Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 15, NWS Las Vegas, NV

July 29, 1998Mohave County, Arizona; Clark County, Nevada

NWS Las Vegas, NV issued this severe thunderstorm warning at Jul 29, 1998, 4:38 PM MST for Mohave County, Arizona; Clark County, Nevada. It was in force for 57 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 29, 1998, 4:38 PM MST (23:38 UTC)
Expired: Jul 29, 1998, 5:35 PM MST
In force: 57 min
Issued by: NWS Las Vegas, NV
Area: Whole counties

Counties Mohave County, AZ, Clark County, NV

The nearest sounding before it

Mercury/Desert R, NV (KDRA), launched 12:00Z, 11.6 hours before the alert went out and 162 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: 24 J/kg
Mixed-layer CIN: -353 J/kg
Mixed-layer LCL: 3642 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 76 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 292340 RRA
SVRLAS
AZC015-NVC003-300035-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
438 PM PDT (438 PM MST) WED JUL 29 1998

*  SEVERE THUNDERSTORM WARNING FOR
   EAST CENTRAL CLARK COUNTY IN SOUTHERN NEVADA
   WEST CENTRAL MOHAVE COUNTY IN NORTHWESTERN ARIZONA

*  UNTIL 535 PM PDT (535 PM MST)

*  SOME LOCATIONS AFFECTED
   LAS VEGAS BAY
   CALLVILLE BAY
   BOULDER BEACH

*  AT 435 PM...RADAR INDICATED A SEVERE THUNDERSTORM NEAR
   BOULDER BEACH IN THE LAKE MEAD RECREATION AREA. THE
   MOVEMENT WAS TO THE NORTHEAST AT 10 MPH AND IS EXPECTED
   TO AFFECT THE BOULDER BASIN AND CALLVILLE BAY WITHIN THE
   NEXT HOUR.

   DAMAGING WINDS IN EXCESS OF 55 MPH ALONG WITH HAIL UP TO
   THREE-QUARTER INCHES IN DIAMETER AND VERY HEAVY RAIN ARE
   LIKELY WITH THIS STORM.


WHEN THUNDERSTORMS ARE OCCURRING... PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING. DO NOT STAND BY WINDOWS. DO NOT USE TEbLEPHONES OR
ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM HAS
PASSED. MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.

KOSIER

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 29, 2:10 PM MST, 2 hours 28 minutes earlier.

Area forecast discussion, Jul 29, 2:10 PM MST, 2 hours 28 minutes before

MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
210 PM PDT WED JUL 29 1998

SYNOPSIS...A TROUGH OF LOW PRESSURE CURRENTLY LOCATED OFF THE
NORTHERN CALIFORNIA COAST WILL MOVE EAST INTO THE NORTHERN GREAT
BASIN THE NEXT FEW DAYS. THIS WILL BRING A DRIER SOUTHWESTERLY FLOW
TO THE AREA ALONG WITH BREEZY CONDITIONS. TEMPERATURES WILL BE NEAR
NORMAL TO SLIGHTLY BELOW NORMAL.

DISCUSSION...VISIBLE SATELLITE IMAGERY INDICATING CONVECTION BREAKING
OUT OVER EASTERN MOHAVE COUNTY IN ARIZONA AND ALSO IN CENTRAL NEVADA
ALONG NORTHERN NYE COUNTY BORDER. WATER VAPOR IMAGERY CONTINUES TO
SHOW DRYING TAKING PLACE WITH EXCEPTION OF ABOVE MENTIONED AREAS. THE
DEW POINT AT DRA HAD FALLEN INTO THE LOWER 30S BY MID AFTERNOON.
MODELS ALL PRETTY SIMILAR ON EVOLUTION OF TROUGH AS IN MOVES INLAND
NEXT 48 HOURS. THE NGM AND AVN AS WELL AS THE NOGAPS INDICATING A
DEEPER TROUGH THAN THE ETA MODEL. WITH REMAINS OF "DARBY" AMPLIFYING
RIDGE IN THE PACIFIC...TRENDS FAVOR THE DEEPER NGM/AVN SOLUTION.
ALSO...ETA HAS SEEMED TO UNDER-FORECAST THE DEPTH OF THESE TROUGHS
MOST OF THIS YEAR SO AM LEANING MORE TOWARD NGM/AVN. EITHER WAY...FOR
OUR AREA IT PROBABLY DOESN'T MATTER TOO MUCH AS ETA ALSO INDICATING
DRYING FOR ALL OF THE AREA. WITH MOISTURE BOUNDARY STILL CLOSE TO
MOHAVE COUNTY...WILL CONTINUE MENTION OF CONVECTION FOR THAT AREA
INTO THURSDAY THEN DRY FOR ALL AREAS FRIDAY. WINDS COULD GET CLOSE TO
ADVISORY LEVELS THE NEXT FEW DAYS...ESPECIALLY IF NGM/AVN CORRECT.
TEMPERATURES WILL COOL A FEW DEGREES NEXT FEW DAYS AS
HEIGHTS/THICKNESS DECREASE. DURING EXTENDED...TROUGH SHIFTS TO THE
NORTHEAST WITH HIGH STRENGTHENING EARLY NEXT WEEK. WILL GO DRY FOR
NOW BUT WILL LIKELY SEE AN INCREASE IN MOISTURE AGAIN BY TUESDAY AT
THE LATEST. LAS 0000. KOSIER

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 2:05 PM MST	Flash Flood Warning	VEF	Mohave	2 hr
Jul 29, 3:21 PM MST	Severe Thunderstorm Warning	VEF	Clark	64 min

Nearby

Severe Thunderstorm Warnings in Arizona, 1998 Severe Thunderstorm Warnings in Nevada, 1998 Every severe thunderstorm 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.