Flash Flood Warning 51, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
205 PM MST Thu Aug 24 2023

.SYNOPSIS...Monsoon moisture will dwindle over the coming days as
a high pressure system moves over Arizona. Look for daytime
temperatures to climb with the bulk of shower and thunderstorm
activity confined to the Mogollon Rim and White Mountains region.

&&

.DISCUSSION...A moist monsoon air mass will remain over northern
Arizona through this evening with some drying set for Friday and
over the weekend. The remnants of Harold will clear the state to
the northeast overnight.

For tonight and Friday...The remnants of Harold will exit Arizona.
Isolated showers and perhaps a stray thunderstorm will continue
overnight but most locations will remain dry. On Friday, high
pressure currently centered over Oklahoma, will begin to shift
westward toward Arizona. There will be some drying and
stabilization with the exit of Harold but with daytime heating enough
moisture will linger for scattered afternoon storms from the
Grand Canyon across the Mogollon Rim to the White Mountains.
Otherwise, warmer under the building high with generally light
and variable winds.

Saturday through the middle of next week...The center of high
pressure will wobble around the southwest United States gradually
shifting westward to over California by next Wednesday. Enough
moisture will linger as the high center moves from east to west
across Arizona to interact with daytime heating for a chance of
showers and thunderstorms each day over the Mogollon Rim and
White Mountains through about Sunday. After Sunday, as the high
moves over California, the main influence of this high will be to
push drier air from north to south across Arizona. At this time it
looks like a near shutdown of monsoon activity from Monday through
Wednesday of next week while the high center reside over
California. Otherwise, daytime temperatures will be on the rise
with daily light breezes.

&&

.AVIATION...For the 00Z TAF Package...Outside of showers and
thunderstorms, expect mainly VFR conditions through the TAF
period. ISOLD - SCT SHRA/TSRA until 02Z then clearing. Any
thunderstorms may produce heavy rainfall, frequent lightning, and
gusty, erratic winds in excess of 30 knots. ISOLD-SCT -SHRA/TSRA
after 17Z. Brief reductions in visibilities and ceilings are also
likely. Winds will generally be less than 10 kts away from storms.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Today through Saturday...Scattered showers
and thunderstorms today will become more isolated Friday...and
fewer on Saturday. Some storms will produce heavy rainfall,
frequent lightning, and gusty, erratic outflow winds of 30 to 40
mph. Away from storms, expect light westerly and northerly winds
at 5 to 15 mph.

Sunday through Tuesday...Slightly drier each day with daily
scattered showers and thunderstorms forecast over the White
Mountains and Mogollon Rim. Isolated activity is expected elsewhere.
Expect winds generally less than 15 mph away from thunderstorms.

&&

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

&&

PUBLIC...McCollum
AVIATION...MAS
FIRE WEATHER...MAS

For Northern Arizona weather information visit
weather.gov/flagstaff