High pressure over the Desert Southwest in early May allowed for temperatures to climb to around 100 , which is about 10 degrees above normal for this time of the year. Phoenix officially hit 100 for the first time in 2021 on the 5th with temperatures peaking at 100 again on the 6th.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 PSR wrote it up.
High pressure over the Desert Southwest in early May allowed for temperatures to climb to around 100 , which is about 10 degrees above normal for this time of the year. Phoenix officially hit 100 for the first time in 2021 on the 5th with temperatures peaking at 100 again on the 6th. According to the Maricopa County Department of Public Health, two heat-associated fatalities occurred during this event.
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 Phoenix, AZ wrote its last area forecast discussion before the first event at May 5, 4:41 PM MST, 19 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 441 PM MST Wed May 5 2021 .UPDATE...00Z aviation discussion. .SYNOPSIS... High temperatures will be near 100 degrees today through Friday. Temperatures are expected to cool into the mid 90s this weekend and into early next week along with a return of breezy conditions. No precipitation is in the forecast through the next 7 days. && .DISCUSSION... The lower troposphere has warmed a few degrees from this time 24 hours ago, as evident on aircraft soundings, and a negatively tilted ridge is in place across the region. A few cirrus have been passing over the area, but coverage is not enough to have any sensible influence on temperatures this afternoon. The latest NBM is still showing around 40-60% chance of reaching or exceeding 100 degrees in Phoenix this afternoon and a 70-80% Thursday. Sky Harbor is still yet to reach the mark this year and if able to today or tomorrow it will be only a few days later than normal. Regardless if 100 is reached, temperatures will present a moderate heat risk for Phoenix and other metropolitan areas. Thursday, the ridge axis will shift to western NM with more of a southerly to south-southwesterly synoptic flow prevailing over the area. As a 700 mb high slides into West Texas a moisture axis will develop in Mexico and extend north into NM and parts of southeast AZ. Within this moisture axis, most models are developing convection tomorrow afternoon. A few showers and/or an isolated storm cannot be ruled out in southeast Gila county, but HREF suggests most if not all convection will stay just outside the local CWA. Temperatures will cool as a trough progresses into the western CONUS this weekend. WPC cluster analysis is still in favor of a lower amplitude trough, with around 20-30% of the solutions suggesting a deeper trough, mostly dominated by GEFS members. So with the lower amplitude solution favored, temperatures are unlikely to cool too drastically. NBM is showing afternoon temperatures still reaching the mid-90s across the lower deserts Saturday through the middle of next week. Precipitation remains unlikely with this trough as virtually all ensemble members show no measurable precipitation. The trough pattern will at least result in slightly breezier conditions and possibly areas of windy conditions if the lower probability deeper trough solution comes to fruition. WPC clusters show very little agreement for the middle of next week, with a roughly equal proportion of members showing continued weak troughing or ridging rebuilding over the area. && .AVIATION...Updated at 2341Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation impacts expected through the period. Winds will favor normal diurnal trends staying aob 9 kts. Can't rule out a few thermal gusts early this evening, mainly at KDVT. Westerly winds to persist later-than-usual overnight, likely becoming easterly around/shortly after midnight. Typical switch to westerly around 20- 21Z on Thursday (likely after a short period of light southerly crosswinds), with these westerly winds likely persisting well into Thursday night. FEW-SCT decks at times through evening then mostly clear conditions will prevail. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation impacts expected through the TAF period. Skies will be mostly clear with just occasional high clouds aoa 25 kft. At KIPL, winds will favor the southeast through the TAF period with light winds picking up a bit Thursday morning. At KBLH, winds will favor the south-southwest, with a few gusts in the teens possible early this evening. Stronger southerly winds to return Thursday afternoon at KBLH, with sustained winds in the mid-teens with gusts rising into the mid-20's. && .FIRE WEATHER... Saturday through Wednesday: Temperatures will remain above normal through early next week with highs in the mid 90s. Min RHs will remain around 10% or lower most afternoons while recoveries rise into the 20-30% range for most places, except near Imperial and Yuma where maximum values of 30-50% will be common. Breezy conditions are likely each afternoon. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...Benedict AVIATION...Percha/D'Anthony/Feldkircher FIRE WEATHER...Benedict/Hodges
The national radar mosaic for the moment the first event began.
2 heat. Local standard time, as filed.
One direct fatality was reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances, and exact location unavailable.
One direct fatality was reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances, and exact location unavailable.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Heat, Central Phoenix | 2021-05-05 | Unknown | Direct | ||
| Heat, Central Phoenix | 2021-05-08 | Unknown | Direct |
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, May 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: 1057124, 1057125.