Alert archive / California / Flash Flood Warnings in 2018

Flash Flood Warning 21, NWS Las Vegas, NV

July 12, 2018San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 12, 2018, 11:15 AM PDT for San Bernardino County, California. It was in force for 53 min. 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 12, 2018, 11:15 AM PDT (18:15 UTC)
Expired
Jul 12, 2018, 12:08 PM PDT
In force
53 min
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), 146 km from the middle of the area, began a volume at 18:16 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, 6.3 hours before the alert went out and 178 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 2018-07-12Temperature 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 2018-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
1276 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

768 
WGUS55 KVEF 121815
FFWVEF
CAC071-122115-
/O.NEW.KVEF.FF.W.0021.180712T1815Z-180712T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
1115 AM PDT THU JUL 12 2018

The National Weather Service in Las Vegas has issued a

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

* Until 215 PM PDT.

* At 1114 AM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across Highway 62 between Joshua Tree and 29 Palms. 
  Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Twentynine Palms, Twentynine Palms Base, 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 3407 11600 3408 11604 3410 11604 3411 11605
      3412 11605 3412 11626 3408 11626 3408 11631
      3426 11631 3426 11596 3403 11596 3404 11600

$$

Morgan
1 follow-up statement
960 
WGUS75 KVEF 121908
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1208 PM PDT THU JUL 12 2018

CAC071-121918-
/O.CAN.KVEF.FF.W.0021.000000T0000Z-180712T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
1208 PM PDT THU JUL 12 2018

...THE FLASH FLOOD WARNING FOR SOUTHERN SAN BERNARDINO COUNTY IS
CANCELLED...

The thunderstorm over Highway 62 dissipated quickly, and flooding is 
no longer expected to pose a threat. Please continue to heed any 
remaining road closures.

LAT...LON 3407 11600 3408 11604 3410 11604 3411 11605
      3412 11605 3412 11626 3408 11626 3408 11631
      3426 11631 3426 11596 3403 11596 3404 11600

$$

Morgan

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 7:21 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr
Jul 12, 2:51 AM PDTFlash Flood WatchVEFInyo21 hr
Jul 12, 11:26 AM PDTFlash Flood WarningVEFSan Bernardino65 min
Jul 12, 12:48 PM PDTFlash Flood WarningVEFSan Bernardino3 hr
Jul 12, 1:50 PM PDTFlash Flood WarningVEFSan Bernardino110 min
Jul 12, 2:04 PM PDTFlash Flood WarningVEFInyo3 hr
Jul 12, 3:02 PM PDTFlash Flood WarningVEFSan Bernardino2 hr
Jul 12, 3:03 PM PDTFlash Flood WarningVEFSan Bernardino104 min
Jul 12, 4:20 PM PDTFlash Flood WarningVEFSan Bernardino88 min
Jul 12, 4:51 PM PDTFlash Flood WarningVEFInyo3 hr
Jul 12, 4:56 PM PDTFlash Flood WarningVEFSan Bernardino2 hr

Nearby

Flash Flood Warnings in California, 2018Every flash flood warning in 2018

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.