Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 272348
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
348 PM AKDT FRI MAY 27 2016
.SHORT TERM...Upper level trough over the area is bringing a
variety of weather to the panhandle today. The main east/west axis
of the trough is currently stalling over the southern panhandle
and has brought some showers and clouds from frederick sound
southward. Temperatures there are struggling to get out of the
50s. Meanwhile, offshore flow to the north of the trough axis is
bringing mostly clear skies to the northern panhandle with
temperatures jumping into the 60s in many places. The exception
is in Skagway and Haines where mid to high clouds streaming south
over the mountains are bringing mostly cloudy skies.
Much of the forecast for the next 24 hours is going to depend on
how much cloud cover the upper level disturbances being pull west
over the mountains bring. The southern panhandle is likely going
to remain under clouds with scattered showers around into
tomorrow as the main upper level trough remains stalled over that
area. Temperatures as a result will struggle to get out of the 50s
again for tomorrow afternoon.
Forecast becomes trickier farther north as offshore flow will
push for clearer skies while some weak areas of upper level
vorticity coming from the east will try to develop clouds. Decided
to go with partly cloudy skies for tonight for the north as low
level clouds should be kept at bay but higher level clouds will
still migrate over the area but should remain rather thin. Went
more increasing clouds tomorrow as afternoon heating and more
upper level dynamics will likely cause more clouds to develop
across the area particularly across the higher terrain.
Temperatures will likely get into the 60s again for the northern
half of the panhandle tomorrow.
As far as a thunderstorm potential, the central panhandle will
have the best chance tomorrow afternoon with the combo of warmer
temperatures from more breaks in the cloud cover and some upper
level dynamics moving over the area. As such decided to include a
slight chance of thunderstorms over the central panhandle Sat
afternoon. The southern panhandle might see some as well but i
think there will be too much cloud cover (and thus too cool) for
any cells that develop to get past just being a rain shower. The
far north will likely not see any as offshore flow may inhibit
Short range models were in good agreement but differed on exactly
where the showers would concentrate. Used mostly nam for forecast
updates which mainly featured local effect changes due to sea
.LONG TERM.../ Saturday night to Friday / Weekend is looking to be
more of a transition pattern over the weekend, going from a north
flow to weak no flow to a southerly early next week as a complex
multi center upper level low breaks apart and a building ridge
along the west coast to the southern panhandle. As a result much
of the panhandle will be partly to mostly cloudy and a dry outlook
heading into next week. Early into next week with the southerly
flow as a low moves north skirting past the southern panhandle,
rain will spreading in Tuesday across the southern panhandle.
After that through the mid week onshore flow will keep a chance of
rain for southeast Alaska.
End of next week after the ridge builds along the west coast and
British Columbia the early part of June is suggesting a good warm
up for southeast Alaska especially over the southern panhandle.
Forecast confidence is average through the weekend, then lowering
as model solutions differing how to handle the combination of the
low moving into the central gulf from the south and low pressure
moving east along the Aleutian Islands.
.FIRE WEATHER...Conditions have gotten rather dry across the
northern panhandle this afternoon. RH values have plummeted into
the mid to upper 20s for Yakutat, Skagway, Haines, Hoonah, Juneau,
and Gustavus as offshore flow has overpowered the usual afternoon
sea breezes. However, winds have generally been less then 15 kt
and fuels are not that dry right now so fire danger is not that
high. RH values will recover into the 60 to 80 percent range
tonight as temperatures cool off. RH values are expected to drop
again tomorrow in the north into the 20 and 30 percent range as
warm conditions continue. However, more upper level cloud cover
and weaker offshore flow that does not cancel out the sea breezes
may cause highs tomorrow to be just a little cooler so min RH
values may not get as low as today. Winds remain low so no high
fire danger expected into Sat either.
MARINE...Small Craft Advisory for PKZ022.
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