384
FXUS65 KFGZ 050518
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1018 PM MST Thu Jul 4 2024

.SYNOPSIS...Hot and dry conditions will continue for most of
northern Arizona into early next week. The chance for showers and
storms will be limited to the White Mountains through Monday,
with a slow return of monsoon moisture possible later next week.

&&

.UPDATE...It`s been a hot 4th of July across northern Arizona with
high temperatures today reaching the 90s in the mountains and as
high as 113 in the Verde Valley near Cottonwood. Heat will
continue to be the main weather story over the coming weekend. The
good news is that with such a dry air mass in place this evening,
temperatures will cool off nicely overnight. Expect lows in the
40s to low 50s in the mountains and upper 50s to low 70s in the
valleys. No forecast updates are needed this evening.

&&

.PREV DISCUSSION /436 PM MST/...A strong ridge centered near the
California coast will nudge slowly eastward over the next several
days, resulting in a heat wave over the southwest US. An
Excessive Heat Warning starts today below 4000 feet from Yavapai
County to the Grand Canyon and Page/Lake Powell areas. With the
persistence of this pattern in the latest model data, we have
extended this warning all the way through Tuesday evening, and
will need to monitor it each day for the need to extend even
further unfortunately. The northerly flow around the ridge is a
dry one for our area. Surface dewpoints have fallen off into the
20s for the majority of the area, except southern Yavapai where
some 40s/50s linger and a few showers have developed this
afternoon. This air mass is forecast to dry even further for
Friday with dewpoints of 5-10F along/north of the Mogollon Rim
which is just about unheard of for this time of year. This dry air
will actually help things cool off overnight, and we have
undercut the NBM guidance significantly in the high country - some
upper 30s are likely at the usual cold spots (Bellemont, Tusayan)
the next few nights. Winds will be breezy from the north and
northeast at times later this evening through Friday, with some
gusts to 25 mph mainly along/south of the Mogollon Rim. For Sunday
and Sunday night, gradients tighten as a trough passes northeast
of the region. Another round of breezy winds is forecast, from the
W-NW at 10-15 mph and gusts to around 25 mph.

By the middle and latter parts of next week, there is some
indication that the center of the high pressure system will move
north or even northeast of the state. This could allow for a
modest moisture increase from the east, but confidence is low. For
now, we have mainly used a blend of model data which brings a
20-40% chance of showers and thunderstorms to areas along and
south of the Mogollon Rim with lower chances to the north. If this
doesn`t happen, the heat wave will continue.

&&

.AVIATION...Friday 05/06Z through Saturday 06/06Z...VFR conditions
with generally light winds overnight. One exception is that KSEZ
will have NE winds with gusts near 25 knots. Winds becoming N
around 10 kts after 17Z Friday.

OUTLOOK...Saturday 06/06Z through Monday 08/06Z...VFR conditions
continue. Daytime winds N around 10 kts on Saturday, becoming
light and variable overnight. NW winds around 15 kts with gusts to
25 kts on Sunday.

&&

.FIRE WEATHER...This afternoon through Saturday...Hot conditions,
with highs 5-10 degrees above normal. Isolated showers and
thunderstorms over Yavapai County into this evening and then over
southern Apache County Friday and Saturday. Winds north/northwest 5-
10 mph, becoming north to northeast on Friday, and then back to
northwest on Saturday. Minimum afternoon RH 3-12%, recovering
overnight to 15-30%.

Sunday through Tuesday...Hot and dry conditions continue. Slight
chances for showers and thunderstorms gradually increasing each day,
mainly over the eastern Mogollon Rim and White Mountains. North to
northwest winds on Sunday with gusts 20-25 mph. Minimum afternoon RH
5-15%, recovering overnight to 15-45%.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM MST /9 PM MDT/ Tuesday for
AZZ005-006-037.

&&

$$

PUBLIC...MCT/JJ
AVIATION...RR
FIRE WEATHER...MAS

For Northern Arizona weather information visit
weather.gov/flagstaff