Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 120, NWS Phoenix, AZ

July 30, 2021Imperial County, Riverside County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 30, 2021, 6:49 PM PDT for Imperial County, Riverside 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 30, 2021, 6:49 PM PDT (01:49 UTC)
Expired: Jul 30, 2021, 11:03 PM PDT
In force: 4 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Imperial County, CA, Riverside County, CA

The radar

The Yuma radar (KYUX), 135 km from the middle of the area, began a volume at 01:51 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, 1.8 hours before the alert went out and 173 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2564 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: 33 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

239 
WGUS55 KPSR 310149
FFWPSR
CAC025-065-310615-
/O.NEW.KPSR.FF.W.0120.210731T0149Z-210731T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
649 PM PDT Fri Jul 30 2021

The National Weather Service in Phoenix has issued a

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

* Until 1115 PM PDT.

* At 649 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts up to 0.5 inches 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...
  Bombay Beach, Slab City, Niland and Imperial Hot Mineral Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3357 11554 3369 11549 3370 11544 3369 11534
      3356 11532 3340 11520 3319 11555 3321 11559
      3333 11566 3336 11577 3338 11578

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

$$

MS

1 follow-up statement

574 
WGUS75 KPSR 310603
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1103 PM PDT Fri Jul 30 2021

CAC025-065-310613-
/O.CAN.KPSR.FF.W.0120.000000T0000Z-210731T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-Riverside CA-
1103 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL IMPERIAL AND 
RIVERSIDE COUNTIES...

Flood waters continue to recede. The heavy rain has ended and 
flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flash Flood Watch remains in effect until 500 AM PDT for portions 
of Arizona and California.

LAT...LON 3357 11554 3369 11549 3370 11544 3369 11534
      3356 11532 3340 11520 3319 11555 3321 11559
      3333 11566 3336 11577 3338 11578

$$

Hirsch

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 5:04 PM PDT	Dust Storm Advisory	PSR	Imperial	41 min
Jul 30, 5:18 PM PDT	Special Weather Statement	PSR	Imperial	72 min
Jul 30, 5:20 PM PDT	Special Weather Statement	PSR	Riverside	70 min
Jul 30, 5:24 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 hr
Jul 30, 5:29 PM PDT	Severe Thunderstorm Warning	PSR	Imperial	46 min
Jul 30, 5:33 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial	4 hr
Jul 30, 5:39 PM PDT	Areal Flood Advisory	PSR	Imperial	3 hr
Jul 30, 5:52 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 hr
Jul 30, 5:59 PM PDT	Dust Storm Warning	PSR	Imperial	45 min
Jul 30, 6:06 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial	4 hr
Jul 30, 6:11 PM PDT	Severe Thunderstorm Warning	PSR	Riverside	79 min
Jul 30, 6:31 PM PDT	Special Weather Statement	PSR	Imperial	74 min
Jul 31, 2:32 PM PDT	Special Weather Statement	PSR	Riverside	28 min
Jul 31, 3:47 PM PDT	Special Weather Statement	PSR	Riverside	28 min
Jul 31, 4:48 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	3 hr

Nearby

Flash Flood Warnings in California, 2021 Every 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.