Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 1671
The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2012, 2:36 PM CDT for 11 counties in Alabama; 33 counties in Mississippi. It was in force for 54 min.
The area
The outline as issued.
The facts
- Issued
- Aug 1, 2012, 2:36 PM CDT (19:36 UTC)
- Expired
- Aug 1, 2012, 3:30 PM CDT
- In force
- 54 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 44 counties
Colbert County, AL, Fayette County, AL, Franklin County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Marion County, AL, Pickens County, AL, Walker County, AL, Winston County, AL, Alcorn County, MS, Attala County, MS, Benton County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Itawamba County, MS, Kemper County, MS, Lafayette County, MS, Lauderdale County, MS, Leake County, MS, Lee County, MS, Lowndes County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pontotoc County, MS, Prentiss County, MS, Scott County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS
The radar
The Columbus AFB radar (KGWX), 28 km from the middle of the area, began a volume at 19:36 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
Little Rock, AR (KLZK), launched 12:00Z, 7.6 hours before the alert went out and 167 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
- 1994 J/kg
- Mixed-layer CIN
- -151 J/kg
- Mixed-layer LCL
- 1606 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 10 m²/s²
- 0-3 km storm-relative helicity
- -28 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
024
ACUS11 KWNS 011936
SWOMCD
SPC MCD 011936
ALZ000-MSZ000-012030-
MESOSCALE DISCUSSION 1671
NWS STORM PREDICTION CENTER NORMAN OK
0236 PM CDT WED AUG 01 2012
AREAS AFFECTED...CNTRL/NERN MS...NWRN AL
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 011936Z - 012030Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...AN ISOLATED DMGG WIND THREAT MAY DEVELOP ACROSS CNTRL/NERN
MS AND PARTS OF NWRN AL THIS AFTERNOON. TSTMS HAVE BEEN INCREASING
IN COVERAGE IN PROXIMITY TO A SSE MOVING MCV NOW ENTERING NW MS.
THERE IS SOME UNCERTAINTY REGARDING COVERAGE OF THE THREAT...BUT
CONVECTIVE TRENDS ARE BEING MONITORED FOR POSSIBLE WW ISSUANCE.
DISCUSSION...SATELLITE LOOP SHOWS A MCV AND ASSOCIATED CONVECTIVE
DEBRIS CLOUDINESS OVERSPREADING PARTS OF THE MS RIVER VALLEY...WITH
AN INCREASE IN CONVECTION OVER THE PAST COUPLE HRS ACROSS NERN MS.
SFC TEMPERATURES HAVE HEATED UP INTO THE UPPER 90S TO NEAR 100 F
ACROSS NERN MS...WHILE DEWPOINTS HAVE REMAINED IN THE
70S...RESULTING IN MLCAPE VALUES AOA 2000 J/KG. MIDLEVEL FLOW
APPEARS TO BE SOMEWHAT MARGINAL FOR STORM ORGANIZATION...THOUGH ONE
OR MORE MULTICELL CLUSTERS MAY STILL DEVELOP THROUGH STORM MERGERS
WITHIN AREA OF FOCUSED ASCENT ATTENDANT TO THE MCV. STEEP LOW-LEVEL
LAPSE RATES AND OBJECTIVELY ANALYZED DCAPE VALUES GREATER THAN 1500
J/KG WILL BE SUPPORTIVE FOR ISOLATED DMGG WIND GUSTS. IT IS UNCLEAR
WHETHER COVERAGE OF WIND THREAT WILL BE SUFFICIENT FOR WW
ISSUANCE...BUT CONVECTIVE TRENDS WILL BE MONITORED.
..ROGERS/CARBIN.. 08/01/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BMX...HUN...MEG...JAN...
LAT...LON 34808677 34058709 32878804 32358872 32278922 32368998
33009023 33729009 34438965 34868932 34998876 34988736
34808677SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 3:02 PM CDT | Severe Thunderstorm Watch | SPC | Colbert, Fayette, Franklin, Greene, Hale, Lamar and 8 more | 6 hr |
Nearby
Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Alabama, 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.