Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
000
FXAK67 PAJK 231519 CCB
AFDAJK

Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
719 AM AKDT Fri Jun 23 2017

.SYNOPSIS...High pressure ridge along the panhandle Friday will
weaken through the day. A low over the far SW Gulf of Alaska will
continue to track northeast into the central gulf by Saturday
morning. The associated weather front will move across the
central gulf and push into the panhandle on Saturday.

&&

.SHORT TERM...Most of Southeast Alaska Friday morning is sunny
based on satellite imagery and web cams. Clouds are expected to
spread northeast into the southern panhandle then to the coastal
areas north along Baranof and Chichagof Islands later today. Light
rain, may start to spread into west coast area around midnight and
could spread east to the coastal mountain range Saturday morning.
Winds along the coast increasing to 20-25 kt from Mt Fairweather
southward for late tonight then it will lift north to the southern
portion of the marine areas 51 and 52 for Saturday. Likely rain or
better for early Saturday morning is shifting more showery into
Sunday as the PoPs lower to 30 to 50 percent range.

Light winds and sunny conditions for the panhandle...especially
the northern part will see the Friday temperatures rising to the
mid to upper 60s, although with a lesser pressure gradient, an
afternoon sea breeze has a stronger potential of developing and
that could cut the highs back a few degrees. Due to an increased
cloud cover amount over the panhandle Saturday, have lowered the
Saturday high temperatures 1 to 3 degrees as a first step and if
one of the model solutions for the high temperatures were right
may need to lower a couple more.


.LONG TERM...Monday through Friday...As of 930 PM Thu...Period
begins with models in fairly good agreement depicting an upper low
over the central gulf drifting E across the central panhandle
into Mon. As expected, there are minor differences in position
and/or timing of this feature moving inland, but overall agreement
minimizes impacts of these differences on the fcst. This feature
is relatively weak as only the SREF mean SLP indicates a closed
SFC circulation while all other guidance depicts an open wave just
off S Baranof Mon Morning. Chc PoPs will persist Mon before the
upper low pushes E of AOR Tue. Although the low will be inland,
expect enough instability on the back side of it to see some ISOLD
showers Tue over E CWA. Ridge will build over the gulf and push E
over the panhandle Tue into Wed. Model solutions continue to diverge
by mid week, mainly with the strength and timing of the system
pushing into the W gulf. How long the ridge persists over SE will
depend on this next system`s approach. Expect dry weather to
continue Wed before increasing sky cover and precip chances late
next week. Temps will be slightly below normal Mon then slightly
above normal mid next week as supported by NAEFS low level T
standard dev swinging from 1-2 below to 1-2 above normal during the
first half of the week. Given model spreads in the extended it`s
difficult to determine how long the ridge will maintain dry wx
across SE. Therefore, elected to stay close to WPC guidance for the
latter half of next week with cooling temps and increasing precip
chances. Inherited forecast represented this well with very little
change before trending toward WPC.

&&

.AVIATION...IMC Conditions dominate the skies above our airfields.
Change groups this morning were reserved for some sea/channel
breezes developing. A few spots like Skagway, Haines, and
Ketchikan may experience enhanced mesoscale channel breezes this
afternoon. At this time, the only appearance of the front
approaching from the west is a late prob30 group for Sitka
Saturday morning for MVMC conditions with light rain.

&&

.MARINE...Winds along the incoming frontal band Friday night are
roughly small craft strength and they will move across central
gulf and the coastal waters late Friday night and Saturday. Think
that outflow through Cross Sound will be small craft late Friday
night and early Saturday before weakening.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ022-042-043.

&&

$$

Bezenek/BC

Visit us at http://www.weather.gov/Juneau



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.