Alert archive / Louisiana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 175, NWS Shreveport, LA

September 19, 2002Bossier Parish, Louisiana; Lafayette County, Arkansas

NWS Shreveport, LA issued this severe thunderstorm warning at Sep 19, 2002, 4:22 PM CDT for Bossier Parish, Louisiana; Lafayette County, Arkansas. It was in force for 53 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: Sep 19, 2002, 4:22 PM CDT (21:22 UTC)
Expired: Sep 19, 2002, 5:15 PM CDT
In force: 53 min
Issued by: NWS Shreveport, LA
Area: Counties, with a storm outline in the text

Counties Lafayette County, AR, Bossier Parish, LA

The radar

The Shreveport radar (KSHV), 61 km from the middle of the area, began a volume at 21:21 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.

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

Shreveport, LA (KSHV), launched 12:00Z, 9.4 hours before the alert went out and 55 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: 1342 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 797 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 163 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 6.0

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 Sep 19, 3:25 PM CDT, 57 minutes earlier.

Area forecast discussion, Sep 19, 3:25 PM CDT, 57 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
325 PM CDT THU SEP 19 2002

UPPER LOW AND COLD FRONT SWINGING INTO AREA THIS AFTERNOON. WEST
WINDS HAVE OCCURRED AT PARIS. THE UPPER LEVEL SUPPORT ACCORDING TO
MODELS /250 MB DIVERGENCE...RIGHT REAR JET QUADRANT...500 MB PVA/
SEEMS TO BE FAVORING THE NW PORTION THIS EVENING...BUT IF SURFACE
BOUNDARY PUSHES THROUGH THAT AREA SOONER RATHER THAN LATER...WILL IT
LOWER THE RAIN CHANCE THERE?  OR WILL THE UPPER ENERGY FORCE ANOTHER
ROUND OF STORMS? SEVERE THREAT IS MOSTLY TO BE STRAIGHT LINE
WINDS...AND SPC AT 19Z IS NOT OVERLY IMPRESSED. WILL INCLUDE SOME
POSSIBLY SEVERE IN ALL ZONES TONIGHT. LOCALLY HEAVY RAIN ALSO IN
MOST ZONES AS PRECIP WATER IS HIGH AND TRAINING IS TAKING PLACE
ALONG THE SW TO NE ORIENTED LINES OF CONVECTION.

AFTER COORDINATION WITH SPC...THE PREFRONTAL WIND SHIFT MOVING PAST
PARIS NOW MAY EFFECTIVELY BE THE WESTERN EDGE OF THE RAIN AREA. I/LL
HAVE LOWER POPS FOR FAR NW AS CONJECTURED EARLIER...AND LEAVE IT
UP TO EVENING SHIFT TO UPDATE AS NECESSARY.

IN SUM...LIKELIES FOR THE FAR NW...80 PERCENT POPS REST OF AREA
TONIGHT...THEN SLIGHT CHANCE TO CHANCE POPS FRIDAY MORNING. DRY
FORECAST THROUGH MONDAY OF NEXT WEEK...WITH COOL NIGHTS AND
PLEASANT DAYS. TROPICAL STORM ISIDORE WILL MUDDY UP THE FORECAST FOR
NEXT WEEK THOUGH. TPC HESITANT TO COMMIT TO A DIRECTION YET DUE TO
ALL OF THE SYNOPTIC FEATURES AFFECTING US PRESENTLY. BUT IF AVN
SOLUTION VERIFIES...THE SYSTEM WILL SKIRT YUCATAN AND STALL NEAR NW
YUCATAN COAST. THIS UNOFFICIALLY REPRESENTS A PROBLEM FOR OUR
FORECAST...THUS THE LAST DAYS OF THE EXTENDED ARE LOW CONFIDENCE. 17

PRELIMS...

SHV 69/87/60/87/61 8400
MLU 73/87/61/87/61 8500
TXK 66/85/59/85/57 8200
TYR 65/86/59/87/61 8200
LFK 69/87/60/88/62 8400

.SHV...NONE.

In the hours before

Local storm report, Sep 19, 2:55 PM CDT, 1 hour 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT, LA
255 PM CDT THU SEP 19 2002

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

0200 PM    2 N TYLER                 TX   WIND DAMAGE
09/19/02   SMITH                          LARGE TREES DOWN OVER
                                          CR 485. REPORT FROM
                                          LAW ENFORCEMENT

0205 PM    3 S TYLER                 TX   WIND DAMAGE
09/19/02   SMITH                          LARGE TREES DOWN OVER
                                          FM 2964. REPORT FROM LAW
                                          ENFORCEMENT

15

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 19, 1:22 PM CDT	Severe Thunderstorm Warning	SHV	Smith	53 min
Sep 19, 4:03 PM CDT	Severe Thunderstorm Warning	SHV	Caddo	57 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2002 Severe Thunderstorm Warnings in Arkansas, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.