Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 74, NWS Las Vegas, NV

July 31, 2012San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 31, 2012, 2:00 PM PDT for San Bernardino County, California. It was in force for 2 hr. 1 report 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 31, 2012, 2:00 PM PDT (21:00 UTC)
Expired
Jul 31, 2012, 4:00 PM PDT
In force
2 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), 84 km from the middle of the area, began a volume at 21:00 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 31, 2:42 PM PDTFLASH FLOOD9 Nw Needles, CACALIFORNIA HIGHWAY PATROL REPORTS FLOODING ACROSS ROADWAY APPROXIMATELY 5 MILES NORTH OF I-40 ON US 95.

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

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 9.0 hours before the alert went out and 171 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 2012-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 121 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 2012-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
121 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
1334 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-5 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, in the capitals the NWS used until 2016.

826 
WGUS55 KVEF 312100
FFWVEF
CAC071-312300-
/O.NEW.KVEF.FF.W.0074.120731T2100Z-120731T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
200 PM PDT TUE JUL 31 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...

* UNTIL 400 PM PDT.

* AT 155 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR HIGHWAY 95 AND I-40. LOW 
  WATER CROSSINGS ON HIGHWAY 95 JUST NORTH OF INTERSTATE 40 WILL BE 
  AT RISK OF FLOODING...ALONG WITH GOFFS ROAD.

* LOCATIONS IMPACTED INCLUDE...
  HIGHWAY 95 AND GOFFS ROAD.

THIS INCLUDES INTERSTATE 40 BETWEEN MILE MARKERS 124 AND 136.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. NEVER TRY TO CROSS A FLOODED
ROADWAY OR WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3502 11494 3502 11472 3484 11471 3484 11493

$$

MORGAN
2 follow-up statements
497 
WGUS75 KVEF 312150
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
250 PM PDT TUE JUL 31 2012

CAC071-312300-
/O.CON.KVEF.FF.W.0074.000000T0000Z-120731T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
250 PM PDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR EAST
CENTRAL SAN BERNARDINO COUNTY...

AT 242 PM PDT...THE CALIFORNIA HIGHWAY PATROL REPORTED FLOODING ON 
HIGHWAY 95 FIVE MILES NORTH OF INTERSTATE 40. RADAR SHOWED ONLY 
LIGHT RAIN REMAINING IN THE AREA AT 248 PM PDT...BUT RUNOFF FROM 
EARLIER HEAVY RAIN WILL CONTINUE TO CAUSE FLOODING.

LOCATIONS IMPACTED INCLUDE...
HIGHWAY 95 NORTH OF INTERSTATE 40.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. NEVER TRY TO CROSS A FLOODED
ROADWAY OR WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3502 11494 3502 11472 3484 11471 3484 11493

$$

MORGAN
520 
WGUS75 KVEF 312251
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
351 PM PDT TUE JUL 31 2012

CAC071-312300-
/O.EXP.KVEF.FF.W.0074.000000T0000Z-120731T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
351 PM PDT TUE JUL 31 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 400 PM PDT FOR EAST CENTRAL
SAN BERNARDINO COUNTY...

AT 350 PM PDT...RADAR INDICATED THAT RAIN HAD ENDED NEAR THE 
INTERSECTION OF HIGHWAY 95 AND INTERSTATE 40. THEREFORE...THE FLASH 
FLOOD WARNING WILL BE ALLOWED TO EXPIRE.

LAT...LON 3502 11494 3502 11472 3484 11471 3484 11493

$$

MORGAN

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 5:54 PM PDTSevere Thunderstorm WarningVEFSan Bernardino51 min
Jul 31, 2:29 AM PDTFlash Flood WatchVEFSan Bernardino19 hr
Jul 31, 10:00 AM PDTFlash Flood WarningVEFSan Bernardino2 hr
Jul 31, 10:08 AM PDTFlash Flood WarningVEFSan Bernardino112 min
Jul 31, 10:38 AM PDTFlash Flood WarningVEFSan Bernardino94 min
Jul 31, 11:58 AM PDTFlash Flood WarningVEFSan Bernardino2 hr
Jul 31, 12:03 PM PDTFlash Flood WarningVEFSan Bernardino3 hr
Jul 31, 1:30 PM PDTFlash Flood WarningVEFSan Bernardino49 min
Jul 31, 3:05 PM PDTFlash Flood WarningVEFSan Bernardino42 min
Jul 31, 3:25 PM PDTFlash Flood WarningVEFSan Bernardino65 min

Nearby

Flash Flood Warnings in California, 2012Every flash flood warning in 2012

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.