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FXAK67 PAJK 152230

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
230 PM AKDT Sat Jun 15 2019

.SHORT TERM...Rain has started in earnest today, but is finally
being reported most places as of 2pm. Rainfall rates will
increase through the evening as the front moves in. Waves of low
pressure moving north along the front helped to delay the onset,
and can be seen with satellite imagery. These will help to enhance
the rainfall as they move through tonight, but may also cause
winds to be variable and gusty at times.

The front will push inland to the NE through Sunday morning with
some breaks in the rain behind it. The next frontal band in the
larger cyclonic circulation will move into the outer coast
through Sunday afternoon, so changed Sunday to "periods of rain"
since part of the morning and afternoon should be wet.

The pattern continues on Monday with another wave of low pressure
moving through and more rain. Once this low passes, winds look to
shift from SE to SW. Adjustments to this forecast package were
fairly small. Did keep trending the diurnal temperature range
down, with the cloudy/wet pattern shouldn`t see much change from
night to day.

.LONG TERM.../Monday through Saturday/As of 10 pm Friday. Broad
and slow moving upper low will be traversing the Gulf from west to
east through Tuesday night. Several shortwaves will eject NE`ward
around the upper low and across the central and southern
Panhandle Monday into Tuesday. Model spread continues to be high
on the timing and strength of any particular surface waves
associated with these features. All the same, upper diffluence
and weak to moderate SW`ly moisture transport in the low levels
will keep high chances of rain in the forecast through Tuesday.
Highest rainfall amounts will be along the Coast Mtns and over the
southern Panhandle where the better dynamics and favorable
orographics coincide. A couple of operational solutions track a
tighter surface circulation close to the central outer coast
Monday evening which would likely tighten the gradient and develop
some stronger SE wind over the inside waters. With the spread in
the operational solutions decided to hold off on adjusting winds
significantly at this time.

Ensembles and operational models remain spread on the evolution of
the upper low and the eventual pattern that develops for late
week. As the upper circulation shifts east into BC on Tuesday
night/Wednesday, easterly wave potential will increase so adjusted
precipitation chances over the northern and eastern channels up a
bit through Wednesday. For late week, still looks NPAC ridging
will be suppressed somewhat and the Gulf of Alaska will be in a
weak flow region between this ridge and a cut-off upper high over
the Bering/Chukchi Sea. This pattern leads to the potential for
another upper low or the remnants thereof to be caught in the Gulf
once again and meander around, all of which leads to a very low
confidence forecast. Minimal changes were made to the extended
range forecast after Monday as a result.


.AJK Watches/Warnings/Advisories...
MARINE...Small Craft Advisory for PKZ051-052.




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