Small Craft Advisory 744, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
427 PM AKST Sun Nov 27 2016

.SHORT TERM...An elongated area of low pressure over the eastern
gulf is expected to split into two lows as it moves inland over
the panhandle through early Monday morning. The northern low looks
to move inland near Yakutat while the southern one crosses over
POW island and Dixon entrance. Keeping the northern low in tact
was an adjustment to the inherited forecast and thus affected the
wind field. When the low moves inland Monday morning expect a wind
shift to the west along the outer coast and a southerly push
through the central inner channels. Cross Sound and N. Lynn Canal
can expect a burst of 30kt winds while the other inside marine
areas will see 20-25kt winds.

Showers will be most persistent near the low centers tonight.
Then early Monday morning a more pronounced frontal band looks to
form, extending south along the coast from the northern low near
Yakutat. This band will be just ahead of the wind shift and with cold
air behind it. Have extended the slight chance of thunderstorms
over the gulf through tonight, then along the outer coast with the
frontal band Monday morning. Showers scatter out fairly early on
post front with sunny breaks expected in the afternoon.

Used mainly the NAM for adjustments to the forecast today.
Forecast confidence is average.

.LONG TERM...Active pattern will be the rule into late week. A strong
low will move NE into the gulf Tue, then should come onshore
around Yakutat Bay Tue night. A warm front will move to the NE
gulf Tue morning, with a cold front moving across the area Tue
afternoon and evening. Looks like another low and front will move
into the gulf for Wed night and Thu, but models differ on strength
of the system. System activity looks like it will decrease over
the weekend and early next week, with a colder pattern possibly
developing by early next week.

Big concern is with the Tue system as it will be very dynamic.
Looking like storm force winds will occur ahead of both fronts and
on S side of the low as it wraps up. Low level jet forecast at 925
mb reaches 65-75 KT in these areas. Expecting most land areas to
see strong to very strong winds as well, with strongest winds
along the outer coast. Have issued a high wind watch for zones 23
and 27 for Tue. Many other areas will need strong wind headlines
Tue with winds gusting to 45-55 mph. Later shifts will need to
monitor for possible high winds over the central and southern
inner channel zones Tue as well if system ends up even slightly
stronger than current forecast has it.

Am expecting fairly heavy precip with this system as well. While
most of the area should be warm enough for rain, the far N will
likely see snow with temps hovering near freezing later Mon night
and most of Tue. Snowfall of up to 18 inches is possible for zones
18 and 19 by late Tue afternoon before warmer air moves in and
changes them over to rain. Have issued winter storm watch for
zones 18 and 19 for late Mon night through Tue afternoon. Think
the highest amounts will be near the Canadian border. Elsewhere,
rainfall could reach 3 inches by late Tue afternoon.

Later in the week, still looks wet and mild especially with system
coming in Wed night and Thu. May have another round of fairly
strong winds over the gulf, but not as strong as the Tue system.

For the weekend and early next week, beginning to look like colder
air will move in especially early next week. Later shifts may need
to adjust temps downward especially Sun through Tue.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...High Wind Watch from Tuesday morning through Tuesday afternoon
     for AKZ023-027.
     Winter Storm Watch from late Monday night through Tuesday
     afternoon for AKZ018-019.
MARINE...Gale Warning for PKZ041.
     Small Craft Advisory for PKZ012-013-021-022-031>033-036-042-043-
     051-052.
     Small Craft Advisory due to Seas for PKZ053.
&&

Ferrin/RWT

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