183
FXAK69 PAFG 212231
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
231 PM AKDT Sat Sep 21 2024

.SYNOPSIS...
There is a weak arctic shortwave over the area, which has allowed
for some cooler temperatures and continued rain showers for the
lower elevations, and snow showers for locations around and above
1000 ft, and even down to near the valley floor for locations
north of the Brooks Range. These will continue to weaken and taper
off by tomorrow for most of the Mainland as there will be more of
a persistent northeasterly winds across much of the region with
relatively drier conditions. There will be a strong low pressure
system moving into the Gulf by later tomorrow and through the mid
part of next week, which will help to increase the chance of
shower activity. This will also increase gap flow winds for the
passes of the Alaska Range, but these winds should remain below
criteria. More more impressive system moving into the Gulf towards
next weekend could result in more impactful conditions, depending
on the track of the low, otherwise overall weak arctic waves
passing to the north with an overall active pattern will keep the
chance of showers in place throughout the rest of the week.

&&

.DISCUSSION...

Upper Levels and Analysis...
Weak arctic troughing over the Mainland and a strengthening low to
the south moving into the Gulf, will keep weak instability in
place. Deterministic models are beginning to resolve the major
shortwave and associated low pressure system moving into the Gulf
better over the previous runs, which has the center undergoing
cyclogenesis just south of the Alaska Peninsula. The Canadian has
this deepening the most of all of the models, at around 965 dam
(the others around 970 to 975 dam). The general consensus of the
models has the low moving into the northern Gulf and weakening as
it does, hugging the coastline as it does, with the propagation
slowing down as it nears the Prince William Sound by Tuesday
morning. The gradient from this still looks to be weak enough so
that gap flow through the passes (Windy and Isabel) should not be
of concern. Depending on the development and track of another
major shortwave trough nearing the Gulf the following weekend,
there could be more in the way of impacts to the region, although
at this time there appears to be too much in the way of
inconsistencies between the models to deem either of them
reliable. A weak arctic trough will still be present over the
North Slope through the rest of the week and keep things generally
unsettled.

Central and Eastern Interior...
Showers, and snow showers, possibly down to the valley floor for
areas north of the Brooks Range with minor accumulations, will
continue to be possible through the rest of this weekend.
Lingering showers, and snow above 1000-2000 ft, will continue to
diminish tomorrow, with only spotty rain/snow showers still
continuing to be possible through early next week. The low
pressure to the south will bring in some wrap around moisture over
the eastern Interior around the mid part of next week and will
help to enhance shower activity around that time. It will also
increase gap flow winds for the passes, although at this time, it
appears that these winds will remain below criteria.

West Coast and Western Interior...
It will be generally dry with persistent northeasterly wind flow
and colder air advection in place. There could be a few isolated
snow showers possible through the early part of next week, with an
increase of snow shower activity towards the end of next week as
another arctic wave moves overhead.

North Slope and Brooks Range...
Anaktuvuk Pass has been receiving a couple of inches already
since this morning, and areas of central to west Brooks Range will
continue to see several inches more through tomorrow morning.
Snow showers are also expected to continue through tomorrow
morning for the central and eastern Brooks Range, where anywhere
from 6 to 12 additional inches of snow is expected for the higher
elevations. Weaker snow shower activity over the North Slope will
begin to diminish going into tomorrow. Overall on and off shower
activity will continue to be possible through the early part of
next week, with a slight uptick going into the later part of the
week since there will be another weak arctic wave looks to be moving
overhead by then.

Extended Forecast Days 4-7...
Depending on the track and intensity of a major shortwave trough
entering the Gulf towards next weekend, there could be more
significant impacts to the region. Otherwise, general arctic
troughing will remain in place with another weak wave propagating
over the region by later in the week, which will keep the chance
of rain/snow showers in place through the rest of the week,
especially for the central and eastern portions of the Mainland.

Coastal Hazard Potential Days 3 and 4...None.

&&

.HYDROLOGY...
None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Storm Warning for AKZ809.
PK...Small Craft Advisory for PKZ801-817-854.
     Small Craft Advisory for PKZ850-851.
&&

$$

Steward