30 PM CDT
- In force
- 54 min
- Issued by
- the Storm Prediction Center
All 54 counties
Choctaw County, AL, Sumter County, AL, Washington County, AL, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Tammany Parish, LA, Attala County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clarke County, MS, Clay County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Grenada County, MS, Hancock County, MS, Harrison County, MS, Holmes County, MS, Jackson County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lafayette County, MS, Lamar County, MS, Lauderdale County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pearl River County, MS, Perry County, MS, Pontotoc County, MS, Quitman County, MS, Scott County, MS, Smith County, MS, Stone County, MS, Sunflower County, MS, Tallahatchie County, MS, Wayne County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 51 km from the middle of the area, began a volume at 22:38 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
Jackson, MS (KJAN), launched 12:00Z, 10.6 hours before the alert went out and 61 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
- 1280 J/kg
- Mixed-layer CIN
- -71 J/kg
- Mixed-layer LCL
- 566 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -68 m²/s²
- 0-3 km storm-relative helicity
- 29 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
690
ACUS11 KWNS 022236
SWOMCD
SPC MCD 022236
ALZ000-MSZ000-LAZ000-022330-
MESOSCALE DISCUSSION 0418
NWS STORM PREDICTION CENTER NORMAN OK
0536 PM CDT MON APR 02 2012
AREAS AFFECTED...NRN/ERN MS...FAR SERN LA...FAR WRN AL
CONCERNING...SEVERE THUNDERSTORM WATCH 128...
VALID 022236Z - 022330Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 128
CONTINUES.
ALTHOUGH THE ARCING QLCS HAS LARGELY WEAKENED W OF WW 128...MOST
INTENSE PORTION OF THE QLCS WAS LOCATED JUST N OF JAN WITH A HISTORY
OF PRODUCING DAMAGING WINDS AND SHOULD CONTINUE TO PROPAGATE NEWD.
AIR MASS IS LIKELY MODERATELY UNSTABLE ROUGHLY SW OF A BOLIVAR TO
GRENADA TO KEMPER COUNTY LINE WHERE BOUNDARY LAYER CU ARE PRESENT.
NE OF THIS LINE...LACK OF CU SUGGESTS A SOMEWHAT DRIER BOUNDARY
LAYER AND MODEST MLCIN EVIDENT IN MODIFIED RR FORECAST SOUNDINGS.
RECENT HRRR RUNS INDICATE THE QLCS SHOULD RAPIDLY WEAKEN BETWEEN
00-02Z LIKELY AS A RESULT OF THE AFOREMENTIONED THERMODYNAMIC
CONCERNS. THUS...COVERAGE OF THE DAMAGING WIND THREAT SHOULD BECOME
MORE LOCALIZED AND SUGGESTS A DOWNSTREAM WW MAY NOT BE NEEDED.
FARTHER S IN FAR SERN LA...GUST FRONT HAS SURGED AROUND 5-10 SM
AHEAD OF DEEPER CONVECTION PER KLIX RADAR WITH THE QLCS MOVING E AT
ONLY 20 KT. ALTHOUGH THE AIR MASS ALONG THE CNTRL GULF COAST IS
FAIRLY UNSTABLE WITH MLCAPE AOA 2000 J/KG...MODEST SLY DEEP-LAYER
SHEAR SUGGEST WIND DAMAGE POTENTIAL SHOULD BE RELEGATED TO LOCALIZED
WET MICROBURSTS. AS SUCH...A DOWNSTREAM WW DOES NOT APPEAR LIKELY
ATTM.
..GRAMS.. 04/02/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BMX...MOB...MEG...JAN...LIX...
LAT...LON 29869021 30958986 32498993 33429078 33909084 34519024
34448932 34128850 32248791 31548789 30348840 29468932
29869021SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 2, 9:57 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 27 more | 63 min |
| Apr 2, 10:10 AM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 31 more | 7 hr |
| Apr 2, 12:15 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Avoyelles, Bienville, Bossier and 49 more | 90 min |
| Apr 2, 12:41 PM CDT | Severe Thunderstorm Watch | SPC | Claiborne, Lincoln, Ouachita, Union, Webster | 6 hr |
| Apr 2, 12:50 PM CDT | Severe Thunderstorm Watch | SPC | Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Carroll and 25 more | 7 hr |
| Apr 2, 3:18 PM CDT | Mesoscale Discussion | SPC | Union | 117 min |
| Apr 2, 3:23 PM CDT | Mesoscale Discussion | SPC | East Carroll, East Feliciana, Livingston, Madison, Morehouse, Orleans and 9 more | 2 hr |
Nearby
Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Louisiana, 2012Every mesoscale discussion in 2012
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.