Alert archive / Arkansas / Flash Flood Warnings in 2011

Flash Flood Warning 2, NWS Shreveport, LA

April 21, 20115 counties in Arkansas

NWS Shreveport, LA issued this flash flood warning at Apr 21, 2011, 3:38 AM CDT for 5 counties in Arkansas. It was in force for 4 hr. 4 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 21, 2011, 3:38 AM CDT (08:38 UTC)
Expired: Apr 21, 2011, 7:15 AM CDT
In force: 4 hr
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Flood severity: None

Counties Hempstead County, AR, Howard County, AR, Little River County, AR, Nevada County, AR, Sevier County, AR

The radar

The Little Rock radar (KLZK), 154 km from the middle of the area, began a volume at 08:39 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

Time	Report	Where	Remark
Apr 21, 4:30 AM CDT	FLASH FLOOD	3 Ne Hope, AR	COUNTY ROAD 246 NEAR PERRYTOWN IS WASHED OUT.
Apr 21, 5:06 AM CDT	FLASH FLOOD	Blevins, AR	WATER COVERING ROAD ON HWY 371.
Apr 21, 5:31 AM CDT	FLASH FLOOD	4 Ne Oakhaven, AR	HWY 332 AT DEANN CREEK FLOODED BUT NOT CLOSED.
Apr 21, 5:35 AM CDT	FLASH FLOOD	Prescott, AR	WATER OVER ROAD ON HWY 67. ROAD CLOSED.

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, 8.6 hours before the alert went out and 157 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: 1739 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 1671 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 69 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

258 
WGUS54 KSHV 210838
FFWSHV
ARC057-061-081-099-133-211215-
/O.NEW.KSHV.FF.W.0002.110421T0838Z-110421T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
338 AM CDT THU APR 21 2011

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  HEMPSTEAD COUNTY IN SOUTHWEST ARKANSAS...
  THIS INCLUDES THE CITY OF HOPE...
  SOUTHEASTERN HOWARD COUNTY IN SOUTHWEST ARKANSAS...
  THIS INCLUDES THE CITIES OF...NASHVILLE...MINERAL SPRINGS...
  EAST CENTRAL LITTLE RIVER COUNTY IN SOUTHWEST ARKANSAS...
  THIS INCLUDES THE CITY OF ASHDOWN...
  NORTHERN NEVADA COUNTY IN SOUTHWEST ARKANSAS...
  THIS INCLUDES THE CITY OF PRESCOTT...
  SOUTHEASTERN SEVIER COUNTY IN SOUTHWEST ARKANSAS...

* UNTIL 715 AM CDT

* AT 330 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
HEAVY RAIN DEVELOPING AND SPREADING OVER SOUTHWEST ARKANSAS ACROSS A 
REGION THAT HAS HAD RAINFALL AMOUNTS OF 4 TO 6 INCHES OVER THE PAST 
6 HOURS. THUNDERSTORMS HAVE BEEN MOVING EAST AROUND 25 MPH AND 
TRAINING FROM LOCKESBURG...BEN LOMOND...WILTON AND ASHDOWN TO 
TOLLETTE AND MCNAB...AND BLEVINS...PRESCOTT...EMMET...AND HOPE. 
ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3 INCHES OVER THE NEXT COUPLE OF 
HOURS WILL RESULT IN FLASH FLOODING. 

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
BRIGHT STAR...OZAN...WASHINGTON...OAKHAVEN...BOUGHTON...EMMET AND 
BLUFF CITY...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

LAT...LON 3400 9369 3395 9351 3397 9348 3397 9337
      3392 9330 3385 9328 3382 9318 3382 9313
      3378 9309 3363 9310 3365 9417 3402 9420

$$

06

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 8:33 PM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Nevada	57 min
Apr 20, 8:56 PM CDT	Severe Thunderstorm Warning	SHV	Howard, Sevier	64 min
Apr 20, 10:00 PM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Howard, Nevada	60 min
Apr 20, 10:35 PM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Howard, Sevier	40 min
Apr 21, 12:24 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Nevada	66 min
Apr 21, 1:14 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Nevada	61 min
Apr 21, 7:16 AM CDT	Flash Flood Warning	SHV	Hempstead, Howard, Lafayette, Little River, Miller, Nevada and 1 more	4 hr
Apr 21, 8:20 AM CDT	Severe Thunderstorm Warning	SHV	Columbia, Union	55 min
Apr 21, 8:25 AM CDT	Severe Thunderstorm Warning	SHV	Columbia, Lafayette	31 min
Apr 21, 8:35 AM CDT	Severe Thunderstorm Warning	SHV	Little River, Sevier	55 min
Apr 21, 8:59 AM CDT	Severe Thunderstorm Warning	SHV	Union	31 min
Apr 21, 2:56 PM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Howard	34 min

Nearby

Flash Flood Warnings in Arkansas, 2011 Every flash flood warning in 2011

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.