Arizona, 2020

Drought in Arizona, September 29 to 30, 2020

September 29 to 30, 2020 · NWS TWC · 2 events in 2 counties and zones

The extreme drought (D3) category, which began in late August, continued throughout September across the same sections of southeast Arizona from Tucson north and east, and expanded southward to encompass all of Graham and Greenlee counties along with all but the southwest quarter of Cochise County. 25 of rainfall during September, and record breaking heat continued.

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

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The toll

Deaths
0
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.

The extreme drought (D3) category, which began in late August, continued throughout September across the same sections of southeast Arizona from Tucson north and east, and expanded southward to encompass all of Graham and Greenlee counties along with all but the southwest quarter of Cochise County. Aside from isolated thunderstorms that produced heavy rain near the Pima/Cochise county line on the 8th and in northeast Cochise County on the 9th, most of the area received less than 0.25 of rainfall during September, and record breaking heat continued. While the heavy rain on the 8th doused the relatively small Spud Rock Fire in the Rincon Mountains, several other lightning caused wildfires that started in August continued into September due to the lack of monsoon rainfall. This included the Cow Canyon Fire in Greenlee County, which grew to over 1500 acres toward the end of the month in hot, dry and breezy conditions. Soil moisture readings were well below normal and fell below the 10th percentile ranking. Levels at San Carlos Reservoir fell to less than 5 percent of storage capacity by the end of the month.

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 Sep 29, 3:21 AM MST, 4 hours 39 minutes earlier.

Area forecast discussion, Sep 29, 3:21 AM MST, 4 hours 39 minutes before
Area Forecast Discussion
National Weather Service Tucson AZ
321 AM MST Tue Sep 29 2020

.SYNOPSIS...High pressure will push temperatures back to near
record levels the second half of the week into the weekend.

&&

.DISCUSSION...Our weather will be dominated by a strong ridge of
high pressure from the west coast into the Great Basin and desert
southwest for the next 7 days. That will mean dry conditions with
afternoon highs running 8 to 12 degrees above average.

The hottest days will be Wednesday through Saturday with near
record highs and Tucson continuing to flirt with adding 100 degree
days to the total for the year. We currently stand at 98, only 1
behind the record of 99. October is going to start out way above
average, following what is now guaranteed to be the warmest
September on record. The all time record hottest temperature in
October is 102, and that will be threatened Thursday and/or
Friday.

&&

.AVIATION...Valid through 30/12Z.
Clear skies. Surface winds out of the east and southeast at 12 to
18 kts this morning, diminishing this afternoon. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Dry conditions and warmer than normal for the next
7 days. 20-ft winds will be easterly through Wednesday morning then
settle into normal diurnal trends Wednesday afternoon into the
weekend. Wind speeds will be elevated this morning. Min RH values
will be in the low teens today then drop into the single digits
for some locales Wednesday through the weekend.

&&

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

Meyer/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

2 drought. Local standard time, as filed.

Drought, Eastern Cochise County Below 5000 Feet

When
September 29, 8:00 AM MST to September 30, 11:59 PM MST
Where
Eastern Cochise County Below 5000 Feet forecast zone
Reported by
Drought Monitor
Coordinates
31.880, -109.751 (the zone’s center; the record gives no point)

The extreme drought (D3) category, which began in late August, continued throughout September across the same sections of southeast Arizona from Tucson north and east, and expanded southward to encompass all of Graham and Greenlee counties along with all but the southwest quarter of Cochise County. The area included the San Carlos Apache Tribe lands, the White Mountains, Pinaleno Mountains, Santa Catalina Mountains and the Chiricahua Mountains.

Aside from isolated thunderstorms that produced heavy rain near the Pima/Cochise county line on the 8th and in northeast Cochise County on the 9th, most of the area received less than 0.25 of rainfall during September, and record breaking heat continued. While the heavy rain on the 8th doused the relatively small Spud Rock Fire in the Rincon Mountains, several other lightning caused wildfires that started in August continued into September due to the lack of monsoon rainfall. This included the Cow Canyon Fire in Greenlee County, which grew to over 1500 acres toward the end of the month in hot, dry and breezy conditions. Soil moisture readings were well below normal and fell below the 10th percentile ranking and levels at San Carlos Reservoir fell to less than 5 percent of storage capacity by the end of the month.

Drought, Chiricahua Mountains

When
September 29, 8:00 AM MST to September 30, 11:59 PM MST
Where
Chiricahua Mountains forecast zone
Reported by
Drought Monitor
Coordinates
31.880, -109.751 (the zone’s center; the record gives no point)

The extreme drought (D3) category, which began in late August, continued throughout September across the same sections of southeast Arizona from Tucson north and east, and expanded southward to encompass all of Graham and Greenlee counties along with all but the southwest quarter of Cochise County. The area included the San Carlos Apache Tribe lands, the White Mountains, Pinaleno Mountains, Santa Catalina Mountains and the Chiricahua Mountains.

Aside from isolated thunderstorms that produced heavy rain near the Pima/Cochise county line on the 8th and in northeast Cochise County on the 9th, most of the area received less than 0.25 of rainfall during September, and record breaking heat continued. While the heavy rain on the 8th doused the relatively small Spud Rock Fire in the Rincon Mountains, several other lightning caused wildfires that started in August continued into September due to the lack of monsoon rainfall. This included the Cow Canyon Fire in Greenlee County, which grew to over 1500 acres toward the end of the month in hot, dry and breezy conditions. Soil moisture readings were well below normal and fell below the 10th percentile ranking and levels at San Carlos Reservoir fell to less than 5 percent of storage capacity by the end of the month.

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, September 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: 917549, 917550.