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 18 19 20 21 22 23 24 25 26 27 28
000
FXAK67 PAJK 292342
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
342 PM AKDT SUN MAY 29 2016

.SHORT TERM...Weak trough of low pressure across the panhandle and
northern gulf is dissipating under a slowly building high
pressure area over the Gulf of Alaska and stronger ridge axis
along the British Columbia coast. A surface low around will be
moving north into the south central gulf by Monday afternoon. A
developed weather front associated with the gulf low will spread
north into the eastern half of the gulf and the southern panhandle
monday afternoon.

Scattered shower activity moving west across the panhandle out of
British Columbia Sunday afternoon into Monday. The remains of the
weakening through features will also be pushed north as the
surface ridge noses into the southern panhandle adding to the
support of the showers in north. Most showers will be resulting
in a light rainfall total of only a few hundredths. The steadier
rains with the incoming warm front to the Prince of Wales Island
on Monday will start as light in the afternoon but better totals
should be expected by Monday evening.

Easterly outflow across much of the panhandle area will continue,
the one main change to the wind pattern will be Lynn Canal
changing from the north out flow to southerly wind by Monday
afternoon in response to the building ridge. Forecast confidence
is above average headed into the Monday holiday.

.LONG TERM...As touched on above, a short-wave over the deep
North Pacific will thrust northward to push what remains of the
Upper Low seemingly entrenched over our region of the North
American continent. This heralds a pattern change. So what does
this mean? Instead of scattered showers spreading west from the
mountains or outright dry weather, we will likely see steadier but
generally light rain from a front of marine origins. Atmospheric
river? By all accounts, no. We simply write that rather than east
across the mountains in Canada for our weather makers, we look
sea-ward to the Pacific. And we all know that this usually makes
for wetter days. Onshore flow aloft begins in earnest late Monday
across the Panhandle. And following this road toward the Panhandle
rides a short-wave. However, the track of this feature aims for
light rain across the southern and coastal stretches but mere
chances to no rain at all across the northern areas. As this
feature moves ashore, a more southerly mid-level flow behind it
will translate to higher rain chances Panhandle wide by Wednesday.
While the overall forecast into this weekend looks wet from a
series of waves locking into the eastern gulf, there will
inevitably be periods of ridging between waves to instill drier
conditions. These periods unfortunately cannot be identified until
later. Finally, mariners should be aware of more brisk winds
increasing over the Gulf. At this time, winds will remain lighter
across the Panhandle as a surface ridge is still forecast to
persist.

Only minor tweaks were made to the overall wind field and
shower/rain coverage during the mid-range. New extended WPC
guidance mandated zero change for the long-term. Temperatures will
be seasonable to slightly cooler than average given the light
rains.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...None.
&&

$$

Bezenek/JWA

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.