Brisk Wind Advisory 32, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
547 AM AKST Tue Feb 18 2020

.ANALYSIS AND UPPER LEVELS...

A vertically stacked low is lifting inland over the Kuskokwim
Delta coast. An occluded front associated with this low bisects
the state from north to south. A second low is developing in the
Gulf and lifting northward, steering moist southerly flow into the
northern Gulf coast. A band of precipitation observed on radar
imagery this morning over Cook Inlet has brought a mix of rain
and snow to Southcentral and it continues to gradually push
eastward.

&&

.MODEL DISCUSSION...

Models remain in good synoptic agreement through the middle of the
week. Important differences of note in the short term include the
ending time of snowfall across Southcentral early Wednesday. The
NAM is quick to end snowfall early Wednesday morning, while the
GFS solution continues it a bit longer. Additionally, some model
solutions hang on to warm air over Prince William Sound and the
Matanuska Valley a bit longer in the midlevels, which could limit
overall snowfall amounts in those areas. By Wednesday, models
diverge on the timing and track of the next Bering low as it moves
eastward across the Aleutian Chain.

&&

.AVIATION...

PANC...The threat of LLWS will eventually taper as midlevel
southeasterly flow diminishes this morning. Expect IFR conditions
for most of the day today with snow. Conditions are expected to
improve to MVFR by early Wednesday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2...Tue and
Wed)...

An impressive storm is taking aim on much of Southcentral AK for
today and tomorrow. Strong upper level dynamics are coupling with
abundant moisture to create an atmosphere ripe for strong winds
and heavy snow. Gusty southeast winds will continue very early
this morning for parts of the Turnagain Arm and the Mat Valley.
These winds represent the last of a warm airmass and are helping
to keep temperatures in some of those localized areas above
freezing. The warm 850 mb (5000') pocket continues to linger over
the Western Prince William Sound. However, cold air is driving up
the Cook Inlet from west to east. As these two airmasses collide
through the period, it will create a line of heavy snowfall. The
current band stretches from the Central Kenai up through the
Susitna Valley. Snow rates of an inch or more per hour are
definitely possible with this feature. As we expect it to shift to
the east through the day over the Anchorage Bowl, we have issued
a Winter Storm Warning. Winter Weather Advisories also remain in
effect for the Susitna Valley, the Kenai Peninsula, and the Mat
Valley for accumulating snow.

A new wave is working north through the Gulf of AK. This feature
will eventually become a new closed off area of low pressure
tonight. It will serve to bring another round of moisture from the
Western Prince William Sound up through the Cook Inlet. However,
it will also bring some marginally warmer air as well. So while it
could serve to enhance snowfall for inland areas, it will likely
make for continued rain (or a rain/snow mix) for most of the
coastal locations. The Turnagain Pass, Thompson Pass, and other
higher elevations will remain cold enough for snow and several
feet of snow accumulation are possible through Wed morning. This
wave will be the key feature for how long snow lingers across the
northern Kenai Peninsula, the Cook Inlet, and parts of the Mat-Su
Valleys as well. This forecast package leans more toward the
slower solutions keeping the snow falling through the overnight
hours with several more inches of new accumulation.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...

Blizzard conditions continue across the Kuskokwim Delta coast this
morning, which will improve throughout the afternoon today as the
occluded low lifts north out of the forecast area and winds
weaken. Over the Bristol Bay coast, strong winds, snow, and low
visibilities continue with southeasterly flow, which should switch
over to southwest flow by late morning. Areas of blowing snow will
continue until the winds and precipitation taper off along the
coast by this afternoon. Isolated snow showers will continue
through Wednesday as colder air filters back in across Southwest
Alaska. Expect temperatures across Bristol Bay to be about 10 to
15 degrees cooler tonight into Wednesday than last night, and
about 20 degrees cooler across the Kuskokwim Delta as cold air
advection quickly moves in.

The next significant system will cross over the Alaska Peninsula
on Wednesday, which will bring another round of complicated
weather to the region. Expect strong winds to return to the Alaska
Peninsula and along the Southwest coast of Bristol Bay, along with
concerns for possible blowing snow as the front approaches the
mainland. This system will also bring another round of snowfall
to Southwest Alaska.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

A low near Nunivak Island this morning will continue inland
throughout the afternoon. As it does, winds across the eastern
Bering and Aleutians will weaken through the evening. The next
system is on track to cross over the western Aleutians this
afternoon, progressing over the central Aleutians and Bering
overnight into Tuesday morning. Winds are expected to stay at gale
force level, but could see a swath of storm force gusts with it.

