894
FXUS65 KFGZ 110902
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
202 AM MST Sun Aug 11 2024

.SYNOPSIS...Daily chances for showers and thunderstorms continue
into the start of this week, with a drying trend possible by the
second-half of the the week. Temperatures will be near-normal,
along with generally light winds outside of storms.

&&

.DISCUSSION...Today and Tonight...Overnight showers and thunderstorms
continue over far northern AZ near the UT border. Widespread
cloud cover looks to remain over much of the area through the
overnight as well, which should delay convective initiation later
today. Scattered storms should initiate over the higher terrain
by around noon, gradually moving northward and increasing in
coverage through the afternoon. Given PWATs around an inch most
everywhere and slower storm motion around 5-10 kts, flash flooding
will be the primary threat. HREF PMM guidance mainly signals
towards the greatest flash flood risk being over northwest AZ.
Thus, area slow canyons near the AZ/UT border will be at risk for
flash flooding for much of this afternoon. Without any strong
synoptic forcing and the slow start to convection, confidence
isn`t high enough to warrant a Flash Flood Watch over these areas
at this time, but this doesn`t lessen the risk.

More widespread activity looks to develop as a hi-res guidance
indicate the potential for an MCS moving northward from the Lower
Deserts later this evening and into the overnight hours. Thus,
another round of heavy rainfall looks possible across central AZ and
potentially into northern AZ for the overnight. Latest HRRR runs
continue to back off on this, so confidence isn`t all that high.

Monday and Tuesday...Monsoonal moisture remains in place for the
start of the week, keeping daily chances for scattered showers and
thunderstorms in place across much of the area. Flash flooding will
continue to be the main threats, but an isolated strong to severe
storm can`t be ruled out. The greatest coverage areas may vary
from day to day, as any overnight convection will play a significant
role on how quickly the atmosphere can recover and thus where
storms initiate.

Wednesday through Saturday...By the middle of the week, the jet
begins to become a bit more wavy, and the monsoonal high begins
to shift. Much of the global ensemble members show a downturn in
moisture sometime later this week. The exact timing of this downturn
is uncertain, with the EPS and CMCE means showing Wednesday and
the GEFS mean a bit later. With lessening moisture and higher
heights, temperatures should also begin to gradually increase
through the end of the week.

&&

.AVIATION...Sunday 11/06Z through Monday 12/06Z...Expect cloudy
skies and isolated -SHRA overnight. Most activity along and north
of a KRQE-KINW-KPRC line. Stronger cells may produce brief MVFR
visibilities. Another round of scattered to numerous storms will
develop again after 18Z-20Z Sunday. Winds will generally be light,
except in the vicinity of storms where outflow winds may exceed
30 kts.

OUTLOOK...Monday 12/06Z through Wednesday 14/06Z...Expect
scattered to numerous showers and thunderstorms each day from
18Z-03Z. Stronger storms may produce brief MVFR/IFR visibilities.
Light winds except near storms.

&&

.FIRE WEATHER...Today through Monday...Expect an increase in
thunderstorm coverage today and Monday. Heavy rain and strong
outflow winds will continue to be the primary storm threats.
Otherwise, expect near average temperatures and light west to
southwest prevailing winds each day.

Tuesday through Thursday...A good chance of showers and
thunderstorms continues Tuesday, with a drying trend and decreased
storm coverage by Wednesday and Thursday. Generally light southwest
winds 10 to 15 mph are forecast each afternoon.

&&

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

&&

$$

PUBLIC...Humphreys
AVIATION...RR
FIRE WEATHER...JJ

For Northern Arizona weather information visit
weather.gov/flagstaff