Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 88, NWS Las Vegas, NV

August 11, 2017San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 11, 2017, 2:47 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 11, 2017, 2:47 PM PDT (21:47 UTC)
Expired
Aug 11, 2017, 5:45 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 Santa Ana Mts radar (KSOX), 127 km from the middle of the area, began a volume at 21:48 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, 9.8 hours before the alert went out and 181 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 2017-08-11Temperature 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 2017-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 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
1427 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
-12 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

284 
WGUS55 KVEF 112147
FFWVEF
CAC071-120045-
/O.NEW.KVEF.FF.W.0088.170811T2147Z-170812T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
247 PM PDT FRI AUG 11 2017

The National Weather Service in Las Vegas has issued a

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

* Until 545 PM PDT

* At 244 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain through Homestead Valley. Flash flooding is expected to 
  begin shortly.

* Some locations that will experience flooding include...
  Surprise Valley and Landers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3418 11645 3421 11644 3426 11644 3432 11648
      3436 11641 3441 11640 3443 11614 3415 11613

$$

AA
2 follow-up statements
370 
WGUS75 KVEF 112332
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
432 PM PDT FRI AUG 11 2017

CAC071-120045-
/O.CON.KVEF.FF.W.0088.000000T0000Z-170812T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
432 PM PDT FRI AUG 11 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM PDT FOR
SOUTHERN SAN BERNARDINO COUNTY...

At 431 PM PDT, Doppler radar indicated moderate to heavy rain near 
Landers and Joshua Tree. Flash flooding is likely occurring near 
these areas. 

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3418 11645 3421 11644 3426 11644 3432 11648
      3436 11641 3441 11640 3443 11614 3415 11613

$$
460 
WGUS75 KVEF 120045
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
545 PM PDT FRI AUG 11 2017

CAC071-120055-
/O.EXP.KVEF.FF.W.0088.000000T0000Z-170812T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
545 PM PDT FRI AUG 11 2017

...THE FLASH FLOOD WARNING FOR SOUTHERN SAN BERNARDINO COUNTY HAS
EXPIRED...

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

LAT...LON 3418 11645 3421 11644 3426 11644 3432 11648
      3436 11641 3441 11640 3443 11614 3415 11613

$$

ASG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 1:56 PM PDTFlash Flood WarningVEFSan Bernardino3 hr
Aug 11, 2:42 PM PDTSevere Thunderstorm WarningVEFSan Bernardino48 min
Aug 11, 3:51 PM PDTFlash Flood WarningVEFSan 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.