Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 250, NWS Phoenix, AZ

September 24, 2021Imperial County, California

NWS Phoenix, AZ issued this flash flood warning at Sep 24, 2021, 8:14 AM PDT for Imperial 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 outline as issued.

The facts

Issued
Sep 24, 2021, 8:14 AM PDT (15:14 UTC)
Expired
Sep 24, 2021, 12:15 PM PDT
In force
4 hr
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Imperial County, CA

The radar

The Yuma radar (KYUX), 86 km from the middle of the area, began a volume at 15:16 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 12:00Z, 3.2 hours before the alert went out and 161 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 12:00Z on 2021-09-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 12:00Z on 2021-09-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1990 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

085 
WGUS55 KPSR 241514
FFWPSR
CAC025-241915-
/O.NEW.KPSR.FF.W.0250.210924T1514Z-210924T1915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
814 AM PDT Fri Sep 24 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  Southwestern Imperial County in southeastern California...

* Until 1215 PM PDT.

* At 814 AM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.5 to 1 inch are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  El Centro, Calexico, Brawley, Imperial, Plaster City, Holtville, 
  Westmorland, El Centro Naval Airfield, Mt. Signal, Gordon's Well, 
  Algodones Dunes, Alamorio, Heber, Bonds Corner, Seeley and 
  Dixieland.

This includes the following highways...
	CA Route 86 near mile marker 1...and
	between mile markers 10 and 18.
	CA Route 98 between mile markers 10 and 19.
	CA Interstate 8 between mile markers 16 and 25.
	CA Route 78 between mile markers 14 and 23.
	CA Route 111 near mile marker 1...and
	between mile markers 10 and 18.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3263 11592 3305 11597 3305 11533 3296 11490
      3271 11485

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

INS
2 follow-up statements
221 
WGUS75 KPSR 241841
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1141 AM PDT Fri Sep 24 2021

CAC025-241915-
/O.CON.KPSR.FF.W.0250.000000T0000Z-210924T1915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-
1141 AM PDT Fri Sep 24 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 PM PDT THIS 
AFTERNOON FOR SOUTHWESTERN IMPERIAL COUNTY...

At 1141 AM PDT, Between 1 and 1.5 inches of rain have fallen earlier 
over the warned area. Flash flooding is ongoing or expected to begin 
shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  El Centro, Calexico, Brawley, Imperial, Plaster City, Holtville, 
  Westmorland, El Centro Naval Airfield, Mt. Signal, Gordon's Well, 
  Algodones Dunes, Alamorio, Heber, Bonds Corner, Seeley and 
  Dixieland.

This includes the following highways...
	CA Route 86 near mile marker 1...and
	between mile markers 10 and 18.
	CA Route 98 between mile markers 10 and 19.
	CA Interstate 8 between mile markers 16 and 25.
	CA Route 78 between mile markers 14 and 23.
	CA Route 111 near mile marker 1...and
	between mile markers 10 and 18.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3263 11592 3305 11597 3305 11533 3296 11490
      3271 11485

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MS
959 
WGUS75 KPSR 241909
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1209 PM PDT Fri Sep 24 2021

CAC025-241919-
/O.EXP.KPSR.FF.W.0250.000000T0000Z-210924T1915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-
1209 PM PDT Fri Sep 24 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1215 PM PDT THIS AFTERNOON FOR 
SOUTHWESTERN IMPERIAL COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 700 PM PDT Friday for 
portions of southeast California and southern California.

LAT...LON 3263 11592 3305 11597 3305 11533 3296 11490
      3271 11485

$$

MS

The office that day

Everything else NWS Phoenix, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 24, 7:10 AM PDTSpecial Weather StatementPSRImperial50 min
Sep 24, 7:28 AM PDTAreal Flood AdvisoryPSRImperial46 min
Sep 24, 7:33 AM PDTSevere Thunderstorm WarningPSRImperial42 min
Sep 24, 8:00 AM PDTSpecial Weather StatementPSRImperial45 min
Sep 24, 8:18 AM PDTSpecial Weather StatementPSRImperial42 min
Sep 24, 9:03 AM PDTFlash Flood WatchPSRImperial, Riverside, San Bernardino10 hr

Nearby

Flash Flood Warnings in California, 2021Every flash flood warning in 2021

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.