058
FXUS65 KTWC 210900
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
200 AM MST Fri Nov 21 2025

.SYNOPSIS...An active pattern continues through this weekend as a
second system is expected to arrive late today through Sunday.
Chances for precipitation hold off for much of southeastern
Arizona until Saturday afternoon and evening, though showers may
begin to move into western Pima western to central portions of
Arizona today. Temperatures remain well below normal with the
first widespread freeze expected this morning, mainly in the
valleys south and east of Tucson. Freezing morning temperatures
return early next week.

&&

.DISCUSSION...Water vapor imagery shows large scale troughing over
the Great Basin with a closed low currently centered over the
central California coast. This feature will be our next weather
maker. Here in southeast Arizona skies are clear with the
exception of western Pima County where clouds associated with the
aforementioned low are moving in. These clear skies will allow
temperatures to drop to freezing and a few degrees below freezing
south and east of Tucson. Current obs show some locales have
already dropped below freezing. Cloud cover moving in from the
west will arrive too late to stave off the colder temperatures. A
Freeze Warning is in effect for the valleys of Santa Cruz, Cochise,
and Graham counties until 9 AM. Some areas could see a hard
freeze (28 degrees or less). There is a small chance that patchy
fog could develop in parts of Santa Cruz and Cochise Counties
this morning, but confidence is low in this happening.

Today the closed low will move south becoming centered just off
the northern coast of Baja by this evening. Models bring it
eastward into Arizona beginning Saturday morning into the
overnight hours. Still some small differences in deterministic
solutions, but models do keep the low closed as it moves through.
Precip chances begin today, but only for far western Pima County.
Highs today will continue the trend of being 6-8 degrees below
normal. Precip chances expand further west late Saturday morning,
encompassing all of southeast Arizona late afternoon into the
overnight hours. Isolated embedded thunderstorms will also be
possible Saturday afternoon. Initially the air mass will be
relatively warm with high temperatures only a degree or two below
normal. Snow levels will be at or just above mountain peaks
through Saturday evening, then drop to 7500 feet Saturday night
as cooler air moves in. Initially precip will be all rain, turning
to snow above 7500 feet Saturday night. Right now the bulk of the
precip looks to fall Saturday afternoon and evening with rain
amounts generally 0.1"-0.6" in the valleys and slightly higher in
the mountains. Snow amounts will be on the lighter side, around
1-4 inches for the Catalinas, Pinalenos, and the White Mountains.

Sunday morning precip chances diminish from west to east as the
low moves into Colorado. Precip chances linger Sunday afternoon as
a small shortwave in the wake of the larger low moves through.
Temperatures also cool to 7-10 degree below normal and stay this
way on Monday as well. Freezing temperatures likely return for
areas south and east of Tucson each morning next week beginning
Monday. High temperatures however warm to around normal or just
above normal through Thanksgiving as weak ridging builds in behind
the low. The forecast is also dry for next week`s work week.

&&

.AVIATION...Valid through 22/12Z.
SKC early this morning becoming BKN-OVC AOA 15k ft AGL after
21/14Z. Sfc winds south southeast 5-10 kts through the early
afternoon, briefly becoming north northwest after 21/21Z, then
back to southeasterly this evening and overnight. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Below normal temperatures continue through the
weekend with minimum relative humidities above 30 percent, with a
minor dip to 25 percent in the valleys on today as southeastern
Arizona sits between two systems. The second system arrives late
Friday through Saturday bringing another round of showers and high
elevation mountain snow. Chances for showers remain west of
Tucson through Saturday morning, then spread east Saturday
afternoon and evening lingering Sunday. Temperatures below normal
Sunday and Monday then rise to near normal by the middle of next
week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 9 AM MST this morning for AZZ503-507>509.

&&

$$

Hardin

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