Alert archive / Mississippi / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 451, NWS Jackson, MS

August 20, 2002Choctaw County, Webster County, Mississippi

NWS Jackson, MS issued this severe thunderstorm warning at Aug 20, 2002, 8:02 PM CDT for Choctaw County, Webster County, Mississippi. It was in force for 43 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Aug 20, 2002, 8:02 PM CDT (01:02 UTC)
Expired: Aug 20, 2002, 8:45 PM CDT
In force: 43 min
Issued by: NWS Jackson, MS
Area: Counties, with a storm outline in the text

Counties Choctaw County, MS, Webster County, MS

What was reported inside it

Time	Report	Where	Remark
Aug 20, 8:15 PM CDT	Thunderstorm Wind	Weir, MS	Two trees and one powerline were blown down in the community.
Aug 20, 8:15 PM CDT	Thunderstorm Wind	Countywide, MS	Three trees and several powerlines were blown down across the county.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 1.0 hours before the alert went out and 150 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2515 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 1248 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 42 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Jackson, MS wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 4:05 PM CDT, 3 hours 57 minutes earlier.

Area forecast discussion, Aug 20, 4:05 PM CDT, 3 hours 57 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
315 PM CDT TUE AUG 20 2002

AIR MASS CONTINUES VERY MOIST AND UNSTABLE. BEST DYNAMICS LOCATED
ERN ZONES WHERE LOWLEVEL CONVERGENCE IS BEST. CONVECTION SHOULD BE
GENERALLY DIURNAL.

UPPER TROUGHING INCREASING SLIGHTLY WED. SHORTWAVE SLIPS WWD
UNDERNEATH UPPER RIDGE...MOVING ACROSS MS COAST INTO SRN LA. WEAK
UPPER DIVERGENCE AND WEAK SURFACE BOUNDARY NOTED OVER REGION
TOMORROW. MID/UPPER HEIGHTS SHOW VERY LITTLE CHANGE SO EXPECT WEAK
CAPPING EFFECTS TO LINGER NRN ZONES. WILL KEEP SLIGHT CHANCE NRN
AREAS AND CHC POPS SRN AREAS WITH ISOLATED EVENING CONVECTION FOR
WED NIGHT.

UPPER TROUGH POSITIONED OVER LA/WRN MS BY THU MORNING WITH WEAK
SHEAR ZONE SUGGESTED ACROSS THE AREA. 500 MB HEIGHT REMAIN HIGH.
WITH LOW LEVEL BOUNDARY LINGERING ACROSS CENTRAL/SRN ZONES WILL GO
WITH CHANCE POPS ALL AREAS FOR THU INTO THU NIGHT. TROUGH SHIFTS TO
THE W AND UPPER TROUGHING DIMINISHES FOR FRI AFOR FORECAST AREA. NO
SURFACE FORCING NOTED SO WILL KEEP ISOLATED CONVECTION ACROSS THE
REGION FOR FRI AFTERNOON ADN EVENING.

HEIGHTS BEGIN TO FALL FRIDAY NIGHT AND THE SHORTWAVE TRACK THAT HAS
PERSISTED WELL NORTH OF THE REGION DROPS THIS WAY. SURFACE BOUNDARY
DROPS INTO NRN AREAS BY 00Z SUNDAY. JET MAX REMAINS TO THE NORTH BUT
WILL SEE RIGHT REAR JET QUAD CLOSE ENOUGH TO EFFECT FORECAST
AREA...ESPECIALLY NRN ZONES. UPPER TROUGHING CONTINUES THROUGH
MONDAY...WEAKENING TUESDAY. BY TUESDAY SURFACE BOUNDARY FINALLY
SHIFTS TO THE E BUT WILL MAINTAIN CHANCE OF AFTERNOON ACTIVITY
THROUGH EXTENDED PERIOD.

PRELIM NUMBERS:
JAN 72/93/73/92 2223
MEI 71/93/72/92 2223

.JAN...
AR...NONE.
LA...NONE.
MS...NONE.

In the hours before

Special weather statement, Aug 20, 2:39 PM CDT, 5 hours 23 minutes before

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
211200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
239 PM CDT TUE AUG 20 2002

...THUNDERSTORMS...
ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH 8 PM
TONIGHT ALONG AND SOUTHEAST OF A RAYVILLE TO VICKSBURG TO CANTON
TO KOSCIUSKO TO EUPORA LINE. DAMAGING WIND GUSTS TO 70 MPH WILL
BE THE MAIN THREAT WITH THESE STORMS.

A VERY MOIST AND UNSTABLE AIRMASS IS IN PLACE ACROSS THE LOWER
MISSISSIPPI VALLEY TODAY. A DISTURBANCE IN THE UPPER LEVELS OF
THE ATMOSPHERE WILL MOVE SOUTHWEST ACROSS THE AREA...TRIGGERING
SCATTERED THUNDERSTORMS. DUE TO THE STRONG INSTABILITY IN
PLACE...A FEW OF THESE STORMS MAY BECOME SEVERE OVER PORTIONS OF
NORTHEAST LOUISIANA AND MUCH OF SOUTHERN AND EASTERN MISSISSIPPI.
THE THUNDERSTORMS SHOULD GRADUALLY DISSIPATE AFTER SUNSET.

ACTIVATION OF STORM SPOTTERS...EMERGENCY MANAGEMENT
PERSONNELL...AND HAM RADIO OPERATORS MAY BE NEEDED THIS AFTERNOON
AND EVENING.

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/JAN. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

Local storm report, Aug 20, 3:14 PM CDT, 4 hours 48 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
314 PM CDT TUE AUG 20 2002

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0307 PM    3S NEWTON                 MS   0.88 INCH HAIL
08/20/02   NEWTON

Special weather statement, Aug 20, 4:37 PM CDT, 3 hours 25 minutes before

MSZ030>033-037>039-044>046-049>052-055>058-062>066-202230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
437 PM CDT TUE AUG 20 2002

THE NATIONAL WEATHER SERVICE IN JACKSON HAS CANCELED SEVERE
THUNDERSTORM WATCH NUMBER 623 FOR THE FOLLOWING COUNTIES...

ATTALA           LEAKE              SCOTT            RANKIN
LAUDERDALE       NEWTON             JASPER           CLARKE
SMITH            SIMPSON            JONES            COVINGTON
JEFFERSON DAVIS  LAWRENCE           LINCOLN          NESHOBA

SEVERE THUNDERSTORM WATCH NUMBER 623 REMAINS IN EFFECT UNTIL 7 PM
FOR THE FOLLOWING COUNTIES...

CHOCTAW          CLAY               LOWNDES          WINSTON
NOXUBEE          KEMPER             OKTIBBEHA

The office that day

Everything else NWS Jackson, MS issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 7:06 PM CDT	Severe Thunderstorm Warning	JAN	Clay	44 min
Aug 20, 8:08 PM CDT	Severe Thunderstorm Warning	JAN	Winston	37 min

Nearby

Severe Thunderstorm Warnings in Mississippi, 2002 Every severe thunderstorm warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.