195
FXUS65 KTWC 260803
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
103 AM MST Mon Oct 26 2026

.SYNOPSIS...Dry conditions are expected across southeast Arizona
into Thursday. Showers and thunderstorms will return to the region
late Thursday through the weekend. Afternoon high temperatures will
be near normal today, warming to a couple of degrees above normal
Tuesday through Thursday, then lowering back below normal Friday
through the weekend.

&&

.DISCUSSION...Near zonal flow currently in place across Arizona,
with shortwave ridging just upstream. PW values were in the 0.25-
0.40 inch range across the forecast area, with dewpoints in the
upper 30s to lower 40s. High cirrus level clouds were noted across
much of southeast Arizona, but will shift northeast of the area by
the late morning hours. Otherwise, high pressure aloft will build in
across the desert southwest through Wednesday, with the upper flow
pattern turning increasingly southwest toward midweek. This will
result in dry conditions and warmer temperatures across southeast
Arizona into Thursday.

Late this week into the upcoming weekend the models show an active
pattern, with west coast troughing and southern stream moisture
moving into the southern half of the west coast and across the
Intermountain West. There continues to be timing/track differences,
with the ECMWF now focusing more on the northern half of Arizona
into the Great Basin, while the GFS is focused further south across
the desert southwest. The GFS/ECMWF solutions have flipped over the
last 24 hours. Cluster Analysis is in good agreement with the west
coast troughing late this week/weekend, although most solutions keep
the largest height anomalies to our north/northwest. The EMC GEFS
plumes across southeast Arizona have mean storm rainfall totals of
0.45-0.65 inches, with a couple of solutions indicating 1.0+ inches.
The 24-hour Tucson rainfall NBM probabilities currently have a 38%
probability for 1+ inch and a 10% probability for 2+ inches. The
current NWS forecast for Tucson has 0.18 inches spanning Friday and
Saturday, with 0.82 inches during the Sunday/Monday time frame and
higher totals in the mountains. This seems reasonable given the
model differences at this time. Overall, the weather turns unsettled
late in the day Thursday, with a chance of showers and thunderstorms
Friday and Saturday across southeast Arizona and then the potential
for subtropical moisture plume influence late Saturday into Monday.

High temperatures will be near normal today, warming to 2-4 degrees
above normal Tuesday through Thursday, then lowering to 4-6 degrees
below normal Friday and Saturday.

&&

.AVIATION...Valid through 27/12Z.
SCT-BKN clouds AOA 20k ft AGL mainly from KTUS eastward thru 26/18Z,
then clear skies areawide thru the remainder of the forecast period.
SFC wind 10 kts or less thru the forecast period, favoring a
WLY/NWLY direction during the afternoon/early evening hours and
variable in direction at other times. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Dry conditions are expected across southeast Arizona
into Thursday. Showers and thunderstorms will return to the region
late Thursday through the weekend. High temperatures will be near
normal today, warming to a couple of degrees above normal Tuesday
through Thursday, then lowering back below normal Friday through the
weekend. 20-foot winds will generally be 15 mph or less through
Friday. Minimum RH values will be in the 18-30 percent range in the
valleys today (higher in the mountains) and in the 15-25 percent
range Tuesday and Wednesday. Minimum RH levels will increase late in
the week and over the weekend, with values at 40+ percent.

&&

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

&&

$$

Zell

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