Gale Warning 67, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1044 PM AKST Tue Feb 8 2022

SHORT TERM...Today, a short wave brought precipitation and gusty
conditions to much of the Panhandle. A brief lull is expected
this evening with a decrease in both precipitation and winds. This
break will be short-lived as the well-advertised atmospheric
river begins to affect the area tonight. Rain will start in
earnest around midnight, with the heaviest precipitation rates
expected Wednesday morning. The heaviest precipitation coincides
with a 160 kt jet max over the Panhandle. Generally speaking 2-3
inches of rain is expected with this event with higher amounts
possible over higher terrain and the southern Panhandle. That
said, latest model runs have been trending lower with QPF,
possibly due to the system moving out faster. Rising snow levels
will also contribute to the hydrologic concerns. Snow levels are
expected to rise to around 2,500 feet for the northern Panhandle
and as high as 8,000 feet over the southern Panhandle. The Winter
Weather Advisory for White Pass was extended through noon
tomorrow, but snow will be relegated to the highest parts of the
Klondike. A Flood Watch remains in effect for the entire
Panhandle through Thursday morning. Winds will also be a factor
with this system with gales or small craft conditions expected for
most of the outside and inside waters, and strong gusty winds 40+
mph for many areas of the Panhandle.

As the system exits Wednesday evening, cold air advection takes
over, snow levels fall very quickly, and there is a chance of rain
mixing with or changing back to snow Wednesday night with an inch
or two of slush not out of the question for the northern Panhandle
at sea level, with 4-6 inches over the higher elevations near
White Pass. Precipitation will be diminishing quite rapidly
overnight Wednesday night into Thursday morning as the atmospheric
river moves to our south.

LONG TERM.../Thursday through Sunday/...Thursday brings a much
needed relief in precipitation for the panhandle just in time for
our next system to arrive Friday, but before getting carried away,
more on Thursday. Early Thursday morning will likely see a mix or all
snow before precipitation cuts off completely. Strong cold air
advection will be establishing a colder airmass over the
Panhandle. Additionally, high pressure will begin to build
through the inside waters allowing for sky conditions to break
out. With cooler temperatures moving in aloft and clouds breaking
up, temperatures are expected to cool Thursday through Thursday
night. Day time highs in the mid 30s to low 40s are expected
followed by a sharp cool down over night with temperatures in the
mid 20s to low 30s.

Friday, clouds increase as high pressure becomes displaced to the
east and a low south of the Aleutians brings a front onshore.
Current modeling suggests that this system could process some
tropical moisture with it leading to decent precip accumulations
between 1-2 inches. The big question will be temperatures. With a
cooler airmass in place, precip will likely start as snow across
the north and central panhandle. Confidence is low at the moment
in exact snow amounts, but advisory-warning level amounts are
possible across the northern panhandle. This system does bring
snow levels up to around 2000-3000 ft as warm air transports into
the SEAK. With this, any precip that starts as snow should change
to rain through Friday night with the exceptions of Haines and
Klondike Hwys.

By early Saturday, the main moisture plume slides south and
diminishes. Through the day Saturday, a diminishing trend in
precip will occur. Temperatures warm through the weekend back into
the upper 30s to low 40s with minimal diurnal fluctuation.
Sunday, yet another low brings in more precip with rain looking to
be the predominate precip type.

...Sunday through early next week...

Model guidance diverges into early next week, therefore blended
mainly with WPC which continues the active weather pattern across
the region. Another low moves into the Gulf on Sunday; however low
confidence exists regarding the track; whether it moves towards
the NE Gulf Coast or towards Haida Gwaii. High confidence in a wet
and relatively warmer pattern continuing with renewed chances for
Atmospheric Rivers and heavy rain through mid next week. Lower
confidence in the exact details of each system this far out.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch from Wednesday afternoon through Thursday morning
     for AKZ017>027-029.
     Strong Wind from 6 AM AKST Wednesday through Wednesday afternoon
     for AKZ025-026-028.
     Strong Wind from 3 AM AKST Wednesday through Wednesday afternoon
     for AKZ023-027.
     Strong Wind from Wednesday afternoon through Wednesday evening
     for AKZ020.
     Areal Flood Advisory until 9 AM AKST Thursday for AKZ028.
     Winter Weather Advisory until noon AKST Wednesday for AKZ018.
MARINE...Gale Warning for PKZ012-041-042-051-052-310.
     Small Craft Advisory for PKZ011-013-021-022-031>036-043-053.

&&

BFL/CC/CM

Visit us at http://www.weather.gov/Juneau