Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/05/23

Southeast Alaska Forecast Discussion

National Weather Service Juneau AK

 328 PM AKST Sat Mar 4 2023

.SHORT TERM...
...Northerly Outflow Winds Peak Saturday Night...
High pressure continues to build over the Yukon. This, in
conjunction with a trough of low pressure to the distant south,
is causing winds of 35-40kt gusting to 50-55kt through Lynn Canal.
With those kind of winds blowing at Eldred Rock would certainly
expect strong winds over downtown Haines. Mountain wave guidance
and gusts at the AML dock in Juneau are showing gusts of around
40-45mph as well. Expect the peak in pressure gradient to be
around midnight tonight and kept that trend in the forecast for
the northern panhandle.

...The power of the March sun!...
Temperature ranges have been massive today, with the best example
being as low as 5 degrees early this morning at the Yakutat airport
spiking up to 27 degrees by 11am. Places getting any kind of NE
downslope wind, such as Sitka and Klawock, are adding to that high
with another 10+ degrees. Similarly, those windy or downslope
areas will see temperatures stay warmer than nearby calm areas for
their nighttime lows. Those calm, interior valley locations will
be at least 10 degrees colder (Mendenhall Valley vs. Downtown).
Sunday high temperatures were increased as we expect another sunny
day.

.LONG TERM...Sunday Night through Thursday/ Once again, only minor
changes to the forecast in the mid-range as deterministic and
model guidance continue to support this outflow pattern persisting
into the middle of next week as high pressure remains over the
Yukon Territory. Inner channel winds are expected to decrease
slightly heading into early next week as the low exiting the gulf
to the south will slacken the gradient from north to south. Winds
will remain breezy however and potentially pick up again mid to
late next week as an area of stronger high pressure builds over
the Canadian interior. Though no major changes were made at this
time, some models were suggesting a low approaching the gulf from
the pacific northwest, which would in turn once again further
tighten the gradient over the panhandle. With the orientation of
the gradient over the interior and upper level wind patterns,
there was increasing evidence to support a potential Taku wind
event for Juneau Wedesday afternoon into Thursday morning and
winds downtown were increased accordingly to represent this.

With this outflow event, below normal temperatures are still
expected for the majority of the panhandle with the potential
for temperatures much below normal for the southern half the
beginning of next week and through Thursday. The ECMWF EFI Table
has the majority of the panhandle w The areas most at risk of much
below normal temperatures are those not affected by outflow winds
as large diurnal variations in temperature have already been
observed in areas such as Yakutat and The timing of the coldest
temperatures is still not set in stone this far out, but overall
the panhandle can count on being cold, dry, and breezy for the
first half of next week.

&&

.AVIATION...VFR conditions continue across across the panhandle
as showers continue to exit from the southern panhandle. Outflow
winds remain in place for the northern inner channels with surface
winds remaining around gale force. Pockets of LLWS continue to
remain possible with some reports coming in from aircraft over
Juneau during the afternoon. Expect these pockets to continue as
the outflow pattern remains in place for the panhandle. JAWS
continues to be lit up red and yellow down Gastineau Channel
throughout the day. Expect this to continue throughout the night.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Wind Chill Advisory from 1 AM to 8 AM AKST Sunday for AKZ318.
     Strong Wind through late tonight for AKZ319.
     Strong Wind through Sunday morning for AKZ325.
MARINE...Gale Warning for PKZ012-013-031-042-043-051.
     Small Craft Advisory for PKZ011-021-022-032>034-041-052-053.

&&

$$

SHORT TERM...Ferrin
LONG TERM....STJ
AVIATION...SF

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