Alert archive / Arizona / Flash Flood Warnings in 1998
Flash Flood Warning 42, NWS Las Vegas, NV
NWS Las Vegas, NV issued this flash flood warning at Sep 9, 1998, 4:14 PM MST for Mohave County, Arizona; Clark County, Nevada. It was in force for 56 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
- Sep 9, 1998, 4:14 PM MST (23:14 UTC)
- Expired
- Sep 9, 1998, 5:10 PM MST
- In force
- 56 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, 11.2 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.
- 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 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 Sep 9, 3:35 PM MST, 39 minutes earlier.
Area forecast discussion, Sep 9, 3:35 PM MST, 39 minutes before
MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 335 PM PDT WED SEP 9 1998 SYNOPSIS...A STRONG TROUGH OF LOW PRESSURE APPROACHING THE WEST COAST IS FORECAST TO SLOW AND THEN STALL OVER CENTRAL CALIFORNIA THURSDAY AND FRIDAY. THIS SYSTEM WILL KEEP AN UNSEASONABLY MOIST AND UNSTABLE AIR MASS ACROSS THE REGION FOR A CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS THROUGH THE END OF THE WEEK. DISCUSSION...ACTIVE WEATHER DAY WITH APPROACHING TROUGH ON SCHEDULE AND WATCHES/WARNINGS BEING ISSUED. SURFACE PRESSURE FALLS OVER SOUTH CENTRAL NV WITH DEW POINT AXIS SURGING NWD ALONG CO RVR...ACROSS CLARK AND INTO LINCOLN COUNTIES. THUNDERSTORMS ORGANIZING IN N-S LINES (NEARLY UNIDIRECTIONAL SHEAR WITH VEERING IN LOWER LEVELS) FROM CO RIVER VALLEY AND WRN AZ NORTH INTO CLARK AND LINCOLN COUNTIES IN NV. STORMS STARTING TO REALLY GET GOING AS DIVERGENCE AND UVV APPROACH. AFTER INITIAL WIND GUSTS...CONCERN FOR FLASH FLOODING INCREASING AS STORMS LIKELY TO START TRAINING IN UNIDIRECTIONAL SHEAR ENVIRONMENT. COORDINATED WITH SPC (THANKS RICH AND MIKE) ON SLIGHT RISK AREA WHICH LOOKS GOOD. SEVERE THREAT TO CONTINUE INTO EARLY EVENING WITH INCREASING DIVERGENCE EXPECTED DUE TO ENTRANCE REGION OF JET OVER NV. ALSO WATCHING DARKENING AREA ON WV SATELLITE SWINGING THROUGH BASE OF TROUGH AND APPROACHING SRN CA/SRN NV. SATELLITE AND MODEL OVERLAYS INDICATE THAT NGM DOING BEST AT 18Z AND PREFER NGM/AVN COMBINATION. USING RUC AND LOCAL RAMS MODELS FOR DETAILS TONIGHT. FORECAST PRETTY STRAIGHT FORWARD AS TROUGH IS CUT OFF FROM WESTERLIES THU AND REMAINS OVER CENTRAL CA THROUGH FRI. THIS SIMILAR TO PAST WEEKEND EXCEPT DEEP MOISTURE PULLED UP AHEAD OF TROUGH IS ACTED ON BY DECENT DYNAMICS THU. MOISTURE REMAINS OVER CO RIVER VALLEY AND SRN/ERN NV AND AZ FRI AND EXPECT DYNAMICS TO WEAKEN FOR MORE SCATTERED/DIURNAL NATURE TO STORMS. EXTENDED CONTINUES PESSIMISTIC AND NOT WILLING TO BUY INTO MRF IDEA OF DRYING THINGS OUT BY MON. MOISTURE CONTINUES TO LINGER AT LEAST INTO SUN AS CUT OFF WEAKENS AND SHEARS OUT. THIS PATTERN VERY UNUSUAL AND HAS BEEN PERSISTENT SO WILL WAIT UNTIL I SEE THE WHITES OF THEIR EYES BEFORE DRYING FORECAST OUT PREMATURELY. LAS 6443. NEMETH A FLASH FLOOD WATCH HAS BEEN ISSUED. PLEASE REFER TO THE LATEST FLASH FLOOD WATCH BULLETIN FOR DETAILS. A WIND ADVISORY HAS BEEN ISSUED. PLEASE REFER TO THE LATEST WIND ADVISORY BULLETIN FOR DETAILS.
The office that day
Everything else NWS Las Vegas, NV issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 9, 2:34 PM MST | Severe Thunderstorm Warning | VEF | Mohave | 61 min |
| Sep 9, 4:14 PM MST | Severe Thunderstorm Warning | VEF | Mohave | 56 min |
| Sep 9, 1:49 PM MST | Severe Thunderstorm Warning | VEF | Clark | 61 min |
| Sep 9, 2:53 PM MST | Flash Flood Warning | VEF | Clark | 112 min |
| Sep 9, 3:13 PM MST | Severe Thunderstorm Warning | VEF | Clark | 52 min |
| Sep 9, 3:59 PM MST | Severe Thunderstorm Warning | VEF | Clark | 6 min |
Nearby
Flash Flood Warnings in Arizona, 1998Flash Flood Warnings in Nevada, 1998Every 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.