Gale Warning 116, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
205 PM AKDT Wed Mar 21 2018

.SHORT TERM...The low pressure system across the eastern gulf will
continue slowly moving southward the next few days. A high
pressure system will build from the north in the wake of the
exiting low pressure system. Northerly winds will increase across
most of the inner channels tonight and Thursday especially in
outflow areas. The gale force winds occurring in Lynn Canal will
increase to 50 kt storm force winds tonight and Thursday. Gusts
to 40-50 mph will occur over land areas of Skagway, Haines and
Downtown Juneau tonight.

Drier conditions will occur the next few days across the northern
and central areas of the panhandle as the low pressure system
exits southward and the high pressure system advects drier air
across the panhandle. There is a chance for precipitation across
the southern areas tonight and Thursday as the low pressure
system slowly moves southward.

Temperatures will continue cool tonight, a slight increase in
afternoon high temperatures are likely Thursday with most areas
in the 40's.

Used the GFS and NAM models for any changes in the forecast. Most
changes in the forecast were on Friday. However only made slight
changes to the current forecast.

.LONG TERM.../ Friday through Tuesday / Overall general agreement
is fair for the extended time range. The outflow pattern over the
Northeast Gulf Coast and Northern Panhandle is winding down. A
sharp narrow ridge from the Gulf of Alaska to the Arctic Ocean
will be cutting off over the Arctic and North Slope leaving a
flatter ridge over the gulf by early Sunday before this changes to
more of a southwest flow pattern aloft from the north central
Pacific to the Panhandle by next week. This flow pattern will
result in an active weather pattern due to quick moving short
waves in the 500 mb pattern.

Continuing into later time frames of next week, the models are
handling timing and strengths of the short waves differently
although main idea remains. Only went with minor changes to the
forecast package Friday to early Sunday. A blend of the ECMWF and
GFS was used with a nudge towards WPC or even just leaving alone
as the WPC solution was close to what was in the forecast already.

Slightly lowered winds late weekend into the start of next week
for the inner channels and on land due to the pressure
orientation. Pops got a minor boost roughly the same time frame
with the flow pattern and a short wave approaching the panhandle
with which the models had better agreement. Mainly left the
temperature field alone with out a strong signature to make
alterations.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from 1 AM AKDT Thursday through Thursday afternoon
     for AKZ019-025.
     Strong Wind until 4 PM AKDT this afternoon for AKZ018.
     Strong Wind from 10 PM AKDT this evening through Thursday
     afternoon for AKZ018.
MARINE...Storm Warning for PKZ012-013.
     Gale Warning for PKZ022-031-032-043-051.
     Small Craft Advisory for PKZ011-021-033>035-041-042-053.

&&

BM/Bezenek

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