Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
402 PM akdt Friday Apr 17 2015
Aloft...models in good agreement at least through 60 hours then
start to diverge on placement of upper level lows over the West
Coast. Model consensus does show ridging continuing over the
interior and Canada with a trough over the West Coast. In the
short term an upper low centered near 49n/176w will deepen and
move to the Alaska Peninsula by late Sat night...then weaken into
a broad low center over the southern Bering Sea by Sun afternoon.
Upper level ridging will persist over the eastern interior/Canada
through the weekend.
a 980 mb low pressure system S of the Aleutian Islands will move
northeast to Bristol Bay by Sat night. High pressure in eastern
Siberia will persist through tonight and then lift north. The
aforementioned low will move to near Nunivak Island by sun then
track towards the Bering Strait sun evening.
Over the West Coast and western interior...multiple precipitation
types are expected with the deepening low pressure trough
swinging northwestward to the West Coast. The precipitation
is expected to begin as snow late tonight over zones 214-215-
southern 212. The band of precipitation will expand northward
and westward Sat. By Sat afternoon...the precipitation will
change to rain or mixed rain and snow in zones 214-215 as
temperatures warm. By late Sat night...the transition to rain
or mixed rain and snow is expected to spread as far west as the
Bering Strait coast and to some areas north of the Seward
Peninsula by late Sat night. Snow and blowing snow will likely
reduce visibility over portions of western zone 214 overnight
tonight into Saturday morning. A Winter Weather Advisory has been
issued for zone 214. An advisory might be needed for zone 213 as
well as snow and blowing snow will develop late Sat afternoon and
Sat evening on the Bering Strait coast and Saint Lawrence Island.
Arctic coast...light east to northeast winds will continue
today...with areas of low stratus...flurries and fog. Pressure
gradient tightening along the North Slope Saturday evening into
Sunday afternoon. East winds will gradually increase tonight into
the weekend... with 25-35 miles per hour winds expected over most areas by
sun. Local blowing snow could reduce visibilities around 1 mile at
times. Not looking for any falling precipitation just wind.
Interior...moderately strong south to southeast flow aloft is
expected across the interior Sat through sun as a strong ridge
builds to the north and East. Ridge axis late Sat night will
extend from wrangel island to Barrow then southeastward across
northeast Alaska and into the Yukon territory and British
Columbia. By late Sun night...the ridge axis will shift slightly
to the north and east. With the southerly flow...temperatures
aloft will warm noticeably over the northern Alaska Mainland. 850
mb temperatures will rise to zero degrees celsius...with some
interior areas as warm as +5 degrees celsius by Sat evening. Interior
temperatures over the weekend into Monday will be warm...with
highs approaching 50 in the northern interior. Some southern
interior areas will see highs in the middle to upper 50s.
We also have wind advisories for the Alaska Range over the
weekend. Looking for south winds gusting to 55 miles per hour near Delta
Junction and 65 miles per hour in the passes of the Alaska Range through
minimum relative humidity could approach or go below 30 percent in windy
areas along the Alaska Range. Current afs fuel conditions
are green in zone 226 and Orange (consult) in zone 225. Looking
further down the Road late next week strong ridge could build
back with higher heights and drying conditions.
Wind Advisory for akz223-akz225-akz226-akz227.
Winter Weather Advisory for akz214.
Brisk Wind Advisory for pkz200-pkz210-pkz220-pkz225-pkz230-