Alert archive / Louisiana / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 186, NWS Shreveport, LA

May 20, 2020Natchitoches Parish, Sabine Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at May 20, 2020, 3:26 PM CDT for Natchitoches Parish, Sabine Parish, Louisiana. It was in force for 49 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: May 20, 2020, 3:26 PM CDT (20:26 UTC)
Expired: May 20, 2020, 4:15 PM CDT
In force: 49 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Natchitoches Parish, LA, Sabine Parish, LA

The radar

The Ft Polk radar (KPOE), 64 km from the middle of the area, began a volume at 20:30 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

Shreveport, LA (KSHV), launched 12:00Z, 8.4 hours before the alert went out and 101 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1337 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 105 m²/s²
0-3 km storm-relative helicity: 284 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.3

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 May 20, 1:57 PM CDT, 1 hour 29 minutes earlier.

Area forecast discussion, May 20, 1:57 PM CDT, 1 hour 29 minutes before

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Hazardous weather outlook, May 20, 11:35 AM CDT, 3 hours 51 minutes before

Hazardous Weather Outlook
National Weather Service Shreveport LA
1135 AM CDT Wed May 20 2020

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-
TXZ096-097-108>112-124>126-136>138-149>153-165>167-211645-
Sevier-Howard-Little River-Hempstead-Nevada-Miller-Lafayette-
Columbia-Union-Caddo-Bossier-Webster-Claiborne-Lincoln-De Soto-
Red River-Bienville-Jackson-Ouachita-Sabine-Natchitoches-Winn-
Grant-Caldwell-La Salle-McCurtain-Bowie-Franklin-Titus-Camp-
Morris-Cass-Wood-Upshur-Marion-Smith-Gregg-Harrison-Cherokee-Rusk-
Panola-Nacogdoches-Shelby-Angelina-San Augustine-
1135 AM CDT Wed May 20 2020

This Hazardous Weather Outlook is for portions of south central
Arkansas, southwest Arkansas, north central Louisiana, northwest
Louisiana, southeast Oklahoma, east Texas and northeast Texas.

.DAY ONE...This Afternoon and Tonight...

A rather stout 700mb Theta-e axis has set up across portions of
the Four-States region this morning. This is allowing for
elevated convection to fire and train in some of our southern
counties and parishes. While none of these updrafts have been
severe as of yet, a few have been pushing severe criteria. As
such, a severe storm or two can not be ruled out this afternoon
with peak daytime heating. Additionally, rainfall rates have been
rather steady this morning, and the training nature of these cell
may lead to some localized flash flooding into this evening.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday...

Isolated shower and thunderstorm activity will likely continue as
we enter into prime "popcorn" convective season. This activity
will remain through the weekend, with our next system likely into
Monday. Look for a bump in thunderstorm chances during that
timeframe.

.SPOTTER INFORMATION STATEMENT...

Activation of emergency management personnel...amateur radio
operators...and storm spotters may be needed for this afternoon.
Please relay any information about observed severe weather to the
NWS while following all local, state, and CDC guidelines.

44

In the hours before

Special weather statement, May 20, 9:55 AM CDT, 5 hours 31 minutes before

Special Weather Statement
National Weather Service Shreveport LA
955 AM CDT Wed May 20 2020

LAZ017-201545-
Sabine LA-
955 AM CDT Wed May 20 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN SABINE PARISH UNTIL
1045 AM CDT...

At 955 AM CDT, Doppler radar was tracking a strong thunderstorm 10
miles southwest of Many, or 18 miles north of Toledo Bend Dam, moving
southeast at 30 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Florien, Fisher and Negreet.

LAT...LON 3136 9365 3137 9364 3137 9366 3138 9367
      3139 9367 3142 9370 3155 9358 3136 9326
      3136 9339 3128 9344 3128 9353 3127 9354
TIME...MOT...LOC 1455Z 308DEG 26KT 3144 9358

44

Special weather statement, May 20, 12:14 PM CDT, 3 hours 12 minutes before

Special Weather Statement
National Weather Service Shreveport LA
1214 PM CDT Wed May 20 2020

LAZ017-018-201800-
Natchitoches LA-Sabine LA-
1214 PM CDT Wed May 20 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN NATCHITOCHES AND
NORTHEASTERN SABINE PARISHES UNTIL 100 PM CDT...

