Alert archive / Louisiana / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 133, NWS Shreveport, LA

April 30, 2017Ouachita Parish, Union Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at Apr 30, 2017, 1:18 AM CDT for Ouachita Parish, Union Parish, Louisiana. It was in force for 35 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
Apr 30, 2017, 1:18 AM CDT (06:18 UTC)
Expired
Apr 30, 2017, 1:53 AM CDT
In force
35 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Ouachita Parish, LA, Union Parish, LA

The radar

The Shreveport radar (KSHV), 149 km from the middle of the area, began a volume at 06:20 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 watch it was issued in

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

IssuedProductOfficeLasted
Apr 29, 10:23 PM CDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Shreveport, LA (KBAD), launched 00:00Z, 6.3 hours before the alert went out and 141 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, Shreveport, LA at 00:00Z on 2017-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1748 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, Shreveport, LA at 00:00Z on 2017-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 251 square meters per square second.19395878Sfc1 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
1748 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
772 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
251 m²/s²
0-3 km storm-relative helicity
454 m²/s²
Significant tornado parameter
3.0
Supercell composite
19.0

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 Apr 30, 12:54 AM CDT, 24 minutes earlier.

Area forecast discussion, Apr 30, 12:54 AM CDT, 24 minutes before
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Hazardous weather outlook, Apr 29, 4:51 PM CDT, 8 hours 27 minutes before
Hazardous Weather Outlook
National Weather Service Shreveport LA
451 PM CDT Sat Apr 29 2017

ARZ050-051-059>061-OKZ077-301200-
Sevier-Howard-Little River-Hempstead-Nevada-McCurtain-
451 PM CDT Sat Apr 29 2017

This Hazardous Weather Outlook is for portions of southwest
Arkansas and southeast Oklahoma.

.DAY ONE...Tonight...

Scattered showers and thunderstorms continue across southern
Arkansas this afternoon, with additional thunderstorms moving into
the southeast Oklahoma and southwest Arkansas this evening, ahead
of a slow moving cold front. Therefore, there could be a period
of slow moving thunderstorms containing heavy rain that may cause
flash flooding across the area this evening, before these storms
consolidate into a line of strong to severe thunderstorms and
quickly advance east by tonight. Widespread rainfall amounts of
two to four inches, with isolated higher amounts in excess of five
inches, will be possible this afternoon through tonight. In
addition to the heavy rain and flash flood threat, damaging winds,
isolated tornadoes, and large hail will be possible this evening,
with these threats diminishing from west to east late.

.DAYS TWO THROUGH SEVEN...Sunday through Friday...

Showers and thunderstorms will increase once again Wednesday ahead
of a cold front and associated upper level disturbance. However,
the threat for severe thunderstorms appear low at this time.

.SPOTTER INFORMATION STATEMENT...

Activation of emergency managers, spotter networks, and amateur
radio operators, will be needed late this afternoon through
tonight.

ARZ070>073-LAZ001>006-010>014-017>022-TXZ096-097-108>112-124>126-
136>138-149>153-165>167-301200-
Miller-Lafayette-Columbia-Union-Caddo-Bossier-Webster-Claiborne-
Lincoln-De Soto-Red River-Bienville-Jackson-Ouachita-Sabine-
Natchitoches-Winn-Grant-Caldwell-La Salle-Bowie-Franklin-Titus-
Camp-Morris-Cass-Wood-Upshur-Marion-Smith-Gregg-Harrison-Cherokee-
Rusk-Panola-Nacogdoches-Shelby-Angelina-San Augustine-
451 PM CDT Sat Apr 29 2017

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...Tonight...

Scattered showers and thunderstorms continue to lift across
northern Louisiana and southern Arkansas this afternoon. These
storms are capable of producing large hail, damaging winds, and
brief isolated tornadoes. Meanwhile...discrete thunderstorms are
developing in central and northeast Texas this afternoon, ahead
of a slow moving cold front. These storms will intensify as they
shift east across the region tonight. Some of these storms may
become severe, with damaging winds, isolated tornadoes, large
hail, and locally heavy rainfall possible. The severe weather
threat will gradually diminish from west to east across East Texas
late tonight as these storms move into Southwest Arkansas and
North Louisiana.

.DAYS TWO THROUGH SEVEN...Sunday through Friday...
Strong to possibly severe thunderstorms will be exiting the
eastern sections of north central Louisiana around daybreak
Sunday with the passage of a cold front. The threat for heavy
rainfall will persist through mid morning though, before rain
rates taper as drier air spills eastward. Look for the showers and
embedded thunderstorms to diminish from west to east through mid
afternoon Sunday.

Showers and thunderstorms will increase once again Wednesday
ahead of a cold front and associated upper level disturbance.
Depending on the extent of surface heating and resultant
instability, there is a potential for at least isolated severe
thunderstorms across the region Wednesday, before cooler and drier
air filters southeast behind the cold frontal passage Wednesday
night.

