Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 52, NWS Las Vegas, NV

July 29, 2017San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 29, 2017, 2:53 PM PDT for San Bernardino County, California. It was in force for 3 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 29, 2017, 2:53 PM PDT (21:53 UTC)
Expired
Jul 29, 2017, 6:00 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 Santa Ana Mts radar (KSOX), 141 km from the middle of the area, began a volume at 21:56 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.

What was reported inside it

TimeReportWhereRemark
Jul 29, 4:09 PM PDTFLASH FLOOD5 E Joshua Tree, CAHIGHWAY 62 CLOSED AT CASCADE RD DUE TO FLOODING AND MUD.
Jul 29, 4:10 PM PDTFLASH FLOODTwentynine Palms, CAFIRE DEPT REPORTS SOME MINOR FLOODING ISSUES, MAINLY WITH DEBRIS OVER THE ROADS. NO ROADS CLOSED AT THIS TIME. TIME ESTIMATED BASED ON RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.9 hours before the alert went out and 177 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 2017-07-29Temperature 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 2017-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
1189 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
-11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

551 
WGUS55 KVEF 292153
FFWVEF
CAC071-300100-
/O.NEW.KVEF.FF.W.0052.170729T2153Z-170730T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
253 PM PDT SAT JUL 29 2017

The National Weather Service in Las Vegas has issued a

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

* Until 600 PM PDT

* At 252 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to one-half inch of rain 
  has fallen. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Twentynine Palms, 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 3428 11634 3419 11601 3408 11601 3408 11604
      3410 11604 3411 11605 3412 11605 3412 11626
      3408 11627 3407 11632

$$

KG
2 follow-up statements
127 
WGUS75 KVEF 292316
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
416 PM PDT SAT JUL 29 2017

CAC071-300100-
/O.CON.KVEF.FF.W.0052.000000T0000Z-170730T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
416 PM PDT SAT JUL 29 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 600 PM PDT FOR
SOUTHERN SAN BERNARDINO COUNTY...

At 414 PM PDT, local law enforcement reported flash flooding in 
between Joshua Tree and Twentynine Palms. One to two inches of rain 
has already fallen. Flash flooding is already occurring.

Some locations that will experience flooding include...
Twentynine Palms, 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 3428 11634 3419 11601 3408 11601 3408 11604
      3410 11604 3411 11605 3412 11605 3412 11626
      3408 11627 3407 11632

$$

KG
295 
WGUS75 KVEF 300051
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
551 PM PDT SAT JUL 29 2017

CAC071-300100-
/O.EXP.KVEF.FF.W.0052.000000T0000Z-170730T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
551 PM PDT SAT JUL 29 2017

...THE FLASH FLOOD WARNING FOR SOUTHERN SAN BERNARDINO COUNTY WILL
EXPIRE AT 600 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 3428 11634 3419 11601 3408 11601 3408 11604
      3410 11604 3411 11605 3412 11605 3412 11626
      3408 11627 3407 11632

$$

KG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.