Storm Warning 24, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
248 PM AKST Mon Nov 4 2024

.SHORT TERM...Clearing skies and some showers continue for the
panhandle this afternoon. With the clearing skies, temperatures
are expected to cool this evening with colder air moving in from
Canada as high pressure remains over the area tonight before
moving to the east tomorrow morning. As this high pressure moves
to the east, a storm force front will move into the gulf bringing
sustained gale force winds with storm force gusts to the outer
coast. Locations onshore are expected to see strong winds with
this front moving onshore. Further inland, the colder air that is
expected to settle in during the overnight Monday night will allow
for some mixing and potential snow the northern panhandle.
Although accumulations are expected to be light. The exception to
this being up at White Pass where southwest flow and cold
temperatures aloft will allow for accumulating snow. Snow
accumulations for the lower elevations will be limited as warmer
air is expected to move northward with this front forcing low
elevation cold air to be mixed out but there is still the
potential for a mix of rain and snow from Icy Strait including
Juneau northward. Farther south, rain will be the main
precipitation with the early stages of a prolonged rain event
starting Tuesday and heading into Wednesday.

.LONG TERM...A Rossby wave draped over the Aleutian Arc will
continue to be the catalyst of our weather into the weekend as it
shifts slowly east driving a series of lows and atmospheric
rivers. The first of these series of storms will move over the
Panhandle Tuesday into Wednesday featuring a warm front and stout
isentropic lifting, allowing deep moisture from a moderate to
strong atmospheric river to flourish. As winds reach their peaks
through the early morning hours Wednesday, expect heavy rainfall,
especially in the central and southern Panhandle. Moderate to
heavy rainfall continues through the day before tapering off in
the central and north. Simultaneously a shortwave trough ejecting
off the coast of Japan will undergo cyclogenesis Wednesday,
developing into a severe-gale force low Thursday steering another
round of moderate to heavy rainfall back into the Panhandle.
Certainly, a wet and windy fall pattern.

For impacts, guidance remains consistent with long duration weak
AR conditions through most of the week with peaks of moderate to
strong IVT. The Euro EFI’s highlight more agreement on 3 to 4
inches in the central and south with the EPFT tool indicating 2 to
5 year event. Simply put, expect moderate rainfall through the
week with periods of heavy rainfall. The current forecast reflects
multiple days of 1-2 inches of rainfall with 3-5 inches Wednesday
into Thursday at sea level. Snow impacts remain confined to
highways heading into Canada. Coordination with the River Forecast
Center indicates rises in rivers and creeks are expected but no
significant flooding anticipated at this time.

&&

.AVIATION...Marginal visual conditions based primarily on CIGs
between 1000 and 3000 feet this afternoon with large holes in the
cloud cover. Clearly a convective atmosphere. Conditions will
deteriorate as the airmass stabilizes in advance of the next front
with instrument conditions becoming widespread. More impactful
will be mechanical turbulence and LLWS. 925mb winds along the
outer coast Tuesday afternoon as high as 60 kts - possibly higher.
A stable airmass may prevent these winds speeds from mixing down
to the surface, but it will likely be very rough going below
ridgetops by tomorrow afternoon.

&&

.MARINE...Stout 20-25ft short period southeast seas Tuesday give
way to southwest swell Wednesday with significant heights near 12
to 18ft, the highest of this range north and west of Cape
Edgecumbe. As our next low crosses south of Kodiak Wednesday, the
tightening pressure gradient will cause easterly gales south of
Cape Suckling by Thursday morning with 18 to 22ft seas along the
coastal zones into Friday morning. Winds and seas diminishing by
Friday evening to 11 to 16ft along the coast, highest significant
heights south of Cape Edgecumbe.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind Tuesday afternoon for AKZ317-327.
     Winter Storm Warning from 9 AM to 9 PM AKST Tuesday for AKZ318.
     Strong Wind from Tuesday morning through Tuesday afternoon for
     AKZ323.
MARINE...Gale Warning for PKZ036-641>644-651-652-661>664-671-672.
     Small Craft Advisory for PKZ012-013-021-022-031>035-053.

&&

SHORT TERM...SF
LONG TERM....AP
AVIATION...Fritsch

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