Alert archive / Mississippi / Mesoscale Discussions in 2016
Mesoscale Discussion 621
The Storm Prediction Center issued this mesoscale discussion at May 12, 2016, 2:33 PM CDT for 7 counties in Arkansas; 19 parishes in Louisiana; 47 counties in Mississippi. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- May 12, 2016, 2:33 PM CDT (19:33 UTC)
- Expired
- May 12, 2016, 4:00 PM CDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 73 counties
Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Desha County, AR, Drew 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, Ouachita Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Copiah County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jasper County, MS, Jefferson County, MS, Kemper County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lincoln 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, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Sunflower County, MS, Tallahatchie County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 141 km from the middle of the area, began a volume at 19:33 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, 7.6 hours before the alert went out and 131 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
- 306 J/kg
- Mixed-layer CIN
- -63 J/kg
- Mixed-layer LCL
- 1014 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 28 m²/s²
- 0-3 km storm-relative helicity
- 44 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
309
ACUS11 KWNS 121934
SWOMCD
SPC MCD 121933
MSZ000-ARZ000-LAZ000-122100-
MESOSCALE DISCUSSION 0621
NWS STORM PREDICTION CENTER NORMAN OK
0233 PM CDT THU MAY 12 2016
AREAS AFFECTED...SE AR...NE LA...PORTIONS OF NRN/CNTRL MS
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 121933Z - 122100Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...ISOLATED STRONG WIND GUSTS AND POSSIBLY SOME SMALL HAIL
WILL BE POSSIBLE INTO EARLY EVENING ACROSS PATS OF THE LOWER MS
VALLEY. A WATCH IS NOT EXPECTED AT THIS TIME...BUT TRENDS WILL BE
MONITORED CLOSELY.
DISCUSSION...ISOLATED STORMS WERE DEVELOPING AHEAD OF A SURFACE COLD
FRONT FROM SOUTHERN AR INTO W-CNTRL MS. DEWPOINTS IN THE UPPER 60S
AND STRONG HEATING INTO THE 80S HAS RESULTED IN WEAK TO MODERATE
INSTABILITY. EFFECTIVE SHEAR IS ON THE WEAK SIDE...AROUND 25
KT...BUT FORECAST TO IMPROVE SOME AS THE MAIN UPPER LEVEL TROUGH
SHIFTS EASTWARD INTO THE MID/UPPER MS VALLEY. MODERATE DCAPE AND
STEEP LOW LEVEL LAPSE RATES WILL GENERALLY FAVOR STRONG WIND GUSTS
IN THUNDERSTORM CLUSTERS. GIVEN WEAK SHEAR...CONVECTIVE MODE WILL
LIKELY REMAIN MESSY WITH PULSE-LIKE CLUSTERS MOST LIKELY.
HOWEVER...SHOULD ANY APPRECIABLE COLD POOL DEVELOP...FURTHER
ORGANIZATION INTO FORWARD PROPAGATING LINE SEGMENTS AND ASSOCIATED
INCREASE IN DAMAGING WIND POTENTIAL WOULD BE POSSIBLE. MODEST
MIDLEVEL LAPSE RATES AND WEAK SHEAR WILL GENERALLY LIMIT LARGE HAIL
POTENTIAL...BUT SOME SMALL HAIL WILL BE POSSIBLE WITH STRONGEST
UPDRAFTS. A WATCH IS NOT IMMEDIATELY EXPECTED...BUT TRENDS WILL BE
MONITORED CLOSELY.
..LEITMAN/HART.. 05/12/2016
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MEG...JAN...LZK...SHV...
LAT...LON 32929326 33539288 33849200 34298972 34348866 33518833
32448852 31678949 31419062 31469202 31609271 31759293
32139327 32659336 32929326SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 8:11 PM CDT | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Crawford, Franklin and 5 more | 3 hr |
| May 11, 10:13 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 7 hr |
| May 11, 11:46 PM CDT | Mesoscale Discussion | SPC | Crawford, Franklin, Logan, Scott, Sebastian | 119 min |
| May 12, 2:48 AM CDT | Mesoscale Discussion | SPC | Cleburne, Conway, Craighead, Faulkner, Garland, Greene and 17 more | 87 min |
| May 12, 9:10 AM CDT | Mesoscale Discussion | SPC | Craighead, Crittenden, Cross, Greene, Mississippi, Poinsett | 95 min |
Nearby
Mesoscale Discussions in Mississippi, 2016Mesoscale Discussions in Louisiana, 2016Mesoscale Discussions in Arkansas, 2016Every mesoscale discussion in 2016
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.