Alert archive / Louisiana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 157, NWS Shreveport, LA

August 21, 2002Grant Parish, LaSalle Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at Aug 21, 2002, 6:03 PM CDT for Grant Parish, LaSalle Parish, Louisiana. It was in force for 42 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 21, 2002, 6:03 PM CDT (23:03 UTC)
Expired: Aug 21, 2002, 6:45 PM CDT
In force: 42 min
Issued by: NWS Shreveport, LA
Area: Counties, with a storm outline in the text

Counties Grant Parish, LA, LaSalle Parish, LA

What was reported inside it

Time	Report	Where	Remark
Aug 21, 6:40 PM CDT	Thunderstorm Wind 52 E	Dry Prong, LA	Several large trees down across Hwy 167 at Daniel Road.
Aug 21, 6:50 PM CDT	Thunderstorm Wind 55 E	Dry Prong, LA	Trees and power lines down on Fairfield Road.

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

Shreveport, LA (KSHV), launched 12:00Z, 11.1 hours before the alert went out and 156 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: 629 J/kg
Mixed-layer CIN: -129 J/kg
Mixed-layer LCL: 1101 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: -68 m²/s²
0-3 km storm-relative helicity: -51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

623 
WUUS54 KSHV 212303
SVRSHV
LAC043-059-212345-
/NEW.KSHV.SV.W.0302.212300-212345/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
600 PM CDT WED AUG 21 2002

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  GRANT PARISH IN NORTH CENTRAL LOUISIANA
  LA SALLE PARISH IN NORTH CENTRAL LOUISIANA

* UNTIL 645 PM CDT

* AT 600 PM CDT...THE SHREVEPORT NATIONAL WEATHER SERVICE DOPPLER
  RADAR INDICATED A SEVERE THUNDERSTORM 8 MILES WEST OF              
  MIDWAY...OR   ABOUT 9 MILES WEST OF JENA...MOVING SOUTHWEST AT 20  
  MPH. RADAR ALSO DETECTED ANOTHER SEVERE THUNDERSTORM NEAR DRY PRONG
  ALSO MOVING TO THE SOUTHWEST AT 20 MPH.


* THE SEVERE THUNDERSTORMS WILL BE NEAR...
  JUST WEST OF DRY PRONG AT 625 PM CDT
  15 MILES WEST OF JENA AT 620 PM CDT  

THESE THUNDERSTORMS WILL PRODUCE LARGE HAIL TO NEAR NICKEL SIZE AND 
STRONG DAMAGING WINDS TO NEAR 65 MPH. 

REPEATING...THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE
THUNDERSTORM WARNING FOR...
  GRANT PARISH IN NORTH CENTRAL LOUISIANA
  LA SALLE PARISH IN NORTH CENTRAL LOUISIANA
UNTIL 645 PM CDT.

LAT...LON 3155 9208 3180 9203 3192 9221 3179 9236
          3172 9262 3169 9288 3156 9273 3143 9261

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 Aug 21, 2:40 PM CDT, 3 hours 23 minutes earlier.

Area forecast discussion, Aug 21, 2:40 PM CDT, 3 hours 23 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
240 PM CDT WED AUG 21 2002

STARTING TO THINK THAT THE MODELS ARE OVERDOING THE WWD MOVING UPPER
TROF...AS THERE JUST IS NOT AS MUCH PRECIP DEVELOPING AS PREVIOUSLY
ADVERTISED. WE WILL KEEP THE SAME GENERAL SLIGHT CHANCE AND CHANCE
AREAS...BUT WILL DECREASE THE CHANCE AREA TO 30 INSTEAD OF 40 PCT.
EARLIER RUN OF THE GFS INDICATED A CLOSED LOW FORMING NER BNA IN THE
EXTENDED TERM...BUT MORE RECENT RUNS SEEM TO BE TRENDING AWAY FROM
THAT SOLUTION...SEE PMDEPD. WILL KEEP A SLIGHT CHANCE FOR THE WHOLE
AREA THROUGH SUNDAY...AND THEN NOTHING INTO EARLY NEXT WEEK AS THE
GFS HAS BEEN PRETTY CONSISTENT IN SHOWING SOME DRIER AIR MOVING OVER
THE AREA.

STILL NOT SEEING MUCH CHANGE IN TEMPS ANYWHERE IN THE NEAR
FUTURE...WITH NO AIRMASS CHANGE IN STORE. WE MAY BE A DEGREE OR TWO
COOLER TOMORROW WITH A LITTLE MORE CONVECTION AROUND...BUT IT WILL
NOT BE ANYTHING TO WRITE HOME ABOUT.

FCSTID = 5
SHV   74  95  74  94 /  20  30  20  30
MLU   74  93  74  93 /  20  30  20  30
TXK   75  96  75  94 /   0  20  20  30
TYR   76  95  75  94 /  20  20  20  30
LFK   74  94  74  93 /  20  30  20  30

.SHV...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 6:44 PM CDT	Severe Thunderstorm Warning	SHV	Grant	61 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 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.