High Wind in Arizona, May 20, 2024

Area Forecast Discussion
National Weather Service Flagstaff AZ
1047 AM MST Mon May 20 2024

.SYNOPSIS...Strong winds are expected today along with slightly
cooler temperatures. A few isolated sprinkles or showers will be
possible later this afternoon and evening over eastern Arizona,
however much of the area will remain dry. Dry, mild, and breezy
weather then continues for the remainder of the week.

&&

.UPDATE...A couple of weather systems are impacting the weather
across northern Arizona today. The trough approaching from the
northwest is bringing increase southwest winds, with gusts already
reaching 30 to 40 mph across much of the area, and around 50 mph
in the favored wind corridor just east of Flagstaff around Twin
Arrows and Two Guns. These winds will continue to increase through
the day, with a Wind Advisory in effect. The other system impacting
our weather is a weak trough ejecting northeastward into our area
from the Pacific. This system is bringing increased clouds from
around Flagstaff eastward. Some radar returns are showing up in SW
Arizona and northern Baja, and these are moving up toward central
and eventually eastern Arizona. Isolated to scattered sprinkles or
light showers are expected this afternoon and early evening from
around Happy Jack and Payson eastward. Still expecting only very
light amounts with this, from a trace to a couple hundredths.
Forecasts are on track with only minimal updates needed this
morning.

&&

.PREV DISCUSSION /302 AM MST/...Today...A closed-low off the southern
California coast will eject off the Pacific today, while at the
same time a trough moves into the Great Basin. The two systems
look to phase together today, leading to a strengthening upper-
level jet over Arizona.

Gusty southwest winds ensue over much of the region with the
increased pressure gradient. Model soundings for this afternoon
show ample mixing potential, allowing for the stronger winds aloft
to mix down to the surface. As a result, wind gusts of 35-45 kts
will be possible over a majority of northern Arizona. Locally
stronger winds up to 50 kts will be possible in the typical windier
locations downwind of the Mogollon Rim into the Little Colorado
River Valley.

Given the track of the system, a fairly dry air mass will be in
place over the region (especially at the surface). The dry air mass
combined with gusty winds will lead to areas of critical fire
weather conditions, particularly across the lower elevations north
of the Mogollon Rim.

While dry air will be in place for most, a tongue of mid-level
moisture looks to into central Arizona this afternoon. Thus, there
is a slight chance for a few isolated showers today. However, the
vast majority of the area will remain dry. Moisture through much of
the boundary layer remains scarce, thus much of the increase in
moisture will only result in virga or increased cloud cover. Areas
that do see rain will likely only see a couple of drops to a few
hundredths of an inch. Additionally, given the inverted-v sounding
profile, gusty, erratic winds will be possible around any virga or
showers. The greatest chances for any showers look to mainly by from
the eastern Mogollon Rim into the White Mountains, and maybe over
the higher terrain near the AZ/UT border as well.

Tuesday and Wednesday...Behind the trough, quasi-zonal flow sets in
over Arizona. Winds weaken some, but remain breezy and temperatures
continue to remain within a couple of degrees of normal. Some gusty
winds will remain over portions of eastern Arizona during the
afternoon on Tuesday, potentially continuing near-critical fire
weather conditions into Tuesday for parts of Apache County.

Thursday through Sunday...Dry conditions and slightly cooler than
normal conditions continue into the weekend. Occasional shortwave
passes to the north will result some increased afternoon winds. As a
result, elevated fire weather conditions remain possible into the
end of the week. With the shortwave passes, there remains a chance
for a couple isolated showers over the higher terrain near the
AZ/UT border. However, at this point in time it's too early to
confidently include any mentionable PoPs.

&&

.AVIATION...Monday 20/18Z through Tuesday 21/18Z...Mainly VFR
conditions. This afternoon, southwest winds sustained at 20 to 30
knots will gust past 40 knots north of a KFLG-KSOW line. Winds
will remain a bit weaker elsewhere. Blowing dust may reduce
visibility at times around KINW. A few showers are possible
before 06Z which could kick up erratic winds locally. Expect light
winds and clear skies overnight.

OUTLOOK...Tuesday 21/18Z through Thursday 23/18Z...VFR conditions
and west to southwest winds at 10 to 20 knots gusting 20 to 30
knots each day.

&&

.FIRE WEATHER...Today and Tuesday..Dry and windy conditions today
with a Red Flag Warning in place for portions of northern Arizona.
Look for southwest winds 25-35 mph with gusts 35-50 mph across much
of the area. Lighter winds are forecast for Tuesday with west winds
10-20 mph. Minimum RH 5-15% each afternoon.

Wednesday through Friday...Dry conditions continue with near-normal
temperatures. Southwest winds 10-20 mph on Wednesday, increasing to
15-25 mph on Thursday and Friday. Minimum RH 5-15% each afternoon.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM MST /8 PM MDT/ this evening for AZZ004-
006>017-039-040.

Red Flag Warning until 7 PM MST /8 PM MDT/ this evening for
AZZ107>110-112>114-138>140.

&&

PUBLIC...JJ/Humphreys
AVIATION...Benji
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff