Gale Warning 278, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
333 PM AKDT Tue Nov 1 2016

.SHORT TERM...Satellite imagery this afternoon showing a
weakening weather front extending across the eastern gulf and
tracking northward over the panhandle. This front produced rain
showers over the southern half of the panhandle through the
morning with showers developing for the northern panhandle through
the early evening, however these showers will be lighter and more
intermittent as front shears apart. Next low pressure system
moves up from the NE Pacific into the SE gulf Wednesday afternoon
with rain developing over the far southern panhandle. Temperatures
have risen to the upper 40s to low 50s and expect surface airmass
to sty warm enough to keep most precip as rain. Some clearing
breaks in between the exiting front and the advancing low for
tomorrow. Fog was a question due to the clearing breaks but timing
of these either occurred late in the afternoon or when winds
increased. Cold air at 500 mb with steep lapse rates and
convective environment evident on visible satellite imagery. Ample
CAPE for convection but as strongest forcing for ascent will be in
the mid level westerlies south of the region continued to hold off
on mention of thunder storms. Following this thinking as of the
afternoon any reported lightning strikes have been south of our
AOR.

Gales force winds under low level jet along the front today are
starting to subside with diminishing gulf winds through the
evening. Winds over the southeast gulf will pick up to small
craft levels again as the next low advances.

Main change was to the POP field using a blend of SREF and NAMDNG
to show the break between the exiting front and advancing low.
Otherwise forecast continues on track with average confidence.

.LONG TERM...Model agreement was better today, but still far from
a high confidence scenario. Night shift picked up on an eastward
adjustment to the track of the Wednesday night low and have
continued adjusting the track to the east. With the close
proximity of the low to the panhandle, the biggest manifestation
of these changes will be in the strength of the winds. Current
forecast tracks a gale force low inland near Cape Decision and
then northeast into British Columbia by Thursday evening. Expect
rapid wind shifts over the southern inner channels and coastal
marine zones as the low moves over the area. There will be a
brief break in the action as another gale force low enters the
eastern gulf from the south on friday evening. This second one is
currently forecast to remain over the eastern gulf, spreading gale
force winds up to near Yakutat Bay over the coastal marine zones.
The morning ECMWF and GFS were a reasonably good match for this
low with the GFS being slightly stronger. Afternoon model run
showing the same trend with the Canadian NH now looking more like
GFS. Forecast confidence on this low still below average. 24 hours
later, a third low will approach from the south, taking a track
very similar to the first of these three systems. Current
forecast reflects a preference for the ECMWF with this third low.

In terms of PoP, details still far from certain and confidence is
low, but there is a clear trend back to more typical weather for
this time of the year - and that would be rain, with a chance for
snow at higher elevations. Counting the short term period, there
are 4 fronts forecast to affect southeast Alaska over the coming
week.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Gale Warning for PKZ043-051-052.
     Small Craft Advisory for PKZ022-033-035-036-041.
     Small Craft Advisory due to Seas for PKZ042-053.
&&

PRB/Fritsch

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