Alert archive / Mississippi / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 108, NWS New Orleans, LA

May 12, 2009Walthall County, Mississippi

NWS New Orleans, LA issued this severe thunderstorm warning at May 12, 2009, 9:16 PM CDT for Walthall County, Mississippi. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 12, 2009, 9:16 PM CDT (02:16 UTC)
Expired: May 12, 2009, 9:45 PM CDT
In force: 29 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon

County Walthall County, MS

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 2.3 hours before the alert went out and 130 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: 1616 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 986 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.5

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 New Orleans, LA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 12, 7:56 PM CDT, 1 hour 20 minutes earlier.

Area forecast discussion, May 12, 7:56 PM CDT, 1 hour 20 minutes before

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Hazardous weather outlook, May 12, 7:03 PM CDT, 2 hours 13 minutes before

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In the hours before

Special weather statement, May 12, 3:28 PM CDT, 5 hours 48 minutes before

LAZ039-040-MSZ077-122115-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
328 PM CDT TUE MAY 12 2009

...LINE OF STRONG THUNDERSTORMS MOVING NORTH AFFECTING WASHINGTON
PARISH...PEARL RIVER COUNTY...ST. TAMMANY PARISH...

AT 327 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM 11 MILES
NORTHEAST OF COVINGTON TO JUST WEST OF PICAYUNE...MOVING NORTH AT 10
MPH.

THE LINE OF STRONG THUNDERSTORMS WILL AFFECT AREAS IN AND AROUND...
BUSH AND SUN

THE PRIMARY THREAT FROM THESE STORMS IS PEA TO MARBLE SIZE HAIL. SEEK
SHELTER IN A SAFE HOME OR BUILDING UNTIL THESE STORMS HAVE PASSED.

THESE STORMS COULD PRODUCE RAINFALL AMOUNTS OF ONE TO TWO INCHES IN A
SHORT PERIOD OF TIME...RESULTING IN PONDING OF WATER AROUND LOW LYING
ROADWAYS. REMEMBER...DO NOT DRIVE YOUR VEHICLE INTO WATER COVERED
ROADWAYS. THE DEPTH MAY BE TOO GREAT TO ALLOW A SAFE CROSSING.

22/TD

Local storm report, May 12, 4:12 PM CDT, 5 hours 4 minutes before

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Special weather statement, May 12, 4:43 PM CDT, 4 hours 33 minutes before

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Special weather statement, May 12, 8:55 PM CDT, 21 minutes before

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Nearby

Severe Thunderstorm Warnings in Mississippi, 2009 Every severe thunderstorm warning in 2009

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.