Scientific Forecaster Discussion
fxak69 pafg 222143
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
143 PM akdt Thu Aug 22 2019
Synopsis...a front extending from northwest of Kaktovik extends
southwest through the Brooks range and into the central interior.
This will bring cloudiness and some showers to those areas
through this evening, and the Brooks range will likely see snow
above the 2000 foot level or so. This will push east into Canada
overnight with another taking its place Friday night. All this is
part of a broad cyclonic circulation around a low pressure area in
the northern Arctic. Also associated with this is a deep fetch of
northerly winds, the main impacts from these being 20 to 25 kt
winds along the Northwest Arctic and west coasts with cooler
temperatures behind it, and elevated surf conditions from
approximately Point Barrow to Shishmaref this evening through
22/12z model solutions continue to show good agreement over the
larger scale into the weekend, but start to diverge toward the end
of the weekend, especially in regards to how quickly the
lows/shortwaves rotate around the parent north Arctic low,
especially with the multiple shortwaves moving across the North
Aloft...a 521 dam low near the North Pole is spinning multiple
shortwaves out from its center. One shortwave extends generally
southeast into the northwest territories of Canada, one extends
south into the eastern North Slope, Brooks range, and interior.
Farther west, this is the system bringing a long fetch of
northerly winds into the western Arctic and west coasts, with a
high pressure ridge currently over eastern Russia. A 550 dam area
of low pressure south of St Lawrence extends a trough into the yk
Delta this afternoon.
The low will shift west Friday, strengthening to a 516 dam low,
with shortwaves roughly in the same areas as today. The ridge over
Russia will expand eastward to impact portions of the West Coast,
for the most part keeping precipitation out of the area, at least
in the Seward Peninsula. Saturday, the low drops south and east,
pushing the main shortwave east over far eastern interior and the
Yukon territory, and dropping another shortwave over the West
Coast. Stronger winds can be expected Friday and Saturday with the
tighter pressure gradient anticipated over the North Slope and
western Arctic coast. The low near St Lawrence Island will shift
south to St Paul island by Fri afternoon as a 548 dam low, with a
trough extending through Bethel and into the Alaska Range. This
feature will continue southeast and be over the Aleutians as a 552
dam low by Saturday night.
Arctic coast and Brooks range...
a front dropping south and east will bring showers and increasing
winds from Point Hope to utqiagvik this evening. Overnight and
Friday, this front will push further southeast, with showers from
Nuiqsut east and more snow moving into the Brooks range. As the
low pressure system moves closer to the coast, expect gusty west
winds of 20 to 25 mph from deadhorse east and northwest winds of
15 to 20 mph across the higher elevations of the eastern Brooks
range Friday. Friday night and Saturday, the low will be not far
offshore north of Demarcation Point, with west to southwest winds
of 20 to 30 mph across the eastern portions of the North Slope.
Wave heights of up to 8 feet are expected off shore of Kaktovik at
this point, but impacts should be limited as the winds will be
generally southwesterly, so waves should break away from shore.
Gusty west winds return Sunday, as another shortwave makes its way
across the North Slope. Expect another day of cooler temperatures
Friday before a warmup back to the mid to upper 40s on Saturday
and Sunday. Temperatures will fall again next week, however.
West Coast and western interior...
generally good weather is expected the next few days. Expect a few
showers tonight and Friday over the Seward Peninsula associated
with a weak shortwave, but otherwise weak ridging will keep the
majority of the region dry into the weekend. The main concern will
be the northerly winds increasing tonight through Saturday. Expect
20 to 30 mph winds through this period. Elevated surf is expected
along north facing coastlines from Point Barrow west and down to
Shishmaref, as well as on St Lawrence Island. Temperatures will be
a couple of degrees cooler Friday and Saturday.
Central and eastern interior...
expect light winds and periods of showers through the weekend and
into early next week as weak surface low pressure sits over the
eastern interior. With less than a quarter of an inch of rain
expected over 2 to 3 days, this will not impact the rivers much at
all. Temperatures will remain pretty steady through the weekend,
with a slight cooling trend early next week.
Coastal hazard potential days 3 and 4...none. Expect elevates seas
off the Arctic coast Sunday, but highest wave action is expected
to remain offshore.
have very little concerns regarding fire weather. Relative
humidity values will remain near or above 40 percent across the
state. Winds will be pretty light with no thunderstorm activity
river levels have been falling and will continue to fall for the
next few days, although ground water remains high. Some ponding in
low lying areas along rivers and streams is still possible, but
will be less likely as river levels continue to fall. Any
additional rainfall over the next few days will not significantly
affect water levels. Continue to use caution around waterways as
trees and other debris will be making its way downstream.
Small Craft Advisory for pkz210-pkz220.