Small Craft Advisory 43, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion...CORRECTED
National Weather Service Anchorage AK
729 AM AKST Sun Jan 12 2020

.ANALYSIS AND UPPER LEVELS...

The upper level pattern includes a broad trough over the Bering
and a high amplitude ridge in place over the Gulf and extending
northward over the Interior. A strong upper level jet over the
Alaska Peninsula has aided the development of a triple point low
near Kodiak Island. Meanwhile a front is lifting inland over the
southwest coast. This has brought snow and blowing snow overnight
along the Kuskokwim Delta and Bristol Bay coasts. The leading
edge of cloud cover from this front is approaching Southcentral
this morning.

&&

.MODEL DISCUSSION...

Models continue to remain in decent agreement through the short
term. There are some minor differences in timing and track of the
developing triple point low near Kodiak Island Sunday night.
However, there is good agreement this low will weaken and move
quickly to the southeastern Gulf early next week. Overall,
forecast confidence is average.

&&

.AVIATION...

PANC...Patchy fog over Knik Arm may linger near the terminal
through the early morning hours. Otherwise, VFR conditions and
light winds will persist into Sunday afternoon. Expect conditions
to drop to MVFR in snow Sunday evening as a weak front moves into
the area.

&&

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

A upper level long wave trough heads east across Southcentral
today/tonight. At the surface a weakening front over the western
Gulf of Alaska brings clouds and light snow into Southcentral
today and tonight. Snow accumulations overall will be fairly low.
The more significant change will be the moderation of surface
temperatures today and tonight. Light snow in many areas will
diminish overnight with the passage of the upper trough/surface
front. Cold advection from the west spreads with the passage of
the upper trough Monday through Monday night. Whether or not
temps return to their recent norms will depend on residual cloud
cover.

A weak triple point low moving east across the Gulf today will
bring westerly gales to the western Gulf. Gusty outflow winds
across the northern Gulf will diminish some today. As the surface
low shifts east tonight expect a resurgence in the outflow
conditions on Monday/Monday night along with the eastern Kenai
Peninsula.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Today
through Tuesday Night)...

An occluded front continues to push across the interior of
Southwest Alaska this morning with widespread light snow falling
from just south of Iliamna to Aniak and Hooper Bay. Winds continue
to gust across the Kuskokwim Delta and Bristol Bay coasts, but
overall winds are diminishing and conditions are improving along
the coast as the bulk of the precipitation moves farther inland.
Winter Weather Advisories remain in effect with snow totals of 3
to 6 inches expected along the Kuskokwim Delta and 4 to 8 inches
for areas north of King Salmon. Snow will also work into the
middle and upper Kuskokwim Valley this morning, but it will have
to overcome a deep layer of cold and dry air. This broader area of
snow will persist across the Kuskokwim Valley and Alaska Range
through Sunday night.

Behind the front, a broad onshore flow will develop and persist
into Monday. This set up will allow scattered snow showers to
linger across the coast and higher elevations of the Kilbuck and
Alaska Ranges. By Monday night, clouds and any remaining isolated
snow showers will diminish as a strong ridge of high pressure
builds in. This ridge will usher in clear and dry conditions,
allowing for another cooling trend with temperatures dropping back
toward 0F by Tuesday night.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Today through Tuesday Night)...

Strong westerly flow will persist across the Bering through Monday,
with colder air wrapping around the backside of a strong low
lifting into the Gulf of Anadyr. Along the western Aleutians, a
weak surface low will spin up, quickly tracking east to the
Pribilofs by Monday morning then to the AKPEN by Tuesday morning.
On Monday night, a stronger surface low will develop south of
Shemya, tracking north towards Kamchatka by Tuesday afternoon. Its
front will drag much warmer air north as it produces storm-force
winds and widespread rain across the western Bering and Central
Aleutians. Ahead of the front, a strong ridge of high pressure
will build across the eastern Bering and Aleutians. This ridge
will help slow the progression of the front by late Tuesday with
it eventually stalling just west of the Pribilofs. By Tuesday
night, a new low develops along the front south of Adak.

&&

.MARINE (Days 3 through 5)...
The western gulf will see gusty northerly flow Monday through
Wednesday of next week as the pressure gradient tightens between low
pressure near the Gulf and a ridge moving to the Southwest Mainland.
Small craft to gale force winds will taper down for a short time
Monday night; however, gusty winds return by late Tuesday morning.
Across the Bering, relatively quiet weather on Monday is followed by
a gale force front moving to the western waters Monday night. This
front moves slowly across to the central waters on Wednesday. There
is still high uncertainty on the strength of the front on Wednesday
and should be monitored as it has the potential to be stronger than
currently forecast.

