Winter Weather Advisory 4, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
136 PM AKST Sat Jan 9 2021

.SYNOPSIS...
Upper level ridging over the Canadian Rockies and the eastern
interior combined with a large complex of low pressure over the
Gulf of Alaska will maintain south-southeast flow over the
interior. The complex of lows to the south will continue to keep
the cool northerly flow over the Bering and Chukchi Sea.

&&

.DISCUSSION...

Upper Levels and Analysis...
A 210 kt jet is screaming across the North Pacific today pushing
into a stubborn Canadian Rockies upper ridge. This is keeping the
eastern interior under the influence of the upper ridge with
weakening southerly flow aloft. On Sunday afternoon the ridge is
nudged a bit further east for weaker southeast flow over the
Alaska and Brooks range for the interior and the upper low complex
over the southwestern Gulf of Alaska will continue northerly flow
through the Bering Strait and west coasts. On Monday and into
Tuesday the upper low over the Gulf of Alaska drifts north and
puts the eastern interior more into a easterly wave pattern and
northerly flow continues for the Bering Strait and west coast.

Model Discussion...
The 12Z model suite resolves the hemispheric and synoptic patterns
in similar fashion with the low pressure complex fusing over the
southwestern Gulf of Alaska and upper ridging being displaced from
the Canadian Rockies off to the east. The issues to be resolved
will be mesoscale features in the form of easterly waves moving
into the interior spawned from the system to the south and long
term continued north winds through the Bering Strait region. It
looks like an ensemble approach or chef's choice approach to the
forecast for the details today. Main issues will be wind in the
Bering Strait region, local winds through the Alaska range passes,
and light snowfall, if any, in the eastern interior Sunday night
into Monday.

Central and Eastern Interior...
Strong winds through the Alaska range should continue the slow
trend downwards. The region will continue with above normal
temperatures through the period with higher elevations on a warmer
side than valley locations with the strong inversion holding on
in most low land areas. The wind will mainly pull back and drop
below advisory criteria for the period however any slight
readjustment of the upper levels could spring a situation or two
in the period where wind advisory conditions could be warranted.
The light snow problem is a with a easterly wave moving through
the region late on Sunday and into Monday. Took a good look at the
isentropic layers for the period. Models have different timings,
however bring the same story. The main take away is that in the
snow production zone -8c to -15c or 280k-300k layer the upglide of
moisture is not favorable for snow however mainly cloud
production. As the waves moves north to northwest some upglide
occurs and a chance of light snow is warranted north of Fairbanks
on Monday.

West Coast and Western Interior...
The pattern will continue to hold keeping the northerly flow going
for windy conditions for the region for the period along the coast
and over open waters, and in the interior lighter however still
northerly flow regime is instore for the region. Mostly dry
through the period with only limited chance of snow on late Monday
and Tuesday as the waves move around the upper low situated to the
south of the region.

North Slope and Arctic Coast...
Southerly flow continues across the Slope lasting into Sunday when
a wave shots through in the lower levels of the atmosphere and
ridging continues aloft. This should limit any snowfall to the
light category on Sunday. Monday and Tuesday the eastern slope
will have the influence of lower atmospheric waves moving through
however mainly very light snowfall at best. Main element to
remark about that the southern component of the wind will shift
into the more seasonal northeast direction and remain for the
remainder of the period enhancing more stratus typical north slope
issues.

Extended Forecast Days 4-7...
Generally quiet Tuesday and Wednesday with temperatures not really
straying far from the warmer temperatures already experienced.
Right now, models think the Interior will remain dry into next
weekend with snow for the West Coast, Western Interior, and North
Slope near mid-week as a couple of shortwave troughs move from
the Y-K Delta region to the Arctic Coast.

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ200-PKZ220-PKZ225.
&&

PROTON JAN 21