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Southeast Alaska forecast discussion 
National Weather Service Juneau Alaska
456 PM akdt Thursday Oct 8 2015

Short term...occluded front over the northern Gulf and Southeast Alaska will
drift north and weaken. A powerful storm will develop over the NE
Pacific and move north into the eastern Gulf Friday. This storm will contain
the remnants of hurricane oho. Models still were handing the
storm system differently as far as track and intensity
basically stayed with current track/strength we were showing

Main forecast concerns will be winds and rainfall. Rainfall will
be discussed in the hydrology section below. Winds will be on the
increase from the south late tonight and Friday as the powerful storm
takes shape and heads northward. The pressure gradient orientation will
shift to favor more northeasterly winds later tonight...but as the main low
moves into the Gulf Friday morning...the gradient will shift to favor
more S-southeast winds. Also...the strongest winds around the low will be
on its east-S expect the highest winds to occur when any
given area is on that side of the low. Delayed the onset of the
High Wind Warning for zones 27 and 28 until 15z Friday...and held off
start in zones 23 and 26 until 21z Friday. These are the times the
gradient orientation will become more favorable for more
widespread high winds in those areas. The stronger winds will
reach the north-Central Area in the afternoon...but are not expected
to reach high wind levels at this time. The pael area will start
with strong winds sooner though as the Ely flow will be fairly
strong there earlier in the morning. The highest winds are
expected along the southern outer coast and adjacent marine
waters...with up to hurricane force winds expected.

Otherwise...temperatures will likely not drop much tonight with warmer
air aloft streaming in from the S tonight and Friday. Friday still looks
to be very mild due to the tropical origins of the system coming
in...with above average high temperatures expected despite the rain.

Long term...the storm above appears to make landfall a few miles
north of Cape Spencer Friday evening. This portion of the forecast
has not changed much. But in conjunction with a plethora of either
high wind warnings for the southern Panhandle and the coast and
strong winds headlined over much of the north central
Panhandle...we added Glacier Bay/Gustavus for strong wind Friday
evening and extended the strong winds for Hoonah/Angoon through
Friday evening and Juneau through Friday night.

A weaker wave behind the storm containing the remnants of oho will
move into the southern Panhandle/Dixon Entrance area Friday along
a stalled boundary. This stalled boundary Friday night and wave on
Saturday will keep rain in the forecast Friday night into
Saturday. But rainfall amounts will not approach the buckets
falling with the system Thursday night/Friday. Totals over the
south should range between 0.50 to 1.5 inches. Meanwhile to the offshore component to winds aloft will allow a break in
the rainfall. This break could be key in keeping potential Hydro
issues for the northern Panhandle on Sunday in check.

The big change was raising wind speeds for a storm on Sunday that
refuses to be upstaged by a Friday storm adorned with a name.
Winds at 925 mb are again approaching 80 knots in some of the
models...notably the European model (ecmwf). Although at this point...this storm
looks to track farther offshore. But another high wind watch could
be placed for Prince of Wales Island. While these values are all
impressive...we have merely nudged marine winds to gale with no
storm force appearing at this time. But if models keep supporting
strength, look for these winds at this issuance time on Friday.
Meanwhile this storm also looks to germinate from a deep
baroclinic zone across the north central Pacific and carry a good
swath of moisture such that heavy rain should once again spread
into the southern and central coastal Panhandle for Sunday.

The extended remains virtually untouched with a progressive
onshore pattern keeping things wet. No real sign of cold air to
lower snow levels significantly.

Confidence in forecast trends rising for such a volatile
period through Sunday. Average for next week. Used European model (ecmwf)/NAM for
updates Friday night with a wide ensemble of Gem, NAM, GFS, and
ecwmf for Saturday to handle the wave in the southern Panhandle.
Then ecwmf/GFS/Gem through Sunday night with wpc leading off


Hydrology...rainfall is going to be on the heavy side especially
over the southern 2/3rds of the area. Very high precipitation water values and
strong moisture flux will occur over the area late tonight and
Friday. In most areas...generally 2 to 4 inches of rain will occur
through Friday. Rainfall could exceed 5 inches in some areas...with the
most likely spots being along S facing slopes over the southern area.
Due to a long stretch of drier weather during the past
week...river levels are on the low side except over the far S
where locally heavy rain fell today. We are not expecting any
flooding at this point through Friday...but some streams could get close
to bankfull.


Ajk watches/warnings/advisories...
public...High Wind Warning from 1 PM to 7 PM akdt Friday for akz023-026.
High Wind Warning from 7 am to 4 PM akdt Friday for akz027-028.
Strong wind from Friday afternoon through late Friday night for
Strong wind from Friday afternoon through late Friday night for
Strong wind from Friday morning through Friday evening for
Strong wind from Friday evening through late Friday night for
Marine...hurricane force wind warning for pkz036-041.
Storm Warning for pkz022-033-035-042-043.
Gale Warning for pkz012-013-021-031-032-034.
Small Craft Advisory for pkz011-051>053.




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