Alert archive / Louisiana / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 159, NWS New Orleans, LA

November 21, 2007Saint Helena Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Nov 21, 2007, 9:03 PM CST for Saint Helena Parish, Louisiana. It was in force for 14 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: Nov 21, 2007, 9:03 PM CST (03:03 UTC)
Expired: Nov 21, 2007, 9:17 PM CST
In force: 14 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon

County Saint Helena Parish, LA

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Nov 21, 5:29 PM CST	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 3.1 hours before the alert went out and 177 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: 586 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 1050 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 154 m²/s²
0-3 km storm-relative helicity: 176 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.7

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 Nov 21, 9:01 PM CST, 2 minutes earlier.

Area forecast discussion, Nov 21, 9:01 PM CST, 2 minutes before

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Hazardous weather outlook, Nov 21, 7:21 PM CST, 1 hour 42 minutes before

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In the hours before

Local storm report, Nov 21, 3:25 PM CST, 5 hours 38 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
325 PM CST WED NOV 21 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0315 PM     HAIL             5 S TYLERTOWN           31.04N 90.14W
11/21/2007  E0.75 INCH       WALTHALL           MS   LAW ENFORCEMENT

            PENNY SIZE HAIL COVERING GROUND.

&&

Local storm report, Nov 21, 3:41 PM CST, 5 hours 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
341 PM CST WED NOV 21 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0320 PM     TSTM WND GST     3 SE TYLERTOWN          31.09N 90.11W
11/21/2007  E0.00 MPH        WALTHALL           MS   LAW ENFORCEMENT

            SEVERAL TREES BLOWN DOWN NEAR THE COMMUNITY OF LEXIE.

0330 PM     TSTM WND DMG     SE TYLERTOWN            31.12N 90.14W
11/21/2007                   WALTHALL           MS   LAW ENFORCEMENT

            SEVERAL TREES BLOWN DOWN ON HIGHWAY 48.

&&

Local storm report, Nov 21, 8:18 PM CST, 45 minutes before

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Special weather statement, Nov 21, 8:26 PM CST, 37 minutes before

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Local storm report, Nov 21, 8:52 PM CST, 11 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 21, 7:33 PM CST	Severe Thunderstorm Warning	LIX	Pointe Coupee, West Feliciana	42 min
Nov 21, 8:32 PM CST	Severe Thunderstorm Warning	LIX	Iberville, Pointe Coupee, West Baton Rouge	28 min
Nov 21, 9:48 PM CST	Special Marine Warning	LIX		57 min
Nov 21, 7:03 PM CST	Severe Thunderstorm Warning	LIX	Wilkinson	42 min
Nov 21, 7:46 PM CST	Severe Thunderstorm Warning	LIX	Amite, Wilkinson	29 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2007 Every severe thunderstorm warning in 2007

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.