High pressure building overhead brought three days of excessive heat to portions of the Mojave Desert.
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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.
High pressure building overhead brought three days of excessive heat to portions of the Mojave Desert.
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 3, 10:32 AM MST, 28 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 1032 AM PDT Tue Aug 3 2021 .SYNOPSIS...High pressure will build over the Mojave Desert through the middle of the week with temperatures trending upward through Thursday. An Excessive Heat Warning is in effect for portions of the area on Tuesday and expanding in coverage on Wednesday and Thursday. Temperatures will moderate back to around their seasonal normals over the weekend. && .UPDATE...This morning's sounding says it all...dry and hot. Other than a shallow layer of mid level moisture around 600 mb, the atmosphere is bone dry. Visible satellite imagery verifies this shallow layer with high based cumulus developing over the mountains. Temperatures yesterday overachieved with respect to the high temperature which came in roughly 2-3 degrees warmer than the NBM mean. In retrospect, using a blend of the NBM and the NBM 75th percentile would probably have given a better forecast in general areawide. Back to the morning sounding, 850mb and 700mb temps are up 5 and 3 degrees Fahrenheit, respectfully. Using the above blend bumped our forecast high in Las Vegas up to 109 for this afternoon which also lined up nicely with a local method of using temps aloft to calculate the high temperature. Other than that, expect mostly light winds today with some locally breezy winds in the Owens Valley. The forecast update for today will be out shortly. && .PREVIOUS DISCUSSION...152 AM PDT... .DISCUSSION...through Monday. The main weather issue over the next few days will be the heat. The forecast trends of the past couple of model runs continued in terms of the heat lingering into Thursday. So I have extended the excessive heat warning through 8 pm Thursday evening and I expanded the warning to now include northeast Clark County on Wednesday and Thursday. The 596 dm ridge of high pressure sets up over southern Nevada today and remains nearly stationary through Wednesday. By Thursday afternoon, the ridge gets nudged into central Arizona by a shortwave trough that moves onshore in northern California. Temperatures on Thursday will be quite similar in most locations to those levels on Wednesday. The gradient between the ridge and trough will enhance southwest winds and mixing on Thursday. At this point the strongest winds are expected from the Death Valley National Park and into central and southern Nye County as well as across the western portions of Lincoln County. At this point, winds should remain below critical fire weather thresholds but we will need to monitor over the next day or so to see if winds trend any higher. A small number of ensemble members and WPC cluster solutions do indicate the potential for slightly stronger wind gusts in those locations, in the 35 to 40 mph range. The eastern Pacific is fairly active with tropical systems, currently Hurricane Hilda and Tropical Storm Ignacio are located well southwest of the southern tip of the Baja of California. These systems will likely have no impact on our weather, but additional tropical development is possible over the next week and may be close enough to influence moisture up the Gulf of California and into the Desert Southwest. Otherwise, the ridge continues to flatten out and diminish to our south on Friday and transition into a more zonal flow by Saturday. With this pattern, the ensembles have backed off on any substantial increase in moisture over the weekend. Enough moisture may make it back in to provide an isolated thunderstorm over eastern Mohave County on Saturday afternoon. Isolated to scattered thunderstorms are possible across the eastern half of Mohave County each on Monday and Tuesday afternoon/evening. && .AVIATION...For McCarran...Light winds favoring typical diurnal patterns are expected today with just a few clouds in the afternoon around 10kft AGL. For the rest of southern Nevada, northwest Arizona and southeast California...Conditions today will be similar to Monday, with southeasterly breezes at KBIH in the afternoon, as well as the typical breezy evening westerly winds at KDAG. But otherwise, light winds are expected across the region with dry conditions. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && UPDATE...Salmen DISCUSSION...Czyzyk AVIATION...Outler For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter
The national radar mosaic for the moment the first event began.
3 excessive heat. Local standard time, as filed.
Excessive Heat Warning criteria were reached three days in a row.
Excessive Heat Warning criteria were reached three days in a row.
Excessive Heat Warning criteria were reached three days in a row.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, August 2021
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: 981071, 981072, 981073.