Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 80, NWS Las Vegas, NV

July 28, 2021San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 28, 2021, 1:21 PM PDT for 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 outline as issued.

The facts

Issued
Jul 28, 2021, 1:21 PM PDT (20:21 UTC)
Expired
Jul 28, 2021, 4:00 PM PDT
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 135 km from the middle of the area, began a volume at 20:23 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, 8.4 hours before the alert went out and 175 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-pSkew-T log-p diagram, San Diego, CA at 12:00Z on 2021-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 12:00Z on 2021-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1533 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

979 
WGUS55 KVEF 282021
FFWVEF
CAC071-282300-
/O.NEW.KVEF.FF.W.0080.210728T2021Z-210728T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
121 PM PDT Wed Jul 28 2021

The National Weather Service in Las Vegas has issued a

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

* Until 400 PM PDT.

* At 121 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain south of Joshua Tree. Between 0.75 and 1.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly and will impact Park Blvd and Indian Cove Roads south of 
  Highway 62. Additional flooding may impact Highway 62
  between Twentynine Palms and Yucca Valley. 

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

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Joshua Tree Lake Campground and Joshua Tree.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3408 11632 3414 11636 3419 11637 3422 11635
      3425 11630 3426 11627 3426 11620 3424 11615
      3419 11609 3412 11606 3412 11609 3412 11611
      3412 11614 3412 11616 3412 11621 3412 11623
      3412 11625 3412 11626 3411 11626 3408 11626

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

$$

CO
2 follow-up statements
910 
WGUS75 KVEF 282125
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
225 PM PDT Wed Jul 28 2021

CAC071-282300-
/O.CON.KVEF.FF.W.0080.000000T0000Z-210728T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
225 PM PDT Wed Jul 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 4 PM PDT THIS 
AFTERNOON FOR SAN BERNARDINO COUNTY...

At 225 PM PDT, Heavy rain has begun to diminish across the Joshua 
Tree area. While rain has ended...excessive runoff from earlier 
rainfall will continue and will impact Highway 62...especially 
between Mantonya Road and Copper Mountain Road. Continue to avoid 
flood waters and heed road closures.

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

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Joshua Tree Lake Campground and Joshua Tree.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3408 11632 3414 11636 3419 11637 3422 11635
      3425 11630 3426 11627 3426 11620 3424 11615
      3419 11609 3412 11606 3412 11609 3412 11611
      3412 11614 3412 11616 3412 11621 3412 11623
      3412 11625 3412 11626 3411 11626 3408 11626

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

$$

CO
007 
WGUS75 KVEF 282250
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
350 PM PDT Wed Jul 28 2021

CAC071-282300-
/O.EXP.KVEF.FF.W.0080.000000T0000Z-210728T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
350 PM PDT Wed Jul 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 4 PM PDT THIS AFTERNOON FOR 
SAN BERNARDINO COUNTY...

Heavy rainfall has ended and flooding is no longer expected to pose 
a threat. Please continue to heed remaining road closures.

LAT...LON 3408 11632 3414 11636 3419 11637 3422 11635
      3425 11630 3426 11627 3426 11620 3424 11615
      3419 11609 3412 11606 3412 11609 3412 11611
      3412 11614 3412 11616 3412 11621 3412 11623
      3412 11625 3412 11626 3411 11626 3408 11626

$$

CO

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 27, 5:56 PM PDTAreal Flood AdvisoryVEFSan Bernardino2 hr
Jul 28, 12:59 PM PDTAreal Flood AdvisoryVEFSan Bernardino22 min

Nearby

Flash Flood Warnings in California, 2021Every 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.