Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 33, NWS Shreveport, LA

September 17, 2021Bossier Parish, Caddo Parish, Louisiana

NWS Shreveport, LA issued this flash flood warning at Sep 17, 2021, 10:03 AM CDT for Bossier Parish, Caddo Parish, Louisiana. It was in force for 110 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 17, 2021, 10:03 AM CDT (15:03 UTC)
Expired
Sep 17, 2021, 11:53 AM CDT
In force
110 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon
Flood severity
None

Counties Bossier Parish, LA, Caddo Parish, LA

The radar

The Shreveport radar (KSHV), 39 km from the middle of the area, began a volume at 15:06 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, 3.1 hours before the alert went out and 37 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 12:00Z on 2021-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 975 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2021-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 square meters per square second.1939Sfc1 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
975 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
544 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

015 
WGUS54 KSHV 171503
FFWSHV
LAC015-017-171815-
/O.NEW.KSHV.FF.W.0033.210917T1503Z-210917T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Shreveport LA
1003 AM CDT Fri Sep 17 2021

The National Weather Service in Shreveport has issued a

* Flash Flood Warning for...
  Northwestern Bossier Parish in northwestern Louisiana...
  Northwestern Caddo Parish in northwestern Louisiana...

* Until 115 PM CDT.

* At 1003 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 2 to 3 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Shreveport, Bossier City, Vivian, Blanchard, Benton, Oil City, 
  Mooringsport, Hosston, Belcher, Gilliam, Cavett, Dixie and Caddo 
  Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3296 9397 3296 9373 3254 9372 3256 9399

FLASH FLOOD...RADAR INDICATED

$$

13
2 follow-up statements
398 
WGUS74 KSHV 171632
FFSSHV

Flash Flood Statement
National Weather Service Shreveport LA
1132 AM CDT Fri Sep 17 2021

LAC015-017-171815-
/O.CON.KSHV.FF.W.0033.000000T0000Z-210917T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bossier LA-Caddo LA-
1132 AM CDT Fri Sep 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 115 PM CDT THIS 
AFTERNOON FOR NORTHWESTERN BOSSIER AND NORTHWESTERN CADDO PARISHES...

At 1132 AM CDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Between 3 and 6 inches of rain 
have fallen. Additional rainfall amounts up to 1 inch are possible 
in the warned area.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Benton, Mooringsport, Hosston, Belcher, Gilliam, Cavett and Dixie.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3293 9393 3296 9373 3263 9372 3263 9397

FLASH FLOOD...RADAR INDICATED

$$

13
990 
WGUS74 KSHV 171653
FFSSHV

Flash Flood Statement
National Weather Service Shreveport LA
1153 AM CDT Fri Sep 17 2021

LAC015-017-171703-
/O.CAN.KSHV.FF.W.0033.000000T0000Z-210917T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bossier LA-Caddo LA-
1153 AM CDT Fri Sep 17 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN BOSSIER AND 
NORTHWESTERN CADDO PARISHES...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3293 9393 3296 9373 3263 9372 3263 9397

$$

13

Nearby

Flash Flood Warnings in Louisiana, 2021Every flash flood warning in 2021

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.