A big push of monsoon moisture fueled an outbreak of thunderstorms over the Desert Southwest. Many storms in the Mojave Desert produced flash flooding and severe weather.
Every event with a place to put it. Tap one for its entry below.
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 big push of monsoon moisture fueled an outbreak of thunderstorms over the Desert Southwest. Many storms in the Mojave Desert produced flash flooding and severe weather.
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 Jul 24, 12:00 PM PST, 38 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 100 PM PDT Mon Jul 24 2017 .SYNOPSIS...A significant push of monsoon moisture will spread northward today bring the threat of heavy rain and thunderstorms to much of the area over the next couple of days. The greatest threat will occur today and Tuesday afternoon before a drying trend begins mid to late week. && .SHORT TERM...Today through Wednesday Heavy thunderstorms have developed this afternoon concentrated along the Spring Mountains west of Las Vegas. Some of these storms have produced rainfall rates over 2 inches per hour, and additional thunderstorm development is likely though the afternoon. Meanwhile...vorticity maxima moving northwest from central Arizona will arrive in our forecast area this evening to be located near Lake Mead around 5 pm. This will serve as an additional mechanism of upward motion and a focus for additional thunderstorm development. This disturbance will continue northward tonight and scattered to numerous thunderstorms are likely to persist across Lincoln, Northern Mohave and Clark counties. Given the extremely moisture rich airmass, thunderstorms will be possible both day and night, and it wont take much to trigger thunderstorm activity even during the very early morning hours. Several convective allowing models are suggesting an uptick in convective activity early Tuesday morning across the I-15 corridor from Las Vegas to St George...and given the very anomalous moisture in place as well as slow storm motion....decided to extend the Flash Flood Watch for those areas through Tuesday evening to account for potential flood impacts tomorrow morning and afternoon. Have left San Bern and southern Mohave counties out of the watch extension at this time. On Wednesday....things will tend to dry out as a weak southwest flow gradually dries out the mid and upper levels of the atmosphere. Low level moisture will remain above normal however and scattered afternoon and evening storms will remain a possibility for much of the region, but coverage and intensity will trend less. Temperatures today and tomorrow will struggle to beat triple digits in areas where rain and clouds are abundant, but will return closer to normal on Wednesday. Further West, across Inyo and Western San Bern counties, near to slightly above normal temperatures can be expected each day. .LONG TERM...Thursday through Saturday. Gradual drying and warming is expected for Thursday as weak southwest flow returns to the region. Enough moisture is likely to remain in place for afternoon showers/storms over favored high terrain. By Friday, high pressure once again pushes back to a favorable location near the Four Corners, allowing for a moist southeasterly flow into the region. However, this is where guidance begins to diverge, with the GFS keeping the high and favorable flow well into the weekend while the ECMWF is significantly different, pushing the high to near Reno and keeping much of the moisture to the south of Las Vegas. For now I've split the difference, increasing dew points, and PoPs over the area, but with a emphasis on areas south of Las Vegas. && .FIRE WEATHER...Scattered showers and thunderstorms will occur over much of the region today with any storm capable of producing very heavy rainfall. Although storms will be possible in Inyo County today, those are expected to be more isolated. However, areas of far southeastern Inyo could see more scattered storms. Conditions will gradually dry out midweek onward, with thunderstorms decreasing in coverage each day. Temperatures will be near normal to somewhat below normal through Wednesday, before returning to slightly above normal late in the week. && .HYDROLOGY... Creeks, streams and rivers in northern Inyo County have shown decreasing flows over the last couple of days. However, some road closures continue in the area. Bishop Creek Bypass and Big Pine Creek Bypass continue to be utilized to minimize flows through Bishop and Big Pine. Remember, never drive through flooded roadways or around barricades. Also, pastureland or farmland adjacent to creeks, streams or rivers could experience areas of standing water. && .AVIATION...For McCarran...Showers and thunderstorms may frequently cause gusty and erratic winds through Tuesday. Outside of that, winds should favor a southeasterly direction around 10 knots with gusts to 18 knots at times. Showers and thunderstorms will be around at times through Tuesday with night time activity possible in additions to the usual afternoon and evening activity. Cigs above 10 kft prevailing but could drop to 7 kft with storm over the terminal. For the rest of southern Nevada, northwest Arizona and southeast California...Scattered showers and thunderstorms are expected to impact much of the region through Tuesday with potentially heavy rainfall. Cigs will generally be around 10-12k feet, but could fall to as low as 5k feet in heavier storms. Winds will generally be from the south to southeast at 10-15 knots with gusts to 20 knots, but more gusty and erratic near any storms. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather and especially flood impacts the next several days as an active monsoon pattern unfolds. && Short Term...Outler Fire Weather...Gorelow Aviation...Harrison Long Term...Wolcott 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
113 PM PDT MON JUL 24 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1254 PM FLASH FLOOD 6 N MT. CHARLESTON 36.34N 115.65W
07/24/2017 CLARK NV COUNTY OFFICIAL
SR156 CLOSED AT SR158 DUE TO DEBRIS AND
FLOODWATER ON THE ROADWAY. VIA REGIONAL
FLOOD.
&&
COThe Las Vegas radar (KESX), 75 km away, was scanning. The volume nearest the first event began at 20:40 UTC.
6 flash flood, 2 thunderstorm wind. Local standard time, as filed.
Cima Road was damaged by heavy flooding.
This gust was measured at the Twentynine Palms (KNXP) ASOS.
Portions of Highway 62 were washed out.
Debris flowed over Old Spanish Trail Highway.
Thunderstorm winds blew down a power pole along Utah Trail.
Highway 127 was flooded.
Twenty-two bridges were damaged by flooding in the Essex/Danby area along National Trails Highway, five of which were completely destroyed. Amboy Road washed out just south of National Trails Highway.
Highway 127 was flooded at mile marker 12.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2017Every state in 2017This day in weather historyWarnings in California, July 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: 709565, 709566, 709567, 709568, 709569, 709570, 709571, 709572.