Scientific Forecaster Discussion
fxus65 kfgz 122128
Area forecast discussion
National Weather Service Flagstaff Arizona
228 PM MST Thu Dec 12 2019
Synopsis...dry and mild conditions will continue through Friday.
A cold front will cross the region this weekend bring gusty
southwest winds and a chance of snow and rain showers. Expect much
colder daytime temperatures Sunday through Tuesday.
Discussion...it's a warm mid-December afternoon across northern
Arizona, with temperatures currently running around 5 to 15
degrees above normal. Similar weather is expected on Friday as a
weak ridge of high pressure remains overhead.
We will see conditions change over the weekend as a cold front
drops south toward the state. Ahead of the front, gusty winds will
develop northeast of the Mogollon Rim overnight Friday into
Saturday. These winds will become more widespread across the area
on Saturday as the pressure gradient tightens. Wind gusts of
30-40 mph will be possible, with the strongest speeds along and
north of the Mogollon Rim. Gusty winds will continue Saturday
night into Sunday, especially across the eastern rim and White
Mountains where higher gusts up to 50 mph are not out of question.
Winds will shift to a northerly direction later Sunday behind the
front and remain breezy into early next week.
As for precipitation, expect showers to develop Saturday
afternoon, mainly over the higher terrain. More widespread shower
activity will occur overnight Saturday into Sunday as the cold
front pushes south through the region. Snow levels will initially
be around 6,000-7,000 feet before falling to as low as 4,000 feet
on Sunday. Snow accumulations will be highest over far northern
Arizona including the Kaibab Plateau, Black Mesa, and Chuska
Mountains where generally 2-6 inches of snow is possible.
Moisture will be more limited to the south with up to an inch in
Flagstaff, and little if any accumulation south of Interstate 40.
Showers will wind down from northwest to southeast Sunday night.
A cold and dry airmass will move into northern Arizona behind the
front through early next week. Temperatures will struggle to get
out of the low to mid 30s over the higher terrain Sunday and
Monday. Breezy northerly winds will make it feel even colder. A
gradual warming trend and dry conditions are expected through the
remainder of the forecast period.
Aviation...for the 00z package...VFR conditions and light winds
will prevail for the next 24 hours. Aviation discussion not updated
for taf amendments.
Fire weather...dry and mild weather will continue Friday. An
approaching cold front will bring gusty southwest winds and
increasing chances for rain and snow showers on Saturday.
Sunday through Tuesday...the cold front will cross the region on
Sunday, with continued chances for rain and snow showers mainly
north of I-40. Behind the front, expect much colder temperatures and
breezy northerly winds into early next week.