133
FXUS65 KTWC 181002
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
302 AM MST Thu Dec 18 2025

.SYNOPSIS...

Dry and warm weather continues, with potentially record breaking
high temperatures Friday into early next week. A Pacific system
approaches by middle to late next week, however uncertainty
remains on if temperatures will cool to near normal or how much
moisture will move into southestern Arizona.

&&

.DISCUSSION...

The story for southeastern Arizona remains centered on well above
normal temperatures continuing into next week. Today in the upper
levels, a ridge remains over the eastern Pacific centered west of
the Baja peninsula. NAEFS analysis highlights the anomalous
nature of this ridge, with 500mb heights exceeding the 97th to
99th climatological percentiles for this time of year. In the
eastern periphery of this ridge center, forecast high
temperatures today sit 11-14 degrees above normal. This ridge will
shift east across northern Mexico Friday through Monday, which
will bring the warmest temperatures of the period. Forecast highs
increase to 15 to 19 degrees above normal with a few daily records
likely to fall.

The ridge will have been pushed east by a digging Pacific trough,
expected to set up active southwest flow over the west coast and
into the Great Basin region next week. Southeastern Arizona will
likely sit on the edge of this trough`s influence, with most
guidance keeping the negative upper level height anomalies
west/north of the area. From the middle to late periods of next
week there should be a modest arrival of precipitation chances for
southeastern Arizona along with a downward trend in temperatures.
However with troughing likely to remain to the west, chances for
impactful precipitation are low and temperatures should generally
remain above normal through the next work week.

&&

.AVIATION...Valid through 19/12Z.

Mainly SKC with a few high level cirrus streaming through the
area. Surface winds under 10 kts and terrain driven through the
forecast period. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...

Warm and dry conditions continue into early next
week. Highs 11 to 14 degrees above normal today, then 15-19
degrees above normal Friday through monday. Minimum relative
humidity values of 12-22 percent each day through early next week.
20-foot winds less than 15 mph and terrain driven. A Pacific
system approaches mid-week next week, increasing humidity values
and bringing slight chances for light precipitation.

&&

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

$$

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