Area Forecast Discussion
Issued by NWS Anchorage, AK

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000
FXAK68 PAFC 141414
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
514 AM AKST Sat Jan 14 2017

.ANALYSIS AND UPPER LEVELS...
A broad upper level trough continues to dig over western Alaska.
Clouds and moisture are spreading northward ahead of a northward
moving low and associated warm front over the Northern Gulf coast
and into the Southcentral interior. Rain and snow persisted
through the overnight period and has now started to taper off as
the low move further inland. With the exception of increasing
clouds and lingering showers 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 reported observations.

&&

.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. With the
next system approaching the area on Sunday, models have started
to lock into a common solution. The 00Z GFS was the preferred
solution for this upcoming system, with the NAM (previous outlier)
now trending heavily toward the GFS in it`s 06Z run. With the NAM
shifting more westward and aligning with the other models,
forecast confidence has increased regarding another round of snow
over Southcentral Sunday through Monday.

&&

.AVIATION...
PANC...IFR to LIFR conditions in snow are expected to continue
through this 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)...
Snow will continue to taper off this morning around northern Cook
Inlet. Strong cold advection is beginning to spill over the Alaska
Range into Southcentral Alaska.

This cold dense air will bring strong winds through the gaps in
the Alaska Range and, combined with the track of the low, may
cause an interesting weather situation around Homer and Kachemak
Bay today. Winds typically are very strong through Kamishak Bay
and the track of the low may bring these strong winds into
Kachemak Bay today. Not only would this bring Gale force winds
into Kachemak Bay, it brings the potential for snow in these gusty
winds. This is a low probability event as the Kamishak Gap wind
needs to be sufficiently cold and directly hit Kachemak Bay.
However, this pattern is what can cause this to happen and if it
does it will bring snowfall and limited visibility in the snow and
strong winds. Once again, it has a low probability of occurring,
but this pattern is what can cause this to happen and if it does
it would bring in challenging travel conditions to the Kachemak
Bay area today.

By Sunday night the next snow system will move into
Southcentral Alaska. This is taking a very similar track to the
one going through this morning. At this time models are indicating
snow amounts around southcentral being around or a little more
than this current system.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA...
As the upper low moves off to the northeast it will pull down
colder air over southwest Alaska. These cold temperatures will
last into early next week. Winds look to stay weak through this
time period as well with the low moving away from the area.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS...
Cold northerly flow will dominate the Bering and Aleutians into
early next week. However, with the main low moving away from the
Bering, winds will not be as strong as the last couple days. Even
so, freezing spray will remain a concern in the cold northerly
flow for marine areas around the Bering and Aleutians. This flow
will also bring snow showers to areas around the Bering and
Aleutians.

&&

.LONG TERM FORECAST (Days 3 through 7)...
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 111 145
MARINE...Gale Warning 120 130 131 139 141 150 155 180 185
 Heavy Freezing Spray 130 138 139 140 141 150 155 160 165
  179 180 181 185

&&

$$

SYNOPSIS AND MODEL DISCUSSION...TP
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...DEK



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