Heavy Freezing Spray Warning 22, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
847 PM AKST Fri Jan 13 2017

.ANALYSIS AND UPPER LEVELS...
A broad upper level trough continues to dig over western Alaska.
Clouds and moisture are spreading north into Southcentral/northern
Gulf ahead of a north moving low and associated warm front. Rain
and snow developed along the North Gulf with light snow inland
across Southcentral Alaska. With the exception of increasing
clouds over Bristol Bay ahead of the Gulf system, much of
Southwest Alaska is under the influence of dry and cold offshore
flow. Cold northerly flow across the Bering Sea is evident by buoy
observations and the presence of open cell cu.

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.MODEL DISCUSSION...
The numerical models are in good synoptic agreement through
Sunday afternoon. Generally will be leaning toward the higher
res models for details, especially across Southcentral.

&&

.AVIATION...
PANC...IFR to LIFR conditions in snow are expected to develop this
evening and continue into Saturday morning. conditions should
improve by late morning with ceiling/visibilities approaching
MVFR. Gusty south winds will move up Cook Inlet and affect the
airport for much of the day.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A surface low in the western Gulf of Alaska is on track to push
a front across the southern mainland tonight. Snow intensity is
expected to increase through the evening hours as the atmosphere
has saturated throughout the column aloft as sampled by the
Anchorage sounding this afternoon. This event will bring widespread
snow accumulations across Southcentral with the highest amounts
expected along the mountain ranges. Winter weather advisories were
issued with the afternoon package for the Anchorage area, Mat-Su
Valleys and the areas along and east of the Parks Highway for
tonight into Saturday. Snow is expected to diminish by midday
Saturday, however there is still some uncertainty on how quickly
the surface low moves northeast.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA...
The main feature continues with the offshore northerly flow
heading into the weekend. Look for cooler temperatures combined
with winds to bring wind chills ranging from 20 to 35 below in
the Kuskokwim Delta and Lower Kuskokwim Valley. The Bristol Bay
interior will have more cloud cover and wind chills only ranging
from 10 to 25 below. Meanwhile, a storm force low tracks into the
Prince William Sound region by Saturday. This allows wrap-around
moisture to spill over the Aleutian/Alaska Ranges resulting in
light snow through Saturday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS...
The colder air continues to filter into the Bering and spreads
into the Aleutian Chain. This northerly flow results in gap winds
along the Alaska Peninsula tonight before tapering off by
Saturday afternoon. A showery regime will dominate through the
weekend with continues supply of arctic air spreading across the
region. With widespread cold temperatures, heavy freezing spray
will be quite prevalent across the Bering, along the coastline
near the Eastern Aleutians and the Alaska Peninsula through Saturday.

&&

.LONG TERM FORECAST (Days 3 through 7)...
Confidence is increasing that a second stronger low will track
through the Gulf and into Prince William Sound late Sunday night,
bringing another round of widespread snow to much of Southcentral
and the North Gulf Coast. There is still one notable outlier (the
NAM) which remains further to the east with the low track, this
was however ignored for today's forecast updates. This will need
to be monitored as a trend towards this more eastward track would
result in significant differences in snowfall forecast for Western
Prince William Sound. This low will also be much stronger than is
currently moving through the Gulf. Now that model agreement has
improved in the low track, gap winds throughout the North Gulf
Coast were increased and areas of blowing snow into Thompson Pass
were added to the forecast. Over the Southwest Mainland and Bering
Sea this system will provide little change to the current pattern
with continued cold and northerly flow throughout the Bering.

Once the Gulf low dissipates over the Mainland on Tuesday, there
is very good agreement that the arctic trough over the Southwest
will significantly broaden and shift east to cover the Mainland.
This would bring clearing skies with colder temperatures to much
of the South Mainland for the middle of next week. There is a
chance that this colder air could remain into late next week,
however uncertainty begins to increase significantly beyond next
Thursday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory 101 111 145.
MARINE...Heavy Freezing Spray Warning 130 138 139 140 141 150
									  155 160 165 179 180 181 185.
 		 Gale Warning 120 130 131 139 141 150 155 180 185.

&&

SYNOPSIS AND MODEL DISCUSSION...BC
SOUTHCENTRAL ALASKA...KH
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PD
LONG TERM...DEK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1225 AM AKST SAT JAN 14 2017

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

0800 PM     SNOW             5 SSE ANCHORAGE         61.15N 149.82W
01/13/2017  M2.7 INCH                           AK   NWS EMPLOYEE

            NEAR LAKE OTIS AND 72ND

0900 PM     SNOW             4 E ANCHORAGE           61.21N 149.76W
01/13/2017  M3.0 INCH                           AK   NWS EMPLOYEE

            DEBARR/BONIFACE AREA

0930 PM     SNOW             GLENNALLEN              62.08N 145.60W
01/13/2017  E3.0 INCH                           AK   NWS EMPLOYEE

0950 PM     SNOW             3 ESE KENAI             60.53N 151.12W
01/13/2017  M3.0 INCH                           AK   TRAINED SPOTTER

            NEAR WOODS DR

1000 PM     SNOW             1 E EAGLE RIVER         61.32N 149.54W
01/13/2017  M5.3 INCH                           AK   NWS EMPLOYEE

1030 PM     SNOW             2 SSE EAGLE RIVER       61.29N 149.55W
01/13/2017  M5.8 INCH                           AK   NWS EMPLOYEE

1100 PM     SNOW             3 SW ANCHORAGE          61.19N 149.93W
01/13/2017  M5.0 INCH                           AK   NWS EMPLOYEE

            SPENARD AREA

1115 PM     SNOW             2 N RABBIT CREEK        61.11N 149.83W
01/13/2017  M3.5 INCH                           AK   NWS EMPLOYEE

            LAKE OTIS/HUFFMAN AREA.

1115 PM     SNOW             4 S ANCHORAGE           61.16N 149.89W
01/13/2017  M4.9 INCH                           AK   NWS EMPLOYEE

            ARCTIC/RASPBERRY AREA

1200 AM     SNOW             5 SW ANCHORAGE          61.16N 149.98W
01/14/2017  M4.0 INCH                           AK   OFFICIAL NWS OBS

            DAILY SNOWFALL TOTAL FOR 1/13 AT THE NWS FORECAST OFFICE
            ON SAND LAKE RD.

&&

CB