165
FXUS65 KTWC 121013
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
313 AM MST Wed Mar 12 2025

.SYNOPSIS...

After showers move through southeastern Arizona this morning,
skies will become mostly sunny for the day. A stronger system is
expected to impact the region Thursday into Friday. A front
associated with this system will bring widespread chances for rain
and mountain snow from west to east Thursday afternoon through
early Friday morning. Strong winds with the potential for blowing
dust are expected to develop late Thursday morning and persist
into the evening. Well below normal temperatures are expected to
follow on Friday.

&&

.DISCUSSION...

Today, shortwave ridging will cross southeastern Arizona between
the exiting shortwave to the east and a deeper trough approaching
from the northwest. Showers and mountain snow will be exiting far
eastern Arizona by mid-morning, with some lingering light activity
possible on the back edge of the exiting wave north and east of
Tucson. Otherwise skies should clear, winds will be light, and
temperatures a few degrees below normal.

Thursday sees the approach and arrival of a deeper Pacific trough
and frontal passage. An impressive 100 knot jet streak in the
mid- levels will be ejecting through the base of the trough as it
crosses southern Arizona late Thursday, a magnitude exceeding the
99th percentile on NAEFS climatology for this time of year. First,
a tightening pressure gradient Thursday will lead to windy
conditions from the late morning through much of the evening.
Southwest winds at the surface ahead of the trough axis will
increase to 25 to 35 mph with gusts to 55 mph, diminishing from
west to east through the evening and overnight. The higher end of
the range of wind gusts will likely be atop higher terrain as well
as southern areas including Cochise County and especially around
Sierra Vista. Isolated strong wind gusts also can`t be ruled out
in any initial shower activity that could tap into strong flow
dipping towards the lower levels. A Wind Advisory has been issued
from late Thursday morning through Thursday evening. Blowing dust
will be a distinct possibility with this wind and may need
addressed in the near future with a headline.

Widespread chances for showers and mountain snow will also be
associated with this frontal passage, moving from west to east
from the mid-afternoon into the early Friday morning hours. As the
left exit region of the upper jet and strongest synoptic ascent
crosses central Arizona, the greatest precipitation potential will
generally be found further north. How this plays out in the
forecast rain amounts is a range of 0.1" to near 0.5", with higher
amounts possible in Pinal and Graham counties. Snow water
equivalent forecast ranges from 0.5" to 0.75", with higher amounts
in the White Mountains. This translates to 5 to 10 inches of snow
in the forecast above 7000 feet in the Catalina, Rincon,
Pinaleno, and White Mountains, which is currently covered by a
Winter Weather Advisory. Snow levels will likely drop on the back
side of the exiting precipitation late Thursday night and early
Friday, which could end up in some very light snow down into the
4000-4500 foot elevation range.

Friday and Saturday will likely see southern Arizona under
northwest flow aloft, producing well below normal temperatures and
breezy west to northwest winds. An embedded shortwave within the
northwest flow aloft should bring a shot of light showers late
Friday into Saturday. Sunday and Monday sees temperatures quickly
rebound as a ridge builds over the region. Then a trough will
likely cross Tuesday and Wednesday, however recent model trends
have taken this trough north. This should keep the precipitation
potential drier for southeastern Arizona while still bringing
winds into the area.

&&

.AVIATION...

Isolated to scattered showers crossing southeastern Arizona with a
frontal passage this morning, associated with 3k-5k ft ceilings.
Showers will exit from west to east by mid-morning, vacating
KTUS-KOLS by 12/12Z and KSAD-KDUG by 12/15Z. Skies generally clear
behind these showers, with some lingering clouds at 5k ft through
the day. Surface winds generally south to southwest through today
and under 12 kts.

&&

.FIRE WEATHER...

Light winds and minimum relative humidities generally above 25-30
percent across southeastern Arizona today. A stronger system is
expected to impact the region Thursday into Friday. Strong
southwest winds of 25-35 mph are expected with gusts up to 55 mph
from late Thursday afternoon through the evening. Widespread
chances for rain and mountain snow will cross from west to east
from Thursday afternoon through the overnight hours. Minimum relative
humidities are expected to be high enough Thursday to prevent
greater fire weather concerns. Below average temperatures and high
minimum relative humidities remain in place through Saturday with
breezy conditions. Becoming warmer and drier Sunday and Monday.

&&

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 11 AM to 11 PM MST Thursday for AZZ503-504-
506>509-511>515.

Winter Weather Advisory from noon Thursday to 5 AM MST Friday
for AZZ510-511-514.

Wind Advisory from 11 AM to 8 PM MST Thursday for AZZ501-502-505.

&&

$$

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