Gale Warning 195, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
341 PM AKDT SUN MAY 15 2016

.SYNOPSIS...A weak trough over the central panhandle will continue
to lift north through Sunday night with a ridge over high pressure
building north. A upper low will lift out of the North Pacific
through tonight and beginning to weaken to a trough as it gets
absorbed by trailing upper low to the its Southwest. The trailing
upper low will begin to lift a weather front into the southeast
gulf and spread light precip into POW by Monday afternoon along
with min small crafts winds.

&&

.SHORT TERM...The current satellite imagery shows an area or low
sea stratus along the Eastern Gulf of Alaska from Cross Sound to
the west and to the South. There is also an area of mid-level
clouds just south of Angoon being advected north from the building
ridge. The northern half of the panhandle will be mostly cloudy by
late this evening with the marine layer moving into Yakutat this
evening. The cloud cover limited the temperature over the
southern areas today with highs only in the upper 50s but with
ample amount of sunshine over the northern areas that temps
climbed into the upper 60s/lower 70s. The entire forecast area
will be much cooler tomorrow with highs in the 50s.

There are some scattered showers associated with the southerly
push of moisture from moderate mid-level dynamics. These showers
will become more widespread through tonight with a more
significant PVA as the upper shortwave lifting over the area. The
showers will become more scattered tomorrow morning over the
southern half with more upper level ridging and anti-cyclonic
rotation. But the periods of light rain will develop late in the
afternoon near POW from the approaching weather front from the
Southwest. The northern areas will see widespread showers Monday
morning but they too will the showers decrease to scattered by the
afternoon.

Windwise...the winds over the northern half will see an increase
from the south from the building ridge and the thermal gradient
that developed through today. At this time places are seeing light
north winds to south winds to 15 kt. Those South winds are
expected to increase through this evening with N/S channels being
closer to 20 kt. There will be another increase to the winds over
the far southern areas through Monday afternoon to min small craft
as the front from the SW moves closer to the panhandle and
sharpens up the surface ridge. Also the winds with the front over
the gulf will increase to 25 kt over the far western areas of area
41 by late Monday afternoon with seas building to 7 ft.

Overall there is about average forecaster confidence through the
short term period with lower confidence on the southerly push of
winds and amount of rain over the northern two thirds of the area.
Used mainly the 12z gfs/nam for any changes done from the previous
forecast. The larges change was to increase pops over the northern
areas tonight and Monday.

.LONG TERM...15/12Z models in reasonable agreement Mon Nite thru
Thu then a strong signal is sent that an upper ridge will build
over the central Gulf and will move slowly eastward through
Saturday. First, another late season low busts through the present
high pressure with a pretty strong front Monday night through
Tuesday. Next, with high pressure rebuilding this weather system
is sluffed-off toward the SE. Had to forecast minimum gale force
southeasterlies and some small crafts as the front and low come up
into the eastern Gulf. We'll position the surface low center 55N
143W at 00Z UTC on Wednesday then start to see it slide SE.
Forecasting some moderate NW on the outside waters behind this
system as the ridge builds. Sticking with yesterday's forecast of
some nice weather Thursday through Saturday for the Panhandle.
Moderated the max-temps to the 60s but these could be higher with
lots of sunshine. Tried to tag some sea breezes with heating
inside. Sunday gets tricky: scenarios either something busting
through the ridge or a marine push, but didn't want to advertise
too nice weather that day. Confidence moderate Tue and Wed, and
high for Thu-Sat. - JC

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Small Craft Advisory FOR PKZ012-036-041-042.
&&

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