Alert archive / Louisiana / Flash Flood Warnings in 2012

Flash Flood Warning 11, NWS Shreveport, LA

March 20, 2012Grant Parish, Natchitoches Parish, Winn Parish, Louisiana

NWS Shreveport, LA issued this flash flood warning at Mar 20, 2012, 3:03 PM CDT for Grant Parish, Natchitoches Parish, Winn Parish, Louisiana. It was in force for 6 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: Mar 20, 2012, 3:03 PM CDT (20:03 UTC)
Expired: Mar 20, 2012, 9:00 PM CDT
In force: 6 hr
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Flood severity: None

Counties Grant Parish, LA, Natchitoches Parish, LA, Winn Parish, LA

What was reported inside it

Time	Report	Where	Remark
Mar 20, 3:15 PM CDT	FLASH FLOOD	3 Se Natchez, LA	WATER COVERING HWY 119 AT MULTIPLE LOCATIONS NEAR NATCHEZ
Mar 20, 6:05 PM CDT	FLASH FLOOD	5 Se Natchez, LA	HIGHWAY 119 HAS BEEN CLOSED DUE TO FLOODING.
Mar 20, 6:30 PM CDT	FLASH FLOOD	7 Wnw Natchitoches, LA	POSEY ROAD FLOODED ALONG A MILE AND A HALF STRETCH WITH A FEW FEET OF WATER COVERING THE ROAD IN SOME LOCATIONS
Mar 20, 7:10 PM CDT	FLASH FLOOD	5 Sw Winnfield, LA	HARRINGTON ROAD OFF OF HIGHWAY 1228 IS COVERED IN HIGH WATER. NUMEROUS OTHER PARISH ROADS ACROSS THE PARISH ARE BEGINNING TO FLOOD AS WELL.
Mar 20, 8:40 PM CDT	FLASH FLOOD	1 Ese Natchitoches, LA	WATER COVERING FISH HATCHERY ROAD JUST EAST OF NATCHITOCHES
Mar 20, 8:40 PM CDT	FLASH FLOOD	1 Se Natchitoches, LA	MOBILES HOMES FLOODED ON CEDAR GROVE DRIVE
Mar 20, 8:40 PM CDT	FLASH FLOOD	6 Ne Robeline, LA	WATER COVERING OLD BETHEL CHURCH ROAD

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, 8.1 hours before the alert went out and 152 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: 395 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 754 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 221 m²/s²
0-3 km storm-relative helicity: 306 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

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

902 
WGUS54 KSHV 202003
FFWSHV
LAC043-069-127-210200-
/O.NEW.KSHV.FF.W.0011.120320T2003Z-120321T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
303 PM CDT TUE MAR 20 2012

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  GRANT PARISH IN NORTH CENTRAL LOUISIANA...
  WINN PARISH IN NORTH CENTRAL LOUISIANA...
  THIS INCLUDES THE CITY OF WINNFIELD...
  NATCHITOCHES PARISH IN NORTHWEST LOUISIANA...
  THIS INCLUDES THE CITY OF NATCHITOCHES...

* UNTIL 900 PM CDT

* AT 259 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MONTGOMERY
  AND COLFAX...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL OF ONE TO OVER TWO INCHES HAS ALREADY OCCURRED ACROSS 
THE WARNED AREA THIS AFTERNOON. ADDITIONAL RAINFALL AMOUNTS OF TWO 
TO FOUR INCHES ARE POSSIBLE...AS ADDITIONAL INTENSE THUNDERSTORMS 
MOVE BACK INTO THE REGION FROM THE SOUTH. 

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...
EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER
GROUND.

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

&&

LAT...LON 3138 9266 3140 9270 3151 9272 3134 9295
      3136 9324 3180 9328 3215 9245 3188 9232
      3179 9237 3176 9234 3170 9237 3169 9235
      3161 9238 3159 9230 3158 9232 3149 9227
      3150 9224 3149 9224 3147 9220

$$

VII

1 follow-up statement

642 
WGUS74 KSHV 210017
FFSSHV

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
717 PM CDT TUE MAR 20 2012

LAC043-069-127-210200-
/O.CON.KSHV.FF.W.0011.000000T0000Z-120321T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NATCHITOCHES LA-GRANT LA-WINN LA-
717 PM CDT TUE MAR 20 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM CDT FOR
WINN...GRANT AND NATCHITOCHES PARISHES...

AT 717 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
DETECT SHOWERS AND EMBEDDED THUNDERSTORMS PRODUCING VERY HEAVY RAIN OVER 
THE WARNED AREA. SEVERAL ROADS IN SOUTHERN NATCHITOCHES PARISH ARE CLOSED 
DUE TO HIGH WATER. IN ADDITION...ROADS THROUGHOUT WINN PARISH ARE BEGINNING 
TO BECOME COVERED IN HIGH WATER. TRAVEL IS STRONGLY DISCOURAGED ACROSS 
NATCHITOCHES...GRANT...AND WINN PARISHES TONIGHT...AS ADDITIONAL HEAVY 
RAINFALL WILL OVERSPREAD THESE AREAS OVERNIGHT.   

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WINNFIELD...
NATCHITOCHES AND MONTGOMERY

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF ONE TO TWO INCHES ARE POSSIBLE IN
THE WARNED AREA THROUGH 9 PM.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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 3138 9266 3140 9270 3151 9272 3134 9295
      3136 9324 3180 9328 3215 9245 3188 9232
      3179 9237 3176 9234 3170 9237 3169 9235
      3161 9238 3159 9230 3158 9232 3149 9227
      3150 9224 3149 9224 3147 9220

$$

15

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 19, 8:36 PM CDT	River Flood Warning	SHV	Caddo	6 days
Mar 20, 10:55 AM CDT	Tornado Warning	SHV	De Soto, Sabine	35 min
Mar 20, 11:06 AM CDT	River Flood Warning	SHV	Bossier, Webster	32 days
Mar 20, 11:16 AM CDT	River Flood Warning	SHV	Bienville, Bossier, Webster	12 days
Mar 20, 11:17 AM CDT	River Flood Warning	SHV	Lincoln, Ouachita, Union	7 days
Mar 20, 11:31 AM CDT	Tornado Warning	SHV	De Soto, Natchitoches, Sabine	29 min
Mar 20, 11:35 AM CDT	Severe Thunderstorm Warning	SHV	Natchitoches, Sabine	55 min
Mar 20, 12:10 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, De Soto, Natchitoches, Red River, Sabine	65 min
Mar 20, 12:30 PM CDT	Severe Thunderstorm Warning	SHV	Grant, Natchitoches, Sabine, Winn	60 min
Mar 20, 12:54 PM CDT	Tornado Warning	SHV	Natchitoches, Winn	36 min
Mar 20, 1:04 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, Jackson, Lincoln, Natchitoches, Red River, Winn	41 min
Mar 20, 1:34 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, Grant, Jackson, Natchitoches, Winn	56 min
Mar 20, 6:24 PM CDT	Flash Flood Warning	SHV	Natchitoches, Sabine	3 hr

Nearby

Flash Flood Warnings in Louisiana, 2012 Every flash flood warning in 2012

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.