Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS Shreveport, LA

April 30, 20215 counties in Texas

NWS Shreveport, LA issued this flash flood warning at Apr 30, 2021, 4:11 AM CDT for 5 counties in Texas. It was in force for 3 hr. 7 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
Apr 30, 2021, 4:11 AM CDT (09:11 UTC)
Expired
Apr 30, 2021, 7:15 AM CDT
In force
3 hr
Issued by
NWS Shreveport, LA
Area
Storm-based polygon
Flood severity
None

Counties Angelina County, TX, Cherokee County, TX, Nacogdoches County, TX, San Augustine County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 147 km from the middle of the area, began a volume at 09:11 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.

What was reported inside it

TimeReportWhereRemark
Apr 30, 4:30 AM CDTFLASH FLOOD4 Ssw Nacogdoches, TXHWY 59 SOUTH FLOODED AT THE INTERSECTION OF COUNTY ROAD 522.
Apr 30, 4:30 AM CDTFLASH FLOOD5 Wnw Wells, TXFM 1247 JUST SOUTH OF FM 1911 WAS FLOODED AND CLOSED.
Apr 30, 4:30 AM CDTFLASH FLOOD5 Wsw Nacogdoches, TXWATER COVERING THE ROAD ALONG COUNTY ROAD 715 AT FM 225.
Apr 30, 4:30 AM CDTFLASH FLOOD6 Ese Nacogdoches, TXWATER COVERING THE ROAD ALONG HWY 21 AT COUNTY ROAD 508.
Apr 30, 4:30 AM CDTFLASH FLOOD9 Sw Nacogdoches, TXWATER COVERING BOTH LANES ALONG HWY 7 AT THE INTERSECTION OF FM 2782.
Apr 30, 4:45 AM CDTFLASH FLOOD8 Nnw Chireno, TXFM 95 FLOODED AT POLLY BRANCH.
Apr 30, 6:15 AM CDTFLASH FLOOD7 N Broaddus, TXFM 1277 WAS FLOODED AND CLOSED ABOUT 1 MILE NORTH OF HIGHWAY 103. FM 1992 WEST OF HIGHWAY 147 WAS ALSO FLOODED AND CLOSED. OTHER VARIOUS ROADWAYS ACROSS SAN AUGUSTINE COUNTY WERE FLOODED.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 9.2 hours before the alert went out and 155 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 2021-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 357 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 00:00Z on 2021-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -16 square meters per square second.1939587897Sfc1 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
357 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
1268 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
42 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

328 
WGUS54 KSHV 300911
FFWSHV
TXC005-073-347-405-419-301215-
/O.NEW.KSHV.FF.W.0003.210430T0911Z-210430T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Shreveport LA
411 AM CDT Fri Apr 30 2021

The National Weather Service in Shreveport has issued a

* Flash Flood Warning for...
  Northwestern Angelina County in eastern Texas...
  Central Nacogdoches County in eastern Texas...
  Northern San Augustine County in eastern Texas...
  Southwestern Shelby County in eastern Texas...
  Southeastern Cherokee County in northeastern Texas...

* Until 715 AM CDT.

* At 411 AM CDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  3 and 6 inches of rain have fallen. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar and automated gauges.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Lufkin, Nacogdoches, Hudson, San Augustine, Wells, Woden, Melrose, 
  Martinsville, Etoile, Pollok, Neuville, Bland Lake, Forest, 
  Chireno, Redland, Denning, Clawson, Jericho, Central and Calgary.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

&&

LAT...LON 3151 9510 3161 9481 3173 9436 3170 9400
      3147 9399 3131 9472 3134 9496 3135 9496
      3138 9496 3138 9495 3140 9498 3141 9498
      3142 9501 3144 9501 3145 9505 3147 9507
      3146 9507 3147 9510 3149 9511 3150 9509

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

19

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 29, 11:15 PM CDTSpecial Weather StatementSHVShelby45 min
Apr 30, 12:04 AM CDTSpecial Weather StatementSHVShelby41 min
Apr 30, 12:39 AM CDTSpecial Weather StatementSHVShelby51 min
Apr 30, 1:24 AM CDTSpecial Weather StatementSHVSabine51 min
Apr 30, 3:28 AM CDTAreal Flood AdvisorySHVAngelina, Cherokee, Nacogdoches, Sabine, San Augustine, Shelby3 hr
Apr 30, 5:10 AM CDTRiver Flood WarningSHVNacogdoches, Rusk, San Augustine, Shelby46 days
Apr 30, 5:12 AM CDTRiver Flood WarningSHVSabine, San Augustine40 hr
Apr 30, 5:14 AM CDTRiver Flood WarningSHVAngelina, Houston, Polk, Trinity, Tyler51 days
Apr 30, 6:22 AM CDTAreal Flood AdvisorySHVAngelina, Nacogdoches, Sabine, San Augustine113 min
Apr 30, 7:18 AM CDTRiver Flood WarningSHVAnderson, Cherokee, Houston, Trinity13 hr
Apr 30, 9:39 AM CDTRiver Flood WarningSHVBowie, Red River25 hr

Nearby

Flash Flood Warnings in Texas, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.