Arizona, 2020

Drought in Arizona, December 1 to 31, 2020

December 1 to 31, 2020 · NWS TWC · 14 events in 14 counties and zones

The exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. 5 inches below normal.

Where it happened

Every event with a place to put it; 14 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
14

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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

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 Nov 30, 1:45 PM MST, 10 hours 15 minutes earlier.

Area forecast discussion, Nov 30, 1:45 PM MST, 10 hours 15 minutes before
Area Forecast Discussion
National Weather Service Tucson AZ
145 PM MST Mon Nov 30 2020

.SYNOPSIS...Dry weather will continue through the work week with a
chance of showers this weekend mainly east of Tucson. Gusty
southeasterly winds will diminish this afternoon with lighter winds
thereafter through Wednesday before increased easterly winds
Thursday into Friday. Near normal temperatures through Wednesday
then slightly below normal into the weekend.

&&

.DISCUSSION...Winds continue to diminish across the forecast area
this afternoon and the Wind Advisory that previously in effect was
allowed to expire at 12 PM. A fairly quiet weather regime is
expected through Wednesday as southeast Arizona will remain under
northwesterly flow aloft with near normal temperatures and generally
light winds.

The upper air pattern this week is quite atypical with blocking
resulting in a persistent ridge across the west coast with upper
high extending from the Pacific Northwest into adjacent Canada.
Meanwhile, an elongated east-west trough and associated upper low
will be present from the Central Plains into the Central Rockies. A
disturbance on the western flank of this trough will drop down
towards the Four Corners Wednesday and then perhaps develop into
some kind of closed low, perhaps aided by an additional disturbance
trying to break through the west coast ridge. Bottom line is for
Thursday into Friday we are confident that cooler temperatures will
move in with increased easterly winds again.

Confidence diminishes significantly this weekend into early next
week as models are inconsistent on the strength and location of the
aforementioned upper low. Will lean towards the mean EPS solution
and WPC mean cluster solution which depicts an upper low near or
just southwest of us but not nearly as deep as the 12Z deterministic
ECMWF. The location and depth of the upper low will determine just
how much moisture is able to be pulled northward into the area. For
now, have introduced slight chance showers this weekend for locales
mainly east of Tucson. Low confidence continues into early next
week on just how fast anything pushes to the east away from our
area. During this time frame from the weekend into early next week
near to slightly below normal.

&&

.AVIATION...Valid through 02/00Z.
SCT-BKN clouds above 20k ft until early this evening then SKC. Gusty
ELY to NELY surface winds 12-20 kts with locally higher gusts up to
30 kts through 01/01Z then easing to less than 15 kts. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Seasonal temperatures and humidity levels through
the forecast period. Diminishing easterly winds this evening with
much less wind on Tuesday and Wednesday. Another round of strong
east to northeast winds is looking more likely for Thursday into
Friday, again potentially resulting in local elevated to near
critical fire weather conditions for a period of time. A developing
cut-off low over the state late in the week with bring a slight
chance of valley rain and mountain snow showers to areas east of
Tucson this weekend.

&&

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

&&

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

14 drought. Local standard time, as filed.

Drought, Tohono O Odham Nation

When
December 1, 12:00 AM MST to December 31, 11:59 PM MST
Where
Tohono O Odham Nation forecast zone
Reported by
Drought Monitor
Coordinates
32.501, -111.567 (the zone’s center; the record gives no point)

The exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Upper Santa Cruz River and Altar Valleys

When
December 1, 12:00 AM MST to December 31, 11:59 PM MST
Where
Upper Santa Cruz River and Altar Valleys forecast zone
Reported by
Drought Monitor
Coordinates
31.812, -111.318 (the zone’s center; the record gives no point)

The exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Tucson Metro Area

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, South Central Pinal County

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Southeast Pinal County

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Upper San Pedro River Valley

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Eastern Cochise County Below 5000 Feet

When
December 1, 12:00 AM MST to December 31, 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Upper Gila River and Aravaipa Valleys

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, White Mountains of Graham and Greenlee Counties

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Galiuro and Pinaleno Mountains

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Chiricahua Mountains

When
December 1, 12:00 AM MST to December 31, 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Dragoon/Mule/Huachuca and Santa Rita Mountains

When
December 1, 12:00 AM MST to December 31, 11:59 PM MST
Where
Dragoon/Mule/Huachuca and Santa Rita Mountains forecast zone
Reported by
Drought Monitor
Coordinates
31.834, -110.796 (the zone’s center; the record gives no point)

The exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Santa Catalina and Rincon Mountains

When
December 1, 12:00 AM MST to December 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 exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

Drought, Baboquivari Mountains

When
December 1, 12:00 AM MST to December 31, 11:59 PM MST
Where
Baboquivari Mountains forecast zone
Reported by
Drought Monitor
Coordinates
32.097, -111.790 (the zone’s center; the record gives no point)

The exceptional (D4) and extreme (D3) drought categories continued across a large part of southeast Arizona during December, with the exception of western Pima County. Precipitation totals for the month, which occurred primarily on December 9-10, totaled 0.10 to 1 inch or about 0.5 to 1.5 inches below normal. Soil moisture readings remained below the 5th percentile ranking in most areas, and below the 10th percentile ranking near the New Mexico state line. Levels at San Carlos Reservoir dropped slightly, to around 2 percent of storage capacity.

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, December 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: 932120, 932121, 932122, 932123, 932124, 932125, 932126, 932127, 932128, 932129, 932130, 932131, 932132, 932133.