Area Forecast Discussion
Issued by NWS Anchorage, AK
FXAK68 PAFC 231213
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
413 AM AKDT Thu Mar 23 2017
.ANALYSIS AND UPPER LEVELS...
Ridging remains over the Bering with upper level low pressure to
the east over Southcentral Alaska. This setup has continued to
bring outflow winds to the southern mainland while also keeping
the majority of precip out over the Gulf or over coastal mountain
ranges. Additionally, areas around Cook Inlet and areas of
southwest Alaska have seen clear skies. West of the ridge,
remnants of an old front continue to push north through the
Models remain in good agreement over the next couple days and
forecast confidence is high.
PANC...VFR conditions and light winds will persist.
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A low pressure trough continues over the northern Gulf of ALaska
with higher pressure inland. Weak to moderate outflow winds are
expected to continue over the North Gulf Coast and the eastern
Kenai Peninsula through Friday. Isolated to scattered snow showers
with the proximity of the upper trough overhead will linger along
the Gulf Coast and portions of the Copper River Basin into
Friday night. The March sun and relatively cloud free nights
inland will continue to produce large temperature swings in those
areas with little wind over the next couple of days.
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The upper level ridge over the eastern Bering will persist through
the weekend with a cold upper level trough stretching from
northern Alaska into Southcentral Alaska. This flow pattern will
put Southwest Alaska under northwesterly flow aloft with the
surface winds out of the north to northeast bringing continued
cool, dry and generally sunny weather.
.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
A gale force frontal system approaching from the south will reach
the western and central Aleutians early Friday morning. The front
will lift into the southern Bering Friday and Friday night.
Several additional frontal waves spinning around the parent low
south of the Aleutians will rotate north across the Aleutians
Saturday and Sunday.
.LONG TERM FORECAST (Days 3 through 7)...
Northwest upper level flow and ridging over the Bering will remain
dominant as the extended period forecast begins Friday evening.
At the same time a sprawling low over the North Pacific extending
into the southwest Bering Sea will be slowly moving east. This
means the sensible weather pattern of mostly dry and offshore flow
over Southern Alaska will still be dominant before larger changes
begin to develop Sunday and into next week. After weeks of
dominant ridging over the Bering Sea, this feature will begin to
weaken and retrograde northwest, allowing for a pattern change as
the arctic trough over Southern Alaska merges with a series of
weak North Pacific lows. Right now, there is uncertainty of
exactly where the arctic trough stalls, but it is most likely that
the trough stalls near the Alaska Range with most of the
precipitation (rain and snow along the coast) remaining east of
the Alaska Range. By midweek and beyond, uncertainty grows with
the details, but it seems quite likely, based on the shifting
blocking high, that storminess will be on the increase as the NPAC
jet strengthens and amplifies.
MARINE...Gales...172 173 174 175 176 177 178.
Heavy Freezing Spray...121 126 127 129.
SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR