Alert archive / California / Flash Flood Warnings in 2026

Flash Flood Warning 42, NWS Las Vegas, NV

September 24, 2026San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Sep 24, 2026, 3:15 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
Sep 24, 2026, 3:15 PM PDT (22:15 UTC)
Expired
Sep 24, 2026, 6:15 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), 152 km from the middle of the area, began a volume at 22:18 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 10.3 hours before the alert went out and 182 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 2026-09-24Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 12:00Z on 2026-09-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 square meters per square second.1939Sfc1 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
1521 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
-24 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

962 
WGUS55 KVEF 242215
FFWVEF
CAC071-250115-
/O.NEW.KVEF.FF.W.0042.260924T2215Z-260925T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
315 PM PDT Thu Sep 24 2026

The National Weather Service in Las Vegas has issued a

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

* Until 615 PM PDT.

* At 315 PM PDT, emergency management reported thunderstorms
  producing heavy rain across the warned area. Between 0.75 and 1.25
  inches of rain have fallen. Additional rainfall amounts of 0.75 to
  1.5 inches 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...Emergency management reported.

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

* Some locations that will experience flash flooding include...
  Twentynine Palms and Twentynine Palms Base.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.

&&

LAT...LON 3412 11610 3423 11609 3424 11593 3404 11594
      3403 11600 3408 11600 3408 11604 3411 11604
      3411 11605 3412 11605

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Murdock
2 follow-up statements
333 
WGUS75 KVEF 242345
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
445 PM PDT Thu Sep 24 2026

CAC071-250115-
/O.CON.KVEF.FF.W.0042.000000T0000Z-260925T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
445 PM PDT Thu Sep 24 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM PDT THIS
EVENING FOR SAN BERNARDINO COUNTY...

At 445 PM PDT, emergency management reported thunderstorms producing
heavy rain across the warned area. Between 0.75 and 1.25 inches of
rain have fallen. Additional rainfall amounts up to 0.25 inches 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...Emergency management reported.

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

Some locations that will experience flash flooding include...
  Twentynine Palms and Twentynine Palms Base.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.

&&

LAT...LON 3412 11610 3423 11609 3424 11593 3404 11594
      3403 11600 3408 11600 3408 11604 3411 11604
      3411 11605 3412 11605

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Murdock
442 
WGUS75 KVEF 250110
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
610 PM PDT Thu Sep 24 2026

CAC071-250120-
/O.EXP.KVEF.FF.W.0042.000000T0000Z-260925T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
610 PM PDT Thu Sep 24 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 615 PM PDT THIS EVENING FOR SAN
BERNARDINO COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

&&

LAT...LON 3412 11610 3423 11609 3424 11593 3404 11594
      3403 11600 3408 11600 3408 11604 3411 11604
      3411 11605 3412 11605

$$

Murdock

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 Las Vegas, NV wrote its last area forecast discussion before this flash flood warning went out at Sep 24, 12:57 PM PDT, 2 hours 18 minutes earlier. Its key messages:

  • * Temperatures continue to warm through Saturday, with readings running 3 to 6 degrees above normal. * A few isolated thunderstorms are expected this afternoon, mainly in Mohave County and portions of San Bernardino County. * Increasing confidence in clouds, rainfall, and cooler readings Sunday through Tuesday as tropical moisture spreads northward.
Area forecast discussion, Sep 24, 12:57 PM PDT, 2 hours 18 minutes before
Area Forecast Discussion
National Weather Service Las Vegas NV
1257 PM PDT Thu Sep 24 2026

..KEY MESSAGES...

* Temperatures continue to warm through Saturday, with readings
  running 3 to 6 degrees above normal.

* A few isolated thunderstorms are expected this afternoon, mainly
  in Mohave County and portions of San Bernardino County.

* Increasing confidence in clouds, rainfall, and cooler readings
  Sunday through Tuesday as tropical moisture spreads northward.

&&

.DISCUSSION...Today through Wednesday.

Weak ridging aloft will remain over the region through Saturday,
supporting a gradual warming trend across the region. Temperatures
will climb a few degrees both this afternoon and again Friday, with
readings reaching 3 to 6 degrees above normal by Saturday. Highs in
the desert valleys will range from the 90s to low 100s, with
overnight lows generally in the 70s to low 80s. Higher elevations,
such as the Spring Mountains near Las Vegas, will see high
temperatures topping out in the low 70s each day through Saturday.

A few isolated showers and thunderstorms are possible across Mohave
County and portions of San Bernardino County this afternoon as a
disturbance moving around a trough located off the SoCal coast moves
across the region. Moisture remains limited in most areas, although
PWATs of 1.00 to 1.20 inches are being noted in the lower Colorado
River Valley near Lake Havasu City. SBCAPE is also marginal, with
values generally remaining below 750 J/kg. However, as noted in
earlier discussions, DCAPE values approaching 1500 J/kg suggest the
strongest storms could produce localized strong wind gusts. Brief
heavy rainfall and lightning are also possible with any storms that
develop. Convection should diminish quickly after sunset as daytime
heating is lost and subsidence increases behind the departing and
weakening wave.

A more complex forecast looks to unfold late in the weekend and
early next week as a deepening trough drops into California and
tropical moisture from Hurricanes Odalys and Polo gets drawn into
the Southwest United States. Model guidance continues to come into
better agreement with the evolution of these systems, but
inconsistencies in timing remain, with the GFS being more
progressive with the trough while the ECMWF is slower and holds it
back. The current thinking is that the majority of the moisture from
these systems will move south and east of the region, but some
precipitation will be possible over southern and eastern areas
Sunday through Tuesday. WPC has included these areas in a Marginal
Risk outlook for Days 4 and 5 (Sunday and Monday), with portions of
eastern Mohave County included in a Slight Risk area on Day 5
(Monday). Cooler temperatures are also expected during this period
as increasing cloud cover and the potential for precipitation keep
maximum temperatures in the 80s, which is a few degrees below normal
for this time of year.
&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Overall,
winds will generally remain less than 10 knots through Friday
morning and follow typical daily diurnal directional trends. There
is a 20 percent chance of seeing a gust or two to 15 knots out of
the southeast (130 to 170 degrees true) between 22Z and 01Z,
although any gusts should be short lived. Model guidance continues
to indicate a low chance (10 to 20 percent) of breezy southeasterly
outflow winds from convection over Arizona moving into the valley
during the late evening (05Z to 07Z). Winds on Friday are expected
to remain light, with speeds remaining below 8 knots. No
operationally significant cloud cover is expected through the TAF
period.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Light winds will persist
at most area terminals through the TAF period. The exception will be
in the northern Owens Valley, including KBIH, where southerly winds
with a few gusts to around 20 knots are possible this afternoon and
early evening. A few thunderstorms are possible this afternoon and
evening, mainly south of I-15, including KDAG, KEED and KIFP. Gusty
outflow winds will be the main concern, with the best chance of
direct impacts at KEED and KIFP. CIGs may also fall below 10kft AGL
near activity. Elsewhere, VFR conditions are expected. All sites
should see diminishing cloud cover overnight and Friday morning. &&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.

&&

DISCUSSION...Planz
AVIATION...Planz

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 24, 2:38 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr

Nearby

Flash Flood Warnings in California, 2026Every flash flood warning in 2026

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.