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049
FXAK67 PAJK 172239
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
239 PM AKDT Tue Oct 17 2017

.SHORT TERM...Surface analysis and satellite imagery depict a
storm force low near 53N/160W this afternoon. Models in good
agreement with the progression of this low as it moves into the
Gulf of AK overnight then begins to weaken. Winds will increase
to gales over the gulf and nearshore waters tonight with modeled
LL winds near 40kts ahead of and along the front. Will also see a
period of strong winds along the central and southern outer coast
late tonight/early Wed with marginal strong winds over AKZ026-028
too. SCA winds will develop over inner waters as well. An area of
instability near the upper low center will move across the
southern gulf Wed so included mention of SChc TSTMS over the gulf.
Modeled instability parameters suggest some potential for thunder
over AKZ027 by Wed afternoon. Forecaster confidence was too low
to include mention over land areas attm, but will continue to
monitor the potential. Still not expecting SN down to sea level
with this system with an inch or two accumulation over the higher
elevations of the Klondike. Conditions gradually improve Wed as
the low begins to dissipate. Given the good model agreement with
the progression of this low forecast confidence is good.

.LONG TERM.../Thursday through Tuesday/Little change made to
longer range forecast. Models in generally good agreement on the
large scale features but have important differences on smaller
scale features. Main system of concern in long range is a complex
low expected to move into the gulf by the weekend. Models hint at
a deeper system than current forecast shows but have important
detail differences that make it impractical to change much right
now. Still plenty of time to make adjustments on this system since
we are talking 4-5 days out.

Otherwise, pattern will remain on the cool and wet side for much
of the time. Still looks like any airmass cold enough for snow
near sea level will stay W of the area through at least early
next week. Later next week, will need to monitor a system that
could have the remnants of tropical cyclone Lan embedded with it.

&&

.MARINE...Storm force low near 53N/160W will move into the gulf
overnight and across the S gulf Wed. Gales will develop over the
offshore and nearshore zones overnight as the front pushes E ahead
of the low. A pocket of cold air aloft with the low will increase
instability across the S gulf Wed with a slight chance of thunder
Wed through Wed evening. Fresh to strong Nly winds will develop
behind the surface low and generate a short period N sea on top of
a 10-15 ft SW swell around 16 seconds resulting in some confused
seas. Conditions improve slightly late Wed into Thu before
deteriorating again as another storm force low moves into the
gulf.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from 1 AM AKDT Wednesday through Wednesday morning
     for AKZ023-027.
MARINE...Gale Warning for PKZ022-041>043-051-052.
     Small Craft Advisory for PKZ012-021-031-033>036.
     Small Craft Advisory due to Seas for PKZ053.

&&

$$

BC/RWT

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