Arizona, 2018

Drought in Arizona, May 22 to 31, 2018

May 22 to 31, 2018 · NWS TWC · 3 events in 3 counties and zones

Extreme drought, (D3 category), which began in January, expanded during May to cover large sections of Pima and Pinal Counties. Extreme drought continued across Santa Cruz County and parts of Cochise, Graham and Greenlee Counties as only one light rainfall event occurred during May.

Where it happened

Every event with a place to put it; 3 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
3

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.

Extreme drought, (D3 category), which began in January, expanded during May to cover large sections of Pima and Pinal Counties. Extreme drought continued across Santa Cruz County and parts of Cochise, Graham and Greenlee Counties as only one light rainfall event occurred during May.

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 May 22, 11:20 AM MST, 40 minutes earlier.

Area forecast discussion, May 22, 11:20 AM MST, 40 minutes before
Area Forecast Discussion
National Weather Service Tucson AZ
Issued by National Weather Service Phoenix AZ
1120 AM MST Tue May 22 2018

.SYNOPSIS...
Dry conditions through the upcoming holiday weekend. Gusty winds
will occur today and should return again this weekend as a couple of
low pressure systems move north of the area. High temperatures will
warm above seasonal normals later this week and continue into the
weekend.

&&

.DISCUSSION...
An upper level low centered over southern Nevada this morning is
currently bringing clouds and showers to the Great Basin along
with isolated thunderstorms. Just to the south, the Desert SW
sits under very dry southwesterly flow where mostly clear skies
are being observed. In response to this low pressure system,
breezy southwesterly winds will again develop over our CWA this
afternoon as daytime heating mixes higher momentum air down to the
surface. Gusts are forecast to be of similar magnitude to what
was observed on Monday, albeit slightly weaker, ranging from 20 to
30 mph in and around Tucson today. Given the dry and breezy
conditions across our CWA, a Red Flag Warning remains in effect
from noon to 7 PM MST today for the White Mountains.

In addition to the winds, modest cooling from Monday's
temperatures is expected this afternoon as cooler air from the
aforementioned low pressure system works its way into our area.
Looking at the latest 12Z sounding, 850 mb temperatures have
cooled roughly 2 F over 24 hours ago while surface temperatures
are reporting similar to slightly cooler conditions. Everything
considered, the forecast looks on track and no changes have been
made.

&&

.AVIATION...Valid through 23/18Z.
Under clear skies, gusty SSW winds will be the main aviation
concern. Gusts nearing 25-30kt will prevail through sunset, then
weaken later this evening. Directional headings this afternoon will
be somewhat more due south than is typical. The usual light and
variable drainage wind will settle in overnight. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...A Red Flag Warning is in effect from noon to 7 PM
MST today for the northern portions of Fire Weather Zone 153; or,
more specifically for the Alpine District. The combination of strong
and gusty south to southwest winds, low relative humidity, and a
very high fire danger will create critical fire conditions.

Otherwise, dry conditions will continue into early next week.
Although gusty southwest winds will occur this afternoon elsewhere
across southeast Arizona, wind speeds are not expected to meet Red
Flag criteria. 20-foot winds will generally be less than 15 mph
Wednesday through Friday. Gusty afternoon winds should return this
weekend into early next week as another low pressure system moves
north of the area.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon today to 7 PM MST this evening for
AZZ153.

&&

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The radar

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

Open the radar archive at this moment

Event by event

3 drought. Local standard time, as filed.

Drought, Western Pima County

When
May 22, 12:00 PM MST to May 31, 11:59 PM MST
Where
Western Pima County forecast zone
Reported by
Drought Monitor
Coordinates
32.097, -111.790 (the zone’s center; the record gives no point)

Extreme drought (D3 category) expanded across the western half of Pima County and parts of southeast Pinal County during May. Light rainfall amounts occurred on one day during the month, but this was not sufficient to stave off the drought's expansion. Soil moisture values in the western deserts were ranked below the 10th percentile.

Drought, South Central Pinal County

When
May 22, 12:00 PM MST to May 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)

Extreme drought (D3 category) expanded across the western half of Pima County and parts of southeast Pinal County during May. Light rainfall amounts occurred on one day during the month, but this was not sufficient to stave off the drought's expansion. Soil moisture values in the western deserts were ranked below the 10th percentile.

Drought, Southeast Pinal County

When
May 22, 12:00 PM MST to May 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)

Extreme drought (D3 category) expanded across the western half of Pima County and parts of southeast Pinal County during May. Light rainfall amounts occurred on one day during the month, but this was not sufficient to stave off the drought's expansion. Soil moisture values in the western deserts were ranked below the 10th percentile.

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 2018Every state in 2018This day in weather historyWarnings in Arizona, May 2018

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: 753408, 753409, 753410.