Alert archive / Louisiana / Flash Flood Warnings in 2017

Flash Flood Warning 9, NWS New Orleans, LA

May 20, 2017Pearl River County, Mississippi; Saint Tammany Parish, Washington Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at May 20, 2017, 6:15 PM CDT for Pearl River County, Mississippi; Saint Tammany Parish, Washington Parish, Louisiana. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 20, 2017, 6:15 PM CDT (23:15 UTC)
Expired: May 20, 2017, 8:15 PM CDT
In force: 2 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Flood severity: None

Counties Saint Tammany Parish, LA, Washington Parish, LA, Pearl River County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.3 hours before the alert went out and 56 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: 2399 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 567 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 64 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

398 
WGUS54 KLIX 202315
FFWLIX
LAC103-117-MSC109-210115-
/O.NEW.KLIX.FF.W.0009.170520T2315Z-170521T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
615 PM CDT SAT MAY 20 2017

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  Northwestern St. Tammany Parish in southeastern Louisiana...
  Eastern Washington Parish in southeastern Louisiana...
  Northwestern Pearl River County in southern Mississippi...

* Until 815 PM CDT

* At 613 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Flash flooding is expected to
  begin shortly.

* Some locations that will experience flooding include...
  Bogalusa, Covington, Varnado, Sun, Bush, Enon, Crossroads and
  Angie.

Additional rainfall amounts of 2 to 4 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

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

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3098 8967 3059 8976 3061 8987 3047 9007
      3048 9014 3074 9009 3097 8991

$$

32

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 1:11 PM CDT	Areal Flood Advisory	LIX	Pearl River, Walthall	2 hr
May 20, 2:22 PM CDT	Special Weather Statement	LIX	Amite, Pike	38 min
May 20, 3:15 PM CDT	Flash Flood Warning	LIX	Amite, Wilkinson	90 min
May 20, 3:29 PM CDT	Flash Flood Watch	LIX	Amite, Pearl River, Pike, Walthall, Wilkinson	6 hr
May 20, 1:16 PM CDT	Areal Flood Advisory	LIX	Ascension, Livingston, Saint Helena	119 min
May 20, 3:50 PM CDT	Special Weather Statement	LIX	East Feliciana	55 min
May 20, 4:28 PM CDT	Special Weather Statement	LIX	East Baton Rouge, East Feliciana, West Baton Rouge	62 min
May 20, 5:05 PM CDT	Special Weather Statement	LIX	Ascension, Livingston, Tangipahoa	40 min
May 20, 5:52 PM CDT	Special Weather Statement	LIX	Livingston, Saint John the Baptist, Saint Tammany, Tangipahoa	38 min
May 20, 5:57 PM CDT	Special Marine Warning	LIX		33 min
May 20, 6:20 PM CDT	Special Weather Statement	LIX	Tangipahoa	40 min

Nearby

Flash Flood Warnings in Louisiana, 2017 Flash Flood Warnings in Mississippi, 2017 Every flash flood warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.