Flash Flood Warning 25, NWS Las Vegas, NV

Issued

Aug 11, 1998, 4:20 PM PDT (23:20 UTC)

Expired

Aug 11, 1998, 6:20 PM PDT

In force

2 hr

Issued by

NWS Las Vegas, NV

Area

Whole counties

County San Bernardino County, CA

The Edwards AFB radar (KEYX), 129 km from the middle of the area, began a volume at 23:21 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.

000 
TTAA00 KLAS 112321
FFWLAS
CAC071-120120-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
420 PM PDT TUE AUG 11 1998


*  FLASH FLOOD WARNING FOR
   WESTERN SAN BERNARDINO COUNTY IN SOUTHEASTERN CALIFORNIA

*  UNTIL 620 PM PDT

*  SOME LOCATIONS AFFECTED
   BARSTOW
   DAGGETT
   TRONA

*  AT 415 PM PDT...THE CALIFORNIA HIGHWAY PATROL REPORTED FLASH
FLOODING OCCURRING ON HIGHWAY 247 SOUTH OF BARSTOW. THE LINE OF
THUNDERSTORMS PRODUCING THE FLASH FLOODING WAS MOVING NORTHWEST
TOWARD THE BARSTOW/DAGGETT AREA. IN ADDITION...ANOTHER VERY STRONG
THUNDERSTORM WAS LIKELY PRODUCING FLASH FLOODING IN THE FAR
NORTHWEST PORTION OF SAN BERNARDINO COUNTY NEAR TRONA AND HIGHWAY
178. THESE STORMS WERE PRODUCING RAINFALL RATES OF 1.5 TO 2.5
INCHES PER HOUR.

PEOPLE IN WESTERN SAN BERNARDINO COUNTY...ESPECIALLY IN AND AROUND
THE BARSTOW/DAGGETT AREA AND THE FAR NORTHWEST PORTION OF THE
COUNTY NEAR TRONA SHOULD REMAIN ALERT FOR FLASH FLOODING. THESE
STORMS WILL ALSO PRODUCE HAIL...WIND GUSTS TO 50 MPH AND FREQUENT
DEADLY LIGHTNING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY AND THE ROAD BENEATH MAY NOT BE INTACT. VEHICLES
CAUGHT IN RISING WATER SHOULD BE ABANDONED QUICKLY. IT ONLY TAKES
A FOOT OR TWO OF FLOWING WATER TO WASH MOST CARS AWAY. REMEMBER...
MOST DEATHS IN FLASH FLOODING OCCUR IN AUTOMOBILES.

SKRBAC

NWS Las Vegas, NV wrote its last area forecast discussion before this flash flood warning went out at Aug 11, 3:00 PM PDT, 1 hour 20 minutes earlier.

MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
300 PM PDT TUE AUG 11 1998

SYNOPSIS...A HIGH PRESSURE SYSTEM AT UPPER LEVELS OF THE ATMOSPHERE
WILL BUILD OVER NORTHERN NEVADA THROUGH THURSDAY..PRODUCING A MOIST
EASTERLY FLOW ACROSS THE SOUTHERN GREAT BASIN AND MOJAVE DESERT. THIS
MOISTURE WILL HELP TO FUEL ISOLATED TO SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS.

DISCUSSION...SATELLITE LOOP SHOWED THAT ISOLATED CONVECTION FIRED
RAPIDLY LATE THIS MORNING. THIS ACTIVITY CONTINUES EARLY THIS
AFTERNOON WITH THE STRONGEST STORMS NOW ACROSS THE HIGHER ELEVATIONS
OF SAN BERNARDINO AND INYO COUNTIES IN SOUTHEAST CALFORNIA PER KEYX
RADAR. THROUGH THURSDAY...MODELS AGREE ON BUILDING AN UPPER HIGH
ACROSS NORTHERN AND CENTRAL NEVADA. LOW LEVEL MOISTURE PROGGED TO
DECREASE SLIGHTLY THROUGH THE PERIOD...HOWEVER...MID LEVELS WILL
REMAIN MOIST AS AN EAST AND SOUTHEAST FLOW PERSISTS. THE ETA WAS THE
ONLY MODEL THAT SHOWED A PRETTY SIGNIFICANT VORT CROSSING SOUTHERN
ARIZONA ON THURSDAY. THIS WOULD CERTAINLY HELP TO INITIATE CONVECTION
ACROSS SOUTHERN PORTIONS ON THURSDAY. IN GENERAL...HOWEVER...EXPECT
MOST OF THE DYNAMICS TO BE PROVIDED BY OROGRAPHICS. WENT WITH CHANCE
POPS ACROSS THE HIGHER ELEVATIONS AND SLIGHT CHANCE POPS ELSEWHERE
THROUGH THURSDAY. THROUGH THE EXTENDED PERIOD...WILL CONTINUE WITH A
LOW GRADE MONSOON TYPE FORECAST. STILL TOO MUCH UNCERTAINTY EXISTS ON
WHETHER AN UPPER TROUGH ALONG THE WEST COAST WILL BE STRONG ENOUGH TO
DRY THINGS OUT ON SUNDAY.

LAS 1111. MATUSIEWICZ

Flash Flood Warnings in California, 1998Every flash flood warning in 1998

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.