An unseasonably strong cold low pressure system brought rain and locally heavy mountain snow to southeast California. Isolated flash flooding and dense fog also occurred.
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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.
An unseasonably strong cold low pressure system brought rain and locally heavy mountain snow to southeast California. Isolated flash flooding and dense fog also 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 9, 6:24 PM PST, 36 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 724 PM PDT Thu May 9 2019 .SYNOPSIS...An unusual May weather pattern will bring periods of shower and thunderstorm activity along with cooler temperatures to the region through the weekend. A concentrated band of rainfall is likely to develop across southern Nevada and eastern California tonight which may result in localized flash flooding. Conditions will dry out and temperatures will climb by early next week. && .UPDATE...Storms over Inyo and San Bernardino counties were intensifying this evening as 300 mb difluence, low level convergence, and low level shear all overlapped. Farther north and east, storms over Lincoln County had been struggling as too many updrafts competed for too little instability. Updated grids to raise PoPs in San Bern county and increase QPF for Inyo and San Bern as a tongue of precipitable water greater than 0.75 inch was poking north into the storm environment. No changes beyond the immediate term. Will continue to monitor. && .PREV DISCUSSION... 315 PM PDT Thu May 9 2019 .SHORT TERM...through the weekend. Shower and thunderstorm activity has increased this afternoon as low pressure from the intermountain west retrogrades west and forms a closed low over Nevada and California by Friday morning. A persistent band of showers extending from southern Inyo through Mohave County has continued to move east today, but this area has generally been rather stable and only light to moderate rainfall has been reported. Further north, closer to the developing low, thunderstorms have been developing with some heavier rain embedded in some of these storms. This trend is expected to continue into this evening with majority of the hires models showing showers and thunderstorms developing across Inyo, Nye, Lincoln, and Clark Counties. Increasing instability, plenty of deep moisture and additional energy from the low should help generate these storms which are likely to continue through much of the overnight period. Rainfall totals across Inyo could range from a quarter to half an inch with half an inch to over an inch across southern Nye, Lincoln, and parts of Clark County. It is noted that PW values forecast for this evening are approaching record territory for this time of year. At this time, changes to the current flash flood watch are not needed. The area may see a slight break in coverage Friday morning, but with afternoon heating and increased instability in the afternoon showers and thunderstorms are once again expected to develop. At this time storms look to be a bit more scattered across the region, but with plenty of moisture still available any storm will be capable of producing flash flooding. In addition to heavy rainfall, some winter weather will also be possible in the high Sierra, mainly above 8,000 feet. While snow amounts will be fairly minimal by Sierra standards, 3-6 inches of wet slushy snow may catch outdoor enthusiasts by surprise and can prove dangerous for those unprepared for the conditions. As such, issued a Winter Weather Advisory through Friday afternoon for the higher Sierra elevations. Rainfall will become more scattered over the weekend with the best forcing pulling west and south with the low. However, precipitable water values will remain quite high through the weekend and the region will remain in a broad cyclonic flow pattern with daily chances of scattered shower and thunderstorm activity. At least isolated flash flooding will remain possible. Temperatures through the weekend will remain several degrees below normal thanks to the abundance of moisture and cloud cover. .LONG TERM...Monday through Wednesday. Closed low which plagued the forecast during the short term period will begin to lift eastward Monday with ridging attempting to rebuild over the Southwest. There will still be an abundance of low level moisture across the region Monday which will be slow to mix out for the early part of next week, so at least a few terrain driven showers will remain possible Monday and Tuesday afternoons. Thereafter, an increasing southwesterly flow aloft will begin to scour out any remaining moisture thats left across our region. Meanwhile, temperatures will climb a few degrees each day, returning to above normal territory Tuesday onward. && .HYDROLOGY...Widespread moderate to heavy rainfall is expected to produce higher than normal flows in area creeks, washes, and drainage basins across southern Nevada and Eastern California. The Amargosa River, Fortymile Wash, Meadow Valley Wash, and Muddy River may experience elevated flows and increased flash flood risk. Washes and drainages around the Las Vegas metro area will also be prone to rapid rises in water levels. Heavy precipitation in the Sierra along with mid-slope snowmelt may cause elevated water levels in the eastern Sierra drainages as well. Flash Flood Watch is in effect Thursday afternoon through Friday afternoon with these concerns in mind, though at least isolated flood potential will linger through the weekend. && .AVIATION...For McCarran...Scattered light showers still moving east across the Las Vegas Valley this afternoon with CIGS around 10-12k feet. Some scattered clouds around 6-7k feet, but cigs are expected to lower this evening as showers and thunderstorms become more widespread. The greatest threat of rain looks to be between 03z and 10z overnight and then again after 18z on Friday with cigs certainly possible to 5k feet or less. East winds around 6-8 kts into this evening, but may turn more northerly after 05z with speeds around 10- 15 kts which may continue through the night. Additional scattered showers and thunderstorms are possible Friday with cigs down to around 5k feet at times. For the rest of southern Nevada, northwest Arizona and southeast California...East to northeast winds over most areas into this evening before shifting more to the north and northeast after 04z. Wind speeds should generally remain at 10 kts or less. Weather conditions will start to deteriorate after sunset with precipitation increasing over most areas. Lowering cigs down to 5k feet at times and increasing precipitation chances are expected through Friday. && .SPOTTER INFORMATION STATEMENT...Spotter activation is requested today and Friday as widespread shower and thunderstorm activity is expected. Reports of flooding or excessive rain rates are encouraged. && UPDATE...Morgan SHORT TERM/AVIATION...Gorelow LONG TERM/HYDRO...Outler For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter
The Edwards AFB radar (KEYX), 161 km away, was scanning. The volume nearest the first event began at 02:59 UTC.
1 flash flood, 1 heavy snow, 1 dense fog. Local standard time, as filed.
Twenty Mule Team Road was closed due to flood damage. Time estimated from radar.
Aspendell received 8.6 inches of snow.
Visibility was reduced to 150 feet at Mountain Pass.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, May 2019
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: 814713, 814715, 814714.