Strong high pressure centered over the Desert Southwest allowed for temperatures to reach or exceed 110 degrees during the early part of July. According to the Maricopa County Department of Public Health, 18 heat-associated fatalities occurred during this time.
Every event with a place to put it; 6 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.
Strong high pressure centered over the Desert Southwest allowed for temperatures to reach or exceed 110 degrees during the early part of July. According to the Maricopa County Department of Public Health, 18 heat-associated fatalities occurred during this time.
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 Jul 3, 2:36 PM MST, 2 hours 24 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 236 PM MST Fri Jul 3 2020 .UPDATE...Updated Fire Weather Discussion. && .SYNOPSIS... A slight chance of isolated showers and thunderstorms will linger around Phoenix and parts of the lower deserts through early to mid afternoon. As high pressure builds into the region, a warming trend will allow highs to climb back above normal by this weekend, and continue well into next week. Also a drying trend will not favor storm development for the holiday weekend or through the early part of next week. A lack of significant moisture for the rest of next week will also help to maintain dry conditions. && .DISCUSSION... Yesterday's disturbance that came up from the south only produced very isolated and modest area precipitation south and southwest of Phoenix along with some locally gusty outflow winds. However it also ushered in a regional wall of very moist air into AZ, including S-Central AZ. The 12Z Phx sounding showed the moistest airmass so far of the Monsoon season with a PW that increased to 1.69", mixing ratio of 11.3 gm/kg and MUCAPE of 567 j/kg. The moist, moderately unstable airmass combined with a very thin, weak mid tropospheric disturbance SW of Phoenix to produce some very isolated showers this morning near Gila Bend and SW Maricopa cty. Most of this mornings HREF members indicated a chance of isolated showers and a couple of embedded storms in and around Phoenix and Gila Cty through about early to mid afternoon and becoming increasingly isolated for the later half of the afternoon. As a result expect a lingering slight chance of isolated showers and a storm for this afternoon. Midday ACARS Phx soundings indicated a CAP near H5 (that had increased since 12Z) that is making it difficult for the patchy CU field SW to S of Phoenix from growing much since the end of the isolated morning showers there. A gradual drying trend is also underway with PWs already decreasing with drier air beginning to move into the region. By late afternoon to early evening expect the chances for convection to rapidly diminish as high temperatures top out just below normal near 105. However the scattered storms in the N AZ high country will wait until the evening before tapering off. A warming trend gets underway on Saturday as the ridge continues to work its way west closer to the region and with the continued influx of drier air. Above normal highs will climb to near 108 to 110 by Saturday and remains near 110-111 through Tuesday. The gradual drying trend will last until around Sunday night to early Monday as the ridge axis retrogrades further to the W-SW. A modest increase in moisture for early next week will likely not be enough to dampen the very hot temperatures or to increase any storm chances. Moisture and instability along the S flank of the ridge will keep the best storm chances confined mostly to SE AZ and NW MX for next week. && .AVIATION...Updated at 1808Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: The potential is still there for isolated showers & storms late this morning into the early parts of the afternoon. PHX & DVT will have the best chances. Any shower/storm will be very short-lived and produce brief heavy rain, lightning, and gusty winds. Outside of any shower/storm, skies will remain mostly clear with few-sct high clouds mainly above 8-10 kft through the TAF period. Winds will be light today and favor the southwest to west. Winds will eventually return back to the east overnight, but due to light wind speeds, directions will likely be more variable at times. Southeast California/Southwest Arizona including KIPL and KBLH: Skies will be mostly clear with a few high clouds around 10 kft. At KBLH, winds will favor a southerly component with a few gusts up to 20 kts possible this afternoon. At KIPL, winds will be light, favoring the south-southwest with periods of light and variable wind directions. && .FIRE WEATHER... Monday through Friday: Overall, conditions will be hot and dry. Daytime minimum humidity values will drop below 15% for most places while overnight recoveries will rise into the 20-40% range. Wind speeds will generally be light, outside of typical afternoon breezes, with directions following local terrain influences. Moisture will mostly be insufficient for thunderstorms but a few isolated cells may form on any particular day, primarily over the White Mountains and in southeast Arizona. As of now, these locations seem too far to send any outflow winds into south-central Arizona. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...Sawtelle AVIATION...Feldkircher FIRE WEATHER...Sawtelle/AD
The national radar mosaic for the moment the first event began.
6 heat. Local standard time, as filed.
Two heat-associated fatalities were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and location unavailable.
One heat-associated fatality was reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and location unavailable.
Three heat-associated fatalities were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and location unavailable.
Four heat-associated fatalities were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and location unavailable.
Five heat-associated fatalities were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and location unavailable.
Three heat-associated fatalities were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and 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 | 2020-07-03 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-03 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-04 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-05 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-05 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-05 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-06 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-06 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-06 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-06 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-07 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-07 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-07 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-07 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-07 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-08 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-08 | Unknown | Direct | ||
| Heat, Central Phoenix | 2020-07-08 | Unknown | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2020Every state in 2020This day in weather historyWarnings in Arizona, July 2020
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: 991997, 991998, 991999, 992000, 992001, 992002.