Snow Squall Warning 1, NWS Flagstaff, AZ

089 
WWUS55 KFGZ 132157
SQWFGZ

Snow Squall Warning
National Weather Service Flagstaff AZ
255 PM MST Sat Mar 13 2021

AZC005-025-132205-
/O.EXP.KFGZ.SQ.W.0001.000000T0000Z-210313T2200Z/
Yavapai-Coconino-
255 PM MST Sat Mar 13 2021

...THE SNOW SQUALL WARNING FOR YAVAPAI AND COCONINO COUNTIES WILL
EXPIRE AT 300 PM MST...

The snow squall which prompted the warning has weakened and exited 
the area the Kachina Village area. Therefore, the snow squall 
warning will be allowed to expire for the Kachina Village area. Snow 
and ice-covered roads will continue to make travel difficult. A new 
snow squall warning has been issued 3:15 PM MST for Munds Park and 
the southern portion of the snow squall warning. 

LAT...LON 3514 11158 3477 11154 3479 11172 3515 11177
TIME...MOT...LOC 2155Z 274DEG 21KT 3507 11138 3468 11142 

$$

ET

Area Forecast Discussion
National Weather Service Flagstaff AZ
934 AM MST Sat Mar 13 2021

.SYNOPSIS...An area of low pressure will continue to bring rain
and snow showers today. Hazardous winter travel conditions are
expected at times above 4000 to 5000 feet. Dry and warmer
conditions will return Sunday with gusty west to northwest winds.
Southwest winds Monday afternoon will be gusty ahead of a quick
moving cold front Tuesday. Temperatures will warm to above normal
the latter half of the week with a return of dry conditions.

&&

.DISCUSSION...A broad, cold upper level low is currently centered
near southwest Utah with wrap around moisture beginning to spread
into western Coconino and Yavapai counties. One of the disturbances
within this low will rotate from northwest to southeast through
the area today.

Latest hi-res model guidance is in good agreement on this feature
bringing widespread rain and snow shower activity from midday
through the early-mid evening hours. Very cold air aloft (-28 to -30
C at 500 mb) will combine with daytime surface heating to produce
fairly intense precipitation rates at times. This will especially
be true along the upslope areas south of Flagstaff from Kachina
Village to Munds Park and across to Happy Jack and Forest Lakes.
12Z HREF guidance indicates brief periods of 1-2 in/hr snowfall
rates are possible this afternoon in these areas. Enough
instability will be present along and south of the Mogollon Rim
that a few claps of thunder are possible in the more intense
showers. Snowfall amounts will be highly variable due to the
showery nature of the precipitation and will also be limited at
times due to the mid-March sun. However, we do expect some travel
impacts this afternoon with very low visibility and periods of
snow-covered roads in the high snowfall rates. This is especially
true along I-17 south of Flagstaff. Drier air will push in behind
the system this evening bringing an end to the shower activity.

Only minor updates were made this morning to the snowfall amounts.
The remainder of the forecast is on track.

&&

.PREV DISCUSSION /422 AM MST/...Radar and surface observations
show light snow showers along the Mogollon rim and extending
north to Highway 160. Satellite imagery shows the low pressure
circulation centered over Utah with a deep trough extending south
to the Gulf of California. The precipitation band ahead of the
trough is shifting east with a second band of wrap-around moisture
and shower activity starting to move into Mohave County. Expect
wide spread showers across the region today with snow down to
4000-5000 feet as this wrap-around moisture moves east across
northern Arizona. The GFS deterministic model indicates the low
pressure system is a complex system of multiple lows circulating
about each other with one of the lows circling to the west and
south before it moves to the east across norther Arizona this
afternoon. This motion is evident in the nighttime microphysics
composite satellite imagery indicating the model is well
initialized and tracking with the meteorological conditions.
Expect a slight chance for thunder along and south of the
Mogollon rim through the afternoon as the cold air (<-45C) aloft
in this low moves across the area. Look for periods of heavy snow
possible with these showers, especially along I-17 from
Mountainaire south to Munds park, and east to Mormon Lake and
Happy Jack. The Winter Weather Advisory will be allowed to expire
this morning at 5 AM as the heavier snow today will generally be
localized to areas of strong upslope conditions and not wide
spread across forecast zones. We will provide specific messaging
for areas impacted by the heavier snow showers as needed. The
showers will end west to east through the evening with a few
lingering showers over the higher terrain along the New Mexico
border and in the White Mountains lasting into Sunday morning.
Skies will clear out Sunday, allowing the area to warm
significantly over the Saturday highs. The gradient tightens
behind this low as it moves into New Mexico that will bring gusty
west to northwest winds along and northeast of the Mogollon Rim
Sunday afternoon.

