Storm Warning 6, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
530 AM AKST Sun Jan 28 2024

.SHORT TERM.../Through Sunday night/ Short range forecast
continues to be warm and wet with increasing winds added to the
mix. The cause is a series of at least three troughs/fronts that
will be moving north through the eastern gulf and panhandle over
the next 24 hours. The first of which is just starting to effect
the southern outer coast as of 5 am, number two will move in this
afternoon, and the third (and likely strongest of the three)
features will move in late Sun night.

All of these features will be bringing more rain, more warmth, and
more wind to the panhandle through Sun night. Temperatures
expected to remain in the 40s for most areas. Rain will be the
primary precip type for areas below 2000 feet in elevation with
around 1 to 2 inches of rainfall through Sun night. These two
combined will continue the fast melt of the low elevation snow
pack over the northern half of the area.

As for winds and seas, wide spread gales across the gulf and
southern inner channels expected, especially tonight as the
latter two systems come inland (the third system starts to spread
some storm force winds into the SE gulf late). Small craft
conditions for much of the rest of the inner channels. Seas in the
gulf will be approaching 33 feet by late tonight with the strong
and continuous southerly flow pushing wave heights higher and
higher. As for on land, wind gusts to 65 mph still expected with
the latter two system tonight (the third one especially) as
forecast 850 mb winds continue to push into the 70 to 80 kt range.
High wind warnings remain up for tonight for the south as a
result.

.LONG TERM...During the mid-range an open Rossby wave will
continue to steer a robust jet and associated storm track across
the Pacific, with a series of systems lifting into the Gulf. The
first set in the mid-range will hit the region late Sunday in the
form of a negatively tilted trough, with 70-90 knot winds at
500mb and cyclonic vorticity advection maximum off right off the
Panhandle Coast early Monday morning, likely bringing high to
strong wind warnings for most of the region. Guidance continues to
trend towards a 955 to 960mb surface low, but will have to watch
the jet dynamics to see if we can further drop forecasted surface
pressure. While there is some disagreement on strength of surface
winds and storm motion, with implications on wave heights, likely
to see periods of storm force winds along the coast, bringing 25
to 32 foot seas into the eastern Gulf. There is a possibility of
35+ foot seas if we get the right dynamic fetch, but thinking
guidance is going a little bullish, stay tuned.

As the aforementioned system makes landfall along the northern
coast late Monday, an open longwave trough will begin to meander
towards the western seaboard bringing elevated southerly winds and
swell Tuesday. As the trough axis hits the coast Tuesday
northerly near-gale winds will begin to envelop the gulf and
persist into Thursday.

Regarding precipitation, CW3E Atmospheric River guidance and the
ECMWF EFI table continues to show agreement on heavy precipitation
continuing to envelope the Panhandle Monday, with the NBM
highlighting a 25% chance of exceeding 2-year ARIs along the
Takshanuk Mountains, the Northern Coast Mountains, and Boundary
ranges. Another area of concern for heavier precip is Baranof
Island and Prince of Wales.

While we expect all rain for communities through early Monday,
the story changes as colder air moves in on the backside of the
low, reducing 850mb temperatures by late Monday. Snow impacts the
northern coast and Haines/Skagway areas first, with snow filling
in across the area Wednesday through Friday. While there is a
variety of solutions regarding snow totals, all outcomes continue
to look well within normal ranges for this time of year.

&&

.AVIATION...Rain increases with lowering CIG and VIS from MVFR to
move widespread IFR. Primary impact will be mechanical turbulence
and LLWS. Some locations along the outer coast will be seeing up
to 65 kts down to 2000 ft as the low level jet moves NE over the
Panhandle through Sunday.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 9 AM AKST this morning for AKZ318-319.
     High Wind Watch from late tonight through Monday evening for
     AKZ318.
     Strong Wind from this evening through late tonight for AKZ323.
     High Wind Watch from late tonight through Monday afternoon for
     AKZ323-325.
     Strong Wind from 9 AM AKST this morning through late tonight for
     AKZ327.
     Strong Wind from noon AKST today through this afternoon for
     AKZ328.
     High Wind Warning from 6 PM this evening to 6 AM AKST Monday for
     AKZ328-330-332.
     Strong Wind from this evening through late tonight for AKZ329.
     Strong Wind from 3 PM AKST this afternoon through this afternoon
     for AKZ330-332.
MARINE...Storm Warning for PKZ661-662.
     Gale Warning for PKZ033-035-036-641>644-651-652-663-664-671-672.
     Small Craft Advisory for PKZ011-012-021-022-031-032-034-053.

&&

SHORT TERM...EAL
LONG TERM....AP
AVIATION...PRB

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