Flash Flood Warning 70, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
241 PM MST Wed Dec 4 2019

.SYNOPSIS...Another Pacific storm system will produce continued
breezy and cool conditions, along with rain and mountain snow
showers, through early Thursday. Yet another weather system
promises to move across the northland late this upcoming weekend,
continuing the unsettled weather pattern.

&&

.DISCUSSION...SHORT TERM (through Thursday afternoon)...The main
story over the next 24 hours will be an approaching low pressure
system and its associated front. Ample moisture out ahead of the
front has contributed to scattered showers, low ceilings, and
patchy fog across much of the region today. Expect a 3-6 hour
period of widespread moderate to heavy precipitation (mainly in
the form of rain below 8,000 feet) as the front crosses northern
Arizona this evening. The combination of rain and melting snow
will lead to high flows on creeks and streams through Thursday,
especially Oak Creek, the Verde River, and the Agua Fria. Snow
levels will fall behind the front to around 6,500-7,000 ft from
Flagstaff westward and 7,500-8,000 ft southeast of Flagstaff. For
our population centers near these elevations, the deep moisture
will have departed by the time snow levels bottom out. Therefore,
little to no snow accumulation is anticipated. Drier air will push
into the region on Thursday morning, bringing an end to showers.
Daytime temperatures on Thursday will be similar to what we are
seeing today.

LONG TERM (Thursday night through Tuesday)...A shortwave ridge
will build over the Southwest and southern Rockies region behind
the incoming low pressure system. Drier westerly flow aloft will
accompany this ridge and limit chances of precipitation while it
is located over the Southwest through Saturday afternoon.

Temperatures will begin to warm as mid-level heights rebound
with the shortwave ridge. Daytime temperatures will increase
about ten degrees between Thursday and Saturday. The warmer
temperatures forecast Saturday will be above normal across much
of the northland.

A Pacific Northwest trough will begin to dig southwestward
Saturday afternoon. A plume of moisture off the southern
California coast could interact with this trough and bring showers
beginning Saturday evening to northern Arizona. All GEFS members
are showing chances of measurable precipitation from Saturday
overnight into Sunday evening. Chances of precipitation in this
period were increased only slightly with this forecast. This will
be a drier system, but storm total precipitation amounts will
continue to be monitored. Only slight chances for showers are
expected by the early morning hours Monday.

The operational GFS is much more progressive on this late weekend
system and moves the deep moisture out of the area faster than
the operational ECMWF. These models display about a twelve hour
difference in the timing for the final showers within southeastern
areas of the County Warning Area. This timing will continue to be
monitored, especially for eastern Arizona.

Drier air behind this frontal passage will help to clear skies
from Monday morning into the afternoon. Temperatures are forecast
to rebound slightly behind the front for Monday and Tuesday.

&&

.AVIATION...For the 00Z package...MVFR and localized IFR conditions
are forecast to continue through early Thursday morning. A period of
moderate to heavy precipitation will move from west to east tonight
as a cold front crosses the area. Shower activity will quickly
diminish Thursday morning, with improving ceilings and visibilities
through the rest of the TAF period. Aviation discussion not updated
for TAF amendments.

&&

.FIRE WEATHER...A quick moving low pressure system will bring breezy
southwest winds along with rain and high elevation snow showers to
the area through early Thursday. Fair weather can be expected
Thursday afternoon into Friday.

Saturday through Monday...Dry conditions can be expected for most
locations through Saturday afternoon. More widespread chances for
wetting rains return Sunday. Chances for showers decrease Monday.

&&

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

&&

SHORT TERM...TPS
LONG TERM...NL
AVIATION...TPS
FIRE WEATHER...TPS/NL

For Northern Arizona weather information visit
weather.gov/flagstaff

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1124 AM MST WED DEC 4 2019

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

0800 AM     SNOW             TS'AH BII KIN           36.65N 110.76W
11/30/2019  E4.0 INCH        COCONINO           AZ   TRAINED SPOTTER

            ESTIMATED STORM TOTAL FROM THE MORNING OF
            THE 29TH THROUGH EARLY IN THE MORNING OF THE
            30TH.

&&

NL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1125 AM MST WED DEC 4 2019

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

0800 AM     SNOW             1 SSW KEAMS CANYON      35.79N 110.20W
11/30/2019  E3.0 INCH        NAVAJO             AZ   DEPT OF HIGHWAYS

            ESTIMATED STORM TOTAL FROM THE MORNING OF
            THE 29TH THROUGH EARLY IN THE MORNING OF THE
            30TH.

&&

NL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1127 AM MST WED DEC 4 2019

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

0800 AM     SNOW             SECOND MESA             35.79N 110.50W
11/30/2019  E2.0 INCH        NAVAJO             AZ   LAW ENFORCEMENT

            ESTIMATED STORM TOTAL FROM THE MORNING OF
            THE 29TH THROUGH EARLY IN THE MORNING OF THE
            30TH.

&&

NL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1128 AM MST WED DEC 4 2019

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

0800 AM     SNOW             KYKOTSMOVI VILLAGE      35.88N 110.61W
11/30/2019  E1.0 INCH        NAVAJO             AZ   LAW ENFORCEMENT

            ESTIMATED STORM TOTAL FROM THE MORNING OF
            THE 29TH THROUGH EARLY IN THE MORNING OF THE
            30TH.

&&

NL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1131 AM MST WED DEC 4 2019

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

0800 AM     SNOW             BLACK MESA              36.35N 110.07W
11/30/2019  E4.0 INCH        NAVAJO             AZ   TRAINED SPOTTER

            ESTIMATED STORM TOTAL FROM THE MORNING OF
            THE 29TH THROUGH THE MORNING OF THE 30TH.

&&

NL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
221 PM MST WED DEC 4 2019

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

0200 AM     AVALANCHE        13 N FLAGSTAFF AIRPORT  35.33N 111.67W
11/30/2019                   COCONINO           AZ   PUBLIC

            AVALANCHE DEBRIS WERE SEEN FROM TWO
            DIFFERENT NATURAL AVALANCHES AT AROUND
            11,700 FT ON A NORTHEASTERLY AND
            NORTH-NORTHEASTERLY SLOPES IN THE KACHINA
            PEAKS WILDERNESS AREA. ESTIMATED TIME.

&&

MAS