Tucson, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

310
FXUS65 KTWC 180855
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
155 AM MST Sat Jan 18 2025

.SYNOPSIS...Cool northwest flow aloft will result in below normal
high temperatures through Tuesday, along with cold mornings. Highs
warm to around seasonable levels the second half of the next work
week, with above normal temperatures next weekend. Dry conditions
persist through next week.

&&

.DISCUSSION...Cool northwest flow aloft will prevail across the area
through Monday as a highly amplified ridge develops off the west
coast. The flow will turn more northerly late Monday and Tuesday as
a system drops southward through the Intermountain West and then to
our east along the southern front range of the Rockies. The second
half of next week the ridge shifts eastward across the western
United States.

High temperatures will be 1-4 degrees below normal through Monday
and then 5-8 degrees below normal on Tuesday with the northerly flow
aloft. Low temperatures in the Tucson Metro (and lower deserts)
through Monday will be in the lower to mid 30s, with colder
temperatures in the outlying metro area and along washes. The
typical cold spots in eastern Santa Cruz, the San Pedro River valley
and the Sulphur Springs valley will dip down into the mid teens to
lower 20s. Winds shift around to an easterly direction next Monday
night through Wednesday morning, with gusty east-southeast winds in
locations prone to easterly winds, especially during the morning
hours Tuesday.

The highest threat for overnight low temperatures dipping below
freezing across the lower deserts and the Tucson Metro will be next
Tuesday and Wednesday mornings. NBM probabilities currently show the
Tucson International Airport having a 50% chance of temperatures
below the freezing mark (32 degrees) Tuesday and Wednesday morning,
but only a 20% chance of falling to 28 degrees or lower. However,
the stronger easterly winds Tuesday morning may keep temperatures
above freezing in easterly wind exposed locations.

The west coast ridge shifts eastward across the western United
States the second half of next week leading to warmer temperatures
and highs topping out right around seasonal normals Wednesday and
Thursday. Highs warm to above normal levels Friday and Saturday of
next week. The deterministic GFS/ECMWF, ensembles and Cluster
Analysis tool all show this ridge across the western United States
mid to late next week, just varying degrees of height anomalies.

Significant differences in model solutions then crop up in the 8-10
day window (outside of our forecast period), with some models
continuing a ridge across the western United States, while others
have a deep trough. Cluster Analysis is weighted heavily towards the
trough solution. Time will tell.

&&

.AVIATION...Valid through 19/12Z.
Clear skies/SKC conditions and SFC wind generally 12 kts or less at
most locations thru the forecast period. The exception will be in
the upper Gila River valley near KSAD between 18/20Z and 19/01Z when
SFC wind will be 12-16 kts with gusts to around 25 kts. SFC wind
direction will be NWLY between 18/18Z and 19/02Z and variable in
direction at other times. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Dry conditions will prevail across southeast Arizona
the next 7 days. 20-foot winds will be 15 mph or less today through
Monday afternoon. Winds then shift around to an easterly direction
Monday night through Wednesday morning, with gusty east to southeast
winds in locations exposed to that wind direction. Min RH values
will be 15-20 percent in the valleys today, lowering to 8-14 percent
Sunday through Tuesday and then down to 5-10 percent the second half
of next week. Min RH values in the mountains will be 20-30 percent
today, 10-20 percent Sunday and Monday and then 7-15 percent the
second half of next week.

&&

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

&&

$$

Zell

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