Alert archive / Louisiana / Flash Flood Watches in 2018

Flash Flood Watch 4, NWS New Orleans, LA

May 25, 201810 parishes in Louisiana; Pearl River County, Pike County, Walthall County, Mississippi

NWS New Orleans, LA issued this flash flood watch at May 25, 2018, 10:41 AM CDT for 10 parishes in Louisiana; Pearl River County, Pike County, Walthall County, Mississippi. It took effect at May 25, 2018, 1:00 PM CDT. It was in force for 51 hr.

The area

The counties it named.

The facts

Issued: May 25, 2018, 10:41 AM CDT (15:41 UTC)
In effect from: May 25, 2018, 1:00 PM CDT
Expired: May 27, 2018, 3:37 PM CDT
In force: 51 hr
Issued by: NWS New Orleans, LA
Flood severity: None

Counties Assumption Parish, LA, East Baton Rouge Parish, LA, Iberville Parish, LA, Saint Bernard Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Pearl River County, MS, Pike County, MS, Walthall County, MS

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 3.7 hours before the alert went out and 207 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: 930 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 829 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: -4 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS New Orleans, LA wrote its last area forecast discussion before this flash flood watch went out at May 25, 9:23 AM CDT, 1 hour 18 minutes earlier.

Area forecast discussion, May 25, 9:23 AM CDT, 1 hour 18 minutes before

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Hazardous weather outlook, May 25, 4:00 AM CDT, 6 hours 41 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 25, 8:30 AM CDT	Special Marine Warning	LIX		30 min
May 25, 9:15 AM CDT	Special Marine Warning	LIX		60 min
May 25, 9:17 AM CDT	Special Marine Warning	LIX		58 min
May 25, 12:22 PM CDT	Special Weather Statement	LIX	Saint Charles	53 min
May 25, 2:43 PM CDT	Special Weather Statement	LIX	East Baton Rouge	62 min
May 25, 2:44 PM CDT	Special Weather Statement	LIX	Tangipahoa	61 min
May 25, 3:22 PM CDT	Special Weather Statement	LIX	East Baton Rouge	23 min
May 25, 3:59 PM CDT	Special Weather Statement	LIX	Saint Helena	31 min
May 25, 4:16 PM CDT	Storm Surge Watch	LIX	Saint Bernard	30 hr
May 25, 4:16 PM CDT	Tropical Storm Watch	LIX	Saint Bernard, Saint James, Saint John the Baptist	42 hr
May 25, 4:35 PM CDT	Special Weather Statement	LIX	Saint Helena	25 min
May 25, 4:38 PM CDT	Coastal Flood Advisory	LIX	Saint John the Baptist	24 hr
May 25, 5:03 PM CDT	Special Weather Statement	LIX	Pointe Coupee	27 min
May 25, 12:23 PM CDT	Special Weather Statement	LIX	Jackson	67 min
May 25, 4:32 PM CDT	Special Weather Statement	LIX	Walthall	28 min
May 25, 5:00 PM CDT	Special Weather Statement	LIX	Pike	30 min

Nearby

Flash Flood Watches in Louisiana, 2018 Flash Flood Watches in Mississippi, 2018 Every flash flood watch in 2018

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.