.SPOTTER INFORMATION STATEMENT...

Activation of emergency managers, spotter networks, and amateur
radio operators, will be needed tonight.

Palmer

In the hours before

Local storm report, Apr 29, 10:00 PM CDT, 3 hours 18 minutes before
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Local storm report, Apr 29, 10:54 PM CDT, 2 hours 24 minutes before
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Special weather statement, Apr 29, 11:03 PM CDT, 2 hours 15 minutes before
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Local storm report, Apr 29, 11:29 PM CDT, 1 hour 49 minutes before
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Local storm report, Apr 29, 11:31 PM CDT, 1 hour 47 minutes before
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Special weather statement, Apr 29, 11:39 PM CDT, 1 hour 39 minutes before
Special Weather Statement
National Weather Service Shreveport LA
1139 PM CDT SAT APR 29 2017

LAZ017-TXZ153-165>167-300530-
Sabine LA-Sabine TX-Angelina TX-San Augustine TX-Shelby TX-
1139 PM CDT SAT APR 29 2017

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN SABINE PARISH...
SOUTHEASTERN SHELBY...SOUTHEASTERN ANGELINA...SAN AUGUSTINE AND
SABINE COUNTIES UNTIL 1230 AM CDT...

At 1138 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Pineland, or 12 miles north of Ebenezer, moving
northeast at 55 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Milam, Many, San Augustine, Zwolle, Hemphill, Pineland, Patroon,
Bland Lake, Rosevine, Macune, Zavalla, Huxley, Noble, Broaddus,
Bronson, McElroy, Yellowpine, Chinaquapin, Hurstown and Sexton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

A severe thunderstorm watch remains in effect until 600 AM CDT for
northwestern Louisiana...and eastern Texas.

LAT...LON 3108 9446 3125 9436 3122 9433 3123 9432
      3124 9434 3127 9434 3132 9432 3183 9401
      3157 9342 3116 9384 3114 9402 3111 9406
      3108 9424
TIME...MOT...LOC 0438Z 217DEG 46KT 3121 9411

24

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 29, 7:17 PM CDTSpecial Weather StatementSHVMarion58 min
Apr 29, 7:28 PM CDTTornado WarningSHVSmith, Wood32 min
Apr 29, 7:47 PM CDTSevere Thunderstorm WarningSHVFranklin, Smith, Wood43 min
Apr 29, 7:59 PM CDTSevere Thunderstorm WarningSHVFranklin, Red River, Titus, Wood33 min
Apr 29, 8:12 PM CDTSevere Thunderstorm WarningSHVSmith, Upshur, Wood63 min
Apr 29, 8:18 PM CDTSevere Thunderstorm WarningSHVFranklin, Morris, Red River, Titus57 min
Apr 29, 8:23 PM CDTSpecial Weather StatementSHVBowie67 min
Apr 29, 8:25 PM CDTSevere Thunderstorm WarningSHVSmith, Wood65 min
Apr 29, 8:26 PM CDTTornado WarningSHVSmith, Wood49 min
Apr 29, 8:35 PM CDTTornado WarningSHVSmith, Wood40 min
Apr 29, 9:15 PM CDTSevere Thunderstorm WarningSHVBowie, Camp, Franklin, Marion, Morris, Red River and 4 more44 min
Apr 29, 11:39 PM CDTSpecial Weather StatementSHVSabine, San Augustine51 min
Apr 30, 4:19 AM CDTLake Wind AdvisorySHVBowie, Camp, Cass, Cherokee, Franklin, Gregg and 12 more15 hr
Apr 30, 1:29 AM CDTSpecial Weather StatementSHVBossier46 min
Apr 30, 1:46 AM CDTSpecial Weather StatementSHVLaSalle44 min
Apr 30, 2:16 AM CDTSpecial Weather StatementSHVJackson, Winn29 min
Apr 30, 3:09 AM CDTTornado WarningSHVJackson, Winn51 min
Apr 30, 3:19 AM CDTSpecial Weather StatementSHVUnion41 min
Apr 30, 3:53 AM CDTSevere Thunderstorm WarningSHVCaldwell, Jackson, Ouachita52 min
Apr 30, 4:13 AM CDTAreal Flood AdvisorySHVCaldwell, Jackson, Lincoln, Ouachita, Union, Winn3 hr
Apr 29, 7:15 PM CDTSpecial Weather StatementSHVHoward, Little River, Sevier60 min
Apr 29, 9:00 PM CDTSpecial Weather StatementSHVSevier45 min
Apr 29, 11:03 PM CDTSpecial Weather StatementSHVColumbia, Nevada27 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2017Every severe thunderstorm warning in 2017

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.