300
FXUS65 KFGZ 211729
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1029 AM MST Sat Sep 21 2024

.SYNOPSIS...A low pressure system crossing through Arizona will
bring cooler temperatures, breezy winds, and chances for showers and
thunderstorms through this afternoon. Warmer and drier weather is
expected to return for much of the upcoming week.

&&

.UPDATE...Upper level low pressure moved into Arizona overnight
bringing showers and thunderstorms across the area. The upper low
is centered over north central Arizona this morning with a more
organized band of rain and thunderstorms stretching from near
Holbrook north to the Utah border and west towards Page. This band
will continue to gradually move north and east through the morning
hours. With the low overhead early in the day, we expect
additional convective showers to develop with daytime instability,
and this is in line with this morning`s hi-res guidance.
Precipitation chances were nudged upward for early this
afternoon, particularly from Flagstaff northwest toward the Grand
Canyon. Precipitation amounts should mostly remain less than 0.25
inches. We should start to see a drying trend with decreasing
convection by late afternoon with showers coming to an end by
early evening. Today will be the coolest day yet this season with
temperatures nearly 10 degrees below average.

&&

.PREV DISCUSSION /454 AM MST/...An upper level low is located along
the Arizona-California border early this morning. The low will
push towards the east-northeast through the day today, exiting off
towards Four Corners by late tonight. Scattered showers and
thunderstorms have developed mainly along the rim. As we go
through the day, the precipitation will start to push off to the
east and northeast. Temperatures remain warm near the surface with
colder air aloft. This cold pool combined with the instability
available this morning has allowed for some of the stronger storms
to contain a decent amount of small hail (around 1/2" or so).
Storm motion is fairly quick so do not expect there to be any
flooding concerns through the event. Some of the stronger storms
may be able to drop a quick 0.25- 0.50" of rain but most areas
will see less than 0.25". Snow levels remain high, above 10,000
ft, so expect that only the highest elevation will see snow with
this event. While amounts will be fairly light, we could see a few
tenths of an inch of snow up on the San Francisco Peaks. As the
low tracks towards Four Corners, dry air will start to be wrapped
into the west/northwest side of the low. As this occurs we should
start to see the precipitation come to an end and drier conditions
will arrive across the area this evening.

Temperatures will warm and conditions dry out for Sunday and through
much of the coming week. The trough moving through the Four Corners
area around Tuesday looks weaker than it did even a day ago so that
has brought the chances for more preciptation down. Maybe a few
isolated showers find their way in but it is looking to be drier
than previously thought. Should the trough become stronger, chances
may return but more than likely confined to extreme eastern Arizona.
The ridge building down from the northwest becomes more dominant
through midweek and expect us to remain warm and dry as we head
towards the end of the week.

&&

.AVIATION...Saturday 21/18Z through Sunday 22/18Z...Scattered
-SHRA/-TSRA with localized/brief MVFR conditions spreading
 eastward through the day. Precipitation chances will come to an
 end area wide by around 00Z. West to northwest winds 10-20 kts
 this afternoon turning light overnight.

OUTLOOK...Sunday 22/18Z through Tuesday 24/18Z...Dry weather and
VFR conditions are forecast. Variable winds mostly 10 kts or less
for Sunday through Tuesday morning.

&&

.FIRE WEATHER...Today and Sunday...An area of low pressure will
bring chances for showers and thunderstorms through this afternoon.
Dry and warmer weather arrive Sunday. West to northwest winds 10 to
20 mph are expected today and northerly winds at 5 to 10 mph on
Sunday.

Monday through Wednesday...Warm days and dry conditions will
continue through Wednesday. Light and variable winds under 10 mph
are forecast for Monday with northerly winds at 10-20 mph expected
to develop on Tuesday and Wednesday.

&&

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

&&

$$

PUBLIC...MCT/Meola
AVIATION...McCollum
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff