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Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
220 PM akdt Mon Aug 19 2019

Discussion...

River levels will remain high across much of northern Alaska over
the next few days. Further details on this can be found in the
hydrology section of the discussion.

Cooler weather is expected for the North Slope Tuesday and for
much of northern Alaska through mid-week. Periods of showers are
possible across the North Slope and eastern interior through Wed,
then a generally cool and wet pattern into the weekend.

North Slope and Brooks range:
a strong low aloft over the northwest territories today will move
west to around Demarcation Point by early Tuesday morning, then
drop south over the eastern Brooks range Tuesday night. Wednesday
the low will continue south and then east. This will bring two to
four inches of snow to the eastern Brooks range tonight through
Tuesday night. This same system will bring approximately a
quarter of an inch to a half an inch of rain to areas from Nuiqsut
east during the same time period. Showers will move into the
western North Slope late Wednesday as a low pressure system drops
south into the Beaufort Sea, and these showers will continue off
and on through the end of the week. While not currently expecting
coastal issues with the low dropping south, a long fetch of
northerly winds with no near shore ice present will prompt US to
keep an eye on the coastal situation as this system approaches Thu
and Fri.

Central and eastern interior:
there is still model discrepancy as to how far south the low
center discussed above will move, with the 19/12z NAM/GFS
solutions taking it as far as Fort Yukon before heading east,
where the 19/12z ec solution continues to take it further south
toward Fairbanks before moving it east through Eagle. Model
solutions regarding that are closer to consensus than previous
model runs have been. We trended toward the slightly more
southerly track to put at least a chance of precipitation in the
forecast for the Fairbanks area. All solutions have the low moving
back into the Yukon territory by Wednesday night.

West Coast and western interior:
meanwhile, ridging over the Bering Sea and a trough over the West
Coast will bring rain to the y-k Delta and Seward Peninsula
regions through this afternoon. As the Combination Ridge/trough
move south tonight, the trough will weaken, with rain ceasing over
the Seward Peninsula but continuing over the y-k Delta tonight
before finally continuing south Tuesday morning. Northerly winds
will keep temperatures cool through the remainder of the week. A
low dropping from the Arctic into the Beaufort Sea will increase
northerly winds along the West Coast Thursday and into the
weekend. While not currently expecting issues with this, with the
long fetch over open water, this will be an area to keep an eye on
for coastal issues as we approach Thursday and Friday.



Coastal hazard potential days 3 and 4...
a 500-600 mile fetch of the Chukchi Sea with north-northwest winds blowing
20-25 kt from Thu and Fri into Sat may cause elevated surf at
Shishmaref and the Bering Strait Thu into the weekend. At this
time do not expect high surf as it normally requires winds 25kt or
greater, but there normally is not a 500+ mile fetch length for
several days, so this will need to be watched as we get closer to
Thu, Fri.

&&

Fire weather...
no major fire concerns for northern Alaska for the next few days.
Winds are expected to be fairly light across the West Coast and
interior, with minimum relative humidity values above 30 percent and temperatures
topping out in the 50s to around 60 degrees in most locations. The
driest areas will be portions of the upper Tanana Valley from DOT
Lake to Northway where minimum relative humidity values may drop into the upper
20s on Tuesday.

&&

Hydrology...
High River levels will continue for the next several days across
the Tanana river basin from Shaw creek to the city of Tanana, with
most rivers either cresting today, or starting to drop. The
current Flood Warning was extended for the chena river upstream
of the Moose Creek dam into Tuesday afternoon. Flood advisories
remain for low lying areas along the Tanana river from Shaw creek
to the city of Tanana,for the Nenana river from Anderson to the
city of Nenana, and for low lying areas areas along the chena
river from the Moose Creek dam to Fairbanks. Water levels on the
Salcha river have dropped below flood stage, but water levels will
still remain high over the next few days. Ground water flooding
seeping into basements is possible in all of these areas through
the week.

&&

Afg watches/warnings/advisories...
Small Craft Advisory for pkz210-pkz220-pkz225.

&&

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