Area Forecast Discussion
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FXAK67 PAJK 252220

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
220 PM AKDT Fri May 25 2018

.SHORT TERM.../ Friday night to Sunday / The parent low of the
gale force front looks to spin incessantly in the eastern gulf
through the holiday weekend. Predicting the exact track of the low
has been a conundrum over the last couple of days. The NAM in
particular and now the ECMWF and GFS has been trending the low
closer to the eastern gulf coast including Sitka and Pelican on
Sunday morning. Thus, we have raised wind speeds to gusts of 40 to
45 mph with plenty of rain. Uncertainty grows by Sunday
afternoon, as the ECMWF has been bullish on a wave developing
along a stalled front across the eastern Pacific. While all models
push a wave into the North American Coast, the ECMWF sends a
potentially angry wave into the Dixon Entrance area, north of the
other solutions possibly affecting Ketchikan and Metlakatla. We
are more confident for winds along the eastern gulf coast than any
wind potential for the southern Inner Channels; however, to
hedge, we have raised wind speeds to at least 20 kt through
Clarence Strait and have bumped up breezes for Ketchikan. Thus, we
want Ketchikan area residents and mariners to be aware that the
forecast could worsen markedly for Sunday afternoon/evening.

Finally, it is certain that it should rain through Monday for most
areas of the Panhandle, and we increased pops to reflect this.
Going outdoors? Wear a raincoat. And do not forget it. Sunday`s
wave activity indicated by the ECMWF, if verified, would
significantly raise rainfall amounts over the far south on Sunday,
but that solution is not favored at this time.

We used ECMWF, GFS, Canadian GEM, SREF, and even some ideas of
the disfavored NAM for forecast changes.

.LONG TERM.../Sunday through Friday as of 10 PM Thursday/ What a
difference a day makes for the models. Yesterday the ECMWF was the
outlier, today it is the NAM. The GFS continues to be the go-to
model. Used a blend of the ECMWF and GFS for Sunday-Tuesday, using
more WPC and ECMWF Wednesday-Friday.

The low coming in over the holiday weekend is still showing a
stronger signature. Increased winds in the gulf about 5 kts
Sunday and Monday, with SCA winds through Sunday night. By Tuesday
night winds should be 15 kt or less across the entire AOR.

The 3 day weekend will end wet, but there is drier weather
developing over the area by mid week between systems. Most of the
Panhandle will be dry by Wednesday evening as a ridge of high
pressure builds over the area. By Friday evening the ridge will
be weakening and rain will starts moving in along the entire
outer coastal areas and continue to spread inland overnight.

Lowered temperatures again for Sunday-Tuesday a couple of
degrees. Temperatures are still expected to remain in the mid to
upper 50s during the day and range into the 40s overnight. With
less clouds possible with the building ridge, temperatures should rise
a few degrees through mid-late week. Expect to also see a larger
diurnal swing between daytime highs and overnight lows. The other
concern will be fog Wednesday early morning and depending on
clouds and daytime drying, Thursday night could have fog
development as well.


.AVIATION...Widespread rain over SE AK with front moving inland
today. Marginal ceilings 2500 to 3000 feet this afternoon. Will
likely see more lower ceilings as they lower through the early
evening. May have some improvements late over the southern part of
the panhandle that could generate some breaks. If that is the case
then patchy fog might develop south of Sumner Strait. Next
frontal band approaching the southern panhandle, around sunrise
Saturday and with a strong low level jet, the possibility of LLWs
from the Klawock, Ketchikan and possibly for Sitka by midday.


.MARINE...Gale force winds developing over the Eastern Gulf
overnight with a strong front moving into the southeast Gulf of
Alaska. Will likely see the Gale for winds spread into Clarence
Strait on Saturday. Small Craft Winds spreading into surrounding
marine channels on Saturday.


.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind for AKZ023, AKZ027, and AKZ028 Saturday.
MARINE...Small Craft Advisory for PKZ041-042.
         Small Craft Advisory due to Seas for PKZ043.




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