As this low moves into the eastern Bering by Thursday morning,
concerns for strong northwest winds arise for areas along the
northern side of the eastern Aleutians (including Dutch Harbor)
and Alaska Peninsula (including Cold Bay). Widespread snow showers
with gusty winds could lead to possible blowing snow conditions
for these areas.

&&

.MARINE (Days 3 through 5 Thu through Sat)...

Some gales are expected on Thursday and Thursday night to the
south of the eastern Aleutians and Alaska Peninsula as a system
moves east into the Gulf. Gale to near storm force winds are
expected along the north Gulf coast on Thursday associated with
this same system. On Friday night and Saturday, Gale force west to
northwest winds are expected over the Gulf and south of the Alaska
Peninsula. A storm system moving into the western and central
Aleutians on Saturday should produce gale force winds.

&&

.LONG TERM FORECAST (Days 4 through 7 Fri through Mon)...

On Friday morning the pattern will consist of an upper level
trough over southwest Alaska extending southeastward into the Gulf
of Alaska. The trough will very slowly slide northeast across
southern Alaska through Sunday as the main upper low retreats
northward. A weak ridge will then build over southern Alaska
Sunday night, sliding eastward on Monday. An upper level low just
south of the western Aleutians on Saturday will move eastward
through Sunday, possibly moving north into the central Aleutians
on Monday. The exact path and timing of this feature is somewhat
uncertain at this time.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning 101.
		 Blizzard Warning 131. Winter
		 Weather Advisory 111 121 145.
MARINE...Storm Warning 119.
	     Gale Warning 125 128 150 155 172-179 413 414.
		 Freezing Spray 179 180 185 411 412 414.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KO
SOUTHCENTRAL ALASKA...MSO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...ALH
MARINE/LONG TERM...BL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
313 PM AKST TUE FEB 18 2020

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

0215 PM     SNOW             KNIK RIVER              61.46N 148.91W
02/18/2020  E12.0 INCH       MATANUSKA-SUSITNA  AK   PUBLIC

            SPOTTER ESTIMATED 12 INCHES OF SNOW.

&&

ED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
314 PM AKST TUE FEB 18 2020

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

0314 PM     SNOW             SNOWLINE DRIVE          61.12N 149.73W
02/18/2020  E3.0 INCH        ANCHORAGE          AK   PUBLIC

            SPOTTER ESTIMATED 3 INCHES OF SNOW.

&&

ED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
318 PM AKST TUE FEB 18 2020

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

0317 PM     SNOW             EAGLE RIVER             61.32N 149.54W
02/18/2020  M3.5 INCH        ANCHORAGE          AK   NWS EMPLOYEE

            SPOTTER REPORTED 3.5 INCHES OF SNOW.

&&

ED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
320 PM AKST TUE FEB 18 2020

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

0200 PM     SNOW             EAGLE RIVER             61.32N 149.57W
02/18/2020  E4.0 INCH        ANCHORAGE          AK   PUBLIC

            SPOTTER ESTIMATED 4 INCHES OF SNOW.

&&

ED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
323 PM AKST TUE FEB 18 2020

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

0310 PM     SNOW             NORTHWOOD ST.           61.16N 149.92W
02/18/2020  M5.2 INCH        ANCHORAGE          AK   NWS EMPLOYEE

            SPOTTER MEASURED 5.2 INCHES OF SNOW.

&&

ED

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE ANCHORAGE AK
330 PM AKST TUE FEB 18 2020

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

0900 AM     SNOW             5 SW ANCHORAGE          61.16N 149.98W
02/18/2020  M4.4 INCH        ANCHORAGE          AK   NWS STORM SURVEY

0800 AM     HEAVY SNOW       6 NNW BENTALIT          61.65N 150.68W
02/18/2020  M9.0 INCH        MATANUSKA-SUSITNA  AK   PUBLIC

            LAST 24 HRS. 31F. VIS LESS THAN 1/4 MILE.
            SNOWING HEAVILY.

0700 AM     SNOW             4 SW TRAPPER CREEK      62.19N 150.50W
02/18/2020  M5.0 INCH        MATANUSKA-SUSITNA  AK   CO-OP OBSERVER

            31F SNOWING HEAVILY.