At 1213 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Kurthwood, or 16 miles northeast of Anacoco,
moving southeast at 15 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Many, Provencal, Robeline, Bellwood, Kisatchie and Gorum.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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 3136 9299 3136 9303 3137 9303 3136 9326
      3163 9349 3176 9328 3139 9290 3139 9291
      3137 9291 3137 9295 3135 9295 3135 9298
TIME...MOT...LOC 1713Z 312DEG 15KT 3147 9323

50

Special weather statement, May 20, 1:01 PM CDT, 2 hours 25 minutes before

Special Weather Statement
National Weather Service Shreveport LA
101 PM CDT Wed May 20 2020

LAZ017-018-201845-
Natchitoches LA-Sabine LA-
101 PM CDT Wed May 20 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN NATCHITOCHES AND
NORTHEASTERN SABINE PARISHES UNTIL 145 PM CDT...

At 101 PM CDT, Doppler radar was tracking a strong thunderstorm 12
miles northwest of Kurthwood, or 17 miles north of Anacoco, moving
southeast at 20 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Many, Provencal, Robeline, Bellwood, Kisatchie and Mount Carmel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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 3136 9299 3136 9303 3137 9303 3136 9336
      3166 9355 3174 9330 3137 9293 3137 9295
      3135 9295 3135 9298
TIME...MOT...LOC 1801Z 319DEG 16KT 3150 9326

50

Special weather statement, May 20, 3:11 PM CDT, 15 minutes before

Special Weather Statement
National Weather Service Shreveport LA
311 PM CDT Wed May 20 2020

LAZ017-018-202100-
Natchitoches LA-Sabine LA-
311 PM CDT Wed May 20 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN NATCHITOCHES AND
NORTHEASTERN SABINE PARISHES UNTIL 400 PM CDT...

At 310 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Many, or 21 miles west of Natchitoches, moving
southeast at 35 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Many, Pleasant Hill, Florien, Provencal, Fisher, Robeline, Mount
Carmel, Belmont, Bellwood and Marthaville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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 3144 9347 3184 9364 3185 9362 3184 9345
      3148 9299
TIME...MOT...LOC 2010Z 308DEG 30KT 3170 9346

50

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 9:40 AM CDT	Areal Flood Advisory	SHV	Sabine, San Augustine, Shelby	3 hr
May 20, 10:13 AM CDT	Flash Flood Warning	SHV	Sabine, Shelby	3 hr
May 20, 8:37 AM CDT	Special Weather Statement	SHV	Sabine	38 min
May 20, 9:55 AM CDT	Special Weather Statement	SHV	Sabine	50 min
May 20, 11:08 AM CDT	Areal Flood Advisory	SHV	Natchitoches, Sabine	3 hr
May 20, 12:14 PM CDT	Special Weather Statement	SHV	Natchitoches	46 min
May 20, 12:59 PM CDT	Flash Flood Warning	SHV	Natchitoches, Sabine	7 hr
May 20, 1:01 PM CDT	Special Weather Statement	SHV	Natchitoches	44 min
May 20, 3:11 PM CDT	Special Weather Statement	SHV	Natchitoches	49 min
May 20, 4:15 PM CDT	Special Weather Statement	SHV	Sabine	45 min
May 20, 4:25 PM CDT	Severe Thunderstorm Warning	SHV	Natchitoches, Sabine	65 min
May 20, 4:49 PM CDT	Special Weather Statement	SHV	Sabine	41 min
May 20, 5:21 PM CDT	Severe Thunderstorm Warning	SHV	Natchitoches, Sabine	39 min
May 20, 5:29 PM CDT	Special Weather Statement	SHV	Natchitoches	61 min
May 20, 5:52 PM CDT	Special Weather Statement	SHV	Red River	53 min
May 20, 6:44 PM CDT	Special Weather Statement	SHV	Natchitoches	46 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2020 Every severe thunderstorm warning in 2020

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.