Scientific Forecaster Discussion
fxak69 pafg 201557
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
657 am akst Tue Feb 20 2018
the long wave pattern consists of a high amplitude ridge over the
eastern Pacific and Mainland Alaska, and a deep trough over the
Bering and northwest Pacific. A series of strong short wave troughs will
make their way northeast across the Bering Sea and Alaska this
week, causing the long wave ridge to weaken and the flow pattern
to become more zonal. This will cause northern Alaska to remain
warmer, wetter and windier than normal through at least Friday.
a 970 mb low near Anadyr will cape navarin will move to 200 nm
northwest of Cape Lisburne as a 989 mb low by 3pm Tue, and to 300
nm north of Prudhoe Bay as a 1000 mb low by 3pm Wed. An occluded
front associated with this low lies from the low to wrangel island
to Barrow to Denali, and will move to Barter Island to Northway
by 3pm Tue, then move east of the alcan border. Snow along the
front will move east with the front today, with snow ending west
of the front. Expect 1 to 2 inches of snow with the front. Also
expect west winds 15 gusting to 25 mph with the front over the
interior, and winds of 25g40 mph with the front over the North
The poison tail portion of the front which wraps around the low
has storm force SW winds in the southeast quadrant of the low.
This is causing gusts to 90 mph over St Lawrence Island, the
Bering Strait, and from Kivalina to Cape Lisburne. These winds
will continue through this afternoon and then decrease tonight.
These strong SW winds blowing over a 1000 mile fetch of the Bering
Sea are likely causing coastal flooding at Gambell now, and
possibly piling ice on the coast of Little Diomede and at Wales.
This has caused sea levels to rise to 5 feet above normal at Nome
and pushed water upriver over the ice on the Snake River. Similar
conditions are expected along much of the coast from the Yukon
Delta to Nome. Sea levels there will peak out this morning.
From the Bering Strait to Point Hope, sea level rises of 3-4 feet
above normal are expected. This could cause minor flooding of the
lagoons along the coast at Shishmaref, Deering, Kotzebue, and
Kivalina. Ice appears to be broken up and thin enough that it
should only push onto the beach and then pile up there.
Another low south of Shemya will move to the central Bering Sea
this afternoon, to near provideniya as a 1006 mb low by 3pm Wed,
and over the interior of Alaska Thu. This will bring another round
of snow, blowing snow, and possible freezing rain to the West
Coast and interior from Wed into Thu. The eastern interior near
Fairbanks could see significant snow and winds from Wed night
through Thu night.
models all 4 mb too weak on high pressure over the Copper River
basin and alcan border at 06z. Otherwise models initialize well.
Models show similar solutions through 3pm Wed. After that time
the NAM and GFS show similar solutions through Thu, while the
ecmf is faster on Thu moving a low east across the interior. We
favor the slightly slower GFS/NAM solutions for Wed night and
Coastal hazard potential days 3 and 4...none.
coastal Flood Warning for akz213.
Coastal flood advisory for akz207-akz209-akz210-akz211-akz212-
Winter Storm Warning for akz201-akz208-akz210-akz211-akz217.
Blizzard Warning for akz207-akz209-akz213.
Winter Weather Advisory for akz202-akz203-akz204-akz206-akz214-
Gale Warning for pkz200-pkz215-pkz230.
Storm Warning for pkz210-pkz220-pkz225.
Brisk Wind Advisory for pkz235-pkz240-pkz245.