Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
227 am akdt Monday Oct 20 2014
Models...have been handling features well over the past week or
so in the short term. They do have issues as you get out into the
Middle Range as they diverge greatly by Sunday. Handling of the low
on Thursday is reasonable so will use a blend nudged to the
current grids through the week.
Aloft...at 500 mb...trough remains over southwest Mainland and
pattern over the state will continue to transition as the 516 dam
closed low moves south then east and merges with a 514 dam low
south of the Gulf of Alaska. Weak ridging will develop west to
east over the interior beginning Tuesday. Ridge lying north to
south over the Kamchatka peninsula will move east over the central
Bering Sea by Wednesday morning...and over the West Coast by
Thursday morning. A 535 dam high over the high Arctic will weaken
and dissipate by Wednesday morning. A trough extending from a low
in high in the Canadian Arctic will back over the Arctic coast
with a 527 dam low developing over Barrow by Wednesday morning. At
850 hpa...temperatures steady next 24 hours...then a slow cooling
trend through the remainder of the week.
Surface...a 1040mb high in the high Arctic remains quasi
stationary through the week as it weakens to 1035mb. 980mb low in
the northern Gulf will move over the southwest Mainland then be
absorbed by a 982mb that is 400nm south of Kodiak this morning and
will be 200nm southwest of Sitka by Tuesday afternoon...then
wobble west to 300nm south of Prince William Sound by Wednesday
morning. A ridge of high pressure over the western Bering Sea
will move to the central Bering Sea by Wednesday morning...then
over the West Coast by Thursday morning. A 1000mb low will develop
over the Kamchatka peninsula Tuesday evening and move to the Gulf
of Anadyr by Thursday morning. Cyclonic flow will continue over
Mainland Alaska with strong easterly flow over th Arctic coast and
coastal waters. The gradient over the interior will weaken
Wednesday...with the strong gradient hanging on over the Arctic
Arctic coast and Brooks range...strong easterly flow will continue
and may increase slightly today. Strongest gusts will be around 50
miles per hour. Winds on the coast diminishing Thursday morning...but hanging
on into Friday over the coastal waters. No change in the
flurries...snow showers...occasional freezing drizzle...patchy
fog...local blowing snow...low stratus ceilings. Temperatures will
remain pretty steady...but fall a degree of two through the week.
No significant snow or ice accumulation is expected.
West Coast and western interior...offshore flow over most of the
West Coast will continue with northerly winds in the Bering Strait
of 20 to 30 miles per hour. Inland winds northeast to east at 5 to 15 miles per hour
with some gusts over the hills to 25 miles per hour. Scattered snow showers
will continue south of the Seward Peninsula and over St Lawrence
Island with a few flurries in the middle Yukon valley possible.
Areas in the lower Yukon Delta could see around one inch of
snow...otherwise no significant snow accumulation is expected.
Temperatures over the coast steady with interior areas seeing
temperatures fall a couple degrees through middle week.
Central and eastern interior...mostly cloudy conditions persist
across the area today with some scattered snow showers along the
alcan border. A shortwave will move north to south across the
area beginning Tuesday morning producing flurries for most areas
by days end. No significant accumulation is expected.
Northeasterly winds persisting across the area through Wednesday
with winds diminishing over the hills Wednesday afternoon. Winds
today will be strongest on hills and down valley with gusts to
around 30 miles per hour. Temperatures steady today into Tuesday then a slow
cool down through Friday.
Coastal hazard potential days 3 and 4...a 994mb low will move to
the Gulf of Anadyr early Thursday morning with frontal system
reaching the coast Thursday afternoon. Models currently have west
to southwest winds persisting into Saturday. This could push
water into Norton Sound for an extended period of time.
Heavy freezing spray warning for pkz220-pkz225-pkz230-pkz235-
Gale Warning for pkz225-pkz230-pkz235-pkz240-pkz245.
Small Craft Advisory for pkz210-pkz220.
Sdb Oct 14