Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 97, NWS Phoenix, AZ

July 25, 2021Imperial County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 25, 2021, 6:54 PM 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
Jul 25, 2021, 6:54 PM PDT (01:54 UTC)
Expired
Jul 25, 2021, 11:00 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), 80 km from the middle of the area, began a volume at 01:58 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, 1.9 hours before the alert went out and 199 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 2021-07-26Temperature 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 00:00Z on 2021-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.1939Sfc1 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
1166 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

331 
WGUS55 KPSR 260154
FFWPSR
CAC025-260600-
/O.NEW.KPSR.FF.W.0097.210726T0154Z-210726T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
654 PM PDT Sun Jul 25 2021

The National Weather Service in Phoenix has issued a

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

* Until 1100 PM PDT.

* At 654 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 2 inches of rain have 
  fallen. Additional rainfall amounts up 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...
  Ted Kipf Road or Niland-Glamis Road.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3316 11512 3318 11511 3318 11500 3318 11499
      3316 11498 3313 11498 3309 11499 3307 11500
      3301 11510 3301 11515 3301 11517 3303 11519
      3308 11523 3311 11523 3313 11522 3315 11517

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

$$

Iniguez
2 follow-up statements
505 
WGUS75 KPSR 260424 RRB
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
924 PM PDT Sun Jul 25 2021

CAC025-260600-
/O.CON.KPSR.FF.W.0097.000000T0000Z-210726T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-
924 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS 
EVENING FOR CENTRAL IMPERIAL COUNTY...

At 924 PM PDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.5 and 2 inches of rain have 
fallen. 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...
  Ted Kipf Road or Niland-Glamis Road.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3316 11512 3318 11511 3318 11500 3318 11499
      3316 11498 3313 11498 3309 11499 3307 11500
      3301 11510 3301 11515 3301 11517 3303 11519
      3308 11523 3311 11523 3313 11522 3315 11517

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

$$

Iniguez
224 
WGUS75 KPSR 260555
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1055 PM PDT Sun Jul 25 2021

CAC025-260605-
/O.EXP.KPSR.FF.W.0097.000000T0000Z-210726T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-
1055 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 11 PM PDT THIS EVENING FOR 
CENTRAL IMPERIAL COUNTY...

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

LAT...LON 3316 11512 3318 11511 3318 11500 3318 11499
      3316 11498 3313 11498 3309 11499 3307 11500
      3301 11510 3301 11515 3301 11517 3303 11519
      3308 11523 3311 11523 3313 11522 3315 11517

$$

Iniguez

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 6:13 PM PDTFlash Flood Warning Considerable damage threatPSRRiverside4 hr
Jul 25, 6:35 PM PDTFlash Flood Warning Considerable damage threatPSRRiverside4 hr
Jul 25, 8:08 PM PDTFlash Flood Warning Considerable damage threatPSRImperial4 hr
Jul 26, 1:52 AM PDTAreal Flood AdvisoryPSRImperial3 hr
Jul 26, 3:36 AM PDTFlash Flood Warning Considerable damage threatPSRRiverside6 hr
Jul 26, 6:49 AM PDTAreal Flood AdvisoryPSRRiverside3 hr
Jul 26, 8:01 AM PDTAreal Flood AdvisoryPSRRiverside, San Bernardino3 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.