Heavy Snow in Alaska, April 21 to 24, 2019

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
530 AM AKDT Sun Apr 21 2019

.DISCUSSION...
An active weather pattern is expected over the next few days
across much of northern Alaska. We have have a few issues to deal
with tonight. The biggest issue is a weather system is expected
to bring heavy snowfall to parts of the central and eastern
Interior Monday night into early Wednesday. The models are in good
agreement with the overall synoptic scale pattern out through the
Tuesday afternoon.

Central and Eastern Interior: An area of low pressure will move
north of the Alaska Range into the western Interior this evening.
When the low moves north of the range, we expect east to northeasterly
winds to kick up across the Interior, but especially over the
summits and higher terrain north and west of Livengood. Wind gusts
as high as 40 mph are expected over summits along the Steese,
Elliott and Dalton Highways. Winds will die down during the day on
Monday. The ongoing wind advisories for zones 219, 220 and 221
look to be in good shape. Some southerly gap winds are expected
tonight along the Parks Highway north of Denali Park. Monday, a
Pacific low that is currently in the Gulf of Alaska will move
north into the southwest Yukon Territory. Precipitation will
spread from southeast to northwest across much of the central and
eastern Interior Monday evening. In many locations the
precipitation will start off as rain; however, the rain will
transition over to snow by Midnight Monday night. The snow will
continue all day Tuesday into Tuesday night along a trough that
will remain relatively stationary along a line from just north of
Eagle to Tanana to Galena. The big questions is when will the snow
taper off. The GFS has snow lingering around much longer into
Wednesday while the NAM and the ECMWF have the snow tapering off
late Tuesday night. Some locations across the Interior will see 7
to in excess of 10 inches of snow with this system. The heaviest
band of snowfall will stretch from the Fortymile Country into the
southern half of zone 220 and the northern portions of zones 222
and 221. Fairbanks will see 4 to 6 inches of snow; however, higher
amounts are expected in the hills north of town. In anticipation
of the snow I am opting to issue Winter Storm Watches for zones
220 and 224. Monday evening we expect southerly gap winds with
gusts up to 50 mph to develop in the eastern Alaska Range. The
strong winds may even reach the Alaska Highway especially between
Tok and Dot Lake. The gap winds are expected to die down late
Tuesday Morning.

North slope and Brooks Range: Some patchy fog and/or lower
stratus is expected today along the coast, primarily from
Utqiagvik east. Northeasterly winds along the Arctic Coast will
increase Monday evening as a surface low moves north into the
Interior. This will likely cause blowing snow that will reduce the
visibility to less than one mile at times. The gusty northeasterly
winds are expected to continue into Wednesday. This evening we
expect northerly gap winds to develop to develop in the Brooks
Range with the strongest winds expected east of the Dalton
Highway.

West Coast and Western Interior: A surface low will push into the
central Interior this evening. This will bring snow to the Yukon
Valley (west of Galena). The low will continue to track to the
north and west reaching Norton Sound by Monday morning. The lower
Yukon Valley will see 3 to 6 inches of snow this evening into
Monday. The eastern coast of Norton Sound will see around two
inches as the low passes over. As the low moves across the area
Sunday night, the winds across much of the west coast and western
Interior will increase. Blowing snow will be an issue tonight
into early Monday across the Yukon Delta, the lower Yukon Valley
and over the east coast of Norton Sound as well as in the Nulato
Hills. The ongoing Winter Weather Advisories for zones 212, 214,
215 and 216 look to be in good shape. Strong northerly downslope
winds will develop in the Kobuk and Noatak Valleys late this
evening. This will cause blowing snow in the northern half of
zones 208 and 217. I opted to issue Winter Weather Advisories for
theses zones in anticipation of the blowing snow. On Monday, gale
force winds are expected over the southern Chukchi Sea, through
the Bering Strait southward to St. Lawrence Island. The strongest
wind will mostly remain out over the ocean; however, we do expect
the strong winds on St. Lawrence Island, Diomede and the coast of
the Bering Strait. Winds will die down from east to west late
Monday as the surface low tracts off to the west. A weather system
will spread snowfall into the western Interior from the east late
Monday with snowfall continuing into Tuesday night.

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

&&

.FIRE WEATHER...
Drier conditions and warmer temperatures expected across the
Interior today. Minimum RH will range from 20-30 percent south
and east of Fairbanks and 30 to 50 percent north and west of
Fairbanks. East to northeasterly winds will pick up this afternoon
as an area of low pressure moves north into the western Alaska
Range. Easterly winds of 20 to 30 mph will be combined with RH
values under 30 percent today in the area around Delta Junction.

Significant precipitations is expected across much of the
Interior late Monday into Tuesday night. This will help to keep
the minimum RH values above 40% for most of the area Monday and
Tuesday (although the upper Tanana Valley will see minimum RH
values as low as 30% on Tuesday).

&&

.HYDROLOGY...
Cooler than normal temperatures over the Eastern Interior will
continue through the weekend and into next week slowing the
breakup process; however, extreme caution should be used crossing
any of the Interior rivers as the ice continues to rot and be
eroded from below, and any runoff will be moving into the mainstem
rivers. Caution should also be used on lakes as the ice melts at
different rates.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Advisory for AKZ219-AKZ220-AKZ221.

Winter Weather Advisory for AKZ212-AKZ214-AKZ215-AKZ216.

Heavy Freezing Spray Warning for PKZ200-PKZ210.
&&

APR 19