Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
300 PM akdt Sat may 18 2013
Discussion...
in the upper levels...a deep long wave trough of low pressure
extends from north of wrangle island to the low pressure located
just north of Kodiak Island. This long wave trough and slowly get
pushed eastward as high pressure over the Bering Sea builds over
the area. This will push the precipitation towards Yukon
territory by Sunday afternoon into evening. A surface low
pressure system in the chukotsk peninsula will move towards the
Seward Peninsula and be located north of Cape Lisburne on Sunday
afternoon allowing for tightening of the surface pressure gradient
and increasing winds as well as allowing for upslope flow for
orographic precipitation. Aloft and at the surface...high
pressure will move towards the central and interior Alaska as the
next strong low pressure system begins to move eastward across the
Bering Sea. Except for some minor differences...the models are in
generally good agreement and give way to higher confidence of
precipitation and and cooler temperatures across the West Coast of
Alaska.
North Slope...fairly quiet in the North Slope area at this time.
Early in the morning fog and low stratus caused some low
visibilities of 1 to 2 miles. Expect areas of fog to redevelop
overnight into tomorrow morning once again. Gusty winds along and
north of Barter Island will continue through tomorrow morning as
the surface pressure gradient tightens associated with the low
pressure. However...winds will diminish tomorrow as the surface
pressure sue weakens.
Western Alaska...high pressure currently over the West Coast as
the approaching front associated with surface and upper level low
pressure systems over the Bering Sea approaches on Sunday through
Monday. This system will continue to effect the West Coast
through the remainder of the work week. The southerly to
southwesterly flow will strengthen over the Bering Strait and West
Coast and allow for upslope precipitation over the typical
locations on the Seward Peninsula and northward. Will also see
areas of fog developing along the West Coast. Increasing winds
over the Bering and chukchi seas will allow for brisk wind
advisories to be hosted through Sunday afternoon...but will need
to be extended.
Central and interior...winter weather that returned to the area
and will slowly diminish through tonight for many locations.
Winter weather warnings and advisories over Alaska Range will be
allowed to expire as little additional snow accumulation is
expected. Only exception will be for public zone 220 for the Yukon
uplands areas east of Fort Yukon and public zone 224 that has been
extended through tomorrow morning for areas northwest of Tok.
Additional snow accumulations is anticipated for up to 3 to 4
inches at higher elevations in these two areas. Thus the winter
weather warning and advisory will remain in effect for these two
locations. Otherwise much colder than normal air mass over the
central and interior Alaska today will gradually warm over the
next couple of days. By Wednesday temperatures will be near normal
if not slightly above as high pressure builds into the area. This
will have subsequent effect on the river break up.
&&
Fire weather...
none.
&&
Hydrology...
breakup is in progress on the upper Yukon river and ice will
proceed to move slowly over the next couple of days. A Flood
Watch for ice jam flooding is still in effect along the Yukon
river for Circle City. Also still in effect is the Flood Advisory
for ice jam flooding along the Tanana river in Salcha as an ice
jam continues cause minor flooding that is impacting several
residential yards. More snow melt is expected into early next
week as temperatures warm across the central and eastern Alaska.
A Flood Advisory has been issued through tomorrow afternoon for
areas along the chena river near nordale. There is some minor
flooding that is occurring.
&&
Afg watches/warnings/advisories...
Winter Storm Warning for akz218.
Flood Watch for akz220.
Winter Weather Advisory for akz224.
Brisk Wind Advisory for pkz200-pkz210-pkz220-pkz225-pkz230-
pkz240-pkz245.
&&
$$
Mak may 13
