An area of high pressure over the Desert Southwest allowed for temperatures to climb high enough to result in several heat-associated fatalities. Eight heat-associated fatalities (one direct and seven indirect) were reported by the Maricopa County Department of Public Health.
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.
An area of high pressure over the Desert Southwest allowed for temperatures to climb high enough to result in several heat-associated fatalities. Eight heat-associated fatalities (one direct and seven indirect) were reported by the Maricopa County Department of Public Health.
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 Aug 28, 1:55 PM MST, 3 hours 5 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 155 PM MST Tue Aug 28 2018 .SYNOPSIS... Unusually dry air will remain parked over the Desert Southwest this week resulting in a break from thunderstorm activity. With the lack of humidity and clouds, temperatures will trend slightly warmer than average, yet remaining below record levels. Shower and thunderstorm chances may return to Arizona and possibly southeast California later this weekend, though more widespread coverage may not arrive until next week. && .DISCUSSION... Seasonally strong troughing across the northern/central Rockies has continued to depress subtropical high pressure to the south and east bringing a belt of anomalously strong westerly winds through the forecast area. In fact, u-wind component anomalies greater than two normalized standard deviations through the middle troposphere has just about scoured away all appreciable moisture necessary for deep convection in the Southwest. Both 12Z KPSR and KTWC sounding data sampled total column Pwats under one inch and a notable lack of moisture around the H7 layer further exemplifying the deficiency of thunderstorm ingredients. The center of the subtropical ridge will only slowly migrate back into central New Mexico/SE Arizona over the next several days with a pronounced westerly jet axis maintaining its general position from southern California through the central Rockies. Thus while some more organized convection will edge into northern Sonora/far SE Arizona, other than shallow Gulf moisture, more appreciable moisture will have far more difficulty advecting into the CWA. As a result, there still is no signal of rainfall chances locally until at least the weekend. H5 heights should fall within a fairly narrow 590-592dm range yielding afternoon highs some 3F-6F above normal. While not near record levels, there are indications that some SE California communities could exceed another bout of 110+F temperatures and flirt with excessive heat criteria. The forecast picture continues to be more muddled into the weekend and especially into early next week with little change in model trends after the 12Z iteration. While the operational GFS and ECMWF become more widely divergent in solutions, even NAEFS members become quite chaotic in nature by the weekend with significant differences emerging. While there are several NAEFS members supporting some sort of mean trough over the western Conus, the depth and propensity to develop a cutoff low seen in recent ECMWF solutions has very little ensemble support. Subsequently, robust moisture return advertised by the operational ECMWF is far more muted (at best) among ensembles; and in reality, the ensemble majority suggests better quality moisture and storms remaining trapped south of the international border until early/middle of next week. Considering the time of year, getting late in the monsoon and heading into September and the lack of confidence in closed low solutions well into the extended, tend to favor the GFS and will keep POPs rather low and only in the slight chance category over south central Arizona. Actually due to low confidence, very little change was made to our POP forecasts in the extended. High temps trend back down towards seasonal normals given at least a modest increase in humidity during the extended period. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Minimal aviation concerns through the TAF period. Winds will follow normal diurnal tendencies with some gustiness in the afternoon. Skies will stay mostly clear with cloud decks aoa 20 kft. Zero chance of seeing storms over or near terminals. Southeast California/Southwest Arizona including KIPL and KBLH: Minimal aviation concerns today. Winds will follow normal diurnal tendencies with some gusts up to 20 kts expected at BLH. Skies will stay mostly clear throughout the day with some thicker cirrus clouds moving overhead during the overnight hours. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday: Humidity levels will slowly increase over the weekend though it is highly uncertain whether more widespread wetting rains will spread into the districts or remain relegated to mountainous areas. Eastern Arizona will experience the best storm chances into early next week. Minimum humidity levels in a 10-25% range will steadily increase towards a 15-40% range with fair to good overnight recovery. Any initial storms over the weekend will generally be more effective wind producers over higher terrain with a tendency for strong, erratic outflow winds to eventually descend into lower elevations next week. && .SPOTTER INFORMATION STATEMENT... Spotter reports will not be needed this week. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...MO/CB AVIATION...Hernandez FIRE WEATHER...MO/AJ
The national radar mosaic for the moment the first event began.
6 heat. Local standard time, as filed.
One indirect fatality was reported by the Maricopa County Department of Public Health.
Two indirect fatalities were reported by the Maricopa County Department of Public Health.
One direct fatality was reported by the Maricopa County Department of Public Health.
One indirect fatality was reported by the Maricopa County Department of Public Health.
Two indirect fatalities were reported by the Maricopa County Department of Public Health.
One indirect fatality was reported by the Maricopa County Department of Public Health.
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, Scottsdale/Paradise Valley | 2018-08-28 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-08-29 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-08-29 | Unknown | Indirect | ||
| Heat, North Phoenix/Glendale | 2018-08-29 | Unknown | Direct | ||
| Heat, Central Phoenix | 2018-08-30 | Unknown | Indirect | ||
| Heat, Scottsdale/Paradise Valley | 2018-08-30 | Unknown | Indirect | ||
| Heat, Scottsdale/Paradise Valley | 2018-08-30 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-08-31 | Unknown | Indirect |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2018Every state in 2018This day in weather historyWarnings in Arizona, August 2018
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: 867355, 867356, 867357, 867358, 867359, 867360.