A heatwave due to a strong upper ridge formed across the region, with excessive heat warning conditions developing by the end of the period. Nine fatalities due to the heat (5 direct, 4 indirect), were reported by the Maricopa County Department of Public Health.
Every event with a place to put it; 16 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.
A heatwave due to a strong upper ridge formed across the region, with excessive heat warning conditions developing by the end of the period. Nine fatalities due to the heat (5 direct, 4 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 Jun 8, 9:59 PM MST, 1 hour 1 minute earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 959 PM MST Fri Jun 8 2018 .UPDATE...Updated Aviation discussion. && .SYNOPSIS... Dry conditions will persist into the weekend as strong high pressure remains centered just southeast of the region. Expect only very minor daily high temperature changes through early next week with readings averaging about five degrees or so above seasonal normals. Overall dry conditions should prevail for the lower deserts into next week, but a potential increase in moisture across portions of Arizona may bring at least a slight chance of thunderstorms to high terrain areas, especially later in the week. && .DISCUSSION... The Southwest remains situated along the southeastern periphery of stronger southwesterly flow aloft, as upper troughing is positioned along the Pacific Coast, and a midlevel anticyclone is centered over eastern New Mexico. Afternoon satellite imagery shows isolated thunderstorms developing across far southeastern Arizona once again today. The overall spatial distribution of moisture is similar to previous days, meaning south-central Arizona will remain dry. The aforementioned trough over the Northwest and Great Basin will gradually shift northeastward, allowing for midlevel heights to build across the southern High Plains and Southwest. This will result in an eastward expansion of the broad mid/upper-level ridge, with the primary anticyclone expected to become centered over New Mexico/West Texas by early next week. There is some increase in moisture across southeast Arizona Saturday that continues to be advertised by some model guidance, so cannot rule out an outflow boundary trying to advance northwestward into south-central Arizona Saturday evening. High temperatures will remain fairly steady throughout this pattern transition, with forecast highs ranging between 108-110 each day at Phoenix and 105-108 at Yuma. Breezy conditions are also possible this weekend amidst the warm temperatures, which could create some elevated fire weather concerns. Attention continues to remain focused on the potential for increasing thunderstorm activity next week across Arizona. The forecast evolution of the large-scale pattern remains fairly consistent through Wednesday, in which Arizona will be situated within general southerly flow aloft and will import moisture northward. Should start to see isolated thunderstorms developing across southeast Arizona as early as Tuesday, expanding northward by Wednesday to include portions of central/eastern Arizona. This means there's at least some potential for blowing dust associated with thunderstorm outflows from southeast Arizona as early as Tuesday, perhaps persisting each day through next weekend. The NAEFS ensemble mean shows around 1-1.25 inch of PW into the region by Thursday, while the GFS remains more bullish featuring PW values near 1.5 inch. The latter would be near climatological records, meaning this would be an extreme outlier for mid-June. Still quite a bit of model disagreement regarding the large-scale pattern evolution beyond Wednesday, especially with the development of a trough near the Pacific coast. The ECMWF maintains a much stronger trough, and consequently, the midlevel ridge would be situated farther west, likely suppressing convection and resulting in warmer temperatures. Other solutions show a decaying tropical system potentially moving northward across Arizona, which would have a significant impact on temperatures. Still appears that moisture will remain well above- seasonal normals regardless of the exact pattern evolution, meaning the potential for thunderstorms will exist across the higher terrain and one or more dust storms next week across the lower deserts. Will have to see if we can get a favorable enough environment for thunderstorms across the lower deserts. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: The pressure gradient will tighten Saturday ahead of a weak trough across Arizona and a deeper low-pressure system across the Pacific Northwest. Breezy conditions will develop during the afternoon with gusts to 20 kt possible. Winds will then subside during the evening, however the onset of the downslope flow will be delayed somewhat until around 10z Sunday. Southeast California/Southwest Arizona including KIPL and KBLH: Wind will be the primary aviation weather impact. Gusts to 20-25 kt will be possible during the afternoon and late evening at KIPL/KBLH. Gusts will diminish during the evening, though sustained winds around 10 kt will persist. && .FIRE WEATHER... Monday through Friday: Seasonably warm temperatures will continue through the middle of next week as high pressure aloft builds over the Southern Plains and expands west. Typical afternoon breezes will be possible most days and could result in localized elevated fire weather conditions. Warm temperatures and dry low-level air will continue to bring RH minimums near 10 percent each afternoon through early next week, but moisture will begin to increase slightly by the middle of next week. Isolated thunderstorms may be possible across the higher terrain north and east of Phoenix by Tuesday of next week, posing a threat for lightning-induced fires considering how dry fuels are across the region. Additionally, gusty and erratic outflow winds will be possible around any thunderstorm that does forms. Higher confidence exists in moisture making it into the region later in the week with most thunderstorm activity remaining relegated to the higher terrain of south-central Arizona. && .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...Rogers AVIATION...Hirsch FIRE WEATHER...Rogers/Wilson
The national radar mosaic for the moment the first event began.
12 excessive heat, 4 heat. Local standard time, as filed.
One indirect fatality due to the heat was reported, with the specifics, such as age, gender, and circumstances unavailable.
One indirect fatality due to the heat was reported, with the specifics, such as age, gender, and circumstances unavailable.
One indirect fatality due to the heat was reported, with the specifics, such as age, gender, and circumstances unavailable.
One indirect fatality due to the heat was reported, with the specifics, such as age, gender, and circumstances unavailable.
Excessive heat warning conditions were observed with 5 direct fatalities due to the heat reported by the Maricopa County Department of Public Health, with the specifics, 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 | 2018-06-08 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-06-09 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-06-10 | Unknown | Indirect | ||
| Heat, Central Phoenix | 2018-06-11 | Unknown | Indirect | ||
| Excessive Heat, Central Phoenix | 2018-06-12 | Unknown | Direct | ||
| Excessive Heat, Central Phoenix | 2018-06-14 | Unknown | Direct | ||
| Excessive Heat, Central Phoenix | 2018-06-14 | Unknown | Direct | ||
| Excessive Heat, Central Phoenix | 2018-06-15 | Unknown | Direct | ||
| Excessive Heat, Central Phoenix | 2018-06-15 | Unknown | Direct |
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, June 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: 864337, 864338, 864339, 864340, 864342, 864343, 864344, 864345, 864346, 864347, 864348, 864349, 864350, 864351, 864352, 864354.