Heat in Arizona, May 2, 2026

Area Forecast Discussion
National Weather Service Tucson AZ
310 AM MST Sat May 2 2026

.SYNOPSIS...

A Pacific system will approach through early next week, crossing
the region by mid-week. Breezy winds are expected ahead of the
system with chances for showers and thunderstorms arriving late
Monday through Tuesday as a front crosses southeastern Arizona.
High temperatures fall below normal with this frontal passage
Tuesday and Wednesday, then quickly rise through the second half
of the work week.

&&

.DISCUSSION...

In the upper levels today, a vorticity lobe will roll through
eastern portions of southeastern Arizona. Modest instability
associated with this shortwave will bring chances for showers
and potentially a thunderstorm, mainly this afternoon in
northern Graham and Greenlee counties over and near the White
Mountains. A tightening pressure gradient today will lead to
increased southeasterly winds in the Gila River valley of
Graham/Greenlee/Cochise counties. Southeasterly winds of 10-15
mph will become common elsewhere across much of southeastern
Arizona (especially in areas open to southeasterly flow)
through Sunday morning. At its strongest, winds in the Gila
should be around 18-23 mph with gusts up to 35 mph before coming
down somewhat late this afternoon

This east-southeast flow will increase moisture out of New
Mexico and northern Mexico with early morning GOES precipitable
water readings showing 0.5-0.6 inch PWats pushing across the
AZ/NM border. This moisture push will, as mentioned above,
allow for convection off the White Mountains to develop this
afternoon, with potentially some additional very isolated
activity further south. Forecast soundings show very shallow but
adequate instability for some cloud build-ups to develop, but a
mid- level capping inversion in place keeps the forecast
otherwise dry today for most of the area.

Sunday, flow aloft becomes more active as a deep Pacific low
over the California coast nudges closer. Surface winds will
shift from the southeast to southwest during the day, with
sustained winds becoming lighter in the east than in the
previous 36 hours. With precipitable water values of 0.5-0.75
inches and subtle embedded shortwaves ejecting out of the
upstream trough, some shallow convection should attempt to
develop Sunday afternoon. A continuous stream of mid-high level
clouds will keep instability on the low side, but given the
synoptic influence and increased moisture content a few light
showers or a thunderstorm can't be ruled out Sunday afternoon.
The 00Z HREF highlights the eastern counties as the somewhat
higher probability area for rain chances, but the probability is
non-zero across most of southeastern Arizona. Current forecast
chances range from 5-15 percent mainly east of a Dudleyville-
Tucson- Nogales line Sunday afternoon.

Through the first half of the work week, the Pacific low and
associated low-level front will approach and cross the region.
Shower chances begin to increase late Monday ahead of the front
with the brunt of the chances, including a slight chance of
thunderstorms, currently forecast on Tuesday. These forecast
chances Tuesday (20-50 percent along the track of the front)
have come up quite a bit in the last 24 hours as models have
trended deeper with the upper low with a subsequently wetter
solution. Additionally this trend has brought the forecast high
on Tuesday down to about 10 degrees below average with desert
high temperatures in the 70s. While forecast probabilities for
rain showers have come up, the overall track of the low will
still be fairly quick and progressive with a modest moisture
field, which should keep overall rain totals on the light side.
Current forecast rainfall totals range from a few hundredths to
two tenths of an inch, with an isolated chance of up to a half
inch. Winds with the approach and crossing of this low will be
breezy and out of the west/southwest with gusts Monday and
Tuesday afternoon up to 25-35 mph.

Temperatures will remain below normal on Wednesday before
quickly rising through the remainder of the week. The broad
upper level pattern going into next weekend favors above normal
temperatures with ensemble models depicting positive height
anomalies and a western US ridge building in.

&&

.AVIATION...Valid through 03/12Z.

FEW-SCT ceilings at 6-10k feet from KSAD-KDUG through 02/15Z,
then FEW-SCT clouds 9k-12k feet developing after 02/19Z across
much of southeastern Arizona. Isolated to scattered showers in
the vicinity of the White Mountains north of KSAD this afternoon
and evening. Southeast to east winds at KSAD- KDUG 13-18 kts
with gusts to 25 kts, becoming 10-15 kts after 02/19Z.
Southeast- east winds under 12 kts elsewhere.

&&

.FIRE WEATHER...

Minimum relative humidities above 20-25 percent east of Tucson-
Nogales today and Sunday and 10-15 percent to the west. Strong
southeast to east winds through the Gila River valley of 18-23
mph with gusts up to 35 mph through the early afternoon today,
decreasing to 12-17 mph and gusts to 25 mph through tonight.
Winds east to southeast 10-15 mph elsewhere, with somewhat
stronger winds in areas exposed to east-southeast flow.
Scattered showers should develop over the White Mountains this
afternoon with isolated thunderstorms, though the probability of
wetting rain is low. This activity should diminish this early
evening. Erratic wind gusts of 35 mph are possible with any
thunderstorm.

A Pacific system and front begins to approach Sunday, crossing
the region late Monday through Tuesday. Winds turn to the
southwest Sunday afternoon ahead of this system and increase to
15-20 mph Monday and Tuesday afternoons with gusts of 25-35 mph.
A very isolated chance of a shower or thunderstorm in the
eastern counties Sunday afternoon, with isolated to scattered
showers and potentially a thunderstorm associated with the
front late Monday through Tuesday. Minimum relative humidities
increase from 15-25 percent Monday to 20-30 percent Tuesday,
with even higher values in the mountains. A warming and drying
trend is expected through the second half of the work week.

&&

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

&&

DISCUSSION...Edwards
AVIATION...Edwards
FIRE WEATHER...Edwards

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