A weak push of monsoon moisture triggered isolated thunderstorms over the Mojave Desert. A few storms produced severe weather and 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.
A weak push of monsoon moisture triggered isolated thunderstorms over the Mojave Desert. A few storms produced severe weather and 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 10, 3:35 PM MST, 3 hours 25 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 335 PM PDT Thu Aug 10 2017 .SYNOPSIS... Overnight storms will be possible across northwest Arizona going into early Friday morning. Increasing chances for showers and storms are expected from the I-15 corridor eastward Friday through the weekend as moisture continues to surge northward. Temperatures will come back down closer to normal tomorrow through next week with dry pattern settling in on Monday for much of the upcoming work week. && .UPDATE...Had a few impressive thunderstorms develop right along the moisture boundary that setup across far eastern San Bernardino and Mohave County late this afternoon/evening. Radar starting to show a decreasing trend in the storms aligned north-northeast of Kingman. Kept a slight chance of thunderstorms overnight for Mohave County. 1-1.5" PW values that surged northward into the southeast area today is progged to continue spreading north overnight/Friday into Clark County and be aligned basically along and southeast of I-15. Decided to expand POPS for Friday to include at least a slight chance for Las Vegas with a better shot for the surrounding mountains. && ,PREV DISCUSSION...335 PM PDT Thu Aug 10 2017 .SHORT TERM...Today through Saturday. Storms this afternoon are expected to continue developing across eastern and southern Mohave County with locally heavy downpours, gusty winds, and small hail possible. This activity should decrease in intensity and coverage after sunset with a second potential ramp up in storms late tonight into early tomorrow morning across the same area. A rapid gulf surge of moisture pushing northward today with PWATS approaching 1.50-2.00 in. in some areas accompanied by a vort max transitioning towards the area ahead of a trough over northwest Mexico could provide enough support to fuel overnight showers and storms primarily across the southern half of Mohave County and southeast San Bernardino County. Confidence is moderate at this point as timing is still unclear with the possibility of this feature slowing down and activity being pushed towards mid Friday morning. The time of day is also not ideal, however moisture and instability will be present so have increased storms chances after midnight tonight through tomorrow morning. Activity on Friday afternoon is going to be highly dependent on the overnight sequence of events however is does look like the moisture gradient will be pushed further northward on Friday than previously forecast towards the I-15 corridor and eastward. Therefore, have mention of afternoon isolated showers and storms for portions of Clark, Lincoln, eastern San Bernardino counties with higher chances across northwest Arizona and the higher elevations of Clark County. Similar coverage of storms is expected for Saturday with continued chances for isolated strong storms producing locally heavy downpours. Temperatures are expected to come back down closer to normal Friday and Saturday with increasing moisture and cloud cover. .LONG TERM...Sunday through Wednesday night. Sunday remains the best day for isolated showers and thunderstorms over the long term period, with sufficient moisture and instability remaining across the eastern zones. There will still be a slight chance for thunderstorm activity on Monday, although this should be limited to Mohave County. Monday evening and through the rest of the week moisture will be limited as it is scoured by a dry southwesterly flow associated with a trough progressing into British Columbia. Model solutions agree on two impulses moving through the flow and pushing across the southern Great Basin and Mojave Desert, the first will push through Sunday/Monday with a following disturbance swinging through Tuesday/Wednesday. These successive disturbances will continue a dry southwest flow over the region, limiting most thunderstorms and showers. A breezy southwest wind should develop during the afternoons/evenings Monday through Wednesday as the upper disturbances track across the area. Temperatures will be tamed back to around or just below August normals through period. && .FIRE WEATHER... Overnight showers and storms will be possible across northwest Arizona tonight into early tomorrow morning. Activity Friday through Sunday will spread north and west towards the I-15 corridor as monsoon moisture surges northward. Best chances will be across northwest Arizona and the higher elevations of Clark and Lincoln counties with isolated showers and storms possible across the lower elevations. An unseasonable trough will approach the west coast early next week which will help dry out the region beginning Monday under continued southwest flow. && .AVIATION...For McCarran...Rest of today should remain dry with gusty, southwesterly winds decreasing around sunset. Gusts this afternoon are expected to remain around 20 knots. Southwest winds continue through late tonight before becoming light and variable going into early Friday morning. Similar wind pattern is expected for tomorrow with morning easterlies shifting south/southwest around 20z. Speeds tomorrow afternoon look to be slightly lower than today, around 10 knots or less. There will be the possibility of storms across the higher elevations around the valley Friday afternoon and evening which could produce gusty, erratic winds associated with outflow boundaries at the terminal. For the rest of southern Nevada, northwest Arizona and southeast California...South to southwest winds will remain around 10-15 knots gusting near 20 knots through sunset when winds should begin to die down. Afternoon showers and storms across northwest Arizona should weaken after sunset with a second potential ramp up of activity across southern Mohave County late tonight into early tomorrow morning. Diurnal winds overnight will become south to southwesterly Friday afternoon with showers and storms possible along the I-15 corridor eastward. Best chances will be across Mohave County and the higher elevations of Clark and Lincoln counties. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && Update...Pierce SHORT TERM/AVIATION/FIRE WEATHER...Guillet LONG TERM....Boothe For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
529 PM PDT THU AUG 10 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0516 PM FLASH FLOOD 11 W RICE 34.10N 115.05W
08/10/2017 SAN BERNARDINO CA LAW ENFORCEMENT
CALIFORNIA HIGHWAY PATROL REPORTED WATER
FLOWING OVER HIGHWAY 62, WITH ROAD BEGINNING
TO WASH AWAY NEAR MILE MARKER 93.
&&
CFSThe Las Vegas radar (KESX), 133 km away, was scanning. The volume nearest the first event began at 02:01 UTC.
2 flash flood. Local standard time, as filed.
Water flowed throughout a ranch property, including through the garage.
High flow in the Detrital Wash flooded Highway 93 and White Hills Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2017Every state in 2017This day in weather historyWarnings in Arizona, August 2017
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: 715651, 715652.