Scientific Forecaster Discussion
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Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
620 am akdt sun Sep 22 2019
a front that brought precipitation to the interior on Saturday
will bring precipitation to the the North Slope today. A
persistent low over the chukotsk peninsula will keep showery
conditions over the West Coast of Alaska through the middle of the
week while the remnants of a tropical system may bring more active
weather for the West Coast late in the week. Clearing skies are
expected today for the interior.
the models are in generally good agreement with the overall
synoptic scale pattern out through the middle of the week. The
operational models are coming into better agreement than they
have been over the past few days in dealing the remnants of
Tropical Storm Tapah as it moves into the Bering Sea late in the
week; however, model differences do exist with this system,
especially after Thursday afternoon.
Aloft, at 500 mb, a 518 dam low over the chukotsk peninsula will
remain quasi-stationary through Tuesday before moving across the
Bering Strait to the Seward Peninsula on Wednesday. A 538 dam low
currently near Yakutat will move into the Yukon territory today.
A ridge will build into the eastern interior Monday and Tuesday.
This ridge will push to the east on Wednesday as a shortwave
associated with a low over the Seward Peninsula rotates into the
interior. A 514 dam low (remnants of tropical storm tapah) will
move over the Kamchatka peninsula by late Tuesday and will slowly
move through the southwest Bering Sea through Thursday. This low
will push a ridge over Mainland Alaska for Thursday and Friday.
Central and eastern interior: recent precipitation will bring
some patchy fog to the interior this morning; however, we expect
any fog that does form to dissipate rather quickly this morning.
We expect skies to clear out today with mostly clear skies
persisting into Monday night. With the clear skies combined with
a colder airmass in place over the area, we expect the temperature
to drop below freezing across the entirety of the interior tonight,
with many locations expected to fall into the 20s. Temperatures
on Sunday will be slightly warmer than Saturday for most
locations, although the highs will remain under 50 degrees. A
slight warming trend in high temperatures is expected to continue
for Monday. Some precipitation is expected northeast of ft. Yukon
this morning; however, this will dissipate this by this afternoon as
the front moves away. Aside from this, no precipitation is
expected through Monday night. On Tuesday, a shortwave will move
from southwest to northeast across the interior. This will bring
scattered rain and snow showers. The snow level as this system
moves through will be around 1500 ft. A second shortwave will
bring additional chances for rain and snow showers on Wednesday
and Wednesday night.
North Slope and Brooks range: a front is currently bringing a
mixed bag of precipitation to the Beaufort Sea coast as well as
the eastern Brooks range. In the Brooks range, where the
precipitation is falling as snow, we expect an inch or two of
accumulation today. Along the coast, the precipitation will fall
as a mixture or rain and snow. Therefore we really aren't
expecting much if any accumulation of snow. The precipitation in
the Brooks range will taper off overnight. Along the Beaufort Sea
coast, the precipitation will persist into Monday. Although it
will decrease in intensity. Highs today will be in the 30s in the
Brooks range and along the Beaufort Sea coast. Along the Chukchi
Sea coast highs in the low 40s are expected. Lows in the low 30s
are expected tonight along the coast with lows in the 20s across
the Arctic plain and in the upper teens in the Brooks range.
Similar temperatures are expected for much of the workweek.
West Coast and western interior: a low just off the coast from
Scammon Bay will move north to the Seward Peninsula today. This
low will bring showers to coastal area south of the Bering Strait
today. A generally showery pattern will persist for Monday along
the coast due to shortwaves rotating around a low over the
chukotsk peninsula. Showers will continue along the coast on
Tuesday, and will push into the western interior as the low moves
across the Bering Strait to the Seward Peninsula. A quick moving
ridge will provide a respite from the showers on Wednesday.
Wednesday night and Thursday, a front associated with a strong low
over the western Bering Sea will reach the West Coast. The
aforementioned low is the remnants of Tropical Storm Tapah, which
is currently located in the Sea of Japan. This front is expected
to bring strong winds Wednesday night into Thursday as well as
heavy precipitation. While the models have come into better
agreement today with this system, there are still differences in
the timing and track of the low and associated front. Highs today
and Monday will be in the upper 40s to lower 50s. Lows in the 30s
are expected tonight. On Monday night lows in the 30s are expected
along the coast with some locations in the western interior as
well as the interior Seward Peninsula falling into the 20s.
Coastal hazard potential days 3 and 4...remnants of Tropical Storm
Tapah will move into the western Bering Sea and could potentially
produce some elevated surf along the West Coast late in the week.
recent rainfall in the interior will cause some rises on rivers
over the next few days; however, no issues are expected.