Alert archive / California / Flash Flood Warnings in 2024

Flash Flood Warning 24, NWS Phoenix, AZ

July 23, 2024Riverside County, San Bernardino County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 23, 2024, 12:56 PM PDT for Riverside County, San Bernardino County, California. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 23, 2024, 12:56 PM PDT (19:56 UTC)
Expired: Jul 23, 2024, 4:00 PM PDT
In force: 3 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), 152 km from the middle of the area, began a volume at 19:59 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, 7.9 hours before the alert went out and 195 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: 2030 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 33 m²/s²
0-3 km storm-relative helicity: 75 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Phoenix, AZ wrote its last area forecast discussion before this flash flood warning went out at Jul 23, 11:36 AM PDT, 1 hour 20 minutes earlier.

Area forecast discussion, Jul 23, 11:36 AM PDT, 1 hour 20 minutes before

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In the hours before

Special weather statement, Jul 23, 12:09 PM PDT, 47 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
1209 PM PDT Tue Jul 23 2024

CAZ560-231945-
Joshua Tree NP West CA-
1209 PM PDT Tue Jul 23 2024

...A STRONG THUNDERSTORM WILL IMPACT SAN BERNARDINO AND RIVERSIDE
COUNTIES THROUGH 1245 PM PDT...

At 1209 PM PDT, Doppler radar was tracking a strong thunderstorm near
Twentynine Palms. This thunderstorm was nearly stationary.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

This storm will remain over mainly rural areas of San Bernardino and
Riverside Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 3408 11627 3412 11626 3412 11606 3408 11603
      3407 11599 3404 11601 3403 11598 3400 11597
      3396 11624 3408 11631
TIME...MOT...LOC 1909Z 157DEG 4KT 3409 11615

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

INS

Special weather statement, Jul 23, 12:43 PM PDT, 13 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
1243 PM PDT Tue Jul 23 2024

CAZ560-232030-
Joshua Tree NP West CA-
1243 PM PDT Tue Jul 23 2024

...A STRONG THUNDERSTORM WILL IMPACT SAN BERNARDINO AND RIVERSIDE
COUNTIES THROUGH 130 PM PDT...

At 1243 PM PDT, Doppler radar was tracking a strong thunderstorm near
Twentynine Palms, moving northwest at 10 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Lost Horse-Keys Village.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 3408 11631 3408 11627 3412 11626 3412 11606
      3408 11603 3407 11600 3404 11601 3403 11598
      3397 11593 3392 11624
TIME...MOT...LOC 1943Z 141DEG 8KT 3409 11616

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

INS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 6:40 PM PDT	Special Weather Statement	PSR	La Paz	50 min
Jul 22, 6:58 PM PDT	Special Weather Statement	PSR		47 min
Jul 22, 7:09 PM PDT	Special Weather Statement	PSR	La Paz	36 min
Jul 22, 7:40 PM PDT	Severe Thunderstorm Warning	PSR	La Paz	50 min
Jul 22, 8:05 PM PDT	Special Weather Statement	PSR	La Paz	25 min
Jul 22, 8:10 PM PDT	Areal Flood Advisory	PSR	La Paz	2 hr
Jul 23, 2:27 PM PDT	Special Weather Statement	PSR		48 min
Jul 23, 3:11 PM PDT	Special Weather Statement	PSR		34 min
Jul 23, 3:57 PM PDT	Special Weather Statement	PSR		48 min
Jul 23, 12:09 PM PDT	Special Weather Statement	PSR	Riverside	36 min
Jul 23, 12:43 PM PDT	Special Weather Statement	PSR	Riverside	47 min
Jul 23, 3:05 PM PDT	Areal Flood Advisory	PSR	Riverside	3 hr
Jul 23, 4:22 PM PDT	Special Weather Statement	PSR	Riverside	38 min

Nearby

Flash Flood Warnings in California, 2024 Every flash flood warning in 2024

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.