&&

.LONG TERM FORECAST (Days 3 through 7)...
Dry and colder than normal conditions are on tap for much of the
Southern Mainland in the extended forecast Monday night through
Friday. A few snow showers will be possible across the Southwest as
several weak fronts push inland. The Bering will see the most active
weather pattern as a North Pacific storm send a front to the across
the western Aleutians late Monday night. This front moves slowly
east bringing strong gusty winds and rain to the Eastern Aleutians
and Pribilof Islands. There is still some uncertainty on the
strength of this system and it should be monitored for updates. The
forecast for Wednesday night through Friday will generally be a
persistent forecast with dry cold conditions over the Southern
Mainland and active weather over Bering and Gulf.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisories 161 155
         Wind Chill Advisory 131
         Flood Advisory 121
MARINE...Heavy Freezing Spray Warning 119 127 139
Gale Warning
119 120 130 131 132 136 139 150 160 178 185 351 352 411 412.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KO
SOUTHCENTRAL ALASKA...RMC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TM
MARINE/LONG TERM...KH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1138 AM AKST SUN JAN 12 2020

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

1130 AM     SNOW             2 N BETHEL              60.80N 161.76W
01/12/2020  E3.0 INCH        BETHEL             AK   OTHER FEDERAL

            SPOTTER REPORTED 3 INCHES OF SNOW.

&&

MV

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1149 AM AKST SUN JAN 12 2020

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

1147 AM     SNOW             3 SE DILLINGHAM         59.04N 158.47W
01/12/2020  E6.0 INCH        DILLINGHAM         AK   LAW ENFORCEMENT

            SPOTTER REPORTED 6 INCHES OF SNOW.

&&

MV

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1202 PM AKST SUN JAN 12 2020

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

1155 AM     SNOW             2 WSW ILIAMNA           59.76N 154.91W
01/12/2020  E7.0 INCH        LAKE AND PENINSULA AK   OTHER FEDERAL

            SPOTTER REPORTED APPROXIMATELY 7 INCHES OF
            SNOW AS OF 11:55 AM AS WELL AS WINDS TO
            28KTS.

&&

MV

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE ANCHORAGE AK
150 PM AKST SUN JAN 12 2020

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

1155 AM     SNOW             2 WSW ILIAMNA           59.76N 154.91W
01/12/2020  E7.0 INCH        LAKE AND PENINSULA AK   OTHER FEDERAL

            SPOTTER REPORTED APPROXIMATELY 7 INCHES OF
            SNOW AS OF 11:55 AM AS WELL AS WINDS TO
            28KTS.

1115 AM     SNOW             1 SE HOOPER BAY         61.53N 166.09W
01/12/2020  E6.0 INCH        KUSILVAK           AK   LAW ENFORCEMENT

            SPOTTER REPORTED APPROX. 6 TO 12 INCHES OF
            SNOW AND WINDY CONDITIONS LAST NIGHT INTO
            THIS MORNING.

1147 AM     SNOW             3 SE DILLINGHAM         59.04N 158.47W
01/12/2020  E6.0 INCH        DILLINGHAM         AK   LAW ENFORCEMENT

            SPOTTER REPORTED 6 INCHES OF SNOW.

1130 AM     SNOW             2 N BETHEL              60.80N 161.76W
01/12/2020  E3.0 INCH        BETHEL             AK   OTHER FEDERAL

            SPOTTER REPORTED 3 INCHES OF SNOW.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
242 PM AKST SUN JAN 12 2020

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

0235 PM     SNOW             2 WSW ILIAMNA           59.76N 154.91W
01/12/2020  E9.0 INCH        LAKE AND PENINSULA AK   OTHER FEDERAL

            SPOTTER REPORTED FINAL SNOWFALL AMOUNT OF 9
            INCHES AND VERY WINDY AS WELL CAUSING
            DRIFTS.

&&

MV

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE ANCHORAGE AK
243 PM AKST SUN JAN 12 2020

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

0235 PM     SNOW             2 WSW ILIAMNA           59.76N 154.91W
01/12/2020  E9.0 INCH        LAKE AND PENINSULA AK   OTHER FEDERAL

            SPOTTER REPORTED FINAL SNOWFALL AMOUNT OF 9
            INCHES AND VERY WINDY AS WELL CAUSING
            DRIFTS.

&&