397
FXUS65 KTWC 241639
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
939 AM MST Mon Nov 24 2025

.SYNOPSIS...Cooler than normal temperatures today then a warmup to
normal or a few degrees above normal Tuesday into the first part of
the weekend. The next weather system could possibly impact southeast
Arizona late this weekend into early next week bringing cooler
temperatures and precipitation chances.

&&

.KEY MESSAGES...

&&

.UPDATE...Dense fog advisory has been extended and is now in effect
until 11 am MST this morning. Little to no improvement on the fog
situation so far this morning across portions of Cochise, Graham,
and Santa Cruz counties. Webcams and airport observations continue
to show visibility reductions to a quarter-mile or less. Over the
next hour or so the sun should really help progress fog erosion, but
motorists should continue to drive with caution and be prepared for
sudden drops in visibility.

Today, high temperatures will be a slightly below normal topping out
in the 60s across southeast Arizona with mostly sunny skies once the
fog clears out. Overnight, fog formation will again be possible in
our eastern valley locations mainly after 2 am MST. Probably will
not be quite as dense as this morning with lower chances (10-30%)
for visibility reductions to below 1/4 mile.

Looking ahead through the remainder of the week, temperatures will
return above normal for Wednesday through Friday with highs in the
mid 70s as a ridge of high pressure begins to build over the
southwest. Morning temperatures will remain on the chill side
through Wednesday morning, especially for valleys east of Tucson
where lows will be around freezing to the upper 30s.

Next weekend into early next week ensembles show another Pacific
trough potentially moving through, which could bring another round
of precipitation and cooler temperatures. Still a lot of run to run
and model to model differences but increasing confidence in a
pattern change taking place. Right now the NBM introduces PoPs late
Saturday into early next week.

&&

.PREV DISCUSSION... /issued HHHH AM/PM MST Day Month DD YYYY/


.DISCUSSION...Southeast Arizona is now on the back side of a storm
system that has ejected into the central and southern Rockies. All
that is left in the wake of this system is lingering low clouds
which should begin to clear out this evening, but kept slim chances
(10-15%) for isolated showers mainly from Tucson east and north
through early evening.

As the clouds clear out this evening we will have rapid cooling at
the surface where we just had periods of showers increasing the
possibility for patchy fog formation. Latest run of the HREF
depicted low clouds for valley locations that correspond well with
chances for hitting low visibility thresholds tomorrow morning and
perhaps again on Tuesday morning. While widespread dense fog is not
anticipated, chances for patchy fog with visibility reductions to
under 4 miles will increase after midnight and will remain elevated
(20-60%) through mid-morning. Areas that could see impacts from
reduced visibility will be along Interstate 10 near Willox,
Interstate 10 between Tucson and Phoenix, US 191 in the Sulphur
Springs Valley, Arizona Highways 80, 82, 90, and 92. Drivers should
be prepared for reduced visibility and drive with caution.

This afternoon and tomorrow temperatures will be below normal,
although tomorrow will warm by a few degrees areawide. Behind the
exiting storm system a ridge of higher pressure developing just off
the coast of California will result in gradual warming from Tuesday
through Friday. High temperatures warm to a few degrees above normal
Wednesday through Friday. Morning temperatures will be on the cool
side with valleys east of Tucson seeing temperatures at or near
freezing, especially in the Sulphur Springs Valley. Next weekend
into early next week ensembles show another Pacific trough
potentially moving through, which could bring another round of
precipitation and cooler temperatures. Right now the NBM introduces
PoPs Sunday, but lots of uncertainty this far out with the timing of
the trough.

&&

.AVIATION...Valid through 25/12Z.
MVFR and IFR vis possible at KDUG and KOLS due to fog, HREF
probabilities are around 20 percent for vis less than a mile early
this morning at both terminals. If any fog or low stratus does form
it will likely dissipate by 24/15Z. Outside of any low stratus this
morning, skies will be SKC. SFC winds variable less than 5 kts this
morning becoming westerly/northwesterly at 5-10 kts this afternoon
and early evening. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Temperatures will be below normal today, then a
warming trend takes over. Dry conditions are also expected through
at least Friday. Min RH will be 30-60 percent through Tuesday,
dropping to 20-30 percent thereafter. 20 foot winds follow normal
diurnal trends with speeds 5 to 10 mph and occasional afternoon
gusts.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 11 AM MST for AZZ503-507>509

&&

$$

Update...DVS

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