0700 AM     SNOW             1 W VALDEZ              61.13N 146.38W
02/18/2020  M4.7 INCH        VALDEZ-CORDOVA     AK   CO-OP OBSERVER

            CO-OP OBSERVER STATION VCOA2 VALDEZ.

0240 PM     SNOW             PALMER                  61.60N 149.10W
02/18/2020  E5.0 INCH        MATANUSKA-SUSITNA  AK   PUBLIC

            SPOTTER ESTIMATED 5 INCHES OF SNOW.

0215 PM     SNOW             KNIK RIVER              61.46N 148.91W
02/18/2020  E12.0 INCH       MATANUSKA-SUSITNA  AK   PUBLIC

            SPOTTER ESTIMATED 12 INCHES OF SNOW.

0210 PM     SNOW             BUTTE                   61.54N 149.01W
02/18/2020  E8.0 INCH        MATANUSKA-SUSITNA  AK   PUBLIC

            SPOTTER REPORTED ABOUT 8 INCHES OF SNOW.

0915 AM     SNOW             1 NNW PALMER            61.62N 149.13W
02/18/2020  M1.7 INCH        MATANUSKA-SUSITNA  AK   COCORAHS

            COCORAHS STATION AK-MS-11 S WILLIWAW DRIVE
            AT CEDAR HILLS DRIVE.

0907 AM     SNOW             TALKEETNA SPUR ROAD     62.24N 150.09W
02/18/2020  M12.4 INCH       MATANUSKA-SUSITNA  AK   TRAINED SPOTTER

            SPOTTER MEASURED 12.4 INCHES OF NEW SNOW.

0700 AM     SNOW             TALKEETNA 7.6S          62.23N 150.07W
02/18/2020  M8.4 INCH        MATANUSKA-SUSITNA  AK   COCORAHS

            COCORAHS MEASURED 8.4 INCHES OF SNOW.

0340 PM     BLIZZARD         CHEVAK                  61.54N 165.60W
02/17/2020                   KUSILVAK           AK   ASOS

            CHEVAK AIRPORT ASOS REPORTED BLIZZARD
            CONDITIONS SINCE 11:37PM AKST LAST NIGHT.

0930 AM     SNOW             4 WSW STERLING          60.49N 150.91W
02/18/2020  M2.0 INCH        KENAI PENINSULA    AK   COCORAHS

            COCORAHS STATION AK-KP-3 SOLDOTNA 5.1 E.

0443 PM     BLIZZARD         MEKORYUK AIRPORT        60.37N 166.27W
02/17/2020                   BETHEL             AK   ASOS

            MEKORYUK AIRPORT ASOS REPORTED BLIZZARD
            CONDITIONS SINCE 11:13AM AKST THIS MORNING.

0317 PM     SNOW             EAGLE RIVER             61.32N 149.54W
02/18/2020  M3.5 INCH        ANCHORAGE          AK   NWS EMPLOYEE

            SPOTTER REPORTED 3.5 INCHES OF SNOW.

0314 PM     SNOW             SNOWLINE DRIVE          61.12N 149.73W
02/18/2020  E3.0 INCH        ANCHORAGE          AK   PUBLIC

            SPOTTER ESTIMATED 3 INCHES OF SNOW.

0310 PM     SNOW             NORTHWOOD ST.           61.16N 149.92W
02/18/2020  M5.2 INCH        ANCHORAGE          AK   NWS EMPLOYEE

            SPOTTER MEASURED 5.2 INCHES OF SNOW.

0300 PM     SNOW             DIAMOND BLVD. AND JEWEL 61.14N 149.95W
02/18/2020  E5.5 INCH        ANCHORAGE          AK   PUBLIC

            SPOTTER REPORTED 5.5 INCHES OF SNOW.

0230 PM     SNOW             SOUTH ANCHORAGE         61.12N 149.83W
02/18/2020  E7.0 INCH        ANCHORAGE          AK   PUBLIC

            SPOTTER ESTIMATED 7 INCHES OF SNOW.

0200 PM     SNOW             EAGLE RIVER             61.32N 149.57W
02/18/2020  E4.0 INCH        ANCHORAGE          AK   PUBLIC

            SPOTTER ESTIMATED 4 INCHES OF SNOW.

0847 PM     NON-TSTM WND GST POTTER MARSH            61.06N 149.77W
02/17/2020  M84 MPH          ANCHORAGE          AK   MESONET

            MESONET RECORDED A WIND GUST OF 84 MPH.

&&