Alert archive / Nevada / Flash Flood Warnings in 1998

Flash Flood Warning 32, NWS Las Vegas, NV

August 25, 1998Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Aug 25, 1998, 3:48 PM PDT for Clark County, Nevada. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 25, 1998, 3:48 PM PDT (22:48 UTC)
Expired: Aug 25, 1998, 6:00 PM PDT
In force: 2 hr
Issued by: NWS Las Vegas, NV
Area: Whole counties

County Clark County, NV

The nearest sounding before it

Mercury/Desert R, NV (KDRA), launched 12:00Z, 10.8 hours before the alert went out and 99 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 230 J/kg
Mixed-layer CIN: -111 J/kg
Mixed-layer LCL: 2446 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 53 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.

000 
TTAA00 KLAS 252259 COR
FFWLAS
NVC003-260100-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING...CORRECTED FOR WORDING IN FIRST PARAGRAPH
NATIONAL WEATHER SERVICE LAS VEGAS NV
348 PM PDT TUE AUG 25 1998


*  FLASH FLOOD WARNING FOR
   SOUTHERN CLARK COUNTY IN SOUTHERN NEVADA

*  UNTIL 600 PM PDT (600 PM MST)

*  SOME LOCATIONS AFFECTED
   SEARCHLIGHT
   LAUGHLIN
   COTTONWOOD COVE
   CAL-NEV-ARI

*  AT 345 PM PDT...RADAR ESTIMATED RAINFALL RATES OF ONE TO TWO
INCHES DURING THE PAST HOUR IN SEARCHLIGHT. A SPOTTER IN
SEARCHLIGHT REPORTED 1.60 INCHES OF RAIN AS OF 315 PM PDT. AS A
RESULT... THE FLASH FLOOD WARNING FOR SOUTHERN CLARK COUNTY HAS BEEN
EXTENDED UNTIL 600 PM PDT.

ANOTHER STRONG THUNDERSTORM WAS FORMING ALONG THE LAUGHLIN CUTOFF
(HIGHWAY 163) AT HIGHWAY 95. RADAR WAS SHOWING RAINFALL AMOUNTS
OVER HALF AN INCH OF RAIN BETWEEN 315 AND 345 PM PDT AND THE STORM
CONTINUED TO INTENSIFY.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT. IT IS
IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO RIVERS... CREEKS...
AND ARROYOS WHICH CAN BECOME KILLERS IN HEAVY RAINS. DRY CREEK BEDS
AND ARROYOS CAN BECOME RAGING TORRENTS IN A MATTER OF MINUTES IN
VERY HEAVY RAINFALL. CAMPERS SHOULD AVOID .CAMPING ALONG STREAMS
WHEN POTENTIALLY FLOODING RAINFALL THREATENS.

SKRBAC

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Las Vegas, NV wrote its last area forecast discussion before this flash flood warning went out at Aug 25, 3:00 PM PDT, 48 minutes earlier.

Area forecast discussion, Aug 25, 3:00 PM PDT, 48 minutes before

MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
300 PM PDT TUE AUG 25 1998

SYNOPSIS...A MOIST AND UNSTABLE ATMOSPHERE OVER THE REGION WILL
HELP TO PRODUCE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
MAINLY THIS EVENING AND A FEW ON WEDNESDAY ACROSS SOUTHERN
NEVADA...SOUTHEAST CALIFORNIA AND NORTHWEST ARIZONA. AN UPPER LEVEL
TROUGH OVER NORTHERN CALIFORNIA WILL BRING SOUTHWEST WINDS THAT WILL
YIELD A DRIER ATMOSPHERE ACROSS THE MOJAVE DESERT AND SOUTHERN GREAT
BASIN BEGINNING THURSDAY AND LASTING THROUGH THE BEGINNING OF THIS
WEEKEND.

DISCUSSION...THUNDERSTORMS WILL CONTINUE INTO THE EVENING AND SOME
PAST MIDNIGHT ACROSS LOCALES OVER THE FORECAST AREA.  WITH DEEP
MOISTURE LAYER OVER NW AZ AND ALONG THE COLORADO RIVER...FLASH
FLOODING SHOULD BE KEPT IN MIND THIS EVENING...DUE TO STORMS UPSTREAM
IN NE SAN BERNARDINO COUNTY AND SRN CLARK COUNTY HAVING A HISTORY OF
DOING SUCH THIS AFTN.

SOME LINGERING MOISTURE WILL REMAIN OVER SRN NV...NW AZ AND ALONG THE
COLORADO RIVER VALLEY WEDNESDAY...ALLOWING FOR A FEW TSTMS TO DEVELOP
OVER THE SRN THIRD OF THE FA.  GOING WITH A COMPROMISE OF AVN/NGM
SOLUTION AND THE ETA SOLUTION...A MORE DRIER WESTERLY FLOW WILL TRY
TO WORK OVER THE REGION WITH MOST MOISTURE SHUNTED EASTWARD FURTHER
INTO AZ OVR NGT WEDNESDAY AND THURSDAY.  BIG QUESTION FOR SHORT-TERM
AND EVEN MEDIUM RANGE IS HOW MUCH MOISTURE WILL CONTINUE TO BE
ADVECTED OR MAKE THE BEND NORTHWARD INTO THE CO RVR VALLEY REGION
WITH STRONG EASTERLY WAVE NOTED GOING FROM CHIHUAHUA TO SONORA TO THE
BAJA PENINSULA.  REALLY DO NOT THINK S-SWLY WINDS ALOFT ENOUGH TO
PUSH EXISTING MOISTURE OUT THE REGION OR KEEP MORE MOISTURE FROM
BEING ADVECTED IN A NORTHWARD PUSH.

IN EXTENDED...WITH OVER ALL SYNOPTIC PATTERN NOT CHANGING ALL THAT
MUCH...LOW GRADE MONSOON SHOULD CONTINUE OVER EXTREME EASTERN PORTION
OF THE FA IN BATTLE ZONE BETWEEN A MORE MOIST SELY MONSOONAL FLOW AND
rA DRIER SWLY FLOW.
LAS 211-. CORDERO

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 25, 2:02 PM PDT	Flash Flood Warning	VEF	Clark	118 min

Nearby

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

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.