Southeasterly flow pulled monsoon moisture up into the eastern Mojave Desert, fueling scattered thunderstorms as far west as the Colorado River. One storm produced flash flooding.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS VEF wrote it up.
Southeasterly flow pulled monsoon moisture up into the eastern Mojave Desert, fueling scattered thunderstorms as far west as the Colorado River. One storm produced flash flooding.
The local office's own words before the first event, 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 the first event at Aug 22, 4:00 PM PST, 0 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 500 PM PDT Wed Aug 22 2018 .SYNOPSIS...Thunderstorms will continue over northwest Arizona through sunset. Dry conditions will spread across northwest Arizona by Friday. Dry conditions with seasonal temperatures and afternoon breezes are expected through the first half of the weekend. A deepening trough could bring gusty winds to the area on Sunday and Monday. && .UPDATE...Cancelled the Flash Flood Watch for northern Mohave County as this region has stabilized and widespread flash flooding is no longer expected. The updated forecast is out. && .AVIATION...For McCarran...Southeast wind gusts 20-25 kts possible into early evening. By 02Z-03Z this evening gusts should drop off or remain mostly less than 10 kts overnight. Southerly winds expected to increase Thursday afternoon with peak peak wind gusts up to 20 kts. Little in the way of cloud cover expected during the period. For the rest of southern Nevada, northwest Arizona and southeast California...Breezy southerly winds will continue within the Colorado River Valley terminals. Elsewhere, expect diurnal winds to continue. After 03Z this evening, valley gusts should drop off or remain mostly occasional until light diurnal winds kick in by 10-12Z tomorrow morning. No significant cloud cover during the period. && .PREVIOUS DISCUSSION...114 PM PDT... .DISCUSSION... A Flash Flood Watch continues over northern Mohave County through 9 pm. Thunderstorm activity is expected to diminish after sunset with the loss of daytime heating. Low pressure over the northern Great Basin will move into the northern Rockies tonight with shortwave ridging forecast over the area on Thursday. Higher pwats (over an inch) are forecast to be confined to the Colorado River Valley and Mohave County. Instability progs indicate possible thunderstorms over Mohave County again Thursday, ending on Friday as stable conditions overtake the CWA. Temperatures are expected to be seasonal with afternoon breezes. LONG TERM....Saturday through Wednesday. Some slight changes were made to decrease POPs in Mohave County as southwest flow will bring in drier air across much of the region and keep monsoonal moisture confined to central AZ through the weekend. By Sunday, the medium range models bring in a trough across the NW states which will result in increased southwest winds of 20 to 35 MPH across the region. By Monday, the trough will dig further into the Great Basin region resulting in stronger southwest winds of 30 to 40 MPH. This trough will scour out the remaining low grade moisture over northwest AZ and decrease temperatures a tad behind a weak cold front Monday night. By Tuesday, expect breezy southwest winds and slightly below normal to near normal temperatures. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && DISCUSSION...Salmen AVIATION...Pierce LONG TERM...Kryston For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE LAS VEGAS NV
1123 AM PDT WED AUG 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0330 AM FLASH FLOOD COLORADO CITY 36.99N 112.98W
08/22/2018 MOHAVE AZ TRAINED SPOTTER
ALL MAJOR ROADWAYS FLOODED WITHIN COLORADO
CITY. TIME ESTIMATED FROM RADAR.
0540 PM FLASH FLOOD 6 ESE COLORADO CITY 36.96N 112.87W
08/21/2018 MOHAVE AZ DEPT OF HIGHWAYS
ROSY CANYON RD. IS CLOSED FROM CANE BEDS RD.
TO UTAH STATE LINE DUE TO FLASH FLOODING.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
138 PM PDT WED AUG 22 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0620 AM HEAVY RAIN 3 SSE COLORADO CITY 36.96N 112.96W
08/22/2018 M3.70 INCH MOHAVE AZ MESONET
CANE BEDS MOHAVE COUNTY FLOOD CONTROL
DISTRICT ALERT STATION REPORTED 3.70 INCHES
BETWEEN 1130 PM 8/21/18 AND 617 AM 8/22/18.
0115 AM HEAVY RAIN 3 SSE COLORADO CITY 36.96N 112.96W
08/22/2018 M2.09 INCH MOHAVE AZ MESONET
CANE BEDS MOHAVE COUNTY FLOOD CONTROL ALERT
STATION REPORTED 2.09 INCHES BETWEEN 1130 PM
8/21/18 AND 115 AM 8/22/18.
&&The Las Vegas radar (KESX), 16 km away, was scanning. The volume nearest the first event began at 00:00 UTC.
1 flash flood. Local standard time, as filed.
Dirt berms were damaged, and rocks the size of basketballs were washed onto the road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nevada in 2018Every state in 2018This day in weather historyWarnings in Nevada, August 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 779351.