Arizona, 2020

Drought in Arizona, August 25 to 31, 2020

August 25 to 31, 2020 · NWS TWC · 8 events in 8 counties and zones

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of…

Where it happened

Every event with a place to put it; 8 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

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
8

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.

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

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 Aug 25, 2:54 AM MST, 5 hours 6 minutes earlier.

Area forecast discussion, Aug 25, 2:54 AM MST, 5 hours 6 minutes before
Area Forecast Discussion
National Weather Service Tucson AZ
254 AM MST Tue Aug 25 2020

.SYNOPSIS...High pressure aloft centered along the northern Arizona
and New Mexico border will result in near record to record heat
today. High temperatures will gradually lower a couple of degrees
this week and even more over the upcoming weekend. However, readings
will remain above normal. There will be enough moisture in place
across southern Arizona for a chance of showers and thunderstorms,
but most days will be below average for late August, with day to day
variations in coverage and intensity.

&&

.DISCUSSION...Considerable debris clouds hanging on across southeast
Arizona early this morning, with a few weak echos still noted on the
KEMX radar over far eastern portions of the forecast area. Overall,
clouds and any precipitation will continue to diminish through the
early morning hours, with mostly sunny to partly cloudy skies
expected areawide by the mid morning hours.

The upper high will become centered along the northern Arizona/New
Mexico border today, with hot temperatures once again for much of
the lower elevations of Arizona. Expect near record to record heat
today across portions of southeast Arizona and an Excessive Heat
Warning remains in effect until 8 pm MST this evening (refer to
PHXNPWTWC for more information on the Excessive Heat). Otherwise,
the upper high remains in a favorable position for isolated to
scattered storm development across the forecast area this afternoon
and evening, with the highest pops in the White Mountains and from
Nogales westward into central and western Pima county. The rest of
the forecast area will have an isolated threat of thunderstorm
development. SPC has put the western two-thirds of the CWA in a
Marginal Risk, with the main threat being strong wind gusts. Have
also added patchy blowing dust to the grids/forecast for central and
western Pima county this afternoon.

In the Wednesday through Friday time frame, the upper high becomes
elongated southwest to northeast across the desert southwest into
Colorado. High temperatures are expected to lower a couple of
degrees, but will still remain well above normal. Isolated mainly
afternoon and evening showers and thunderstorms will continue across
much of southeast Arizona, with the highest pops along the Mogollon
Rim/White Mountains. Overall, thunderstorm chances will be below
normal for late August during this period.

By this weekend, the models ramp back up shower/thunderstorm chances
across southeast Arizona as the upper high shifts eastward into far
eastern New Mexico. Flow around the upper high will help import
deeper moisture into southern Arizona from Mexico, combined with
moisture surging up the Gulf as a tropical disturbance moves south
of Cabo. With the increased cloud cover and higher precipitation
chances high temperatures will moderate this weekend, lowering to
just a few degrees above seasonal normals by late in the weekend.

&&

.AVIATION...Valid through 26/12Z.
Decreasing debris /mid-level/ cloud cover this morning with SFC
winds ELY/SELY winds 8-12 kts. Expect ISOLD-SCT TSRA/SHRA developing
during the afternoon and evening hours. The strongest storms will be
W-NW of KOLS, with storm outflow wind gusts to 40 kts possible.
Otherwise, SFC winds WLY/SWLY 8-12 kts. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Another hot day today, with isolated to scattered
showers and thunderstorms. Storm activity will decrease the second
half of the work week. Minimum humidities 10-20 percent across the
valleys and 20-30 percent in the mountains, with good overnight
recoveries. Moisture returns to the area this weekend from the
south, resulting in an increase in storm activity. 20-foot winds
generally remain less than 15 mph outside of any thunderstorm gusts,
which could reach 40+ mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
 Excessive Heat Warning until 8 PM MST this evening for AZZ501-502-
 504>506-509.

&&

Discussion...Zell
Aviation/Fire Weather...Rasmussen

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

8 drought. Local standard time, as filed.

Drought, Tucson Metro Area

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
Tucson Metro Area forecast zone
Reported by
Drought Monitor
Coordinates
32.097, -111.790 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, South Central Pinal County

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
South Central Pinal County forecast zone
Reported by
Drought Monitor
Coordinates
32.904, -111.345 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, Southeast Pinal County

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
Southeast Pinal County forecast zone
Reported by
Drought Monitor
Coordinates
32.904, -111.345 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, Upper San Pedro River Valley

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
Upper San Pedro River Valley forecast zone
Reported by
Drought Monitor
Coordinates
32.109, -110.569 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, Upper Gila River and Aravaipa Valleys

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
Upper Gila River and Aravaipa Valleys forecast zone
Reported by
Drought Monitor
Coordinates
33.074, -109.563 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, White Mountains of Graham and Greenlee Counties

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
White Mountains of Graham and Greenlee Counties forecast zone
Reported by
Drought Monitor
Coordinates
33.074, -109.563 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, Galiuro and Pinaleno Mountains

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
Galiuro and Pinaleno Mountains forecast zone
Reported by
Drought Monitor
Coordinates
32.572, -110.328 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

Drought, Santa Catalina and Rincon Mountains

When
August 25, 8:00 AM MST to August 31, 11:59 PM MST
Where
Santa Catalina and Rincon Mountains forecast zone
Reported by
Drought Monitor
Coordinates
32.501, -111.567 (the zone’s center; the record gives no point)

The extreme drought (D3) category was reached in late August across most of Graham County, northern and central Greenlee County, northwest Cochise County and eastern portions of Pima and Pinal counties, including San Carlos Apache tribal lands, the White Mountains, the Pinaleno Mountains and the Santa Catalina Mountains. Below normal precipitation occurred each month from April through August of 2020 and the summer was the hottest on record in many locations. Several lightning caused wildfires and at least one human caused wildfire spread rapidly due to dry fuels, and continued into September. This included the Cow Canyon Fire in Greenlee County, which started on August 18th, but smoldered in heavy fuels with very little growth during August. Soil moisture readings were well below normal and ranked below the 20th percentile. Levels at San Carlos Reservoir fell from around 15 percent in July to less than 7 percent of storage capacity by the end of August.

What these are

Drought
A drought reaching severe (D2) or worse on the US Drought Monitor, or with notable impacts.

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

The same day elsewhere

More

Every storm in Arizona in 2020Every state in 2020This day in weather historyWarnings in Arizona, August 2020

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: 917528, 917557, 917558, 917559, 917560, 917561, 917562, 925374.