745
FXUS65 KTWC 232030
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
130 PM MST Fri Oct 23 2026

.SYNOPSIS...There will be a slight chance of showers and
thunderstorms along the Arizona and New Mexico state line
through mid-day Saturday. Dry conditions are then expected
areawide Sunday into next week. High temperatures will be below
normal into early next week, warming to near normal during the
middle of next week.

&&

.DISCUSSION...There`s an old saying that was passed down to me
from my grandma, "after a storm comes the calm." While today
may not be entirely calm with a slight chance for light showers
remaining along the Arizona/New Mexico border this afternoon,
considerably quieter weather is in store for Southeast Arizona
the next several days following our recent bout with turbulent
weather.

The upper weather pattern this afternoon is defined by a mean
trough across the NRN Intermountain West extending SSW into
southern California...with the latest water vapor imagery
indicating two distinct low centers across northern Nevada and
central California. The recent GOES precipitable water imagery
indicated a significant area of drier air has expanded into the
area, with PWATs between 0.40 and 0.50 across Pima and Santa
Cruz counties. Still some lingering moisture holding onto the
Arizona/New Mexico border with PWATs ranging between 0.65 and
0.75 inches. This is supported by surface dewpoints early this
afternoon, with values hovering from the mid 40s across far
western Pima to the lower 50s in the Tucson Metro, and in the
upper 50s in the Gila River Valley and along the AZ/NM state
line. I would expect decent mixing this afternoon will bring
the dewpoints in Tucson down into the mid 40s, but I am confident
that higher moisture will persist out east, especially given
the higher soil moisture content. The combination of weak mid-
level lift east of the mean trough and this moisture along the
AZ/NM border will result in a slight chance for light showers
this afternoon, possibly persisting into mid-day Saturday.
Otherwise, expect fair weather cumulus from Tucson east today
and clear skies west.

The upper-low to our west eventually ejects NE this weekend with
another kicker low developing along the Pacific Northwest
coastline. Ensemble members are all over the place with regards
to both the north/south and east/west position and movement of
this feature with lots of variance evident on the Empirical
Orthogonal Functions (EOF) of the GEFS/ENS/GEPS Sunday. In
general we will see an upper-low develop, but the amplification
and position will depend on the strength of the upper ridge
building into the Gulf of Alaska. This has ramifications for
what happens later next week, as both the deterministic GFS and
ECMWF are trying to push a slug of subtropical moisture east
toward the Desert Southwest next weekend. If the upper-low
pattern remains an open wave for the majority of next week, we
will see a strong zonal flow directing that moisture plume our
way, possibly getting wrapped up ahead of the upper low as it
swings into California. This potential heavy rainfall event is
getting picked up by the grand ensemble of the NBM, with a
20-40 percent probability for a 48-hr rainfall in excess of an
inch next Sunday and Monday (November 1-2) on the 23/12Z NBM
run. Again, still a lot of variance in the early stages of this
pattern setup, so my confidence is low on the timing and
strengthof any pcpn event we may see (not this weekend but the
next weekend).

Until then...enjoy the calm and take advantage of the beautiful
weekend in store for Southeast Arizona.

&&

.AVIATION... Valid through 25/00Z. SCT-BKN clouds at 5k-8k ft
AGL east KTUS to the AZ/NM state line through mid-day Saturday.
with a slight chance of -SHRA/-TSRA along the AZ/NM border. SFC
wind southwest less than 12 kts west of KTUS, and 10-15 kts with
gusts to 25 kts east of KTUS into this evening, then wind less
than 12 kts and terrain driven overnight. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...High temperatures will be below normal through
Monday, warming to near normal Tuesday and Wednesday of next
week, then lowering back below normal by the end of next week.
There will be a slight chance of showers and thunderstorms
through mid-day Saturday along the Arizona and New Mexico state
line and in the White Mountains. 20-foot winds will generally
be 15 mph of less through at least the middle of next week.
Minimum RH values will be in the 25-40 percent range in the
valleys through Sunday (higher in the mountains), lowering into
the 20-30 percent range next Monday through Wednesday.

&&

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

&&

$$

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