Alert archive / Louisiana / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 189, NWS Shreveport, LA

May 16, 2009Grant Parish, LaSalle Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at May 16, 2009, 3:15 PM CDT for Grant Parish, LaSalle Parish, Louisiana. It was in force for 25 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 16, 2009, 3:15 PM CDT (20:15 UTC)
Expired
May 16, 2009, 3:40 PM CDT
In force
25 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon

Counties Grant Parish, LA, LaSalle Parish, LA

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 8.3 hours before the alert went out and 228 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, Jackson, MS at 12:00Z on 2009-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2152 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, Jackson, MS at 12:00Z on 2009-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -40 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
2152 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
518 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-40 m²/s²
0-3 km storm-relative helicity
-39 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 Shreveport, LA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 16, 11:13 AM CDT, 4 hours 2 minutes earlier.

Area forecast discussion, May 16, 11:13 AM CDT, 4 hours 2 minutes before
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Hazardous weather outlook, May 16, 12:17 PM CDT, 2 hours 58 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1217 PM CDT SAT MAY 16 2009

ARZ050-051-059>061-070-071-OKZ077-TXZ096-097-108>112-171730-
SEVIER-HOWARD-LITTLE RIVER-HEMPSTEAD-NEVADA-MILLER-LAFAYETTE-
MCCURTAIN-RED RIVER-BOWIE-FRANKLIN-TITUS-CAMP-MORRIS-CASS-
1217 PM CDT SAT MAY 16 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
ARKANSAS...SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AHEAD OF AN
APPROACHING COLD FRONT...WHICH IS EXPECTED TO MOVE ACROSS THE
INTERSTATE 30 CORRIDOR THIS EVENING. WHILE A FEW THUNDERSTORMS MAY
BECOME STRONG DURING THE LATE AFTERNOON AND EVENING...THE GREATEST
THREAT WILL BE FROM FLASH FLOODING. THE GROUND IN MOST LOCATION IS
COMPLETELY SATURATED...AND MOST RIVERS AND STREAMS ARE NEAR OR
ABOVE FLOOD STAGE. AS A RESULT...LOCALLY HEAVY RAIN MAY CAUSE
ADDITIONAL FLASH FLOODING THIS EVENING. AS THE COLD FRONT MAKES
ITS WAY SOUTHWARD THIS EVENING...RAINFALL WILL BEGIN TO TAPER OFF.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...
NO HAZARDOUS WEATHER IS EXPECTED.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

ARZ072-073-LAZ001>006-010>014-017>022-TXZ124>126-136>138-149>153-
165>167-171730-
COLUMBIA-UNION AR-CADDO-BOSSIER-WEBSTER-CLAIBORNE-LINCOLN-
UNION LA-DE SOTO-RED RIVER-BIENVILLE-JACKSON-OUACHITA-SABINE LA-
NATCHITOCHES-WINN-GRANT-CALDWELL-LA SALLE-WOOD-UPSHUR-MARION-
SMITH-GREGG-HARRISON-CHEROKEE-RUSK-PANOLA-NACOGDOCHES-SHELBY-
ANGELINA-SAN AUGUSTINE-SABINE TX-
1217 PM CDT SAT MAY 16 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARKANSAS...SOUTHWEST ARKANSAS...NORTH CENTRAL LOUISIANA...
NORTHWEST LOUISIANA...EAST TEXAS AND NORTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...
ORGANIZED THUNDERSTORMS ARE EXPECTED DURING THE EARLY EVENING
NORTH OF THE INTERSTATE 30 CORRIDOR...SOME OF WHICH MAY BECOME
SEVERE...AS A COLD FRONT MAKES ITS WAY THROUGH THE FOUR STATE
REGION.  A FEW OF THESE STORMS MAY PRODUCE DAMAGING WINDS CAPABLE
OF DOWNING TREES AND POWERLINES. IN ADDITION...THE COLD FRONT MAY
MOVE SLOWLY ENOUGH THAT THUNDERSTORMS BEGIN TO TRAIN ALONG THE
BOUNDARY. AS A RESULT...A FEW LOCATIONS MAY EXPERIENCE LOCALIZED
FLASH FLOODING. THE COLD FRONT WILL FILTER INTO THE I-20 CORRIDOR
THIS EVENING AND THE THREAT FOR THUNDERSTORMS WILL BEGIN TO
SUBSIDE DURING THE OVERNIGHT HOURS FOR THE AREAS NORTH OF I-20.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...
SHOWERS AND THUNDERSTORMS WILL BE ONGOING OVERNIGHT ALONG AND
SOUTH OF I-20. STRONG THUNDERSTORMS OR POSSIBLE ORGANIZED BOWING
SEGMENTS MAY PRODUCE DAMAGING WINDS AS HIGH AS 60 MPH. EXPECT THE
THUNDERSTORM ACTIVITY TO BEGIN TO PUSH OUT OF THE FOUR STATE AREA
DURING THE AFTERNOON HOURS ON SUNDAY. THE REST OF THE NEW WEEK IS
EXPECTED TO BE FAIR AND COOL.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING AND DURING THE
EARLY MORNING HOURS OF SUNDAY AS THUNDERSTORMS DEVELOP AHEAD OF AN
APPROACHING COLD FRONT.

18

In the hours before

Local storm report, May 16, 2:30 PM CDT, 45 minutes before
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The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 16, 6:18 AM CDTFlash Flood WarningSHVHempstead, Howard, Little River, Nevada, Sevier3 hr

Nearby

Severe Thunderstorm Warnings in Louisiana, 2009Every 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.