Monsoon moisture, an easterly wave, and unseasonable jet stream dynamics fueled scattered thunderstorms over northwest Arizona. One storm produced flash flooding.
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The episode as NWS VEF wrote it up.
Monsoon moisture, an easterly wave, and unseasonable jet stream dynamics fueled scattered thunderstorms over northwest Arizona. 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 17, 1:17 PM MST, 4 hours 13 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 117 PM PDT Sat Aug 17 2024 .SYNOPSIS...Dry and breezy conditions will continue across western areas through the weekend while isolated to scattered thunderstorms persist across Northwest Arizona and Lincoln County. Drier air will sweep in Monday and Tuesday allowing temperatures to climb and storms to diminish across all but eastern Mohave County. Storm chances will creep back west midweek with a gradual cooling trend. && .SHORT TERM...through Tuesday evening. This mornings round of thunderstorm activity which brought fairly widespread rainfall to Lincoln County has now lifted north to be located near the Salt Lake City metro. Meanwhile, continued south-southwesterly flow aloft and afternoon destabilization has allowed for renewed storm development across northern Mohave County and a few isolated storms developing in Lincoln County. Still expecting fairly robust storms to impact these areas through the afternoon hours, with training storms a concern in northern Mohave County where a Flash Flood Watch remains in effect. Deep layer shear is trending weaker from this morning, but still is sufficient for some degree of storm organization, with gusty winds and hail a possibility. While a stray storm could still develop as far south and west as Las Vegas, the better chances will be confined to areas north and east of the metro. Tomorrow, storm chances will tend to focus across the Arizona Strip, where additional locally heavy rainfall is possible with a tendency for storm training. Elsewhere, drier air will begin to work in from the west and limit storm development north and west of Arizona. Drier air will continue to progressively invade the region Monday and Tuesday, with storm chances becoming confined to the eastern fringes of Mohave County. As the vertical profile dries out, temperatures will begin to climb Monday and Tuesday. Heat risk briefly climbs into the high territory across some of the lower elevations Tuesday, though the risk is brief as heat risk drops back down by Wednesday. .LONG TERM...Wednesday through Saturday. The region will remain sandwiched between West Coast/Great Basin troughing and the monsoonal high over the New Mexico. This will keep relatively moist and monsoonal conditions going across our eastern zones, while western areas remain dry and breezy. A shortwave may lift around the monsoon flow Wednesday and trigger a brief push of moisture westward into the eastern Mojave Desert, similar to the general pattern observed this weekend. NBM PoPs do expand west on Wednesday and Thursday as this feature develops and troughing to our north and west deepens. Thereafter, guidance diverges on how to handle the western US trough, either swinging it through the Great Basin or digging it south along the California coast. Regardless, drier conditions will likely spread eastward with cooler than normal temperatures expected by next weekend. && .AVIATION...For Harry Reid...South to southwest winds are expected this afternoon and early evening with gusts over 25KT likely (80% chance), especially around 21Z. Winds will diminish after sunset with wind speeds dropping below 8KT after 03Z then remaining under 8KT through the night. A repeat in wind patterns is expected Sunday with light winds in the morning become southeast midmorning before turning south-southwest and increasing after 20Z. Winds Sunday afternoon will not be as strong as today with gusts remaining under 25KT. No thunderstorm impacts are expected at the terminals through the period with convection this afternoon centered over Lincoln County through southwest Utah and northwest Arizona. Sunday afternoon convection will develop even further east mainly in western Arizona. For the rest of southern Nevada, northwest Arizona and southeast California...Breezy south to southwest winds are expected again this afternoon across much of the region. Gusts 20-30KT expected this afternoon in many locations. Another round of convection is to develop this afternoon across Lincoln County through southwest Utah and northwest Arizona. Any thunderstorms that develop would bring the risk of sudden gusty winds, lightning, small hail, heavy rain, and CIGs to 8kft-10kft. Winds as well as thunderstorm chances will decrease tonight after sunset with dry conditions and diurnal wind patterns expected overnight. Light winds will continue through Sunday morning before south winds increase Sunday afternoon, though winds on Sunday should be lighter than winds today. && .FIRE WEATHER...Dry and breezy conditions continue across our western zones with critical fire conditions expected today and Sunday across Esmeralda and Nye Counties. Conditions will be more moist further east with isolated thunderstorm activity in Lincoln and Mohave Counties through the weekend. Drier air will push in Monday and Tuesday with storm chances becoming limited to northwest Arizona. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && DISCUSSION...Outler AVIATION...Nickerson For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter
The Cedar City radar (KICX), 80 km away, was scanning. The volume nearest the first event began at 00:30 UTC.
1 flash flood. Local standard time, as filed.
Highway 389 was flooded with water, mud, and debris.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2024Every state in 2024This day in weather historyWarnings in Arizona, August 2024
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: 1207876.