Vail, Arizona Weather Forecast Discussion

388
FXUS65 KTWC 270218
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
718 PM MST Fri Sep 26 2025
.SYNOPSIS...Isolated to scattered showers and thunderstorms
continue through Saturday, with a Flash Flood Watch in effect
through Saturday evening. A drying trend will begin this weekend.
Temperatures will be just below normal through Monday then around
normal thereafter.
&&
.UPDATE...The remainder of the Severe Thunderstorm Watch has
expired as scheduled. Though the radar across southeastern Arizona
is fairly unimpressive this evening, redevelopment of isolated
thunderstorms tonight can`t be ruled out with support via the
upper trough to the west.
&&
.UPDATE... /issued 453 PM MST Fri Sep 26 2025/ Quick update to
cancel the Graham and Cochise county portions of the severe
thunderstorm watch. Widespread cloud cover has kept instability
down through much of the watch area. Isolated convection has
developed in central Pima and Pinal counties, however even further
west instability has struggled to develop. Increasing vorticity
advection from the western trough will continue thunderstorm
chances through tonight, but the severe threat looks to be waning.
The Severe Thunderstorm Watch continues for Pinal, Pima, and
Santa Cruz counties until 7 PM MST.
&&
.PREV DISCUSSION... /issued 226 PM MST Fri Sep 26 2025/ Current
radar shows scattered showers and thunderstorms south of Tucson
with isolated storms in Pinal County. Most of the activity so far
has been to the north in Maricopa County. The closed low is at the
AZ/CA border with the best synoptic scale ascent currently over
Maricopa and Pinal Counties where the strongest storms are. Over
the next few hours it will slowly move eastward with better upper
level spreading over southeast Arizona. All the ingredients are in
place for strong to severe storms from central Pima County
eastward. The 26/18Z KTWC sounding measured SBCAPE of 1600 J/kg,
PWAT 1.27 inches, sfc-6km shear of 35 kts, dry mid-levels between
600mb-400mb, and a veering low level wind profile. This will
support storms capable of damaging winds and hail up to 1.5
inches. Because of this a Severe Thunderstorm Watch is in effect
for all counties except Greenlee. The latest WoFS run (20Z) is
highlighting better chances for severe hail with severe winds a
secondary threat. Over the next few hours it shows Pinal County
and central/eastern Pima County having the best chances for severe
hail. Expect thunderstorms activity in these areas to increase as
better upper level support moves over the area and surface
heating continues. Storms in Cochise County may struggle because
of cloud cover from shower activity. Heavy rainfall will also be a
threat with Santa Cruz County already under a Flash Flood
Warning. WoFS and the HREF are pinpointing Santa Cruz County,
Pinal County, and southwest Cochise County for the best threat for
heavy rainfall. Ensemble mean rainfall totals for those areas are
between 1"-2" with 90th percentile showing localized areas of 3
inches.
Saturday the low will still be along the AZ/CA border, but
moisture will be reduced likely leading to reduced coverage of
storms. This is backed up by hi-res guidance that shows isolated
to scattered showers and thunderstorms from Tucson eastward with
the best chances in Graham and Greenlee Counties. The heavy
rainfall threat is also reduced with HREF 3 hour 40 km
neighborhood probabilities for 1 inch of rain around 10 percent
for areas east of Tucson. Because of this will need to evaluate
the Flash Flood Watch in the future for Saturday. With storms
currently ongoing I will keep it in place for now. Sunday the low
begins to open up and moves through north central Arizona. This
will further reduce PWATS with thunderstorm chances mainly in
Graham and Greenlee Counties.
During the work week high pressure will build to the south
centered over northern Mexico with shortwaves passing well to the
north around the southern periphery of a large closed low in the
Pacific Northwest. This will lead to dry conditions next week with
temperatures right around normal through the middle of the week.
Later in the week ensembles are hinting at the ridge in Mexico
building further north which would raise temperatures to a few
degrees above normal.
&&
.AVIATION...Valid through 28/00Z.
Isolated to scattered shower and thunderstorms tonight mainly
KOLS-KDUG up to KSAD, diminishing after 27/06Z. Pockets of near
MVFR cigs in rain, otherwise SCT-BKN 6k-10k ft ceilings with FEW-
SKC towards KTUS. On Saturday SCT- BKN 6k-10k ft AGL from Tucson
east after 27/18Z. Isold TSRA possible mainly east of Tucson
during the afternoon. Outside of TSs, SFC winds SLY to SWLY at
10-15 kts with gusts up to 25 kts and overnight SELY 5-10 mph.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect scattered showers and thunderstorms today
from central Pima County eastward with some capable of damaging
winds and hail. Tomorrow and Sunday storm coverage decreases with
the best chances east of Tucson. General winds will be south to
southwest through next week with speeds up to 15 mph and gusts up
to 20 mph. The above normal moisture will keep min RHs above 25
percent through most of the weekend. Temperatures will be around
normal through the weekend. Next week, temperatures will be
slightly above normal with winds less than 15 mph and min RHs
18-22 percent in the valleys and 25-30 percent in the mountains.
&&
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Saturday evening for AZZ503>514.
&&
$$
Update...Edwards
Public...Hardin
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NWS TWC Office Area Forecast Discussion