Severe Thunderstorm Warning 111, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1035 AM MST Mon Aug 12 2024

.SYNOPSIS...Daily chances for showers and thunderstorms continue
through Tuesday, before drier conditions set in for the middle of
the week. Monsoonal moisture then looks to gradually return by
the end of the week. Temperatures will be near-normal, along with
generally light winds.

&&

.UPDATE...The morning sounding showed some drying since yesterday
morning (0.94 vs 0.79 inches Pwat). Storm motion today will be
from the southeast to northwest at 10 to 15 kts...and may become
more southwest to northeast later in the day especially over
western Yavapai and Coconino counties. Another active day is in
store.

&&

.PREV DISCUSSION /402 AM MST/...Today and Tonight...Another round of
showers and thunderstorms is expected later this morning and into
this afternoon, with ample monsoonal moisture in place. Storms
look to initially develop over the higher terrain later this
morning and early this afternoon, then gradually pushing northward
off the terrain into the lower elevations through the early
evening hours.

00Z HREF guidance forecasts around 1000 J/Kg from northwest AZ and
eastward along the Mogollon Rim, thus we'll likely see the greatest
coverage over these areas. With ample moisture in place (PWATs
around 0.90-1.10 inches) and slow moving storms (~5-10 kts), flash
flooding will continue to be the main threats with any storms
that develop today. A couple strong to severe storms can't be
ruled out, but any organized severe weather seems unlikely given a
weakly sheared environment with 0-6 km bulk shear < 20 kts.

Latest hi-res and U of A WRF guidance do show a complex of storms
moving northward from the Lower Deserts later this evening, which
may continue showers and storms into the overnight across central
AZ. Confidence isn't all that high given that this will be highly
dependent upon the progression of today's storms, but we'll maintain
a slight chance through the early part of the overnight. Additionally,
some guidance suggests the resulting outflow from this complex
may make it further north into northeastern AZ by the early
morning hours on Tuesday.

Tuesday...Showers and thunderstorms look to return on Tuesday,
although coverage may be a bit less and mainly focused to areas
along and north of the Mogollon Rim. Flash flooding will continue to
be the main threat with any storm.

Wednesday through Sunday...Global ensembles continue to get into
better agreement with a decrease in monsoonal moisture by mid-week as
the upper-level jet becomes wavier and high pressure weakens. As
flow shifts more northerly, drier air is advected into northern AZ.
Thus, any preciptation chances mainly look to be near the White
Mountains each afternoon. Slightly warmer, near-normal temperatures
return for Wednesday and Thursday as well.

This downward trend however looks to be short-lived. Most of the
guidance is in agreement with moisture gradually retuning to the
High Country as the high shifts into a more typical position, and
subsequently a better flow regime. Thus, cooler than normal
temperatures and daily chances for showers and thunderstorms look
to gradually return by the end of the week.

&&

.AVIATION...Monday 12/18Z through Tuesday 13/18Z...Mostly VFR
conditions are expected with SW winds 10-15 kts this afternoon.
Scattered TSRA will develop and move northward throughout the day.
Brief MVFR to IFR in +RA and strong outflow winds in excess of 40
kts possible with the stronger storm cells.

OUTLOOK...Tuesday 13/18Z through Thursday 15/18Z...MVFR conditions
possible in SHRA/TSRA on Tuesday 19Z-03Z. VFR conditions are otherwise
expected with mostly dry conditions prevailing on Wednesday. Daytime
winds W/SW around 10 kts.

&&

.FIRE WEATHER...Today and Tuesday...Scattered to widespread showers
and thunderstorms each afternoon and evening. Heavy rainfall and
gusty, erratic winds will be the main threats each day. Otherwise,
expected west/southwest winds around 10 mph along with slightly
below-normal temperatures.

Wednesday through Friday...Mainly dry conditions, outside of a few
isolated showers in the White Mountains. West/southwest winds 10-15
mph each afternoon and near-normal temperatures.

&&

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

&&

PUBLIC...MAS/Humphreys
AVIATION...MCT
FIRE WEATHER...Humphreys

For Northern Arizona weather information visit
weather.gov/flagstaff

Preliminary Local Storm Report
National Weather Service Flagstaff AZ
1129 AM MST Mon Aug 12 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0756 PM     Flash Flood      Cornville               34.72N 111.91W
08/10/2024                   Yavapai            AZ   Fire Dept/Rescue

            Post event report from Saturday 8/10. Fire
            department reported flooding along Harmony,
            Oak Run Lane, and Page Springs Road.
            Flooding of multiple homes along Alvey and
            Brooks Lanes.

&&

MCT