Scientific Forecaster Discussion
fxak69 pafg 201601
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
701 am akst Wed Nov 20 2019
a strong low over southwest Alaska is causing snow across much of
the interior, with areas of freezing rain in and just north of
the Alaska Range. The snow and freezing rain will taper off over
the eastern interior through tonight, but continue in the western
and central interior. There is a slight chance of freezing rain
in the southeast interior through Fri. Expect another 2-4 inches of snow
through tonight in the western interior and south slope of the
Alaska Range, and 2 inches in the area southeast of DOT Lake late.
NE winds of gale force will continue over the eastern Bering,
with 25-30kt over the West Coast, through tonight and possibly
continue into Fri.
Southerly Chinook winds across the Alaska Range will remain
moderate today, and then increase this evening with gusts 60 to 70 mph
tonight through Thu night.
the long wave pattern consists of a long wave trough over the
Bering Sea with a long wave ridge over the Gulf of Alaska and the the
alcan border. The trough will deepen through Thu as a short wave
trough drops from northwest Alaska southwest into the trough, and several
short waves move from just south of Kamchatka northeast into the
long wave. The trough will then progress east over Alaska by Fri
night as a series of short waves trough move NE across Alaska and
pull the long wave east.
This will keep western Alaska snowy and windy through Fri, while
the eastern interior remain under moderate to strong downslope
conditions, with periods of snow during weak Chinook periods, and
periods of freezing rain near the Alaska Range.
a low pressure trough over the North Slope of Alaska will persist
through Thu. This is causing east winds along the coast along
with snow showers.
A 969 mb low in the southeastern Bering Sea will weaken slowly
through Thu. An occluded front from this low to Old Crow with a
cold front from Old Crow to Denali will move to the yk Delta to
Barter Island by 3pm Wed with a cold front from Old Crow to
Northway, to Nome to Barter Island by 3am Thu, then weakening in
place through Thu night. Snow along with front will taper off
tonight. Expect another 1-2 inch with this front today. Expect 2
inches along the cold front. Expect areas of freezing rain along
and east of the cold front and along the Alaska Range through
This is causing NE gales over the ern Bering with NE winds 25 kt
along the West Coast. The West Coast will see winds decreasing
An Arctic front in Bristol Bay will move over SW interior today,
to Anvik to Denali tonight, and then to Ambler to McGrath Thu.
This will bring another 1-2 inches of snow tot he wrn interior
A second low over the western Aleutians will to Bristol Bay as a
very strong low on Thu, with that low moving over the western
interior of Alaska on Fri. This will bring another round of snow
to SW Alaska Thu night and Fri with another 3-6 inches in the SW
interior and West Coast Thu night and Fri. May need another round
of advisories with this feature.
models initialize well aloft at 00z, and show similar solutions
aloft through 3pm Thu. After that time the NAM is faster than the
GFS and ecmf in bringing north the next strong short wave.
850 mb temps have the 0f isotherm lie from Eagle to Fairbanks to
McGrath and move to Old Crow to Denali by 3am Thu, then moving
over most of the southern interior Thu. This will keep a chance
of freezing rain over the interior south and east of Fairbanks
With precip, then GFS appears to verify better at this time with
location of precip, especially over the southeast interior where
Robertson river has reported 5 inches of snow, and freezing rain,
which are indicated by the GFS and ecmf, but no precip is shown by
the NAM. Prefer the GFS and ecmf today over southeast interior because of
this. Will go with a blend of the GFS and ecmf for precip, since
the NAM is doing poorly now, and also the NAM is too fast after
At the surface at 06z, models verify well on most feature except
the high northwest of Anadyr is about 6 mb stronger than models indicate.
Because of this, there is a stronger gradient and thus stronger
winds over the West Coast and eastern Bering than models would
indicate. For this reason will bump winds speeds up 3-5 kt over
the Bering and West Coast from what models indicate for today and
Coastal hazard potential days 3 and 4...
high surf will continue for the northern shore of St Lawrence
Island now through Friday.
high surf advisory for akz213.
High Wind Warning for akz213.
Winter Storm Warning for akz212-akz215-akz216-akz226.
Winter Weather Advisory for akz211-akz217-akz219-akz220-akz221-
Heavy freezing spray warning for pkz210-pkz220-pkz225-pkz230-
Small Craft Advisory for pkz225-pkz230-pkz235.
Gale Warning for pkz210-pkz220-pkz225.