Alert archive / Louisiana / Flash Flood Warnings in 2012

Flash Flood Warning 19, NWS Shreveport, LA

March 21, 2012Claiborne Parish, Louisiana

NWS Shreveport, LA issued this flash flood warning at Mar 21, 2012, 8:44 AM CDT for Claiborne Parish, Louisiana. 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: Mar 21, 2012, 8:44 AM CDT (13:44 UTC)
Expired: Mar 21, 2012, 10:45 AM CDT
In force: 2 hr
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Flood severity: None

County Claiborne Parish, LA

The radar

The Shreveport radar (KSHV), 91 km from the middle of the area, began a volume at 13:45 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
Mar 21, 9:00 AM CDT	FLASH FLOOD	Homer, LA	ABOUT 10 TO 11 ROADS BARRICADED THROUGHOUT THE PARISH DUE TO FLASH FLOODING

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, 1.7 hours before the alert went out and 82 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 0 m above ground
0-6 km bulk shear: 72 kt
0-1 km storm-relative helicity: -164 m²/s²
0-3 km storm-relative helicity: 465 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

277 
WGUS54 KSHV 211344
FFWSHV
LAC027-211545-
/O.NEW.KSHV.FF.W.0019.120321T1344Z-120321T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
844 AM CDT WED MAR 21 2012

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CLAIBORNE PARISH IN NORTHWEST LOUISIANA...
  THIS INCLUDES THE CITY OF HOMER...

* UNTIL 1045 AM CDT

* AT 840 AM CDT...ALTHOUGH HEAVY RAIN HAS MOVED EAST OF THIS
  AREA...EXTENSIVE RESIDUAL FLOODING OF STREETS WAS STILL 
  OCCURING OVER THE WARNED AREA...BY LAW ENFORCEMENT.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  HAYNESVILLE...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 3275 9283 3272 9283 3269 9286 3261 9286
      3258 9288 3259 9318 3266 9317 3272 9319
      3272 9324 3302 9324 3302 9284 3301 9273
      3281 9274 3277 9272

$$

03

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 20, 8:55 PM CDT	Flash Flood Warning Emergency	SHV	Grant, Natchitoches, Sabine, Winn	10 hr
Mar 20, 9:02 PM CDT	River Flood Warning	SHV	Bienville, Bossier, Red River, Webster	11 days
Mar 20, 9:03 PM CDT	Tornado Warning	SHV	Natchitoches	27 min
Mar 20, 9:15 PM CDT	Flash Flood Warning	SHV	Bienville, De Soto, Red River	9 hr
Mar 20, 9:24 PM CDT	Tornado Warning	SHV	Natchitoches	36 min
Mar 20, 10:20 PM CDT	Tornado Warning	SHV	Grant, Natchitoches	40 min
Mar 20, 10:50 PM CDT	Flash Flood Warning	SHV	Bossier, Claiborne, Webster	10 hr
Mar 21, 1:52 AM CDT	Flash Flood Warning	SHV	Bienville, Jackson, Lincoln, Union	8 hr
Mar 21, 2:49 AM CDT	Tornado Warning	SHV	Grant, Winn	26 min
Mar 21, 3:14 AM CDT	Tornado Warning	SHV	Jackson, Winn	46 min
Mar 21, 5:41 AM CDT	Tornado Warning	SHV	Jackson, Winn	34 min
Mar 21, 6:16 AM CDT	Flash Flood Warning	SHV	Bienville, Red River	3 hr
Mar 21, 6:47 AM CDT	Flash Flood Warning Emergency	SHV	Grant, Natchitoches, Red River, Sabine, Winn	4 hr
Mar 21, 9:36 AM CDT	Flash Flood Warning	SHV	Union	114 min
Mar 21, 10:51 AM CDT	Flash Flood Warning Emergency	SHV	Grant, Natchitoches, Winn	3 hr
Mar 21, 1:53 PM CDT	Areal Flood Warning	SHV	Natchitoches	6 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; radar from the NEXRAD Level II archive.