Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 4, NWS Phoenix, AZ

June 23, 2021Riverside County, California

NWS Phoenix, AZ issued this flash flood warning at Jun 23, 2021, 7:16 PM PDT for 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: Jun 23, 2021, 7:16 PM PDT (02:16 UTC)
Expired: Jun 23, 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 Riverside County, CA

The radar

The Yuma radar (KYUX), 123 km from the middle of the area, began a volume at 02:20 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

Yuma Prvg Ground, AZ (K1Y7), launched 00:00Z, 2.3 hours before the alert went out and 131 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: 433 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 2844 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: -10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

409 
WGUS55 KPSR 240216
FFWPSR
CAC065-240600-
/O.NEW.KPSR.FF.W.0004.210624T0216Z-210624T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
716 PM PDT Wed Jun 23 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  Riverside County in southern California...

* Until 1100 PM PDT.

* At 716 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

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

  SOURCE...Doppler radar.

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

* Some locations that will experience flash flooding include...
  Blythe.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you 
can do so safely.

&&

LAT...LON 3349 11514 3345 11494 3352 11491 3361 11485
      3368 11493 3369 11508

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

$$

INS

2 follow-up statements

615 
WGUS75 KPSR 240445
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
945 PM PDT Wed Jun 23 2021

CAC065-240600-
/O.CON.KPSR.FF.W.0004.000000T0000Z-210624T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-
945 PM PDT Wed Jun 23 2021

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

At 945 PM PDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.5 and 1.5 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly.

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

SOURCE...Doppler radar.

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

Some locations that will experience flash flooding include...
  Blythe.

This includes the following highways...
	CA Interstate 10 between mile markers 124 and 133.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you 
can do so safely.

&&

LAT...LON 3353 11512 3349 11493 3352 11491 3361 11485
      3368 11493 3369 11508

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

$$

INS

136 
WGUS75 KPSR 240556
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1056 PM PDT Wed Jun 23 2021

CAC065-240606-
/O.EXP.KPSR.FF.W.0004.000000T0000Z-210624T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-
1056 PM PDT Wed Jun 23 2021

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

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

LAT...LON 3353 11512 3349 11493 3352 11491 3361 11485
      3368 11493 3369 11508

$$

INS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 23, 5:33 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	2 hr
Jun 23, 5:38 PM PDT	Severe Thunderstorm Warning	PSR	Riverside	37 min
Jun 23, 6:10 PM PDT	Special Weather Statement	PSR	Imperial	50 min
Jun 23, 6:28 PM PDT	Areal Flood Advisory	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.