Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 240057

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
457 PM AKDT Thu May 23 2019

There is an elongated upper low stretching from Bristol Bay into
the northern Gulf of Alaska. An associated surface low is centered
in the northwest Gulf and moving eastward. Considerable cloud
cover and some showers are over much of southern Alaska. An upper
level high is over central and northern Alaska, with an associated
thermal low at the surface. High pressure is over the western
Bering Sea, with a flat ridge over the northeast Pacific to the
south of the Gulf low. There is an upper level low situated to the
south of the central and eastern Aleutians.


The numerical models are generally in good agreement on the
synoptic pattern through Saturday afternoon. This includes better
agreement on the timing of precipitation than in previous runs.
Where they tend to differ is in the surface lows, mainly for the
location of the low in the northern Gulf tonight, and the
development of surface lows near the eastern Aleutians and Alaska
Peninsula Friday night and Saturday.


PANC...VFR conditions will persist. Some gusty southerly winds are
expected this evening (though not as strong as last night).
Confidence in this is not high, but normal diurnal patterns
indicate it is possible. Later this evening through Friday evening
the winds are expected to be fairly light.


2...Thursday afternoon through Saturday afternoon)...

The Gulf low will continue to slowly drift eastward this evening
as the associated occluded front brings light showers to the
northern Gulf coast. Showers will eventually taper this evening
as the front dissipates overnight. A beautiful day is in store for
most of Southcentral Friday as a surface ridge builds through the
day. Cloudy skies in the morning will eventually clear by the
evening ahead of the next system that arrives for the weekend. By
Friday night, a front associated with a gale force low approaches
Kodiak Island, bringing rain and gusty easterly winds Saturday
morning. Gale force winds are expected over the Barren Islands
and through Shelikof Strait Saturday afternoon. As the low
continues to lift northward, the front will eventually move over
Southcentral by Saturday evening.


through Sunday)...

An upper level low and associated surface trough will bring
scattered showers across Southwest this evening. Skies are
expected to clear overnight ahead of a ridge amplifying over the
Bering. Clouds will increase Friday night and rain will develop
from south to north through Saturday as a low tracks over the
Aleutians. Gusty winds are also likely, particularly in the
Kamishak Gap.


through Sunday)...

A North Pacific low will approach the central Aleutians this
evening bringing rain and gusty winds. Rain will taper to
scattered showers and winds will diminish Saturday morning under
the low, although precipitation will generally continue through
the day east of Sand Point. Another low developing near the
Kamchatka Peninsula and its associated front will track over the
western Aleutians bringing rain and gusty winds there as well. The
two systems will interact on Sunday and widespread showers are
likely across the entire region through the holiday weekend.


.MARINE (Days 3 through 5/Sunday through Tuesday)...

Winds will be subsiding on Sunday throughout all Marine areas, as
the low that brought the winds in will be weakening. Some small
craft advisory level winds will remain in the Gulf of Alaska and
western Bering, but should quiet as the day progresses. Past
Sunday there are not any significant impacts to marine areas.
Confidence is high in the forecast for quiet weather.


.LONG TERM FORECAST (Days 3 through 7/Sunday through Thursday)...

It`s still looking like a transition to a wetter pattern for
later in Memorial Day weekend. While the weekend will start with
nice weather in the short term, Saturday into Sunday we are
expecting a shift to wet weather for the remainder of the holiday
weekend. The culprit for dampening this weekend is a broad area of
low pressure moving north into the western Gulf of Alaska. More
details to follow in the coming days with this system.

As far as the rest of the extended forecast, model confidence is
high enough to know we will transition to a wet pattern and
generally stay that way through Thursday. However, model
confidence is not high enough to know specifics with lows and
their associated fronts at this time. Therefore, an ensemble of
models was used to depict the general sense of wet and cool weather
for the next week or so.


MARINE...Gale 132 150 155 174.



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