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FXAK67 PAJK 242311
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
311 PM AKDT TUE MAY 24 2016

.SHORT TERM...Cloud cover and shower activity continues to be
driven by mid/upper level lows moving across the region for the
next 24hrs. One low is departing to the east into Canada this
afternoon and most recently caused a couple light showers over
the southern panhandle around noon. The next low will move into
the northern Gulf overnight. This one looks to have a weak surface
reflection but that will weaken more as the mid level low tracks SE
along the panhandle coast through Wednesday afternoon.

A thicker band of overcast clouds has been stuck between the two
low pressure systems over the central panhandle all day while
elsewhere, especially to the south, sunny breaks have been more
common. Expect clouds to increase overnight as the next low moves
in with scattered showers developing. West facing mountain slopes
have the best chance of seeing a couple hundredths while
locations on the lee side of the mountains will see little to no
precipitation. Tomorrow clouds and showers will start to decrease
over the north as the low moves away and flow aloft turns more
N-NWLY.

Expect temperatures tonight to remain in the mid 40s due to cloud
cover. Tomorrow highs across the central panhandle look to be
fairly similar to day. Northern spots that get some sunshine in
the afternoon could be a couple degrees warmer, while the southern
panhandle should have a little more clouds and thus slightly
cooler.

Models were in good agreement on the overall surface pressure
pattern. Used mainly the GFS22 and CanadianReg for their higher
temporal resolution and good initialization. Forecast confidence
on extent of showers is lower than normal, however very light
amounts should have low impact.

.LONG TERM...Long range models continue to refine the weekend
forecast with an upper level ridge dominating the weather over the
gulf and mainland Alaska. Forecast confidence falls apart rather
rapidly early next week as some operational models (ECMWF) are
eroding the ridge while other (GFS and Gem) keep it rather strong
over the Alaskan interior through next week.

For the panhandle, the main changes to the previous forecast was
for the weekend. The upper level ridge will keep most storms from
the west well away from the panhandle, however a digging trough
from the NE will still bring a chance of rain to some areas.
Exactly where depends on where the trough axis sets up. Current
model trends have the axis setting up around Sumner Strait after
moving through the northern panhandle on Fri. The result are
chance pops for the north on Fri then drying trends for Sat into
Sun due to offshore flow developing (dropped pops to slight
chance across the north as a result) while the southern panhandle
remains with a possibility of a wet weekend with the trough and
onshore flow keeping chances of rain present. This also results in
some wind shifts as a more offshore flow scenario creates more
northerly winds Fri and Sat for the inner channels and W to NW winds
for the gulf.

Extended forecast mainly continues to feature a surface ridge of
some sort over the gulf. Chance to slight chance pops and mostly
cloudy skies remain up for much of the panhandle as there is no
clear signal for any significant rain event or warm or cool trend
and forecast confidence is rather low due to significant model
spread. Instead, flow is mainly along shore to slightly offshore
for most of next week with some weak upper level short waves
moving through from the N or NW. Used mainly WPC for extended
updates.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Small Craft Advisory FOR PKZ012-033.
&&

$$

Ferrin/EAL

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