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FXAK67 PAJK 181400
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
500 AM AKST Sat Nov 18 2017

.SHORT TERM...Saturday through Sunday night...Satellite imagery
and surface analysis indicate gale force low dissipating as it
slides SE across the SE gulf. This will result in diminishing
showers and increasing Nly outflow winds today. Winds will rise to
gales over Lynn Canal, Cross Sound and Yakutat Bay today as
gradient tightens, with SCA over the N inner channels and outer
coast. Outflow also resulting in strong winds along the Klondike
Hwy today. Lowered winds slightly over downtown Juneau and Douglas
because the only Taku ingredient to mention is cross barrier
flow, while a critical layer and inversion are lacking. Clearing
skies overnight into Sun will allow temps to fall sharply after
sunset resulting in cooler temps Sun AM across SE AK. Models
remain in fairly good agreement with another low developing over
the W gulf before sliding SSE across the gulf heading into Mon
although the NAM remains an easterly outlier with the associated
front. This front will begin to impact the N Gulf coast late Sun
night before pushing precip into the panhandle heading into Mon.
Inherited forecast represented this thinking well with only minor
adjustments for local effects. Forecast confidence remains good
through the period.

.LONG TERM.../Monday through Saturday/It is the time of year where
only short reprieves between low pressure systems are common,
this week will be just that way. By Monday, a low center will be
in the south-central gulf/North Pacific, then by early Wednesday
morning the low will cover much of the eastern gulf. Confidence is
good through this time and then starts to falter a bit with more
differences between the models. Used the EC to do a small blend to
the current forecast, an ensemble approach would continue to be
prudent.

By this time temperatures will have warmed over most of the
southern half of the Panhandle to bring in rain for the south and
a mix of rain and snow in the central during the day. Temperatures
will still be cold enough to change to all snow in the
overnight/early morning hours for these areas. The warmer air
should advance up to the Elfin Cove/Gustavus/Hoonah/Juneau
corridor on Thursday. This is where some confidence slips as to
whether the precipitation in the central Panhandle, as far north
as Elfin Cove/Juneau will be snow, rain or a mix of both. Outer
coastal areas will be a more certain rain for the precipitation
type. By the weekend Skagway and Haines will be waffling between
rain and snow for precipitation type, for the near sea level
locations and remaining snow for the highways.

There are reasonably healthy QPF amounts for the southern
Panhandle which could give several inches of rain and/or snow
Tuesday night/Wednesday. Then spread into the central Panhandle
Wednesday. With temperatures rising above freezing during the day
for most locations and then falling below at night amounts will be
tricky. Downsloping winds will likely keep some local areas in
the north relatively drier.

Brisk winds continue around the northern Panhandle with the
northerly wind. In the south the winds will be getting the
influence of the low in the gulf leading to a southeasterly wind.
Wind speeds for much of the Panhandle will range from 15 to 25
mph with higher gusts. A lot of SCA, with some Gales on Monday.
Winds will be on a slow diminishing trend through the week, but
stay mindful for the strong outflow winds in the north through mid
week. These outflow winds will linger between Yakutat and Dry Bay
through Thursday.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through Sunday morning for AKZ018.
MARINE...Gale Warning for PKZ012-013-022-053.
     Small Craft Advisory for PKZ011-021-031-032-043-051-052.
     Small Craft Advisory due to Seas for PKZ041-042.

&&

$$

BC/KV

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