Alert archive / Oklahoma / Flash Flood Warnings in 2021

Flash Flood Warning 31, NWS Shreveport, LA

August 17, 2021McCurtain County, Oklahoma

NWS Shreveport, LA issued this flash flood warning at Aug 17, 2021, 9:43 AM CDT for McCurtain County, Oklahoma. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 17, 2021, 9:43 AM CDT (14:43 UTC)
Expired: Aug 17, 2021, 12:00 PM CDT
In force: 2 hr
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Flood severity: None

County McCurtain County, OK

The radar

The Western Arkansas radar (KSRX), 131 km from the middle of the area, began a volume at 14:42 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, 2.7 hours before the alert went out and 215 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: 1120 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 884 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 18 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

205 
WGUS54 KSHV 171443
FFWSHV
OKC089-171700-
/O.NEW.KSHV.FF.W.0031.210817T1443Z-210817T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Shreveport LA
943 AM CDT Tue Aug 17 2021

The National Weather Service in Shreveport has issued a

* Flash Flood Warning for...
  McCurtain County in southeastern Oklahoma...

* Until noon CDT.

* At 943 AM CDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  2 and 4 inches of rain have fallen. Additional rainfall amounts of 
  1 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 and automated gauges.

  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...
  Idabel, Broken Bow, Wright City, Valliant, Millerton, Haworth, 
  Garvin, Hochatown, Oak Hill, Glover, Mount Herman, Sherwood, 
  Golden, Bethel, Holly Creek, Eagletown, Battiest, Slim, Pickens 
  and Farmers Hill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3451 9447 3403 9449 3374 9469 3390 9505
      3395 9516 3424 9515 3424 9505 3451 9505

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

13

2 follow-up statements

645 
WGUS74 KSHV 171522
FFSSHV

Flash Flood Statement
National Weather Service Shreveport LA
1022 AM CDT Tue Aug 17 2021

OKC089-171700-
/O.CON.KSHV.FF.W.0031.000000T0000Z-210817T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
McCurtain OK-
1022 AM CDT Tue Aug 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL NOON CDT TODAY FOR 
MCCURTAIN COUNTY...

At 1022 AM CDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 2 
and 5 inches of rain have fallen. The expected rainfall rate is 1.5 
inches in 1 hour. Additional rainfall amounts of 1 to 3 inches are 
possible in the warned area. Flash flooding is ongoing or expected 
to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Idabel, Broken Bow, Wright City, Valliant, Millerton, Haworth, 
  Garvin, Hochatown, Oak Hill, Glover, Mount Herman, Sherwood, 
  Golden, Bethel, Holly Creek, Eagletown, Battiest, Slim, Pickens 
  and Farmers Hill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3451 9447 3403 9449 3374 9469 3390 9505
      3395 9516 3424 9515 3424 9505 3451 9505

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1.5 INCHES IN 1 HOUR

$$

50

704 
WGUS74 KSHV 171705
FFSSHV

Flash Flood Statement
National Weather Service Shreveport LA
1205 PM CDT Tue Aug 17 2021

OKC089-171715-
/O.EXP.KSHV.FF.W.0031.000000T0000Z-210817T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
McCurtain OK-
1205 PM CDT Tue Aug 17 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR MCCURTAIN COUNTY...

Flood waters should be receding because rainfall rates have 
decreased over the past hour. Flooding is no longer expected to pose 
a threat. Please continue to heed remaining road closures.

LAT...LON 3451 9447 3403 9449 3374 9469 3390 9505
      3395 9516 3424 9515 3424 9505 3451 9505

$$

50

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 7:57 AM CDT	Areal Flood Advisory	SHV	McCurtain	106 min

Nearby

Flash Flood Warnings in Oklahoma, 2021 Every 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.