Name: Heat in Arizona, July 10, 2021
Start: 2021-07-10T10:00
End: 2021-07-10T20:00
Location: Arizona

Where it happened

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.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 2
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

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.

What happened

The episode as NWS TWC wrote it up.

Hot temperatures around 100 degrees in southern Cochise County were experienced on July 6. The Pima County Medical Examiner confirmed that heat was the primary cause of death for two males found in the desert.

What forecasters said that day

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 Tucson, AZ wrote its last area forecast discussion before the first event at Jul 10, 9:42 AM MST, 18 minutes earlier.

Area forecast discussion, Jul 10, 9:42 AM MST, 18 minutes before

Area Forecast Discussion
National Weather Service Tucson AZ
942 AM MST Sat Jul 10 2021

.UPDATE...

A somewhat hazy morning around Tucson is likely attributed to some
dust activity north of the area last evening.

No major updates to the forecast at this time, as we were left in
great shape by the previous shift. However, we do want to
reiterate a couple of items of particular importance.

High resolution models continue to be in good agreement with the
setup of a rim shot event off of the higher terrain beginning
after 23 UTC this afternoon. Southwesterly propagation of
isolated thunderstorms can be expected, with the main impacts
being blowing dust and brief heavy downpours. Storms should be
moving at a pretty good clip, so flash flooding will be dependent
on antecedent conditions and localized terrain. The timing of the
event is such that it may last into the evening and nighttime
hours over western Pima county.

&&

.PREV DISCUSSION... /issued 340 AM MST Sat Jul 10 2021/

.SYNOPSIS...An active period of daily scattered showers and
thunderstorms during the next 7 days. High temperatures will be
hot this weekend then cooling to below normal level later around
the middle of next week.

&&

.DISCUSSION...Satellite imagery showed considerable debris
cloudiness across southern Arizona from last nights MCS east of
Phoenix. These clouds will be diminishing through the morning
hours. As of 3 am, the Phoenix/Tucson radars was showing MCV
centered near Eloy moving W/SW.

Today, based on latest CAMs, has the look for a classic rim shot
event with scattered strong to isolated severe thunderstorms
propagating SW off the higher terrain late this afternoon into
this evening. In this scenario, parts of the area might end up
under a severe thunderstorm watch box later this afternoon into
this evening. Latest SPC day 1 outlook has most of the area under
marginal risk category. Blowing dust will be an issue this evening
with HREF showing 10-30% chance of wind gusts >50kts and nearly
70% of wind gusts >30kts. PW values are generally around 1.5"
across the area, thus expect isolated heavy downpours. With the
steering flow around 15-20 mph this will limit threat of flash
flooding from an individual storm. However, if an area gets hit
with heavy rain a couple times, that changes the flash flooding
threat equation. Storms will be pushing all the way out into
western Pima County after midnight.

Most times the area will have a down day after a big event,
however with the upper high near Las Vegas on Sunday and N/NE flow
over the area, will see another round of storms propagate off the
higher terrain. At this time, looks like most of the activity on
Sunday will be from Tucson east and south.

Active weather pattern continues most of next week with daily
variations on areal coverage of afternoon/evening thunderstorms.
Went with a blend of NBM/CLIMO PoPs for next week.

Hot temperatures continue this weekend then start to cool below
normal during the upcoming week. Flash flooding threat will be
higher next week.

&&

.AVIATION...Valid through 11/12Z.
Considerable debris cloudiness will be diminishing this morning
becoming scattered in nature by early afternoon. ISOLD-SCT
SHRA/TSRA over the White Mountains this afternoon will propagate
to the southwest through the remainder of the valid period. Best
timing for thunderstorms affecting KTUS is between 11/01z and
11/07z. Wind gusts to 50 kts possible near the strongest TSRA.
Otherwise, surface winds less than 12 kts. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Today is shaping up to be a classic rim shot event
with scattered thunderstorms forming over the higher terrain and
propagating to the southwest. A further increase is expected next
week with a more favorable environment for storms, similar to
last week. Min RH values will generally be in the 15-25 percent
range for lower elevations through Monday with very good overnight
recoveries before increasing Tuesday onward. Surface winds will
be light and follow normal daily trends when not influenced by
storms.

&&

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&

Public...Singer
Aviation...Aviation Forecaster
Fire Weather....Fire Weather Forecaster

Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 heat. Local standard time, as filed.

Heat, Upper San Pedro River Valley

When: July 10, 10:00 AM MST to 8:00 PM MST
Where: Upper San Pedro River Valley forecast zone
Deaths: 1 direct, 0 indirect
Reported by: County Official
Coordinates: 32.109, -110.569 (the zone’s center; the record gives no point)

Temperatures 5 to 10 degrees above normal near 100 degrees, occurred in southern Cochise County causing the Moderate Heat Risk category to be reached on July 10. The Pima County Medical Examiner confirmed that heat was the primary cause of death for one male found in the desert near Palominas and another in the Leslie Canyon area.

Heat, Eastern Cochise County Below 5000 Feet

When: July 10, 10:00 AM MST to 8:00 PM MST
Where: Eastern Cochise County Below 5000 Feet forecast zone
Deaths: 1 direct, 0 indirect
Reported by: County Official
Coordinates: 31.880, -109.751 (the zone’s center; the record gives no point)

Temperatures 5 to 10 degrees above normal near 100 degrees, occurred in southern Cochise County causing the Moderate Heat Risk category to be reached on July 10. The Pima County Medical Examiner confirmed that heat was the primary cause of death for one male found in the desert near Palominas and another in the Leslie Canyon area.

The people who died

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, Upper San Pedro River Valley	2021-07-10	44	Male	Outside/Open Areas	Direct
Heat, Eastern Cochise County Below 5000 Feet	2021-07-10	24	Male	Outside/Open Areas	Direct

What these are

Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Arizona in 2021 Every state in 2021 This day in weather history Warnings in Arizona, July 2021

Sources

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: 976593, 976594.