Alert archive / Mississippi / Severe Thunderstorm Watches in 2015

Severe Thunderstorm Watch 49

April 9, 20154 states

The Storm Prediction Center issued this severe thunderstorm watch at Apr 9, 2015, 6:32 PM CDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 9, 2015, 6:32 PM CDT (23:32 UTC)
Expired
Apr 9, 2015, 11:53 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 64 counties

Ashley County, AR, Chicot County, AR, Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Lawrence County, AR, Lee County, AR, Mississippi County, AR, Phillips County, AR, Poinsett County, AR, Randolph County, AR, St. Francis County, AR, Dunklin County, MO, Pemiscot County, MO, Alcorn County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Chickasaw County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Leflore County, MS, Marshall County, MS, Monroe County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Washington County, MS, Yalobusha County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 24 km from the middle of the area, began a volume at 23:35 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
50%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 9, 6:59 PM CDTSevere Thunderstorm WarningMEGClay, Greene23 min
Apr 9, 7:05 PM CDTSevere Thunderstorm WarningMEGLawrence40 min
Apr 9, 9:45 PM CDTSevere Thunderstorm WarningMEGCraighead, Greene, Lawrence, Poinsett45 min
Apr 9, 9:54 PM CDTFlash Flood WarningMEGCraighead, Greene, Lawrence, Poinsett3 hr
Apr 9, 11:25 PM CDTFlash Flood WarningJANAshley, Chicot3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Little Rock, AR (KBYH), launched 12:00Z, 11.5 hours before the alert went out and 46 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.

Skew-T log-pSkew-T log-p diagram, Little Rock, AR at 12:00Z on 2015-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 91 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Little Rock, AR at 12:00Z on 2015-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 215 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
91 J/kg
Mixed-layer CIN
-182 J/kg
Mixed-layer LCL
880 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
215 m²/s²
0-3 km storm-relative helicity
200 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

440 
WWUS20 KWNS 092331
SEL9  
SPC WW 092331
ARZ000-MOZ000-MSZ000-TNZ000-100600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 49
NWS STORM PREDICTION CENTER NORMAN OK
635 PM CDT THU APR 9 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  EASTERN ARKANSAS
  MISSOURI BOOTHEEL
  NORTHERN MISSISSIPPI
  WEST TENNESSEE

* EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 635 PM
  UNTIL 100 AM CDT.

* PRIMARY THREATS INCLUDE...
  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
    INCHES IN DIAMETER POSSIBLE
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  A TORNADO OR TWO POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH OF
DYERSBURG TENNESSEE TO 20 MILES SOUTHWEST OF GREENWOOD
MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 39...WW 40...WW 41...WW
42...WW 43...WW 44...WW 45...WW 46...WW 47...WW 48...

DISCUSSION...SCATTERED SEVERE THUNDERSTORMS OVER AR WILL SPREAD
EASTWARD INTO PARTS OF TN/MS DURING THE EVENING.  MODERATE
INSTABILITY AND FAVORABLE DEEP LAYER SHEAR VALUES WILL PROMOTE
ROTATING STORMS CAPABLE OF LARGE HAIL AND DAMAGING WINDS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 25030.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 9, 2:15 PM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 32 more2 hr
Apr 9, 2:32 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more7 hr
Apr 9, 3:06 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 13 more7 hr
Apr 9, 3:17 PM CDTSevere Thunderstorm WatchSPCBaxter, Boone, Cleburne, Conway, Faulkner, Fulton and 29 more7 hr
Apr 9, 6:11 PM CDTMesoscale DiscussionSPCArkansas, Baxter, Bradley, Calhoun, Clark, Clay and 57 more64 min
Apr 8, 7:04 PM CDTMesoscale DiscussionSPCBollinger, Cape Girardeau, Iron, Madison, Perry, Sainte Genevieve and 1 more116 min
Apr 9, 12:29 PM CDTMesoscale DiscussionSPCAdair, Clark, Grundy, Knox, Linn, Macon and 5 more91 min
Apr 9, 12:58 PM CDTTornado WatchSPCAdair, Audrain, Boone, Callaway, Carroll, Chariton and 27 more6 hr
Apr 9, 1:32 PM CDTMesoscale DiscussionSPCBarry, Barton, Benton, Camden, Cedar, Dade and 11 more118 min
Apr 9, 3:12 PM CDTMesoscale DiscussionSPCAdair, Audrain, Boone, Chariton, Clark, Cooper and 19 more93 min
Apr 9, 3:45 PM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Carter, Crawford, Franklin and 14 more60 min
Apr 9, 4:40 PM CDTTornado WatchSPCCrawford, Franklin, Iron, Jefferson, Lincoln, Madison and 8 more6 hr
Apr 9, 6:48 PM CDTTornado WatchSPCBollinger, Butler, Cape Girardeau, Carter, Mississippi, New Madrid and 5 more6 hr
Apr 9, 4:06 PM CDTMesoscale DiscussionSPCCarter, Johnson, Unicoi54 min

Nearby

Severe Thunderstorm Watches in Mississippi, 2015Severe Thunderstorm Watches in Tennessee, 2015Severe Thunderstorm Watches in Arkansas, 2015Every severe thunderstorm watch in 2015

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.