Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
434 am akdt Thursday Sep 29 2016
Models...good run to run continuity and initialized well against
the 06z surface analysis. High amplitude ridge will be the main
feature over the next few days for the interior, while the
evolution of the low over Siberia will be the main weather
generator for the West Coast and western Arctic as waves rotate
around the low up the West Coast. Will use a blend of the
solutions for this forecast cycle as they are all handling things
similarly through Sunday. The continue to disagree on just how
warm it will be this weekend, but they all agree it will be warm
so will lean on the conservative side this cycle and go with the
model consensus numbers for temperatures in the short term.
Aloft...at 500 hpa...shortwave will be exiting east this morning
as the ridge continues to build over over Bristol Bay, the
eastern Bering Sea, and Chukchi Sea this morning. The ridge will
continue east to lie from the Shelikof Strait to Point Lay, then
northwest by Thursday evening. By Friday morning the high
amplitude ridge will lie over the central part of the state with
the axis from Kodiak city to Anaktuvuk Pass to Barrow, then
northwest to 76n 180. 564 dam heights extend to north of the
Seward Peninsula this morning and will extend over the Arctic
coast by Friday morning. The ridge will move east a bit to lie
from Prince William Sound to Fairbanks to Prudhoe Bay by Saturday
morning with 564 heights pulling back south of the Brooks range.
The ridge will continue slowly east to lie from Yakutat to
deadhorse and northwest across the Arctic by Sunday morning with
heights over the eastern interior falling to around 550 dam as a
col develops over the area. A strong shortwave will swing around
the siberian low to the eastern Bering Sea by Saturday morning,
then move north up the coast as a 543 dam low develops near Kodiak
Island that will start undercutting the ridge. At 850 hpa...zero
isotherm has moved back south of the Alaska Range this morning but
will move into the lower Yukon Delta later this morning as the
ridge continues to build. By Friday morning it will have surged
north over the Arctic and east to lie from kuparuk to Yakutat, and
will be east of the state late in the morning with above zero
celsius temperatures over the whole forecast area. Temperatures
up to 12 celsius will move over parts of the southern interior
Friday and Saturday, then a slow cooling trend starts Sunday.
Surface...weak surface trough over the eastern interior will
move east and dissipate this morning. Ridge is building over the
interior with 1040 mb high south of the Alaska Range that will
move into the interior later today, then settles in over the upper
Tanana Valley and fortymile country for the weekend. Leeside
troughing will develop north of the Alaska and Brooks ranges
Friday. Gap flow winds will pick up through the ranges on Saturday
with gusts to around 45 mph in the Alaska Range. A weather front
will move to the eastern Bering Sea Saturday and move north up the
coast through Sunday.
Arctic coast and Brooks range...pretty quiet through the weekend.
West winds will turn offshore by Friday morning and this will
usher the marine stratus offshore through at least Saturday. Winds
will be 10 to 20 mph through Friday then diminish a bit to 5 to 15
mph Saturday. A weak disturbance will move east across the area
through Friday bringing a period of rain showers as it moves
through. Temperatures will be on the rise as the surface high
builds north with highs on the coast reaching into the 40s and
inland areas in the 50s. Low will still fall to around freezing
at night with the clearing skies.
West Coast and western interior...still a lot of weather happening
across the area. High surf has settled down, but with winds
remaining relatively strong expect above normal wave action to
continue across the area. A few showers moving across the northern
coastal areas this today will be primarily rain. Warmer
temperatures across the area with the ridge rotating east across
the area today. The next front will spread shower to the coast on
Friday as a front approaches the coast. A low moving north on
Saturday will spread another round of showers from south to north
over the area through Sunday.
Central and eastern interior...ridge building over the area will
bring mostly clear skies and warmer temperatures for the weekend.
Friday morning will be a bit on the cool side in the interior then
warm up nicely for Friday afternoon and Saturday before a slight
cooling trend starting Sunday. A few lingering showers over the
eastern interior this morning will exit the state around noon.
Mostly clear conditions will prevail Thursday night through
Saturday. Southwest winds 5 to 15 mph today will diminish as the
ridge moves over the area today, with light winds Friday and
Saturday in most interior locations. Gap winds will increase to
gusting to 45 mph Saturday through Alaska Range passes as leeside
troughing develops in the interior.
Coastal hazard potential days 3 and 4....moderately strong
southeast winds over the coastal areas through the weekend will
produce some elevated wave action, but no issues are anticipated.
Hydrology...no issues at this time.
Small Craft Advisory for pkz200-pkz220-pkz225-pkz230-pkz240-
Gale Warning for pkz210.
Sdb Sep 16