Area Forecast Discussion
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FXAK67 PAJK 162248

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
248 PM AKDT Thu Aug 16 2018

.SHORT TERM... A ridge of high pressure over the panhandle will
move off to the east late today, but will replaced by a weak
surface low that will move in over the southeastern Gulf late
tonight into Friday. By late Friday, another ridge of high
pressure will begin to rebuild over the eastern Gulf into the

Pressure adjustments were made by nudging to the 12z GFs. The low
that is expected to come into the picture later today is a
relatively new feature just over the last several days. This blend
allowed to speed up the system`s entrance, but slowed down its
exit. Winds were adjusted accordingly in the Gulf. Also, a few
local edits were made (i.e. increasing winds over Northern Lynn
just enough but not to small craft status).

At least the pattern for the short-term will be cooler and
somewhat "drier" in some areas. Temperatures were well within
model spreads, but were blended with the GFS to account for
changes in water temperatures or high elevation points. One
uncertainty in the picture is how far the precip is expected to
push northward. The peak precip is expected early Friday morning
with QPF amounts staying pretty light. With rain shadowing over
Sitka, we may see a "donut hole" of lower QPF. POP`s were blended
with the SREF to increase coverage and improve timing, QPF was the
result of a NBM/RFC blend.

Overall, model guidance has improved over the last few runs.
However, there are still some issues with placement, but not
necessarily timing.

.LONG TERM.../Saturday through Thursday as of 10 pm Wednesday/
Still a lot of disagreements amongst the models on how fast a
front will move in early next week. There seems to be very poor
run to run consistency on it, and given the differences, have
decided to stick with current long range forecast for the most
part. Does appear that the building upper ridge over the area will
be a bit stronger though, which would support a slower front.

The one adjustment made was to boost max temps several degrees
for Sun and Mon, mostly over the central and southern inner
channels. Based on strength of the upper ridge and forecasted
temps in the 925-850 mb layer, they may need a further upward
adjustment. MOS guidance seems too cool for Sun and Mon given the
temps aloft and strong ridging. This pattern of anomalous ridging
over the area has been main theme for the past 2+ months, and
would not be surprised if the ridge held out longer and keeps area
dry and warm for a longer period.


.AJK Watches/Warnings/Advisories...
MARINE...Small Craft Advisory due to Seas for PKZ041.




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