021
FXUS65 KTWC 012124
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
224 PM MST Mon Sep 1 2025

.SYNOPSIS...Isolated thunderstorms possible today with any
thunderstorm potentially producing gusty winds and briefly heavy
rain. Daily chances for thunderstorms mainly south and west of
Tucson continue through Wednesday. Thursday into the weekend rain
chances become more widespread as tropical moisture moves in.
High temperatures will be near normal through mid-week, then
become below normal the second half of the week into the weekend.

&&

.DISCUSSION...Radar shows light showers along the international
border and convection in the White Mountains. Still looking to be
a low-grade monsoon day with storms mainly in the White Mountains
and western/central Pima County. Mid-level easterly flow has
brought slightly dryer air into areas east of Tucson and is
beginning to moisten up areas west of Tucson. These easterly winds
will push any storms that form over the White Mountains and Rim
into Gila and Pinal Counties rather Graham and Cochise Counties
like yesterday. A weak vort max will be moving through northern
Sonora and could provide extra support for storms along the
international border and western Pima County. However lingering
showers and cloud cover could suppress storms in this area. The
main threats today will be strong gusty winds and brief heavy
rainfall.

Tuesday and Wednesday areas east of Tucson continue to be on the
dryer side with PWATs dropping below 1" and areas west of Tucson
will be on the wetter side with PWATs around 1.5". Because of this
the bulk of thunderstorm activity is expected to be west and south
of Tucson with chances also in the White Mountains. This is
reflected in CAMs for Tuesday afternoon and evening, which show
scattered thunderstorms over central and western Pima County.
Storms will be capable strong gusty winds and locally heavy
rainfall. Outflows could also kick up some dust over the Tohono
O`odham and western Pima County.

For the remainder of the work week the weather will be highly
depended on what happens in the tropics. Currently the NHC has an
80 percent chance for tropical cyclone formation off the west
coast of Mexico over the next 48 hours. Once it approaches
southern Baja there is considerable uncertainty with its
trajectory. Some models keep it west of Baja out at sea, while
others curve it northeastward across Baja and the Gulf of
California into Sonora. Even with the uncertainty in its path
there is higher confidence that southeast Arizona will see an
increase in moisture area wide. Widespread rain chances will be
possible starting Thursday and continue into the weekend. Heavy
rainfall leading to flash flooding will be the main concern. Right
now the best moisture looks to be from Tucson south and westward.
As the track becomes more certain the exact areas that could be
under threat for heavy rainfall will become more certain. This
increase in moisture will also lead to a nice cool down with
temperatures falling 4-8 degrees below normal Thursday into the
weekend.

&&

.AVIATION...Valid through 03/00Z.
Expect BKN clouds 8k-12k ft AGL through the period. Isolated
showers and thunderstorms will be possible this afternoon and
evening, with greater coverage more likely south and west of KOLS
and north of KSAD. Tuesday afternoon expect another round of
thunderstorms mainly west of KOLS and KTUS. Surface winds will be
southeasterly 10-15 kts with gusts to 25 knots. The strongest
winds will be at KSAD and KDUG. Aviation discussion not updated
for TAF Amendments.

&&

.FIRE WEATHER...Minimum relative humidity values generally above
20-30 percent across southeastern Arizona through the week. Near
normal temperatures through mid-week, then lower than normal the
second half of the week. Winds today out of the east to southeast
at 12 to 17 mph with gusts of 20 to 30 mph, especially in areas
open to easterly flow such as the Gila River Valley. Southeasterly
winds continue Tuesday then become lighter mid-week. Isolated
thunderstorms today, with greater chances over the White Mountains
and in far southern locations including Santa Cruz through
western Pima counties. An influx of tropical moisture will lead to
widespread rain chances Thursday into the weekend.

&&

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

$$

Hardin

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