A low pressure system in Prince William Sound combined with a high pressure system over the Interior to increase winds through channeled areas. The winds combined with snowfall and transportable snow on the ground created blizzard conditions in Thompson Pass.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS AFC wrote it up.
A low pressure system in Prince William Sound combined with a high pressure system over the Interior to increase winds through channeled areas. The winds combined with snowfall and transportable snow on the ground created blizzard conditions in Thompson Pass.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Anchorage, AK wrote its last area forecast discussion before the first event at Dec 27, 4:11 AM AKST, 1 hour 49 minutes earlier.
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
411 AM AKST Fri Dec 27 2019
.ANALYSIS AND UPPER LEVELS...
Conditions are much more quiet across Southcentral this morning.
Zonal mid-level flow is coinciding with drier air west of and
including Anchorage as is shown on current water vapor imagery.
This is leading to partial clearing over the region which could
bring morning lows down to near zero in low-lying areas. A weak
surface low moving onshore west of Cordova is bringing light snow
to coastal areas as well as the Copper River Delta. This will
gradually taper off this morning before the next system approaches
by evening.
The main story over Southwest Alaska remains the dangerously cold
wind chills (near -50 in some areas). Strong high pressure over
Siberia combined with a number of lows in the North Pacific is
leading to gusty northeasterly winds across portions of the
Kuskokwim Delta and Bristol Bay. Wind Chill Advisories remain in
effect for these areas through noon Saturday.
A very active pattern continues over the Bering. Several low
centers in the North Pacific are bringing widespread easterly
gales leading to periods of blowing snow over the central
Aleutians and Pribilofs.
&&
.MODEL DISCUSSION...
Latest models continue to show the GFS as an outlier with regards
to the low approaching Kodiak Island. Other synoptic models as
well as the mesoscale models indicate a faster and farther
easterly track, thus making this the most likely outcome at this
time. In any case, snow and blowing snow is likely for the city of
Kodiak, though prolonged blizzard conditions appear unlikely. As
the low continues to track northeastward, significant snow
accumulations are likely from Whittier eastward towards Valdez and
the Copper River Valley. As with any forecast, uncertainties
exist as there is often one or more outlier models, however
confidence is not any lower than average in this particular case
and the aforementioned impacts are likely given this system
encompasses a large portion of the Gulf.
&&
.AVIATION...
PANC...VFR conditions and northerly winds near 10 kt will persist
through this evening. Though uncertainty exists regarding the
exact timing, snow will begin Saturday morning with visibilities
causing MVFR conditions and possible IFR conditions in heavier
snow bands.
&&
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A strong low will move northward through the Gulf later today and
tonight. This low will deepen to about 959 mb around midnight
tonight, then weaken as it tracks into Prince William Sound
Saturday morning. This storm will bring significant winds and snow
to Kodiak Island this afternoon through tonight. Both sides of the
Kenai Peninsula will also see some snow and winds, and Winter
Weather Advisories have been issued for those areas. Blizzard
conditions are expected in Thompson Pass tonight into Saturday
morning. Snow will spread inland tonight and Saturday morning,
with the highest amounts expected over the Copper River basin.
Chances of snow will continue through Saturday night with cyclonic
flow aloft due to an upper low that will be moving into southwest
Alaska.
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Brutally cold temperatures expected across the region as arctic
air holds in place. Overnight -35F was observed at Aniak and -19F
at King Salmon. Wind chill advisories have been issued for the
Kuskokwim Delta and Bristol Bay through Saturday afternoon. The
bone chilling temperatures will continue through the weekend.
Storms moving over the North Pacific will usher moisture into the
AKPEN and displace the arctic trough axis. Because the
temperatures associated with the arctic trough are so dangerous,
the position of the arctic trough is under constant monitoring.
Stay tuned for updates.
&&
.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The North Pacific is very active with mature lows near Northern
Japan and south of the Aleutians. The wet and windy pattern will
continue this forecast period. Models struggle with the tracks of
the surface lows, but all of the models show multiple fronts,
prolonged unsettled weather and gale to storm force winds at
times. Any breaks in the pattern that materialize will be short
lived.
