774
FXUS65 KFGZ 160514
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1014 PM MST Sun Sep 15 2024

.SYNOPSIS...Chances for showers and thunderstorms will continue
across the eastern half of the state through Monday evening.
It will be windy and cooler on Monday with gusts 35 to 45 mph.
Mostly dry, cool, and breezy weather then returns on Tuesday
through much of the week.

&&

.UPDATE...Isolated showers and thunderstorms continue this evening
across eastern Gila County and the White Mountains region.
Activity is slowly spreading westward into the eastern Mogollon
Rim area. Current dewpoints are unimpressive across much of
northern Arizona with locations north and west of Payson sitting
in the 30s, low 40s. Recent hi-res guidance is not too promising
in regards to showers and storms reaching as far northwest as
Prescott and Flagstaff overnight and into Monday. Slight chances
(15%) remain in the forecast for these locations, however,
confidence is greater in conditions remaining dry with
precipitation mainly confined to Gila, Navajo, and Apache
counties.

Southwest winds will be gusty for Monday afternoon with widespread
gusts of 35-45 mph. The Wind Advisory looks to be a good call with
no changes needed at this time. The strong low pressure trough
will dig into Arizona Monday into early Tuesday with breezy
southwest winds persisting for Tuesday afternoon. Widespread dry
conditions will take over on Tuesday with high and low
temperatures forecast to be roughly 5-10 degrees below average for
this time of year. Temperatures within a few degrees of the
freezing mark are looking more likely Tuesday night into early
Wednesday morning in the High Country.

The current forecast remains on track with no changes needed at
this time.

&&

.PREV DISCUSSION /147 PM MST/...Scattered showers and thunderstorms
have developed over the southern half of Apache County this
afternoon where the deeper moisture has moved in. Dry but breezy
weather continues elsewhere with gusts in the 25-30 mph range.
Later tonight, as the main low pressure system approaches, low
level winds are forecast to back and pull some additional moisture
north and west. Instability should increase, and scattered
showers and thunderstorms are forecast by most CAMs to develop and
move up into Gila, southeast Coconino, and Navajo/Apache counties
through the overnight hours. With 0-6km wind shear in the 35-40
kt range, a few strong to possibly severe storms could develop,
along with some training cells producing localized heavy rainfall.
PoPs were increased in these areas for the overnight hours with
the afternoon forecast package. This will continue to be the most
favored area for storm development through Monday afternoon and
evening as well, with the Flagstaff region looking to be on the
western edge of the moisture plume and less likely to receive any
significant rainfall out of this system. The latest QPF totals are
highest for the eastern Mogollon Rim, White Mtns, and northern
Gila County ranging from 0.40"-0.80" and localized 1.00"+ amounts.
The other thing we are watching for Monday as the low approaches
is strong gusty southwest winds (unrelated to thunderstorms). With
gusts in the 35-45 mph range forecast by the latest guidance, we
have issued a Wind Advisory for Coconino County, the Yavapai
County mountains including Prescott, and most of Navajo County
from 10 AM until 7 PM MST. With a bit of a slower movement of the
main upper low Monday night/Tuesday, some rain chances will hang
on in far eastern Arizona through Tuesday morning.

Tuesday through Friday - breezy and cool weather is expected, with
highs 5-10 degrees below seasonal averages. As the first low
departs Tuesday, another will dive down the west coast into
central California by Wednesday and then east toward our region by
Thursday or Friday. This low will keep temperatures cool and also
bring a low chance (20-30%) of mainly light showers to NW Arizona on
Thursday, possibly lingering into Friday depending on the timing
of the low. Nights will be cool, with some near or slightly below
freezing low temperatures in the more favorable high-elevation
areas (Bellemont, Tusayan, Ft Valley). Warmer and less breezy
weather is likely to return next weekend.

&&

.AVIATION...Monday 16/06Z through Tuesday 17/06Z...Isolated to
scattered SHRA/TSRA are forecast to persist east of a KPAN- KFLG-
KOV7 line from tonight through Monday. MVFR conditions and hail
are possible with the stronger storms. Outside of storms, expect
SW winds 5-15 kts overnight. After 15Z, winds increasing to
southwest 15-25 kts with gusts 30-40 kts. Winds decreasing after
02Z Tuesday.


OUTLOOK...Tuesday 17/06Z through Thursday 19/06Z...Storms
decrease to isolated coverage after 06Z Tuesday, with dry
conditions area-wide after 18Z Tuesday. Southwest winds 15-25 kts
gusting 25-35 kts Tuesday, decreasing to southwest 10-20 kts
gusting 20-30 kts on Wednesday.


&&

.FIRE WEATHER...Tonight through Tuesday...Moisture increases from
the south resulting in scattered showers and thunderstorms tonight
through Monday night, mainly over the eastern half of the state.
Drier weather arrives Tuesday. South to southwest winds will
increase on Monday, with gusts of 30-45 mph, decreasing to 25-35 mph
Tuesday. Daytime temperatures 5-10 degrees below normal.

Wednesday through Friday...Remaining cool, breezy, and mostly dry.
Another low pressure system could bring a few showers to northwest
Arizona Thursday. Southwest wind gusts 20 to 30 mph Wednesday and
Thursday, west to northwest 15 to 20 mph Friday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 AM MST /11 AM MDT/ to 7 PM MST /8 PM MDT/
Monday for AZZ004>009-012-013-015-016-038>040.

&&

$$

PUBLIC...LaGuardia/JJ
AVIATION...RR
FIRE WEATHER...RR

For Northern Arizona weather information visit
weather.gov/flagstaff