680
FXUS65 KFGZ 131609
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
909 AM MST Sat Jul 13 2024

.SYNOPSIS...Scattered to widespread showers and thunderstorms are
expected each day through next week as we enter into an active
monsoon pattern. Temperatures will remain near average during this
time with typical afternoon winds.

&&

.UPDATE...Looks like today`s target zone for showers and
thunderstorms is from around Prescott northward toward the
Grand Canyon and northwest portion of Coconino County. The flow
has shifted to more southeasterly helping to deliver additional
moisture from over southern Arizona but will also will push
storms that develop over the higher terrain toward the northwest.
Elsewhere, if anything, the southeast flow has moved drier air
from over New Mexico across eastern and northeast portions of
Arizona with isolated thunderstorms anticipated across those
areas. The forecast is generally in good shape but we have lowered
the chances of precipitation across eastern portions of the
forecast area to account for the development described above.

&&

.PREV DISCUSSION /427 AM MST/...Shower activity continues to taper early this
morning with isolated coverage remaining across portions of
Yavapai County. Outside of gusty outflows from decaying showers,
winds are mostly light across northern Arizona with near average
temperatures this morning. Dewpoints are currently in the 40s-50s
range and look to increase gradually across Yavapai and Mohave
counties for later this afternoon. Cloud cover should clear for
the most part by sunrise allowing better surface heating to occur.

With a high pressure system currently centered over the Four
Corners, southerly flow will be enhanced, allowing an increase in
moisture advection to occur. For today, hi-res model guidances
(HREF, HRRR, WRF-ARW, SREF) suggest the greatest chances and
widespread coverage of showers and thunderstorms are from Yavapai
to northwestern Coconino counties beginning by 1200 MST. Taking a
look at the expected mid-level flow, moisture profile, and SBCAPE
for this afternoon across northern Arizona, the bulls eye of
these ingredients happens to be located over the previously
mentioned areas, lining up well with the hi-res model guidance
consensus. As the afternoon progresses, showers and storms will
likely to spread eastward as diurnal convection occurs, however,
scattered activity is forecast. With low to mid-level flow from
the south-southeast today, anticipate storm motions towards the
north and west, but as storm coverage increases throughout the
day, erratic outflows will disrupt the parent flow allowing storms
to move in different directions. With the increase in PWATs and
overall surface moisture, the main threats from storms today will
be the potential for brief heavy rainfall, localized flash floods,
and strong wind gusts. The activity looks to taper after sunset
with isolated showers continuing overnight.

Scattered to widespread activity looks likely on Sunday as the
high pressure remains centered over the Four Corners and moisture
continues to be abundant. By Monday, the high pressure system
begins to shift slightly towards the west, becoming more centered
over Arizona. Model guidance then shows indications of the high
strengthening for much of next week over Arizona and extending
into the Great Basin. Moderate chances for showers and
thunderstorms remain in the forecast at this time across much of
northern Arizona, however, greater POPs (50-70%) have shifted
towards the east from Tuesday onward, specifically along and east
of I-17/US-89. This potential scenario in better storm coverage
towards the east lines up well with both GEFS/EPS PWAT data with a
slight decreasing trend for Flagstaff and Prescott, but an
increasing trend for Show Low and Window Rock. This all depends on
the hard-to-predict `wobbles` of the high pressure system and its
overall strength.

As for temperatures for this weekend and into next week,
anticipate near average to slightly above average (by 5 degrees)
with no Heat Warnings planned at this time.

&&

.AVIATION...Saturday 13/12Z through Sunday 14/12Z...Mainly VFR
conditions. SCT-WDSPRD SHRA/TSRA with MVFR or lower possible,
mainly between 19Z-03Z. Gusty and erratic outflow winds in
vicinity of storms. Otherwise, winds 5-15 kts.

OUTLOOK...Sunday 14/12Z through Tuesday 16/12Z...Mainly VFR
conditions. SCT-WDSPRD SHRA/TSRA with MVFR or lower possible,
mainly between 19Z-03Z each day. Gusty and erratic outflow winds
in vicinity of storms. Otherwise, west winds 10-20 kts.

&&

.FIRE WEATHER...Saturday and Sunday...Monsoon moisture continues to
increase through the weekend bringing along some slightly cooler
temperatures. Expect widespread showers and thunderstorms with the
most activity near the Grand Canyon and along and south of the
Mogollon Rim and White Mountains. Isolated activity further north.
Outside of gusty/erratic outflow winds (35-45 mph), winds will be
southerly around 5 to 15 mph each afternoon.

Monday through Wednesday...Widespread showers and thunderstorms
continue Monday with the most activity along and south of the
Mogollon Rim and the White Mountains. Coverage becomes more
scattered for Tuesday and Wednesday as moisture slightly decreases.
West to northwest winds around 5 to 15 mph each day with gradually
warming temperatures.

&&

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

&&

$$

PUBLIC...McCollum/LaGuardia
AVIATION...Meola
FIRE WEATHER...MAS

For Northern Arizona weather information visit
weather.gov/flagstaff