&&
.MARINE (Days 3 through 5)...
(Sunday through Tuesday)
...Bering Sea and Aleutian Coastal Waters...
Low pressure south of the AKPEN and a second, stronger low well
south of the central Aleutians will continue to bring sustained
north-northeasterly gales across much of the Bering and westerly
gales south of the Chain through Tuesday. An area of storm-force
winds are also possible south of the eastern half of the Chain and
AKPEN late Monday in to Tuesday depending on the strength and
position of the second low as it advances toward Bristol Bay.
An elevated likelihood for freezing spray, some of it heavy, will
persist into early next week. Seas in the 20 to 25 feet range
will transition from west to east for the forecast period. Winds
and waves are expected to relax by Tuesday across the western half
of the Bering and Aleutians as the storm activity moves toward the
Southwest mainland.
...Gulf of Alaska...
Sustained gales, and perhaps a small area of storms, will persist
along the Southcentral coast Sunday as an area of low pressure
tracks northeast from near Kodiak to Prince William Sound. These
winds subside somewhat for Monday as the low and its front weaken.
A large area of westerly small-craft advisory winds with embedded
storm-force winds will redevelop late Monday and continue into
Tuesday as a second low pressure system lifts toward the AKPEN
with a front moving across the Gulf. Seas will generally be in
the 10 to 15 feet range near the coast, and 20 to 25 feet further
offshore for most of the forecast period.
&&
.LONG TERM FORECAST (Days 3 through 7)...
(Sunday through Thursday)
...Southcentral...
An active weather pattern will continue across Southcentral
through the end of the year. One storm system weakens on Sunday
with snowfall across the region and gusty winds along the coast
diminishes. The storm system then arrives quickly on the heels of
the previous, affecting the region Sunday night into Monday with
additional accumulating snowfall. Intrusions of rain, however,
are possible along the coast as some warmer air advects northward.
Yet another storm moves into the area for Monday night into
Tuesday. It is with this system that models begin to diverge
greatly on strength and track, and these significant differences
may play havoc on precipitation type and snow amount over a good
portion of Southcentral. Right now, it does appear that it will
remain just cold enough aloft that precipitation will stay all
snow over interior locations, with another round of accumulating
snow likely. However, enough warm air may move over the coast and
Cook Inlet that a changeover to a wintry mix (freezing rain) is
possible. That is what the latest GFS and ECMWF guidance is
indicating with 850mb (4,000ft above MSL) pushing 0C to +1C by
Monday evening. Snow showers then persist into Wednesday as this
system lifts north as cold air moves back in behind the low.
...Southwest Alaska...
A arctic trough diving south across Southwest Alaska will interact
with a storm system moving from near Kodiak Island to Prince
William sound to bring a reinforcing short of extremely cold air
through Sunday. By late Sunday, a low tracking north toward the
AKPEN will push warmer air and moisture over the region, resulting
in accumulating snowfall for the region. Enough warmer air aloft may
make it into the upper Kuskokwim Valley for a brief changeover to
the wintry mix late Monday before this system lifts north and
ushers in another round of arctic air and continued snow showers
into mid-week..
...Saint Matthew Island, Pribilof Islands, and Aleutians...
Periods of snow showers will continue through next week with a
second round of arctic air diving south across the Bering by
Tuesday.
&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Blizzard Warning: 131.
Winter Weather Advisory: 121 125 141 171.
Wind Chill Advisory: 155 161.
Flood Advisory: 145.
MARINE...Storm Warning: 119 174.
Gale Warning: 120 121 125 127 128 130-132 136-139
150 155 160 165 170-173 175-181 185.
Heavy Freezing Spray Warning: 139 150 160 165 179-181
185.
FIRE WEATHER...NONE.
&&
SYNOPSIS AND MODEL DISCUSSION...AP
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PJS
MARINE/LONG TERM...TM1 blizzard. Local standard time, as filed.
Thompson Pass DOT recorded 10 of snow in 24 hours. They experienced northeasterly winds at 40 mph with visibility near zero at times.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2019Every state in 2019This day in weather historyWarnings in Alaska, December 2019
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 864115.