Upper level ridging over the southwest United States allowed for temperatures to climb to dangerous levels on the 22nd and 23rd of September. Two indirect fatalities were reported by the Maricopa County Department of Public Health.
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.
Upper level ridging over the southwest United States allowed for temperatures to climb to dangerous levels on the 22nd and 23rd of September. Two indirect fatalities 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 Sep 22, 5:13 AM MST, 4 hours 47 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 513 AM MST Sat Sep 22 2018 .UPDATE...Updated Aviation Discussion... && .SYNOPSIS... As drier air continues to move into the region expect a slight warming trend this weekend. Daytime highs will reach the low 100s beginning today and remain very near these above normal levels through the coming week with little day to day change expected. Precipitation and storm chances are very low and generally not expected through the forecast period with the occasional exception of the higher elevations to the east. && .DISCUSSION... Drier air continues to filter into the area as high pressure aloft builds across the desert southwest. Latest plot data showed 500mb heights running near 591dm over the southwest deserts, and highs in the Phoenix area continue to run several degrees above seasonal normals and in the triple digits. Surface dewpoints over the central deserts at 1 am mostly ranged from the upper 40s to upper 50s and were about 5-15 degrees lower than 24 hours ago. Also, the latest Tucson raob showed PWAT down to about 0.9 inches. Over the weekend, the upper ridge over the western CONUS will flatten as short wave energy moves east into the Pacific Northwest; flow will become more zonal over Arizona and moisture will remain limited with little or no CAPE present. Latest SPC general convective outlooks show no thunderstorms across Arizona today or Sunday. High temps will stay at least a few degrees above normal each day with Phoenix peaking around 102 each day. For most of next week, guidance looks to be pretty consistent in calling for a very large, broad upper trof to develop over most of the CONUS, with high pressure persisting over the desert southwest. Flow aloft will continue to be northwest to north most of the week and the airmass will stay on the dry side; CAPE will be limited or non existent each day. On Tuesday, a short wave is forecast to drop southeast through the 4 corners area, moving on the backside of the large trof to our east, and this feature will attempt to pull a bit of moisture north into the high terrain of eastern Arizona. Still, CAPE will be minimal and most likely all we will see over southern Gila County will be buildups - no thunderstorms. As such POPs will stay in the single digits - mostly 5-9 percent over high terrain areas east of Phoenix. POP trends over the 7 day period will mirror the latest NAEFS POPs which keep near zero values over most of the lower deserts each day. High temps all next week will stay above normal with rather small day to day changes. Expect highs in the Phoenix area at or above 100 each day. No precipitation is in the forecast over the central deserts for at least the next 7 days. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL and : Southeast California/Southwest Arizona including KIPL and KBLH: Increased easterly flow today will bring breezy easterly winds in the Phoenix area this morning with gusts up to 20kts. This should also keep winds from switching out of the west this afternoon. Skies will remain clear to mostly clear through Sunday. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Monday through Friday: Temperatures will continue to remain 3-5 degrees above seasonal normals from Sunday through the end of next week. Mainly dry conditions are expected, except for a slight chance for a few isolated showers/storms over the higher terrain north and east of Phoenix on Tuesday, as a bit of moisture is briefly pulled northward into the region. Minimum humidity levels will remain around 10-15 percent for the lower deserts and 15-25 percent for the higher terrain north and east of Phoenix, but with fair to excellent moisture recovery overnight and afternoon wind gusts below 15-20 mph should help mitigate any fire weather concerns. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...CB AVIATION...Kuhlman FIRE WEATHER...Percha
The national radar mosaic for the moment the first event began.
2 heat. Local standard time, as filed.
One indirect fatality was reported by the Maricopa County Department of Public Health, with their details, such as age, gender and circumstances unavailable.
One indirect fatality was reported by the Maricopa County Department of Public Health, with their details, such as age, gender and circumstances 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 | 2018-09-22 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-09-23 | 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, September 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: 867317, 867318.