Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 221401
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
601 AM AKDT Mon Apr 22 2019

.DISCUSSION...
An active start to the week is expected for northern Alaska. A
weather system will bring heavy snowfall to parts of the Interior
tonight into Tuesday. Strong winds and blowing snow are expected
along the west coast today into Tuesday, with strong winds and
blowing snow developing over the North Slope by this afternoon.
Overall, the models are in good agreement out through Tuesday
night with the main synoptic scale features.

Central and Eastern Interior: A 987 mb low just north of of
McGrath has caused the pressure gradient to tighten up across the
northern half of the Interior early this morning. This will is
bringing gusty winds to the northern Interior, especially over
the summits and the higher terrain. The wind advisories that we
have out for zones 218, 219 and 220 out through this evening look
to be in good shape; however, I did extend the advisory in 218
through Tuesday afternoon as the winds look to remain strong
through that time. A 982 mb area of low pressure currently near
Yakutat will move into the near Northway by late this. A trough
associated with this low will stretch to near Galena. The low will
move to near Eagle this evening and stall. This will keep the
trough in place from the low to near Galena through Tuesday night.
Precipitation is expected along the trough. As the trough north
today, the precipitation will spread over much of the central and
eastern Interior, mainly to areas south of Fort Yukon. The
precipitation looks to start out as rain but will transition over
to snow at some point this evening. For Fairbanks, current
guidance suggests that rain will move in after 4 PM and will
transition to snow between 10 PM and midnight. The timing of this
transition over to snow is critical to the snowfall amount
forecast. Currently I don`t have the highest confidence in the
current guidance when it comes to when the transition will occur.
If the transition occurs earlier than expected the snowfall
amounts will be higher than expected, while if the transition
occurs later snowfall amounts will be lower. The most recent run
of the high resolution HRRR model showers the heaviest
precipitation in Fairbanks falling between midnight and 4 AM
Tuesday. 3 to 6 inches of snow is expected in the immediate area
around Fairbanks. Up to 10 inches of snow is exepcted in the
higher terrain north of Fairbanks and south of the Yukon River.
The snow will continue through at least Tuesday evening; however
the other big question today is when will the precipitation will
end. The NAM moves the precipitation out of Fairbanks by Tuesday
evening while the ECMWF has the snow ending late Tuesday night.
The GFS on the other hand, has the snow lingering over the
Fairbanks area through much of the day on Wednesday. At this point
the GFS seems like an outlier after midnight Tuesday night. We
lowered PoPs on Wednesday to account for the uncertainty with the
end time of the precipitation. I also cut back the end time on the
Interior Winter Storm Warnings some to account for the current
uncertainty in the end time of the precipitation; however, the
warnings look to be in good shape otherwise. As the low moves to
the north of the Alaska Range this evening we expect winds to
increase in the eastern Alaska Range as the pressure gradient
tightens up. This will likely cause some blowing snow in zone 226.
The winds in the Alaska range are expected to die down Tuesday
morning.

North Slope and Brooks Range: Most of the issues today will be
wind related. The combination of a trough moving north today
through the Interior combined with persistent strong high
pressure over the Arctic Ocean will really tighten up the pressure
gradient. Strong northeasterly winds will develop as the pressure
gradient tightens up with many locations along the coast seeing
gusts as high as 40 mph. When the winds increase, we expect
blowing snow to develop across most of the north slope. Winter
Weather Advisories for blowing snow were issued by the previous
shift for zones 201, 202, 203, 204, 205 and 206. These advisories
look to be in good shape. Gusty winds along the coast look to
persist into Wednesday. Other than some light snow across the
Arctic Plain on Tuesday, we aren`t expecting any precipitation
this week.

West Coast and Western Interior: An area of low pressure
currently near Galena will move into Norton Sound today. This low
will bring snowfall to Norton Sound, the lower Yukon Valley, the
Yukon Delta and the Seward Peninsula 1 to 2 inches of additional
snow is expected across the Yukon Delta and the lower Yukon
Valley, while up to one inch is expected over Norton Sound and the
Seward Peninsula. Snowfall will move into the western Interior
overnight tonight from the east. 2 to 5 inches of snowfall is
expected over the western Interior through Tuesday evening. As the
aforementioned low moves into Norton Sound it will cause the
pressure gradient over the Bering Sea to tighten up. This will
bring strong winds and blowing snow to much of the west coast.
Gale force winds are expected winds are expected over much of the
northern Bering Sea into the Southern Chukchi Sea. As the
pressure gradient tightens, strong downslope winds are expected to
develop over the Kobuk and Noatak Valleys resulting in blowing
snow developing. The ongoing Winter Weather Advisories for zones
207, 208, 212, 213, 215, 216 and 217 look to be in good shape. I
did opt to issue a Blizzard Warning for zone 214. The winds looked
a little bit stronger in that area than the previous forecast
indicated.

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

&&

.FIRE WEATHER...
A low that is currently near Yakutat will move to near Northway
this afternoon. The low will continue to move north along the
Canadian Border into Wednesday. As the low moves north today it
will advect moisture into the Interior. This will help to keep the
minimum RH values above 40% for most of the area into Wednesday.
Significant rain and snow is expected across much of the Interior
late Monday into Wednesday morning.

&&

.HYDROLOGY...
Cooler than normal temperatures over the Eastern Interior will
continue through the middle of the week and will slow the breakup
process. 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 AKZ218-AKZ219-AKZ220-AKZ221.

Winter Storm Warning for AKZ220-AKZ221-AKZ222-AKZ224.

Winter Weather Advisory for AKZ201-AKZ202-AKZ203-AKZ204-AKZ205-
AKZ206-AKZ207-AKZ208-AKZ212-AKZ213-AKZ214-AKZ215-AKZ216-AKZ217-
AKZ226.

Heavy Freezing Spray Warning for PKZ200.

Small Craft Advisory for PKZ200-PKZ210.

Gale Warning for PKZ210-PKZ220-PKZ225.

Brisk Wind Advisory for PKZ220-PKZ225-PKZ230-PKZ235-PKZ240-
PKZ245.
&&

$$

APR 19


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