Alert archive / Arizona / Flash Flood Warnings in 1999
Flash Flood Warning 42, NWS Las Vegas, NV
NWS Las Vegas, NV issued this flash flood warning at Jul 15, 1999, 5:50 PM MST for Mohave County, Arizona. It was in force for 115 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 15, 1999, 5:50 PM MST (00:50 UTC)
- Expired
- Jul 15, 1999, 7:45 PM MST
- In force
- 115 min
- Issued by
- NWS Las Vegas, NV
- Area
- Whole counties
County Mohave County, AZ
The nearest sounding before it
Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 0.8 hours before the alert went out and 185 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
- 479 J/kg
- Mixed-layer CIN
- -15 J/kg
- Mixed-layer LCL
- 908 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- -10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KLAS 160050 FFWLAS AZC015-160245- BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE LAS VEGAS NV 550 PM PDT (550 PM MST) THU JUL 15 1999 * FLASH FLOOD WARNING FOR FAR NORTHERN MOHAVE COUNTY IN NORTHWESTERN ARIZONA * UNTIL 745 PM MST (745 PM PDT) * SOME LOCATIONS AFFECTED I-15 BETWEEN EXIT 18 AND THE ARIZONA/UTAH BORDER MOUNT TRUMBULL LOOP * AT 550 PM MST RADAR SHOWED A CLUSTER OF NEARLY STATIONARY STORMS OVER THE PAIUTE WILDERNESS AREA. THESE STORMS WERE DEVELOPING TOWARD THE WEST. RADAR ESTIMATED RAINFALL RATES OF UP TO 4 INCHES PER HOUR FROM THESE STORMS. AS A RESULT...FLASH FLOODING OF THE MOKAAC WASH AND BLACK ROCK CANYON IS OCCURRING OR IMMINENT. IT IS IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO WASHES...NARROW STEEP-WALLED CANYONS...AND NORMALLY DRY CREEKS WHICH CAN BECOME KILLERS IN HEAVY RAINS. DRY CREEK BEDS...WASHES...AND NARROW STEEP- WALLED CANYONS CAN BECOME RAGING RIVERS IN A MATTER OF MINUTES IN VERY HEAVY RAINFALL. CAMPERS AND HIKERS SHOULD AVOID CAMPING ALONG STREAMS WHEN POTENTIALLY FLOODING RAINFALL THREATENS.
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 Jul 15, 1:50 PM MST, 4 hours earlier.
Area forecast discussion, Jul 15, 1:50 PM MST, 4 hours before
MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 150 PM PDT THU JUL 15 1999 SYNOPSIS...LINGERING MOISTURE AND A WEAK UPPER LEVEL DISTURBANCE OVER SOUTHERN NEVADA WILL PROVIDE FUEL FOR SOME THUNDERSTORMS THROUGH THE EVENING...MAINLY SOUTH CENTRAL NEVADA...NEAR THE SIERRA...AND IN NORTHERN MOHAVE COUNTY ARIZONA. OTHERWISE INCREASING SOUTHWEST FLOW WILL CAUSE HUMIDITY LEVELS TO SLOWLY DROP EACH OF THE NEXT FEW DAYS. DISCUSSION...WEAK HIGH LEVEL SHEAR VORTICITY SPREADING ACROSS MID TO LOW LEVEL CONVERGENCE ZONE FROM EASTERN SIERRA ACROSS SOUTH CENTRAL NEVADA AND NORTHERN MOHAVE COUNTY THIS AFTERNOON HELPING FIRE LOW-END SCATTERED THUNDERSTORMS. INSTENSITY OF ACTIVITY FAIRLY STRONG WITH STILL GOOD MOISTURE LEVELS...GOOD CAPE...AND SOME ADDED DIRECTIONAL SHEAR. WILL HAVE TO MONITOR THIS AREA REMAINDER OF AFTERNOON AND EVENING. CELL MOVEMENT IS ACTUALLY LESS THAN YESTERDAY. WILL COVER THIS WITH SCATTERED THUNDERSTORMS MAINLY THIS EVENING AND MENTION WIND GUST POTENTIAL TO 40 MPH AND LOCALLY HEAVY RAIN. IN SPITE OF SHARP MID LEVEL DRYING NOTED ON WATER VAPOR SATELLITE...THE LOWER ATMOSPHERE REMAINS ADEQUATELY MOIST FOR AT LEAST ISOLATED THUNDERSTORMS THROUGH EARLY EVENING MOST AREAS TO THE SOUTH. RATE OF DRYING AN ISSUE TODAY. ETA STILL MAINTAINS HIGHEST LOW LEVEL MOISTURE ACROSS CENTRAL AND EASTERN ZONES THROUGH SATURDAY MORNING... WHILE AVN AND NGM SIMILARLY AGRESSIVE IN DRYING. BELIEVE IT WILL TAKE AT LEAST ANOTHER DAY OF SOUTHWEST FLOW ALOFT TO SEE SIGNIFICANT SURFACE DRYING...DESERTS STILL APPEAR UNIFORMLY MOIST...SO ISOLATED THUNDERSTORMS ACROSS MAINLY HIGHER TERRAIN FOR FRIDAY LOOKS VALID AGAIN. PREFER IN-BETWEEN THE TWO CHOICES ON RATE OF DRYING. WILL BANK ON SOUTHWEST FLOW FINALLY BEING STRONG ENOUGH SATURDAY AS NEXT STRONG SHORT WAVE CARVES OUT DEEP LOW ACROSS NORTHERN OREGON TO DROP DEWPOINTS BACK INTO THE 30S/40S WEST OF THE COLORADO AND 40S/50S TO THE EAST. ONE REAL NICE THING WITH THIS: ALTHOUGH TEMPERATURES WILL WARM A DEGREE OR TWO EACH DAY WITH THE DRYING...SLIGHT HEIGHT FALLS WILL KEEP HEIGHTS AND THICKNESSES BELOW NORMAL. SO WE WILL BENEFIT BOTH FROM RETURN TO DRIER AND A LITTLE BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. PLAYING DRY EXTENDED THROUGH MONDAY BEFORE THE MRF BRINGS A SLUG OF MID LEVEL MOISTURE AROUND PERIPHERY OF REBUILDING FOUR-CORNERS RIDGE TUESDAY AND INTO MAINLY SOUTHERN AND EASTERN FORECAST ZONES. THIS APPEARS RELATED TO EVENTUAL DECAYING TROPICAL SYSTEM NOW IN EASTERN PACIFIC AND WILL MAKE THE FAR EXTENDED A BIT OF A GUESS FOR A WHILE. MCQUEEN .LAS...NONE.
The office that day
Everything else NWS Las Vegas, NV issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 15, 7:45 PM MST | Flash Flood Warning | VEF | Mohave | 70 min |
Nearby
Flash Flood Warnings in Arizona, 1999Every flash flood warning in 1999
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.