Alert archive / Nevada / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 40, NWS Las Vegas, NV
NWS Las Vegas, NV issued this severe thunderstorm warning at Sep 9, 1998, 3:13 PM PDT for Clark County, Nevada. It was in force for 52 min. 2 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Sep 9, 1998, 3:13 PM PDT (22:13 UTC)
- Expired
- Sep 9, 1998, 4:05 PM PDT
- In force
- 52 min
- Issued by
- NWS Las Vegas, NV
- Area
- Whole counties
County Clark County, NV
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 9, 3:40 PM PDT | Thunderstorm Wind 50 | Boulder City, NV | |
| Sep 9, 3:50 PM PDT | Thunderstorm Wind | Las Vegas, NV |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Mercury/Desert R, NV (KDRA), launched 12:00Z, 10.2 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.
- Mixed-layer CAPE
- 266 J/kg
- Mixed-layer CIN
- -132 J/kg
- Mixed-layer LCL
- 1582 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 139 m²/s²
- 0-3 km storm-relative helicity
- 189 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 Sep 9, 9:50 AM PDT, 5 hours 23 minutes earlier.
Area forecast discussion, Sep 9, 9:50 AM PDT, 5 hours 23 minutes before
MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 950 AM PDT WED SEP 9 1998 ...CORRECTION FOR FLASH FLOOD WATCH PORTION... SYNOPSIS...A STRONG TROUGH OF LOW PRESSURE APPROACHING THE WEST COAST WILL MOVE INTO CALIFORNIA TODAY THEN REMAIN OVER CALIFORNIA AND WESTERN NEVADA THURSDAY AND FRIDAY. THIS SYSTEM WILL KEEP A MOIST SOUTHERLY FLOW OF AIR ACROSS THE REGION FOR A CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS. DISCUSSION...APOLOGIES FOR THE DELAY IN PRODUCTS THIS MORNING... WANTED TO COORDINATE THINKING WITH SPC (THANKS MIKE V.) AND AREA WSFOS AND WFOS. STRONG UPPER TROF CONTINUES TO APPROACH CA COAST THIS MORNING WITH MAIN VORT CENTER NEAR SFO BAY AREA. BAROCLINIC BAND PUSHING INTO NW NV AND NEARING NRN INYO COUNTY. 12Z DRA SOUNDING INDICATES LITTLE 24 HOUR CHANGE IN MOISTURE/TEMPERATURE PROFILES WITH MODIFIED SOUNDING RESULTING IN -4 TO -7 LIFTED INDEX AND CAPES RANGING FROM 1500 TO 2500 J/KG. BIG CHANGE IS THE INCREASE IN SPEED SHEAR WITH SOME VEERING NOTED IN LOWER LAYERS (BETTER STORM ENVIRONMENT). PREVIOUS STORMS AND RAIN COOLED AIR HAVE STABILIZED LOWER LAYERS A BIT BUT WITH NEARLY FULL SUN ACROSS REGION...ANY CIN WILL BE ERASED WITH THUNDERSTORMS DEVELOPING A FEW HOURS LATER THAN TUE. LOOKING AT MODELS AND UPPER AIR DATA...APPROACHING VORTICITY MAXIMUM AND 75 TO 90 KT JET MAX WILL FOCUS BEST DYNAMIC FORCING ACROSS NRN INYO...ESMERALDA AND NRN/CNTRL NYE COUNTIES THIS AFTERNOON FROM PVA AND JET DIVERGENCE. SHEAR/DIVERGENCE AND FORCING ALSO INCREASING FARTHER S AND E TOWARD LINCOLN/CLARK AND MOHAVE COUNTIES LATE THIS AFTERNOON AND EVENING WITH SIGNIFICANT CONVERGENCE/DIVERGENCE COUPLING FORECAST BY NGM FOR CLARK AND MOHAVE COUNTIES THIS EVENING. PER COORDINATION WITH SPC...STORM ENVIRONMENT A LITTLE BETTER TODAY FOR ISOLATED SEVERE ACROSS NV ZONES AND EVEN NW AZ. WILL BEEF UP PRECIPITATION CHANCES AND ISSUE FLASH FLOOD WATCH FOR NEVADA AND ARIZONA ZONES THIS AFT/EVE WHERE BEST MOISTURE/DYNAMICS AND INSTABILITY ARE EXPECTED. INYO/SAN BERNARDINO COUNTIES MORE OF A QUESTION BUT WILL NUDGE FORECAST IN DIRECTION OF HIGHER PRECIPITATION CHANCES AND SEVERE. ALSO MODIFIED TONIGHT PORTION DUE TO DYNAMIC FORCING MOVING S AND E ACROSS CA/NV/AZ AND TO BLEND BETTER WITH ABOVE MENTIONED ADJUSTMENTS. TROUGH CONTINUES TO SLOW ON MODELS AND SEE NO REASON THAT THU WILL NOT BE ANOTHER ACTIVE DAY FOR AREAS FARTHER S AND E. LAS 664. NEMETH A FLASH FLOOD WATCH HAS BEEN ISSUED. PLEASE REFER TO THE LATEST FLASH FLOOD WATCH BULLETIN FOR DETAILS.
