Alert archive / Louisiana / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 187, NWS Shreveport, LA

August 9, 2018Grant Parish, LaSalle Parish, Winn Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at Aug 9, 2018, 6:12 PM CDT for Grant Parish, LaSalle Parish, Winn Parish, Louisiana. It was in force for 27 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: Aug 9, 2018, 6:12 PM CDT (23:12 UTC)
Expired: Aug 9, 2018, 6:39 PM CDT
In force: 27 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Grant Parish, LA, LaSalle Parish, LA, Winn Parish, LA

The radar

The Ft Polk radar (KPOE), 82 km from the middle of the area, began a volume at 23:12 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.

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 11.2 hours before the alert went out and 233 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: 400 J/kg
Mixed-layer CIN: -117 J/kg
Mixed-layer LCL: 1046 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: -80 m²/s²
0-3 km storm-relative helicity: -75 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 Aug 9, 3:47 PM CDT, 2 hours 25 minutes earlier.

Area forecast discussion, Aug 9, 3:47 PM CDT, 2 hours 25 minutes before

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Hazardous weather outlook, Aug 9, 3:12 PM CDT, 3 hours before

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In the hours before

Special weather statement, Aug 9, 2:05 PM CDT, 4 hours 7 minutes before

Special Weather Statement
National Weather Service Shreveport LA
205 PM CDT THU AUG 9 2018

LAZ002-003-092000-
Bossier LA-Webster LA-
205 PM CDT THU AUG 9 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN WEBSTER AND SOUTHEASTERN
BOSSIER PARISHES UNTIL 300 PM CDT...

At 204 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Bossier City, moving east at 15 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Bossier City, Minden, Haughton, Sibley, Doyline, Dubberly, Dixie
Inn, Eastwood, Fosters, Princeton, Curtis, Taylortown, Fillmore,
Bodcau, Koran, Barksdale Air Force Base, Gilark, Noles Landing and
Lake Bistineau North.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3236 9361 3238 9361 3236 9362 3237 9363
      3240 9362 3241 9366 3242 9367 3243 9366
      3243 9368 3246 9368 3246 9370 3248 9369
      3249 9370 3249 9371 3250 9371 3251 9372
      3272 9339 3250 9320
TIME...MOT...LOC 1904Z 278DEG 11KT 3242 9359

07

Special weather statement, Aug 9, 2:46 PM CDT, 3 hours 26 minutes before

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Special weather statement, Aug 9, 2:59 PM CDT, 3 hours 13 minutes before

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Special weather statement, Aug 9, 3:23 PM CDT, 2 hours 49 minutes before

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Special weather statement, Aug 9, 5:47 PM CDT, 25 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 2:05 PM CDT	Special Weather Statement	SHV	Bossier	55 min
Aug 9, 2:46 PM CDT	Special Weather Statement	SHV	Union	59 min
Aug 9, 2:59 PM CDT	Special Weather Statement	SHV	Natchitoches	61 min
Aug 9, 3:23 PM CDT	Special Weather Statement	SHV	Ouachita	37 min
Aug 9, 5:38 PM CDT	Severe Thunderstorm Warning	SHV	Caldwell, LaSalle	52 min
Aug 9, 5:47 PM CDT	Special Weather Statement	SHV	Grant	43 min
Aug 9, 5:30 AM CDT	Areal Flood Advisory	SHV	Hempstead, Howard, Little River, Nevada, Sevier	3 hr

Nearby

Severe Thunderstorm Warnings in Louisiana, 2018 Every severe thunderstorm warning in 2018

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.