Flash Flood Warning 29, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1025 AM MST Thu Jul 14 2022

.SYNOPSIS...Monsoon moisture will remain in place over the coming
week with daily rounds of showers and thunderstorms, especially
across the higher terrain.

&&

.UPDATE... No significant changes were made to the forecast. The
POPs were edited to match the current radar. Throughout the day,
the POPs were changed to have increasing coverage to scattered and
numerous storm activity. The WPC has put western Yavapai and
Coconino Counties in a slight risk for flash flooding today.

This afternoon, the main hazards will be gusty outflows, small
hail, lightning, and heavy rainfall. Rainfall rates of 1-2in per
hour are possible which will result in localized flash flooding.
There is a higher hail threat today with the increased
instability. Storms are forecasted to taper off around sundown.

&&

.PREV DISCUSSION /252 AM MST/...A strong high pressure system
remained centered near the Four Corners during the morning hours.
Over the next several days there will be little change in the
position or strength of the high with only a slight eastward
drift in response to a passing trough over the northwestern
states. The result, monsoon moisture isn't going anywhere. The
strength of the high will continue to inhibit full scale monsoon
activity across northern Arizona, especially the northeast corner
of the state.

For today...A decent thunderstorm complex over northwest Mexico
will likely push additional moisture across western Arizona as it
collapses this morning. The path of the moisture suggests that the
most vigorous thunderstorm activity will be along and southwest of
a line from extending from the Grand Canyon southeastward through
Flagstaff and Happy Jack. The flow aloft is weak and there is no
major source for lift so we are expecting mainly garden variety
thunderstorms with isolated dumpers capable of producing rainfall
in excess 2 inches. In general, beneficial rain for the majority
of locations. Storms will linger into the evening with any
showers or thunderstorms becoming isolated by midnight.

Friday and beyond...As mentioned, high pressure is expected to
remain in place with only subtle day-to-day variations in the
exact center of the high. Under this pattern moisture will remain
in place with the cycle of afternoon and evening thunderstorms
continuing. The most active thunderstorm weather will likely be
across the White Mountains, Mogollon Rim and Grand Canyon area
southward. Activity will generally be more isolated over the
northeast corner of the state, closer to the center of the strong
high and where lower moisture values will exist.

&&

.AVIATION...For the 18Z TAF package...Mainly VFR conditions are
expected for the next 24 hours. Light winds this morning will become
westerly with gusts of 15 to 20 kts. Scattered showers and
thunderstorms will develop mainly after 20Z with greatest coverage
along and south of a KGCN-KFLG-KSOW line. MVFR conditions possible
in heavier showers. Gusty and erratic winds are likely near
thunderstorms with lightning and small hail. Thunderstorms diminish
after 03Z. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Showers and thunderstorms are expected for today and
Friday. The best coverage will be along and south of the Mogollon
Rim. Gusty outflow winds, lightning, and locally heavy rainfall will
be possible. Rainfall rates of one to two inches per hour are
forecast with stronger storms, resulting in possible flash flooding
on area burn scars.

Saturday through Monday...Shower and thunderstorm activity persists
each day through the weekend. Temperatures remain warm with westerly
afternoon winds.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

PUBLIC...MG/McCollum
AVIATION...LaGuardia
FIRE WEATHER...LaGuardia

For Northern Arizona weather information visit
weather.gov/flagstaff

Special Weather Statement
National Weather Service Flagstaff AZ
1022 AM MST Thu Jul 14 2022

AZZ012-015-141800-
Little Colorado River Valley in Coconino County-Western Mogollon Rim-
1022 AM MST Thu Jul 14 2022

...A strong thunderstorm will impact portions northern
Flagstaff in Coconino County through 1100 AM MST...

At 1019 AM MST, Doppler radar was tracking a strong thunderstorms 10
to 15 miles north of Flagstaff across the San Francisco Peaks area.
These storms were nearly stationary.

HAZARD...Winds of up to 45 mph and penny size hail. Heavy rainfall
         can also be expected with these thunderstorms.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Flagstaff, Flagstaff Mall, Sunset Crater Volcano National Monument,
Timberline, Hutchison Acres, Bonito Campground At Sunset Crater,
Doney Park, Wupatki Trails, Fernwood, Sunset Crater Visitors Center,
Lockett Meadow Campground, Arizona Snowbowl and Little Elden Spring
Horse Camp.

This includes the following highways...
 Route 66 between mile markers 199 and 201.
 Interstate 40 between mile markers 200 and 201.
 U.S. Highway 89 between mile markers 419 and 439.
 Highway 180 between mile markers 234 and 237.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3530 11142 3520 11161 3541 11181 3555 11142
TIME...MOT...LOC 1719Z 161DEG 3KT 3539 11153

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Bain