Alert archive / Oklahoma / Flash Flood Warnings in 2021

Flash Flood Warning 8, NWS Shreveport, LA

May 20, 2021McCurtain County, Oklahoma

NWS Shreveport, LA issued this flash flood warning at May 20, 2021, 6:44 PM CDT for McCurtain County, Oklahoma. It was in force for 61 min. 1 report 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
May 20, 2021, 6:44 PM CDT (23:44 UTC)
Expired
May 20, 2021, 7:45 PM CDT
In force
61 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon
Flood severity
None

County McCurtain County, OK

The radar

The Western Arkansas radar (KSRX), 133 km from the middle of the area, began a volume at 23:47 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
May 20, 7:35 PM CDTFLASH FLOODEagletown, OKWATER OVER SEVERAL ROADS IN AND OUT OF EAGLETOWN, OKLAHOMA. REPORT FROM GAME WARDEN.

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 12:00Z, 11.7 hours before the alert went out and 206 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 2021-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 2021-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 182 square meters per square second.193958Sfc1 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
4 J/kg
Mixed-layer CIN
-179 J/kg
Mixed-layer LCL
739 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
182 m²/s²
0-3 km storm-relative helicity
210 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

308 
WGUS54 KSHV 202344
FFWSHV
OKC089-210045-
/O.NEW.KSHV.FF.W.0008.210520T2344Z-210521T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Shreveport LA
644 PM CDT Thu May 20 2021

The National Weather Service in Shreveport has issued a

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

* Until 745 PM CDT.

* At 644 PM CDT, Storm Spotters reported thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.



  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Storm Spotter.

  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...
  Idabel, Broken Bow, Haworth, Hochatown, Eagletown, Oak Hill, Holly 
  Creek, Goodwater, Cerrogordo, Sherwood, Mount Herman, Shinewell, 
  Bokhoma, Moon, Bethel, America, Plunketville, Tom and Battiest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, country roads, farmland, and other low lying 
spots.

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.

&&

LAT...LON 3440 9495 3379 9483 3365 9450 3443 9448

FLASH FLOOD...OBSERVED
EXPECTED RAINFALL...1-2.25 INCHES IN 1 HOUR 

$$

13

The office that day

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

IssuedProductOfficeCountiesLasted
May 19, 7:59 PM CDTRiver Flood WarningSHVMcCurtain61 hr

Nearby

Flash Flood Warnings in Oklahoma, 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.