Black Mesa, Arizona Weather Forecast Discussion

595
FXUS65 KFGZ 201039
AFDFGZ
Area Forecast Discussion
National Weather Service Flagstaff AZ
339 AM MST Sat Sep 20 2025
.SYNOPSIS...Chances for showers and thunderstorms diminish over the
weekend, especially today, with a bit warmer temperatures. A new
low pressure system forming near San Diego will continue shower
and thunderstorm chances starting Sunday, lasting through next
week.
&&
.DISCUSSION...It looks like an interesting week of weather ahead.
Another low pressure system will develop off the California coast
later today then gradually wobble eastward across the southwest
United States over the coming days. As a result, we are
anticipating periods of enhanced shower and thunderstorm activity
through the coming week.
For today...Low pressure will take shape off the central
California coast. The initial position of the low will place
Arizona under high pressure with a drier westerly flow and
capping layer aloft to inhibit showers and storms. There still
will remain enough lingering moisture for extremely isolated
showers and even a stray thunderstorm, south of Interstate-40.
Otherwise, look for seasonable temperatures, light winds and just
a few fair weather cloud buildups with daytime heating.
On Sunday and Monday...The low looks to dip southwestward along
the California coast. Over Arizona the result will be the
development of a more southwesterly flow which will tap into
subtropical moisture just to our south. As a result, look for some
increase in shower and thunderstorm activity from Sunday into
Monday. The best chances appear to be on Monday when deeper
moisture arrives. Pressure gradients will remain weak supporting
light west to southwest winds each day. Not much change in
temperatures but cloud cover will be on the increase with the push
of moisture.
From Tuesday onward...A difficult forecast period. Once the low
dips southward along the California coast if gets somewhat cut-off
from the main flow. As the saying goes, "A cut-off low is a
weatherman`s woe". Even with all our fancy models this phrase
remains true. We will go with unsettled conditions through this
period with at least slight chances for showers and storms each
day as moisture lingers across the area. The eventual path of the
low will be critical to how much moisture and precipitation
Arizona sees. At this time it appears the low will wobble off the
southern California coast from Tuesday into Wednesday then push
north and east across our area in response to an additional
Pacific system. A few solutions show the potential for heavy rain
toward the end of next week. You will want to check back as we get
a better bead on the eventual path of the California low.
&&
.AVIATION...Saturday 20/12Z through Sunday 21/12Z...Mainly VFR
conditions are forecast. Isolated -SHRA/-TSRA from 18Z-02Z,
mainly south of Interstate-40. Brief MVFR or lower conditions and
gusty, erratic winds possible in and near -TSRA. Light and
variable winds early, then south to southwest at 10-20 kts after
18Z.
OUTLOOK...Sunday 21/12Z through Tuesday 23/12Z...Mainly VFR
conditions will persist. Isolated to scattered -SHRA/-TSRA each
afternoon/evening. Daytime winds southwest to west at 5-15 kts,
becoming light and variable each night.
&&
.FIRE WEATHER...Today and Sunday...For today, look for isolated
afternoon showers and thunderstorms, mainly south of I-40. A slight
increase in activity is forecast for Sunday. Winds will mainly be
light, trending southwest through west.
Monday through Wednesday...A chance of showers and thunderstorms
will persist through the period, especially Monday, as a new low
pressure system forms off the southern California coast. Winds will
remain mainly light.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...McCollum
AVIATION...McCollum
FIRE WEATHER...McCollum
For Northern Arizona weather information visit
weather.gov/flagstaff

NWS FGZ Office Area Forecast Discussion