Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 99, NWS Las Vegas, NV

August 31, 2017San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 31, 2017, 4:08 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
Aug 31, 2017, 4:08 PM PDT (23:08 UTC)
Expired
Aug 31, 2017, 7:00 PM PDT
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Las Vegas radar (KESX), 83 km from the middle of the area, began a volume at 23:09 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 12:00Z, 11.1 hours before the alert went out and 136 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, Las Vegas, NV at 12:00Z on 2017-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 27 joules per kilogram.LCLLFCEL10008507005003002001001 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, Las Vegas, NV at 12:00Z on 2017-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 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
27 J/kg
Mixed-layer CIN
-370 J/kg
Mixed-layer LCL
2599 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
45 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

592 
WGUS55 KVEF 312308
FFWVEF
CAC071-010200-
/O.NEW.KVEF.FF.W.0099.170831T2308Z-170901T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
408 PM PDT THU AUG 31 2017

The National Weather Service in Las Vegas has issued a

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

* Until 700 PM PDT

* At 406 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain south of Cima. Flash flooding is expected to begin 
  shortly.

* Some locations that will experience flooding include...
  Cima, Kelso Cima Road, Cedar Canyon Road, and Elora.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3503 11552 3510 11567 3532 11552 3528 11536

$$

AA
2 follow-up statements
603 
WGUS75 KVEF 010024
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
524 PM PDT THU AUG 31 2017

CAC071-010200-
/O.CON.KVEF.FF.W.0099.000000T0000Z-170901T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
524 PM PDT THU AUG 31 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 PM PDT FOR
NORTHEASTERN SAN BERNARDINO COUNTY...

At 524 PM PDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area.  Flash flooding is expected to begin
shortly.

Some locations that will experience flooding include...
Cima, Kelso Cima Road, Cedar Canyon Road, and Elora.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3503 11552 3510 11567 3532 11552 3528 11536

$$

AA
761 
WGUS75 KVEF 010151
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
651 PM PDT THU AUG 31 2017

CAC071-010200-
/O.EXP.KVEF.FF.W.0099.000000T0000Z-170901T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
651 PM PDT THU AUG 31 2017

...THE FLASH FLOOD WARNING FOR NORTHEASTERN SAN BERNARDINO COUNTY
WILL EXPIRE AT 700 PM PDT...

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

LAT...LON 3503 11552 3510 11567 3532 11552 3528 11536

$$

AA

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 2:31 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr

Nearby

Flash Flood Warnings in California, 2017Every flash flood warning in 2017

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.