Severe Thunderstorm Warning 42, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
840 AM MST Fri Jul 16 2021

.SYNOPSIS...Scattered showers and thunderstorms are expected
across northern Arizona today through the weekend. Localized flash
flood will be possible within the heavier showers and storms.
Temperatures warm slightly by a couple degrees over the weekend.

&&

.DISCUSSION...Ample moisture remains in place this morning across
northern Arizona. A sunny start to the day for most locations will
allow for initiation of showers and storms over the high terrain
between 10:30am and noon. Latest hi-res guidance shows a general
progression into the lower elevations as we head through the
afternoon and evening hours. Mesoanalysis indicates precipitable
water values ranging from 1 - 1.5 inches along and south of the
Mogollon Rim. This will provide an environment capable of
producing heavy rainfall and flash flooding with the stronger
storms. Storm coverage will likely be more isolated and less
intense across northeast Arizona. However, localized flash
flooding is still possible in this area.

Minor updates were made this morning to account for the latest
trends in the hi-res guidance. Otherwise, the forecast is on
track.

&&

.PREV DISCUSSION /215 AM MST/...Chances for showers and
thunderstorms again over northern Arizona this afternoon and into
the evening, especially over the high terrain and areas of eastern
Arizona. Latest hi-res guidance continues to show thunderstorms
beginning to initiate around 11 am MST and 12 pm MST along the
Mogollon Rim, and expanding in coverage as the afternoon
progresses. Localized flash flooding in areas of heavy rainfall
will be possible once again.

The ridge over the southwest begins to wonder eastward into
position over the Four Corners region. The high the then begins to
strengthen late in the weekend and into early next week. With the
high in place, monsoonal moisture is expected to remain in place
over Arizona over the weekend and into much of the upcoming week.
As a result, afternoon showers and thunderstorms are in the
forecast each day, with the greatest chances being over the high
terrain along the Mogollon Rim. Later into next week, moisture
increase which may allow for areas north of the Mogollon Rim to
see better chances for precipitation. Localized flash flooding
will continue to remain a concern with heavy rainfall, especially
over areas that have yet to see wetting rains.

Temperatures remain about the same through the forecast period,
warming slightly over the weekend as the ridges moves east.
Background winds are expected to remain light.

&&

.AVIATION...For the 18Z package...Another round of scattered
thunderstorms is on tap from late this morning through the evening
hours. Near storms, local areas of MVFR ceilings and visibilities
along with wind gusts above 40 mph will be possible. Storm activity
will begin over the higher terrain before pushing into the lower
elevations through the afternoon and evening. Outside of storm
activity, expect light winds and VFR conditions. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
continue across northern Arizona for today and Saturday. Wetting
rains and flash flooding are the main threats. Winds will remain
light, except near thunderstorms where gusty and erratic winds are
possible. Near average temperatures are forecast during this time.

Sunday through Tuesday...Scattered afternoon thunderstorms continue
into Sunday. Moisture will increase for Monday and Tuesday with
higher chances for thunderstorm activity each day. Temperatures
around average likely.

&&

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

&&

PUBLIC...TPS/Humphreys
AVIATION...TPS
FIRE WEATHER...LaGuardia

For Northern Arizona weather information visit
weather.gov/flagstaff

Special Weather Statement
National Weather Service Flagstaff AZ
1252 PM MST Fri Jul 16 2021

AZZ017-018-162015-
Northern Gila County-White Mountains-
1252 PM MST Fri Jul 16 2021

...SIGNIFICANT WEATHER ADVISORY FOR GILA AND NAVAJO COUNTIES UNTIL
115 PM MST...

At 1252 PM MST, Doppler radar was tracking a strong thunderstorm near
Rainbow City, moving south at 5 mph.

Penny size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Whiteriver, Turkey Creek, Seven Mile, Rainbow City, Fort Apache, Fort
Apache Reservation, East Fork and Canyon Day.

LAT...LON 3401 11001 3396 10988 3373 10992 3380 11015
TIME...MOT...LOC 1952Z 017DEG 5KT 3392 10994

ET