High Wind in Alaska, April 25, 2020

Southeast Alaska Forecast Discussion...CORRECTED
National Weather Service Juneau AK
801 AM AKDT Sat Apr 25 2020

.SHORT TERM...Any good driver uses all of their tools at their
disposal to maintain good situational awareness and be able to
react to impending dangers: their eyes, their ears, and of course
their rear view mirrors with the words, "Objects in mirror may be
closer than they appear." Tonight's forecast team is intently
aware of a developing low to our south which may be "stronger than
it appears." IR satellite over the last several hours has
displayed some signs of strengthening with more distinct bands
extending from an apparent low center. Also, both 09Z and 12Z SLP
observations from area buoys are now more inclined to support the
stronger GFS, the middle of the road NAM and Canadian as opposed
to the weaker ECMWF. After coordination with the Ocean Prediction
Center, we elected to significantly strengthen the low forecast to
reach the southeast Gulf of Alaska by this afternoon. But
uncertainty remains. Should the GFS be correct, we may have need
to adjust winds through the southern Inner Channels and Prince of
Wales Island even higher than we did earlier this morning. We
upped Ketchikan, Hydaburg, and Craig gusts to 40 mph this
afternoon and early this evening. Easterly winds on Annette Island
and Haida Gwaii have already begun to gust in excess of 30 mph,
which puts our southern fringes ahead of schedule regarding winds.
Even more uncertainty exists for points north like Wrangell and
Sitka. We bumped Wrangell up this afternoon to 20 mph but
confidence was too low to significantly alter Sitka's winds.

Showers have largely ended across the north early this morning to
leave some offshore breaks, an inversion, and some patchy fog in
their place. Any fog that does form should dissipate by mid-
morning. Meanwhile rain has increased across the far south with
Ketchikan receiving close to a half inch overnight. As the low
angles to the north offshore of Prince of Wales Island, we expect
bands of moderate to heavy rainfall to arrive across the far south
later this afternoon with the strongest winds. It is likely that
bands of rain hold together as they spread northward, but these
bands will be much lighter than what the southern Panhandle
experiences.

Looking forward to Sunday, a new low approaches the eastern gulf
from the North Pacific. What is becoming more apparent is that its
strength will eclipse today's storm. We broadened gale force
winds across the gulf, but later guidance suggests that we need to
look at raising wind speeds Sunday night in line with the
stronger GFS and Canadian models. Thankfully, the second low's
track well offshore should spare much of the Panhandle with
significant wind impacts, although some gusty winds look likely
for the coast from Sitka southward, including Ketchikan and Prince
of Wales. Again the position of the low looks more favorable for
the heaviest rainfall across the south and the eastern gulf coast,
than for the north and the northeast gulf coast. Guidance has
trended this feature westward away from land, even going into
early Monday.

.LONG TERM...Monday to Saturday as of 9 pm Friday...A short
version of the longer term discussion is wet and occasionally
windy through the week.

The remnants of the strong Sunday low pulls into the northeast
Gulf and weakens on Monday. The various operational solutions are
quite different on positions of this feature in the NE gulf for
being roughly 3 days out from the start time Friday afternoon. For
the panhandle however this matters little regarding general
weather, but individual sites could see big differences. Generally
the weather should bring brisk winds and rains that may be
moderate at times and then continued onshore flow from the gulf.

Another low, this one weaker rolls up out of the east Pacific to
the southwest of Prince of Wales Tuesday afternoon and then into
the central panhandle Tuesday night. This system should bring a
renewed round of rain and wind to the southern panhandle, and then
spread the rain to the central panhandle with the remnants headed
to the northern panhandle through early Wednesday. The end of the
week continues to shift somewhat as the long range often does,
however there does not seem to be a break in the wet pattern for
the majority of the forecast area through the end of the month.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from 1 PM AKDT this afternoon through this evening
     for AKZ027.
     Strong Wind from 4 PM AKDT this afternoon through this evening
     for AKZ028.
MARINE...Gale Warning for PKZ036-041-042.
     Small Craft Advisory for PKZ035-043-051.

&&

JWA/Bezenek

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