Alert archive / California / Flash Flood Warnings in 2021
Flash Flood Warning 37, NWS Las Vegas, NV
NWS Las Vegas, NV issued this flash flood warning at Jul 20, 2021, 6:27 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 20, 2021, 6:27 PM PDT (01:27 UTC)
- Expired
- Jul 20, 2021, 9:30 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 Las Vegas radar (KESX), 104 km from the middle of the area, began a volume at 01:32 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
Las Vegas, NV (KVEF), launched 00:00Z, 1.5 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.
- Mixed-layer CAPE
- 183 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 3414 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 52 m²/s²
- 0-3 km storm-relative helicity
- 50 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
130
WGUS55 KVEF 210127
FFWVEF
CAC071-210430-
/O.NEW.KVEF.FF.W.0037.210721T0127Z-210721T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
627 PM PDT Tue Jul 20 2021
The National Weather Service in Las Vegas has issued a
* Flash Flood Warning for...
San Bernardino County in southern California...
* Until 930 PM PDT.
* At 627 PM PDT, Doppler radar indicated thunderstorms producing
heavy rain west of Needles. 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 low-water
crossings, creeks, normally dry washes and roads.
* Some locations that will experience flash flooding include...
Highway 95 and Needles.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be aware of your surroundings and do not drive on flooded roads.
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 3483 11461 3482 11460 3476 11459 3470 11461
3472 11472 3485 11471
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
JS2 follow-up statements
500
WGUS75 KVEF 210302
FFSVEF
Flash Flood Statement
National Weather Service Las Vegas NV
802 PM PDT Tue Jul 20 2021
CAC071-210430-
/O.CON.KVEF.FF.W.0037.000000T0000Z-210721T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
802 PM PDT Tue Jul 20 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM PDT THIS
EVENING FOR SAN BERNARDINO COUNTY...
At 802 PM PDT, Doppler radar indicates heavy rain has ended across
the warned area. However, the warning will be continued due to any
lingering impacts from the earlier heavy rain. Additional flash
flooding is no longer expected.
HAZARD...Life-threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Radar.
IMPACT...Life-threatening flash flooding of low-water crossings,
creeks, normally dry washes and roads.
Some locations that will experience flash flooding include...
Highway 95 and Needles.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be aware of your surroundings and do not drive on flooded roads.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 3483 11461 3482 11460 3476 11459 3470 11461
3472 11472 3485 11471
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
JS003
WGUS75 KVEF 210425
FFSVEF
Flash Flood Statement
National Weather Service Las Vegas NV
925 PM PDT Tue Jul 20 2021
CAC071-210435-
/O.EXP.KVEF.FF.W.0037.000000T0000Z-210721T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
925 PM PDT Tue Jul 20 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 930 PM PDT THIS EVENING FOR
SAN BERNARDINO COUNTY...
The heavy rain has ended and flooding is no longer expected to pose
a threat. Please continue to heed remaining road closures.
LAT...LON 3483 11461 3482 11460 3476 11459 3470 11461
3472 11472 3485 11471
$$
JSThe office that day
Everything else NWS Las Vegas, NV issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 12:13 PM PDT | Flash Flood Warning | VEF | San Bernardino | 3 hr |
| Jul 21, 3:07 PM PDT | Flash Flood Warning | VEF | San Bernardino | 2 hr |
| Jul 21, 4:38 PM PDT | Flash Flood Warning | VEF | San Bernardino | 3 hr |
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.