Alert archive / Arkansas / Flash Flood Warnings in 2011

Flash Flood Warning 13, NWS Shreveport, LA

September 18, 2011Sevier County, Arkansas

NWS Shreveport, LA issued this flash flood warning at Sep 18, 2011, 8:58 PM CDT for Sevier County, Arkansas. It was in force for 2 hr. 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: Sep 18, 2011, 8:58 PM CDT (01:58 UTC)
Expired: Sep 18, 2011, 11:00 PM CDT
In force: 2 hr
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Flood severity: None

County Sevier County, AR

The radar

The Western Arkansas radar (KSRX), 155 km from the middle of the area, began a volume at 02:00 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
Sep 18, 9:00 PM CDT	FLOOD	Horatio, AR	HORATIO GROCERY STORE LOCATED AT MAIN AND 41 FLOODED. EMERGENCY PREPAREDNESS EMPLOYEE REPORTED OVER 5 INCHES OF RAIN IN RAIN GAGE, OVERFLOWED.

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, 2.0 hours before the alert went out and 166 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: 571 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 1671 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 121 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 5.5

Open this sounding in Storm Lab

The text

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

192 
WGUS54 KSHV 190158
FFWSHV
ARC133-190400-
/O.NEW.KSHV.FF.W.0013.110919T0158Z-110919T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
858 PM CDT SUN SEP 18 2011

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHERN SEVIER COUNTY IN SOUTHWEST ARKANSAS...
  THIS INCLUDES THE CITY OF HORATIO...

* UNTIL 1100 PM CDT

* AT 858 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
  VERY HEAVY RAIN FROM STRONG THUNDERSTORMS THAT CONTINUE TO MOVE OVER THE 
  SAME AREAS NEAR HORATIO. DOPPLAR RADAR INDICATES THAT THREE TO NEARLY 
  SIX INCHES OF RAIN HAS FALLEN IN THE LAST COUPLE OF HOURS NEAR HORATIO. 
  THUS...FLASH FLOODING IS LIKELY AS ADDITIONAL HEAVY RAINFALL CONTINUES 
  OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LOCKESBURG
  AND BEN LOMOND...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF ONE TO TWO INCHES ARE POSSIBLE IN
THE WARNED AREA THROUGH 11 PM.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

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.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
SHREVEPORT.

&&

LAT...LON 3399 9407 3378 9404 3384 9430 3388 9434
      3388 9437 3388 9438 3388 9436 3390 9439
      3392 9438 3392 9440 3394 9438 3394 9439
      3401 9441

$$

15

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 18, 7:17 PM CDT	Severe Thunderstorm Warning	SHV	Sevier	58 min
Sep 18, 8:00 PM CDT	Severe Thunderstorm Warning	SHV	Little River	60 min
Sep 18, 8:14 PM CDT	Severe Thunderstorm Warning	SHV	Little River, Sevier	61 min
Sep 18, 9:01 PM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Little River, Miller, Sevier	59 min
Sep 18, 9:48 PM CDT	Severe Thunderstorm Warning	SHV	Columbia, Hempstead, Lafayette, Little River, Miller, Nevada	57 min
Sep 18, 10:46 PM CDT	Severe Thunderstorm Warning	SHV	Columbia, Lafayette	59 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.