Scientific Forecaster Discussion
fxak67 pajk 221327
Southeast Alaska forecast discussion
National Weather Service Juneau Alaska
527 am akdt Fri Jun 22 2018
Short term.../through Sat night/ cooler and cloudier is the main
message for the short range through the beginning of the weekend
as light onshore flow continues. Currently, a very weak upper
trough is moving through the Panhandle bringing cloudy skies to
most areas. There has been enough dynamics to get some
drizzle/showers out of these clouds along the outer coast and
extreme southern Panhandle this morning but no where else. It has
also produced some higher winds in the Lynn Canal and Skagway
area but nothing higher then 20 kt has been observed.
The trough is expected to move into Canada this morning taking
some of the very light precip with it. Onshore flow will continue
through Sat with one more upper level short wave moving through
early Sat. So clouds as well as cooler near normal temperatures
are expected to stick around. Pops through Sat have been lowered
as guidance has been over forecasting chances of precip for the
Inner Channels compared to what has actually been observed over
the last 12 hours.
Into Sat night, the low that has been forecast to move across the
southern Gulf has slowed up a bit in current guidance. This has
resulted in a 3 to 6 hr delay to when the winds turn southeast and
increase in the southern Gulf and southern Panhandle. The onset of
rain has also been delayed. Otherwise, the overall idea for this
system remains the same. Used GFS and NAM for main guidance
Long term.../Sunday through Friday/...a mid-upper trough with a
closed low over the southeastern Gulf will drift east Sunday. The
surface low weakens as it moves inland over haida gwaii by Monday
morning. Brisk southerly winds will be enhanced over the southern
Panhandle especially into Clarence Strait Sunday morning through
Sunday night, but wind speeds should remain below Small Craft Advisory conditions.
A frontal precip band will also lift into the southern and
central Panhandle Sunday morning, spreading northward as it
diminishes throughout the day.
The upper level flow pattern then looks to set up with weak
ridging over the Gulf Monday and Tuesday, leading to more zonal
westerly flow over the eastern Gulf Monday afternoon through
Tuesday. Most of the models are also suggesting an upper low near
the Aleutians will set up a front in the western Gulf by
Wednesday, which will move across the Gulf towards the Panhandle.
Overall the pattern for later in the week looks to be cloudy and
increasing chances of rain into Thursday and Friday.
Most of the operational models again have similar idea to what the
wpc solution has. Much of the current forecast continued inline
with the new wpc solution and only needed minimal changes.
Marine...Small Craft Advisory for pkz012.