Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 90, NWS Phoenix, AZ

July 25, 2021Riverside County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 25, 2021, 3:20 PM PDT for Riverside County, California. It was in force for 5 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, 3:20 PM PDT (22:20 UTC)
Expired: Jul 25, 2021, 8:30 PM PDT
In force: 5 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Riverside County, CA

The radar

The San Diego radar (KNKX), 151 km from the middle of the area, began a volume at 22:20 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

San Diego, CA (KNKX), launched 12:00Z, 10.3 hours before the alert went out and 171 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: 1039 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

220 
WGUS55 KPSR 252220
FFWPSR
CAC065-260230-
/O.NEW.KPSR.FF.W.0090.210725T2220Z-210726T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Phoenix has issued a

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

* Until 730 PM PDT.

* At 320 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...Radar.

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

* Some locations that will experience flash flooding include...
  mainly rural areas of Riverside County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3375 11584 3382 11595 3391 11608 3396 11604
      3400 11595 3395 11586 3391 11578 3384 11569
      3380 11573 3376 11576

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

$$

MS

3 follow-up statements

403 
WGUS75 KPSR 260003
FFSPSR

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

CAC065-260230-
/O.CON.KPSR.FF.W.0090.000000T0000Z-210726T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-
503 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM PDT THIS 
EVENING FOR RIVERSIDE COUNTY...

At 503 PM PDT, earlier this afternoon between 0.5 and 1.5 inches of 
rain have fallen over portions of Joshua Tree National Park. Area 
washes were reported to be flowing.

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...
  mainly rural areas of Riverside County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3375 11584 3382 11595 3391 11608 3396 11604
      3400 11595 3395 11586 3391 11578 3384 11569
      3380 11573 3376 11576

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

$$

MS

356 
WGUS55 KPSR 260224
FFWPSR
CAC065-260330-
/O.EXT.KPSR.FF.W.0090.000000T0000Z-210726T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Phoenix has extended the

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

* Until 830 PM PDT.

* At 724 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 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...
  Central portions of Joshua Tree National Park near the Hexie
  Mountains.

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 3375 11584 3382 11595 3391 11608 3396 11604
      3400 11595 3395 11586 3391 11578 3384 11569
      3380 11573 3376 11576

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

$$

Iniguez

732 
WGUS75 KPSR 260326 RRB
FFSPSR

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

CAC065-260336-
/O.EXP.KPSR.FF.W.0090.000000T0000Z-210726T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-
826 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 830 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 3375 11584 3382 11595 3391 11608 3396 11604
      3400 11595 3395 11586 3391 11578 3384 11569
      3380 11573 3376 11576

$$

Iniguez

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 25, 11:59 AM PDT	Special Weather Statement	PSR	Riverside	31 min
Jul 25, 12:14 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 hr
Jul 25, 12:43 PM PDT	Special Weather Statement	PSR	Riverside	32 min
Jul 25, 1:12 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 hr
Jul 25, 1:24 PM PDT	Special Weather Statement	PSR	Riverside	51 min
Jul 25, 2:15 PM PDT	Special Weather Statement	PSR	Riverside	45 min
Jul 25, 2:34 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	7 hr
Jul 25, 2:38 PM PDT	Special Weather Statement	PSR	Riverside	37 min
Jul 25, 3:14 PM PDT	Special Weather Statement	PSR	Riverside	31 min
Jul 25, 3:41 PM PDT	Special Weather Statement	PSR	Riverside	34 min
Jul 25, 4:01 PM PDT	Severe Thunderstorm Warning	PSR	Riverside, San Bernardino	29 min
Jul 25, 4:18 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 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.