Area Forecast Discussion
Issued by NWS Juneau, AK

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623
FXAK67 PAJK 152233
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
233 PM AKDT Sat May 15 2021

.SHORT TERM.../Through Sunday night/...Another quiet short term
forecast period. Really, the story has not changed since
yesterday with cooler than normal daytime highs, cloudy skies and
non impactful winds on both the inside and outside. One exception
to that will be northern Lynn Canal and Skagway (no surprise
there), where afternoon winds this afternoon of 20 mph gusting to
35 mph will relax by about 9 pm. The one change in this short
term forecast is a diminishing trend in shower activity that will
begin in a small way tonight but then become more noticeable
Sunday night. Heading into the extended range forecast for the
beginning of the work week, things should dry out, but still not
be our typical May weather with sunny skies and warm weather.

A colder low level airmass has moved in over Southeast Alaska from
the west today and that will be reflected mostly in overnight
lows tonight and tomorrow. Look for temps to bottom out in the
very low 40s tonight and mid 30s in central Panhandle locations
for Sunday night. You might want to bring in those potted plants
one more time just to be on the safe side.

.LONG TERM.../Monday to Saturday as of 10 pm Friday/ Moving into
a rather quiet start to the long range forecast as weather
pattern likely moves any impactful systems to the south of the
panhandle due to building ridge over the AK Gulf and jet stream
shift to the south mid week. By late week enough model uncertainty
to keep large spread in position and movement of wave development
near the Aleutians and resulting eastward track, mainly due to
issues handling the developing ridge then eventual break down
along with a possible split flow jet.

Monday starts with upper low moving from the SE Gulf into N
Pacific through mid week with ridge building over the W Gulf. This
ridge shifts east pushing over the E Gulf and AK Panhandle
Thursday into early Friday. By late Friday into Saturday, and
this is where the real model spread happens, an upper low that
moves over the Aleutians earlier in the week will either track to
the SE, missing the region or hit the SE Gulf. Surface features
follow the mid level trend with showers diminishing Monday from N
to S with the low track. Will need to watch the building ridge
and flow pattern which could develop and move in a marine layer
mid week. Kept chance pops for rest of the long range due to
uncertainty in system tracks. The pattern does bring in warmer 850
mb temps so kept the trend of warming high temps as the week
progresses. Winds will be mainly thermally driven with afternoon
sea breeze development until late week with potential front and
small craft winds hitting the E Gulf.

Early on used a blend of GFS/NAM with little change. Kept with
WPC for rest of the long range due to large variation in model
ensembles and operational models. However standardized anomaly
and EFI tables show little in the way of any significant weather
or impacts to watch for. Forecast confidence is still below
average.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

$$

FCF/CRM/PRB

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