932
FXUS65 KTWC 122145
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
245 PM MST Sat Jul 12 2025
.SYNOPSIS...
Above normal temperatures continue through Monday. Increasing
monsoon activity is expected in to begin Sunday, initially in
areas east and south of Tucson. These chances increase across
southeastern Arizona through the work week. As moisture and
storm chances increase, temperatures will drop back down to
seasonable levels Tuesday onwards.
&&
.KEY MESSAGES...
- Scattered thunderstorm activity Sunday afternoon and evening
will likely create blowing dust through areas of Greenlee,
Graham, and Cochise counties. Isolated activity may move as far
west as the Tucson area Sunday evening.
- Increasing chances for monsoon activity is expected this coming
work week. Adequate moisture for increased flash flood concerns
may arrive by mid-week.
- High temperatures transition from above normal through Monday to
near or slightly below normal for the remainder of the week.
&&
.DISCUSSION...
A generally quiet day across southeastern Arizona, with the
exception at time of discussion coming from thunderstorms over the
White Mountains and the high terrain areas of Cochise county.
Flat cumulus across much of southeastern Arizona highlights the
presence of modest low level moisture but dry air and subsidence
in the mid- levels above it, as observed by the 18Z KTWC balloon.
The upper level high currently sitting over southern California
will continue to usher in dry air aloft today and keep
thunderstorm development chances to a minimum.
Tomorrow will see a shift in the direction of the mid-level flow
aloft from northwesterly to north to northeasterly. Open-wave
troughing in the upper levels will dip over eastern Arizona,
bringing upper level support for increased thunderstorm
development Sunday afternoon. While a major increase in
atmospheric moisture isn`t expected with this process, mild
moisture advection and synoptic ascent should be adequate to erode
the earlier capping inversion.
Early Sunday afternoon, thunderstorms will likely build over the
White Mountains and Gila National Forest in New Mexico, then push
south to southwest. Increased mid-level flow of around 20 knots
along with dry air in the mid and lower levels will produce an
environment conducive to strong organized thunderstorm outflows,
especially where thunderstorm clustering is likely through eastern
Graham, southern Greenlee, and Cochise counties. With the 12Z
HREF showing consistency in thunderstorm wind gust probabilities,
a Blowing Dust Advisory was issued through this area with this
forecast shift. HREF neighborhood probabilities (within 40 km of
any point) of 45 mph winds are in the 40 to 70 percent range with
10 to 25 percent chances for 60 mph. Thus not only will blowing
dust be a concern, but an isolated damaging wind gust potential
will also arrive with these thunderstorms. Santa Cruz county also
sees similar probabilities for these strong winds, with less
confidence in blowing dust. Tucson sits on the western periphery
of both thunderstorm and strong gust probabilities as uncertainty
remains in how thunderstorm clusters will evolve westward. That
said, 12Z guidance shows potential for thunderstorm chances to
last well through the evening, increasing overall chances in the
Tucson area to around 40 percent for the day. Thunderstorm motions
and dry air in the atmospheric column will mitigate any flooding
concerns, though brief periods of heavy rains creating street
ponding can`t be ruled out.
Daily thunderstorm chances are expected to become more widespread
through this coming work week as richer moisture sets in. There
will likely be day to day variability in chances as some days may
work over the atmosphere more than others, but the mid-week period
will need to be watched for increasing flash flood risk.
&&
.AVIATION...Valid through 14/00Z.
West to northwesterly winds this afternoon of 10-15 kts, with
15-20 kts and gusts to 30 kts at KSAD. FEW-SCT clouds this
afternoon of 8k-11k feet. Slight chance of a thunderstorm near
KDUG-KOLS late this afternoon and evening. Winds become light late
this evening. Isolated to scattered thunderstorms expected Sunday
afternoon and evening east and south of KTUS. Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...
An uptick in monsoon activity is expected beginning Sunday
through next week as the upper high shifts to a more favorable
location aloft. Temperatures will remain above normal through
Monday, then drop back down to near or slightly below normal by
mid to late next week. Winds will remain westerly from 10-15 mph,
with occasional gusts at or above 25 mph. Afternoon RH values in
the low lying areas will be between 10-15% through Monday, then
20-30% through the remainder of the week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Blowing Dust Advisory from 2 PM to 8 PM MST Sunday for
AZZ507>509.
&&
$$
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