949
FXUS65 KTWC 072034
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
134 PM MST Sun Sep 7 2025
.SYNOPSIS...Drying trend commences today with only slight chances of
precipitation today and tomorrow focused on the higher terrain,
with mostly dry conditions Tuesday. Breezy winds Wednesday and
Thursday along with some increased moisture will result in slight
chances for showers and thunderstorms Wednesday and Thursday,
especially east of Tucson. Most of the week will have near normal
temperatures.
&&
.KEY MESSAGES...
- A drying trend leading to only slight chances (15-20%) of
isolated showers and thunderstorms mainly along the higher
terrain over the next few days.
- Better moisture and forcing mid to late week will allow for some
increased shower and thunderstorm chances (20-40%) and gusty afternoon
winds (20-35 mph), strongest Wednesday-Thursday
- Temperatures remain near normal throughout the week.
&&
.DISCUSSION...
Latest trends and models still indicating isolated showers and
thunderstorms developing along the higher terrain today, mainly
south and east of Tucson. Any storms that do develop will be
moving slowly southeast and may be capable of producing locally
heavy downpours. Not anticipating any significant impacts with any
showers or storms that develop today though. Similar conditions
tomorrow with what little chances (10-20%) we have remaining
mostly confined to the higher terrain. Mostly dry conditions
expected Tuesday.
Over the next few days we will transition from a more ridge
dominate pattern to a more fall-like pattern. Currently we`re
under weak northwesterly flow associated with a short amplitude
ridge overhead. By late Tuesday-Wednesday we will begin to be
influenced by a feature upstream, an upper low currently
circulating near 40N, 135W off the Pacific Northwest coast. This
upper low will dig into CA/NV over the next several days, leading
to increased southwest flow across AZ. This will lead to
noticeably breezy to gusty afternoon winds Wednesday-Thursday,
with gusts to around 20-35 mph. In addition to increased winds,
the added upper-level lift supplied by the upstream low and
southerly flow will aid in enough moisture that our chances of
precipitation increase a bit Wednesday-Thursday as well mainly
from Tucson east. As the low continues to dig into AZ, drier
southwesterly flow will dominate much of southeastern AZ by
Friday, leaving us mostly dry again.
Unfortunately this fall-like pattern won`t influences our apparent
temperatures too much, only slightly nudging temperatures down a
couple of degrees. Overall temperatures will remain near seasonal
normals through the next 7 days.
Looking beyond Friday, the upper low is progged to weaken as it
lifts across the Rockies through the weekend, keeping mostly dry
air in place with weak flow aloft.
&&
.AVIATION...Valid through 08/00Z.
Isolated showers and thunderstorms (-SHRA/-TSRA) mainly focused on
the higher terrain today and tomorrow, will likely remain in the
vicinity of KOLS, with low confidence impacting the terminal
directly today. With any storms today expect variable and gusty
winds to around 30-35 knots. Besides storm influences, winds
should remain fairly light, generally less than 10-12 knots,
favoring northwesterly directions through the afternoon and
resuming typical overnight drainage patterns.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Minimum relative humidities 25 to 50 percent
today, lowering to 15 to 30 percent much of next week. Drier air
today in the valleys with just enough moisture for a slight
chance of showers and thunderstorms focused in the higher terrain.
Similar trends tomorrow with most locales staying dry Monday and
Tuesday with slight chances of showers and thunderstorms mainly
over the higher terrain. Thereafter, some moisture returns for a
slight chance of showers and thunderstorms mainly east of Tucson
mid to late week before drying resumes again Friday into next
weekend. Expect gusty and erratic winds in or near any
thunderstorms. Otherwise, surface winds will be mostly light
through Tuesday, with breezy to gusty winds Wednesday- Thursday,
bringing gusts to around 20-35 mph. High temperatures near normal
for most of this week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Discussion...Peters
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Tucson, AZ 
