Area Forecast Discussion
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Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
424 PM AKDT Thu Oct 17 2019

.SHORT TERM...Dominant point of concern continues to be the
complex low pressure pattern over the Gulf. Satellite imagery
from GOES-17 shows multiple surface lows spinning across the
Northern and Eastern Gulf of Alaska, and upper air observations
continue to indicate that SE Alaska remains under the northern
portion of a broad upper level trof. As a result have opted to
keep showery conditions in place across southeast Alaska through
Friday night. Currently, showers are varying in intensity with
much of the activity being reported originating in the Southern
half of the panhandle.

Rain in the Southern Panhandle is being enhanced by instability
being generated from one of the shortwaves in the gulf which has
worked its way into the Panhandle. As this shortwave continues to
push its way north through the overnight hours, expecting an
increased chance of rain and showers through the central and
corthern parts of SE Alaska. Don`t expect the winds generated by
this shortwave to be too spectacular in most areas, though would
not be surprised if a few gusts are noted as the instability from
the shortwave mixes down some of the stronger winds from aloft.
Given the lack of strong moisture transport for this particular
shortwave, am expecting precip totals for the impulse to stay
relatively low, with amounts lower than an inch everywhere except
the Southern Panhandle where local amounts may be slightly
higher.

The first half of the weekend will bring with it some relief,
especially for the northern parts of the Panhandle, lower POPs
will abound for this particular area, and it`s not entirely
impossible that a few areas may even see a glimpse of the sun,
though think that this would be the exception rather than the
norm. Sunday remains somewhat uncertain. Most models are
indicating that another yet another low pressure system will
approach the panhandle, but exact timing is still up in the air.
Will need to keep an eye on it, and make adjustments where
necessary as certainty increases.

No major changes were made overall to the forecast during the
time period. Precip coverage area was given additional detail
during the next 2 days in the forecast. Some wind directions were
tweaked, and wind speeds were brought down a bit in some
locations across the Panhandle, but nothing truly substantial. No
changes made to Sunday, and am waiting on additional information
before making any changes to said time period. Overall forecast
confidence is moderate in the short term.

.LONG TERM.../Saturday through Thursday as of 10 pm Wednesday/
Looks like a fairly flat pattern aloft with main upper level jet
moving along S of the gulf into southern BC through the weekend.
Next week, some hint that a more amplified flow will develop as a
trof tries to deepen over the eastern Bering/N-central PAC with
ridging building over SE AK and western Canada, but models do not
agree how strong these features will get due to complicated stream
interactions. At the sfc, looks like a series of smaller lows
will move E across the far southern gulf through the weekend, then
a stronger system may move NE toward the AKPEN by the middle of
next week, with a front moving across the gulf during this time.
Models do seem to be in better agreement on the midweek system, so
latest WPC was incorporated to show a stronger system during that
time. Other than that, only minor forecast changes at most were
made.

Models remain in decent agreement that a low will track across
the far southern gulf and reach the far southern panhandle or far
northern Haida Gwaii by Sun afternoon. This will keep highest
precip threat with this system over the southern half of the area.
May see a period of dry weather N as the low slides by to the S.
Looking like weak systems will move into the area early next week,
with the aforementioned stronger system moving in for midweek.
Temps during the period should remain near normal with no
significant warm or cold airmasses expected to move in. Overall
forecast confidence remains about average for the longer term
period.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Areal Flood Advisory until 10 AM AKDT Friday for AKZ028.
MARINE...Small Craft Advisory for PKZ022-041>043-051-052.

&&

$$

GFS/RWT

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