Another trough will pass to the north bringing another chance for
showers mostly north of I-40 overnight Monday into Tuesday. Expect
some gusty southwest winds Monday afternoon ahead of this trough
in Yavapai and Coconino Counties. Accumulations of up to one inch
are possible above about 6500 feet with a few inches possible
above 8000 feet.

A ridge moves into the area later in the week bringing a return of
dry weather and temperatures well above normal by Friday. Models
indicate the synoptic pattern will maintain a general zonal flow
in the long range with embedded shortwaves that may impact the
area. In this pattern, expect mostly fair weather with breezy
afternoon winds and brief periods of unsettled weather every
three to five days. Stay tuned right here to get the latest
updates on when these unsettled periods will occur.

&&

.AVIATION...For the 18Z package...Areas of fog and low clouds lifts
this morning, then widespread snow showers move in after 18Z. Snow
showers quickly drop sites to MVFR/IFR conditions as they progress
from NW to SE across northern AZ. Isolated thunder is possible
within the more intense snow showers near KFLG and along the Rim.
Snow showers diminish after 00Z for much of the area, except for
areas in eastern AZ near KSOW/KSJN/KJTC were showers may linger
through 05Z. Winds pick up after 18Z with W/SW winds 10-15 knots
with local gusts up 20-30 kts near KFLG/KPRC/KINW. Winds begin to
subside after 02Z, becoming light and variable through the remainder
of the period. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Snow showers will continue across eastern Arizona
this morning, and then re-develop across the area this afternoon.
Expect another round of generally light snow accumulations above
4,000 to 5,000 feet through early this evening. Breezy west to
southwest winds today will become stronger westerly winds Sunday.

Monday through Wednesday...Another weak system arrives late
Monday with gusty southwest winds and mainly light precipitation.
Below average temperatures are expected through Tuesday, with
warming beginning Wednesday.

&&

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

&&

PUBLIC...TPS/DB
AVIATION...CH/TPS
FIRE WEATHER...MCT

For Northern Arizona weather information visit
weather.gov/flagstaff

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1003 AM MST SAT MAR 13 2021

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

0745 AM     SNOW             4 NW MCNARY             34.11N 109.90W
03/13/2021  M2.7 INCH        NAVAJO             AZ   TRAINED SPOTTER

            TOTAL SINCE 1:30 AM.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1050 AM MST SAT MAR 13 2021

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

0912 AM     SNOW             NUTRIOSO                33.95N 109.21W
03/13/2021  M1.4 INCH        APACHE             AZ   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1101 AM MST SAT MAR 13 2021

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

1100 AM     SNOW             HOTEVILLA               35.92N 110.66W
03/13/2021  E6.0 INCH        NAVAJO             AZ   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1217 PM MST SAT MAR 13 2021

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

1105 AM     SNOW             SELIGMAN                35.33N 112.88W
03/13/2021  M1.0 INCH        YAVAPAI            AZ   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
202 PM MST SAT MAR 13 2021

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

1251 PM     SNOW             1 SW PARKS              35.26N 111.96W
03/13/2021  M1.0 INCH        COCONINO           AZ   PUBLIC

            1 INCH SINCE 8AM. STORM TOTAL OF 13.5
            INCHES.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
206 PM MST SAT MAR 13 2021

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

1254 PM     SNOW             PINETOP-LAKESIDE        34.15N 109.97W
03/13/2021  M3.0 INCH        NAVAJO             AZ   PUBLIC

&&