995
FXUS65 KFGZ 180959
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
259 AM MST Tue Jun 18 2024

.SYNOPSIS...Temperatures will trend closer to normal through
Wednesday, before warming again late in the week. A chance of
thunderstorms will develop daily from Thursday through the
weekend.

&&

.DISCUSSION...A trough of low pressure entrenched across the
western U.S. is pushing a cool front across far northern Arizona
early this morning. This will ensure our temperatures today remain
a few degrees below average. Today will see the lowest
temperatures of the week with more significant warming later this
week into the weekend. The shortwave that brought yesterday`s
winds continues to push away to the northeast, while a broad
trough is forecast to settle over the southwest through the
remainder of the week. Though we won`t see winds like yesterday,
they will still remain breezy each afternoon with gusts around
25-30 mph. Temperatures remain near to below average through
Wednesday.

From Thursday onward, high pressure building westward from the
southern plains begins to dominate the weather pattern. Rising
heights will lead to warming temperatures, reaching 5-7 degrees
above normal late this week into the weekend. Heat Risk does begin
to increase, but does not look to reach into critical levels. The
lowest elevations of the Grand Canyon could encroach on excessive
heat criteria and we`ll continue to watch for this.

As the high builds west, it opens the door to a southeasterly flow
that draws moisture across New Mexico and Arizona from Thursday
through the weekend. Models have been consistent in showing this
pattern shift over the last few days, and the ensemble guidance
this morning is even more supportive of the increasing moisture.
The best shower and thunderstorm chances will favor eastern and
northeastern Arizona Thursday through Saturday, but enough
moisture will stick around to trigger instability convection each
day into next week. Forecast precipitation amounts are not
impressive as we will be fighting a stout dry boundary layer, but
a few lucky areas may see >0.25". Early monsoonal storm threats of
lightning and gusty outflow winds will be of greatest concern and
could lead to new wildfire starts. Forecast confidence begins to
decrease by the middle of next week as there are differing signals
on how long the available moisture may stick around.

&&

.AVIATION...Tuesday 18/06Z through Wednesday 19/06Z...VFR
conditions will persist through the period. SW wind gusts in the
20-25 knot range will develop over northern Arizona late Tuesday
morning, then subside Tuesday evening.

OUTLOOK...Wednesday 19/06Z through Friday 21/06Z...VFR conditions
will prevail over northern Arizona through the period. Dry
conditions and southwesterly wind gusts up to 20 knots are
forecast for Wednesday. For Thursday, there will be a chance for
afternoon showers and thunderstorms east of a line from KPAN-
KINW-KPGA. SW wind gusts up to 30 knots is also forecast across
eastern Arizona, with SW wind gusts in the 20-25 knot range along
and west of I-17 and Highway 89.

&&

.FIRE WEATHER...Today and Wednesday...Seasonable temperatures with
dry conditions. Breezy west/southwest winds 10-15 mph, becoming
south/southwest for Wednesday. Gusts up to 25 mph possible each
afternoon. Afternoon minimum RH 10-20%.

Thursday through Saturday...Warming temperatures with daily chances
for light showers and dry thunderstorms. Breezy south/southwest
winds with gusts 20-30 mph possible Thursday and Friday, becoming
light on Saturday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

PUBLIC...MCT
AVIATION...TM
FIRE WEATHER...Humphreys

For Northern Arizona weather information visit
weather.gov/flagstaff