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FXAK67 PAJK 261248

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
448 AM AKDT Wed Oct 26 2016

.SHORT TERM...Low pressure system south of Haida Gwaii will begin
to drift to the west and weaken through the day. Cloud cover will
increase through the day under 500 mb vort max bands rotating
around the low. Some shower activity over the southern panhandle
this morning. Expect isolated showers to move northward through
the day under weak deformation area, but not expecting these
showers to progress to the far northern panhandle. Model were a
bit more aggressive on keeping showers intact into the evening so
will need to keep an eye out for that. Any showers will be light
and still expect breaks in cloud cover. Have included patchy fog
tonight due to increased moisture from the showers and potential
cloud breaks causing localized radiational cooling. Next system
will start to move into the south central gulf late tonight with
associated weather front moving over the southern gulf.

Northerly pressure gradient this morning much weaker than
previous day but still some breezy conditions near Skagway and
small craft winds over N Lynn Canal. The gradient will shift as
the Yukon high is more to the east and the gulf low moves to the
west with winds weakening through the day. As the next gulf low
moves in small craft surface winds will develop over pkz310 and
along the coastal waters. The northerly gradient will also
increase once more with winds picking up late tonight over the
northern inner channels.

Models still on track compared to previous forecast, with NAM
preferred model, so little change made to pressure and winds.
Nudged up pops but held off on going as high as the NAMDNG or
SREF. Forecast confidence is above average.

.LONG TERM...A low currently developing south of the peninsula
will become very nearly vertically stacked by the time it enters
the southwestern gulf Thursday morning. The majority of the
associated frontal precipitation will remain south of the
panhandle, but the remnants of a low currently west of Haida Gwaii
will interact with the first low as well as another low that is
tracking north along 130W as of this morning. End result will be
scattered to numerous showers over the southern half of the
panhandle by Thursday afternoon. Scattered shower activity will
spread north overnight Thursday night and then taper off Friday
morning as the dominant low tracks off to the southeast while
remaining well west of the outer coast. A weak surface ridge will
then build in from the southwest across the gulf and provide for
some more dry weather through Sunday. At that time, a powerful low
will be developing over the southern Bering Sea. The low itself is
expected to remain in the Bering, but the associated front will
sweep across the gulf beginning Monday and be over the eastern
gulf by Tuesday morning. At that time, a triple point low will
likely form along the front and rotate the front into the
panhandle. Models differing on where the triple point will form,
but it is looking like this will occur over the northern gulf,
causing high end small craft to gale force southeasterly winds
over the coastal marine zones on Tuesday. The bulk of the frontal
precipitation will not arrive until late on Tuesday, but pre-
frontal rains may arrive late Monday as the surface ridge is
displaced off to the east, so a dry Halloween night is not a sure
thing right now.

Update pressure and wind Friday and Friday night with a blend of
GFS and ECMWF. Blended SREF into PoP through Friday night, the
ECMWF through Sunday night. Used old and new WPC for PoP Monday
onward. Temps primarily from GFS MOS with some help from both
ECMWF MOS and GFS Ensemble. Overall forecast confidence is


.AJK Watches/Warnings/Advisories...
MARINE...Small Craft Advisory for PKZ012-022-041>043-052.
     Small Craft Advisory due to Seas for PKZ051.



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