In the hours before
Special weather statement, Sep 9, 10:10 AM PDT, 5 hours 3 minutes before
AZZ001>003-036-NVZ013>022-100500- BULLETIN...IMMEDIATE BROADCAST REQUESTED FLASH FLOOD WATCH...RESENT FOR CARSON NHP... NATIONAL WEATHER SERVICE LAS VEGAS NV 1008 AM PDT (1002 AM MST) WED SEP 9 1998 ...FLASH FLOOD WATCH FROM NOON UNTIL 10 PM PDT/MST FOR CLARK... ESMERALDA...NYE AND LINCOLN COUNTIES IN NEVADA...AND MOHAVE COUNTY ARIZONA... SOME LOCATIONS IN THE FLASH FLOOD WATCH INCLUDE....LAS VEGAS... HENDERSON...PAHRUMP...GOLDFIELD...TONOPAH...CALIENTE...KINGMAN... LAUGHLIN-BULLHEAD CITY...LAKE HAVASU CITY...THE WESTERN END OF THE GRAND CANYON...AND THE LAKE MEAD NATIONAL RECREATION AREA. SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND ARE EXPECTED TO BECOME WIDESPREAD IN MANY AREAS BY EVENING. SOME OF THE THUNDERSTORMS COULD PRODUCE HEAVY RAIN OF BETWEEN ONE AND TWO INCHES IN LESS THAN ONE HOUR. RAINFALL OF THIS INTENSITY WOULD CAUSE FLASH FLOODING OF WASHES...CANYONS...AND OTHER LOW-LYING OR URBANIZED AREAS. AREAS THAT HAVE RECEIVED RAIN OVER THE PAST FEW DAYS WILL BE ESPECIALLY PRONE TO FLASH FLOODING AS THE SOIL MAY BE SATURATED. A FLASH FLOOD WATCH MEANS THERE IS THE POTENTIAL FOR FLASH FLOODING IN AND CLOSE TO THE WATCH AREA. BE READY TO TAKE QUICK ACTION IF FLASH FLOODING IS OBSERVED OR A WARNING IS ISSUED FOR YOUR AREA. DO NOT BECOME A VICTIM BY ATTEMPTING TO DRIVE OR WADE THROUGH RUNNING WATER YOU COULD BECOME STRANDED OR THE FORCE OF THE CURRENT COULD SWEEP YOU OR YOUR VEHICLE AWAY. LISTEN FOR ADDITIONAL UPDATES OR POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. NEMETH
The office that day
Everything else NWS Las Vegas, NV issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 9, 1:49 PM PDT | Severe Thunderstorm Warning | VEF | Clark | 61 min |
| Sep 9, 2:34 PM PDT | Severe Thunderstorm Warning | VEF | Clark | 61 min |
| Sep 9, 2:53 PM PDT | Flash Flood Warning | VEF | Clark | 112 min |
| Sep 9, 3:59 PM PDT | Severe Thunderstorm Warning | VEF | Clark | 6 min |
| Sep 9, 4:14 PM PDT | Flash Flood Warning | VEF | Clark | 56 min |
| Sep 9, 4:14 PM PDT | Severe Thunderstorm Warning | VEF | Clark | 56 min |
Nearby
Severe Thunderstorm Warnings in Nevada, 1998Every 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.