Alert archive / California / Flash Flood Warnings in 2025

Flash Flood Warning 37, NWS Los Angeles, CA

November 21, 2025Los Angeles County, California

NWS Los Angeles, CA issued this flash flood warning at Nov 21, 2025, 1:45 AM PST for Los Angeles County, California. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Nov 21, 2025, 1:45 AM PST (09:45 UTC)
Expired
Nov 21, 2025, 5:43 AM PST
In force
4 hr
Issued by
NWS Los Angeles, CA
Area
Storm-based polygon
Flood severity
None

County Los Angeles County, CA

The radar

The Santa Ana Mts radar (KSOX), 71 km from the middle of the area, began a volume at 09:44 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.

The nearest sounding before it

San Diego, CA (KNKX), launched 00:00Z, 9.8 hours before the alert went out and 184 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-pSkew-T log-p diagram, San Diego, CA at 00:00Z on 2025-11-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 00:00Z on 2025-11-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -14 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
3 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
1098 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
-14 m²/s²
0-3 km storm-relative helicity
19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

Everything else NWS Los Angeles, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 20, 9:02 PM PSTAreal Flood AdvisoryLOXLos Angeles11 hr
Nov 20, 10:01 PM PSTSpecial Marine WarningLOX14 min
Nov 20, 10:16 PM PSTAreal Flood AdvisoryLOXSanta Barbara, Ventura5 hr
Nov 20, 10:21 PM PSTAreal Flood AdvisoryLOXLos Angeles10 hr
Nov 20, 11:58 PM PSTAreal Flood AdvisoryLOXVentura3 hr
Nov 21, 12:34 AM PSTSpecial Marine WarningLOX116 min
Nov 21, 12:56 AM PSTWind AdvisoryLOXLos Angeles, Ventura40 hr
Nov 21, 12:59 AM PSTSpecial Weather StatementLOXLos Angeles16 min
Nov 21, 1:06 AM PSTSevere Thunderstorm WarningLOXLos Angeles28 min
Nov 21, 1:11 AM PSTFlash Flood WarningLOXLos Angeles3 hr
Nov 21, 1:23 AM PSTSpecial Marine WarningLOX43 min
Nov 21, 1:44 AM PSTSpecial Weather StatementLOXLos Angeles46 min
Nov 21, 2:19 AM PSTFlash Flood WarningLOXLos Angeles4 hr
Nov 21, 2:59 AM PSTSpecial Weather StatementLOXLos Angeles31 min
Nov 21, 2:34 PM PSTSmall Craft AdvisoryLOX23 hr

Nearby

Flash Flood Warnings in California, 2025Every flash flood warning in 2025

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; radar from the NEXRAD Level II archive.