Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 113, NWS Phoenix, AZ

July 30, 2021Riverside County, San Bernardino County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 30, 2021, 3:55 PM PDT for Riverside County, San Bernardino 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, 3:55 PM PDT (22:55 UTC)
Expired: Jul 30, 2021, 8:00 PM PDT
In force: 4 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Riverside County, CA, San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 131 km from the middle of the area, began a volume at 22:58 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 12:00Z, 10.9 hours before the alert went out and 164 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: 2147 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -15 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

398 
WGUS55 KPSR 302255
FFWPSR
CAC065-071-310300-
/O.NEW.KPSR.FF.W.0113.210730T2255Z-210731T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Phoenix has issued a

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

* Until 800 PM PDT.

* At 355 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has 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...
  Key View.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3406 11631 3408 11631 3408 11630 3408 11628
      3408 11626 3412 11626 3409 11620 3404 11614
      3401 11609 3391 11616 3394 11621 3401 11628

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

$$

MS

3 follow-up statements

594 
WGUS75 KPSR 310043
FFSPSR

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

CAC065-071-310300-
/O.CON.KPSR.FF.W.0113.000000T0000Z-210731T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Bernardino CA-
543 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM PDT THIS EVENING 
FOR RIVERSIDE AND SAN BERNARDINO COUNTIES...

At 543 PM PDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 2 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly in 
portions of western Joshua Tree National Park.  Road crossings could 
have swiftly flowing water.

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...
  Key View.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3406 11631 3408 11631 3408 11630 3408 11628
      3408 11626 3412 11626 3409 11620 3404 11614
      3401 11609 3391 11616 3394 11621 3401 11628

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

$$

MS

821 
WGUS75 KPSR 310215 RRA
FFSPSR

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

CAC065-071-310300-
/O.CON.KPSR.FF.W.0113.000000T0000Z-210731T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Bernardino CA-
715 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM PDT THIS EVENING 
FOR RIVERSIDE AND SAN BERNARDINO COUNTIES...

At 715 PM PDT, Earlier today thunderstorms across the warned area 
produced between 1 and 2 inches of rainfall. Washes are likely 
flowing along Park Blvd within the national park.

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...
  Key View.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3406 11631 3408 11631 3408 11630 3408 11628
      3408 11626 3412 11626 3409 11620 3404 11614
      3401 11609 3391 11616 3394 11621 3401 11628

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

$$

MS

920 
WGUS75 KPSR 310254
FFSPSR

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

CAC065-071-310304-
/O.EXP.KPSR.FF.W.0113.000000T0000Z-210731T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Bernardino CA-
754 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM PDT THIS EVENING FOR 
RIVERSIDE AND SAN BERNARDINO COUNTIES...

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 500 AM PDT Saturday for 
portions of Arizona and California.

LAT...LON 3406 11631 3408 11631 3408 11630 3408 11628
      3408 11626 3412 11626 3409 11620 3404 11614
      3401 11609 3391 11616 3394 11621 3401 11628

$$

INS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 2:01 PM PDT	Special Weather Statement	PSR	Imperial	29 min
Jul 30, 3:11 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial	5 hr
Jul 30, 3:45 PM PDT	Special Weather Statement	PSR	Riverside	30 min
Jul 30, 4:20 PM PDT	Special Weather Statement	PSR	Imperial	25 min
Jul 30, 4:37 PM PDT	Special Weather Statement	PSR	Riverside	23 min
Jul 30, 4:48 PM PDT	Special Weather Statement	PSR	Imperial	27 min

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.