Abnormal late-May moisture and weak instability fueled scattered thunderstorms over the Mojave Desert. Flash flooding and isolated severe weather occurred.
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.
Abnormal late-May moisture and weak instability fueled scattered thunderstorms over the Mojave Desert. Flash flooding and isolated severe weather occurred.
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 May 20, 12:46 PM PST, 46 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 146 PM PDT Sat May 20 2023 .SYNOPSIS...Expect another day of scattered afternoon and evening showers and thunderstorms across much of the region on Sunday before presistent troughing and dry southwesterly flow slowly scours out the moisture and brings an end to shower chances by Thursday. Above normal temperatures will continue until Wednesday before more seasonal temperatures overspread the area heading into the weekend. && .DISCUSSION...A shortwave moving into the Pacific Northwest on Sunday will act to nudge the persistent high pressure ridge east of us over the Intermountain Range. Although this signals the beginning a shifting weather pattern, highly anomalous moisture and weak to moderate instability remains in place resulting in another day of scattered afternoon and evening thunderstorms. Storm coverage is expected to be rather widespread with at least a slight chance in nearly every zone in our forecast area. Primary concerns will again be gusty winds and dangerous lightning. Based on the HREF, there should be plenty of sunshine to begin the day with forecast high temperatures remaining several degrees above normal. To begin the work week, the moisture profile is shifting with our southern areas seeing some drying in the mid-levels but still above what would be considered normal. The 150-250% of normal precipitable water values remain over our northern areas and these areas will continue to be under the threat of afternoon/evening thunderstorm activity. Some areas including the Western Mojave Desert and Colorado River Valley are forecast to see afternoon southerly breezes. By Tuesday, most areas will be dry and windy but a chance of showers continue across our far northern Nevada zones. Temperatures on Monday and Tuesday are forecast to approach the century mark in Las Vegas but the current probability of reaching 100 degrees at Harry Reid AP on either day is less than 10%. Wednesday through Saturday... A much quieter period is anticipated. There is a small but lingering chance of showers over parts of southcentral Nevada on Wednesday before dry conditions settle over our entire area Thursday through Saturday. Troughing influences over the western states will return temperatures to a more seasonal level late in the week with afternoon breezes continuing. && AVIATION...For Harry Reid...Very similar setup to yesterday. An easterly wind less than 10 kts will be favored through much of the afternoon with storms developing over the mountains north and west of the valley. Best time for minor to moderate impacts at the terminal from thunderstorms and resultant strong outflow gusts looks fall between 00Z-03Z. Gusts up to 35kts could occur, potentially warranting an AWW if so. Activity should dissipate around 03-04Z leading to partly cloudy skies and winds less than 10 kts overnight into Sunday morning. Another day of thunderstorm forecast over the higher terrain tomorrow which could bring gusty outflow winds to the valley once again in the late afternoon or early evening hours. For the rest of southern Nevada, northwest Arizona and southeast California...Isolated to scattered TSRA expected across the region this afternoon and evening, and again Sunday. All regional terminals can expect at least VCTS after 21Z both days, with possible outflow impacts as well, with gusts up to 30-35 kts, possibly 40+ kts not out of the question, but probability for that is low at any terminal. Coverage should wane significantly by the late evening, but wind direction confidence is very low due to remnant outflows expected to be prominent across the region. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && DISCUSSION...Salmen AVIATION...Pierce For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter
The Las Vegas radar (KESX), 76 km away, was scanning. The volume nearest the first event began at 21:30 UTC.
7 flash flood, 3 flood, 1 thunderstorm wind. Local standard time, as filed.
Cima Road was closed at Interstate 15 due to flooding and erosion on both sides of the freeway. At least one vehicle was stuck with water up to the bottom of the doors.
Flash flooding stranded multiple vehicles at and near Artist's Palette.
Highway 178 was closed east of Highway 127 due to flooding.
Highway 95 was flooded north of Goffs Road.
Highway 178 was closed at the junction of Highway 127 due to flooding.
Flooding northwest of Twentynine Palms washed away multiple vehicles and caused at least one sinkhole in a road.
Highway 190 was flooded with water and debris and partially washed out. One vehicle was stuck.
Water and debris on the ramp from Interstate 15 North to Interstate 40 East contributed to a vehicle spinout.
Flooding and a mudslide affected the East Main Street off ramp of Interstate 15 South.
Highway 127 was flooded just north of the Highway 190 intersection.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2023Every state in 2023This day in weather historyWarnings in California, May 2023
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: 1099758, 1099759, 1099760, 1099761, 1099762, 1099763, 1099764, 1099765, 1099766, 1099767, 1099773.