Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxak69 pafg 242308 cca 

Northern Alaska forecast discussion...corrected
National Weather Service Fairbanks Alaska
308 PM akdt Tue Apr 24 2018

Corrected the surface section


A active pattern across the state today that will most likely
continue through the weekend. The strong low in the Bering Sea
will produce strong gusty winds to many locations in the forecast
area, along with a mix of rain and snow. Winds gusting to 100 mph
may occur on Denali with 70 mph winds expected near Alaska Range
passes and around Delta Junction. Winds gusting around 40 mph can
be expected on most interior summits through Wednesday.
Precipitation type across the area will be extremely difficult to
define as some patches of warmer air aloft move through the area

Models...seem to have a good handle on the movement of the system
as it is moving north to the chuktosk peninsula. Initialized a bit
week with the low center at the surface being 4 to 5 mb lower than
the 24/12z solutions. Solutions are doing well handling the
leeside troughing, and tightening gradients across the state.
Solutions also agree well on the development of a closed surface
low tonight in the Arctic plain that will move to MacKenzie Bay by
Wednesday morning, and the development of a bubble high in the
upper Yukon Flats Wednesday night. The one thing they are, and
always, struggle with is the timing of the individual waves that
will move across the state in the flow. They are struggling with
the longwave trough that will be moving east and northeast across
the state Friday into Saturday. 500 hpa...ridging remains along 77n then southeast
across the Beaufort Sea to the northwest territories, then south
to Skagway and southwest into the northeast Pacific. A broad area
of lower heights around a stacked 502 dam low near St Matthew
cover the western 2/3 of Mainland Alaska, the Chukchi Sea, the
Bering Sea, and south of the Aleutians over the North Pacific. A
strong shortwave moving around the low lies from St Lawrence
Island to the lower Yukon Delta to to the southern tip of Kodiak
Island this afternoon and will move to lie from St Lawrence Island
to Ambler to Eagle by Wednesday morning, and over the Arctic coast
by Wednesday afternoon as the low continues north the chukotsk
peninsula. Ridging over the eastern 1/3 of the state will be
pushed east tonight, but back over the area Wednesday night. A 528
dam closed center develops over MacKenzie Bay Wednesday afternoon
and moves east to Banks Island and merges into broad area of low
pressure over the Canadian archipelago. Another wave moves around
the low to the central Bering Sea Wednesday night then slowly
works its way across the southern half of the state Thursday night
and Friday. At 850 hpa...Chinook is producing a large patch of
above zero temperatures from the Alaska Range north to the Yukon
river today, and will produce a small patch north of the Brooks
range tonight as Chinook winds develop there, though not as
strong. By Wednesday morning most of that warmer air will moderate
back below zero or move off the east and northeast as cooler air
wrapping around the low push over the area with 0 to -10c
temperatures over most of the forecast area through the weekend.
At 925 hpa...tight gradient around the low persists over the area
with southeast to southwest winds 20 to 30 mph, so expect gusts to
40 mph over interior summits through Wednesday night.

Surface...a 969 mb low will move northwest across St Lawrence
Island tonight as it weakens to 976 mb near Gambell Wednesday
morning. Strong pressure gradient across the Alaska Range is
producing winds gusting in excess of 70 mph this afternoon.
Gradient relaxes rapidly over the western Alaska Range this
evening, and over the remainder of the area tonight, but expect
winds to remain gusty to around 45 mph into Thursday morning. The
broad area of low pressure will persist over the western third of
the state and a 994 mb low will develop in the leeside trough
north of the Brooks range tonight, then moving east to makenzie
Bay in the morning. High pressure will build in over the eastern
2/3rds of the state tonight and the leeside trough north of the
Alaska Range will weaken. The low will persist in the vicinity of
the Bering Strait through the week with several waves moving north
over the West Coast and western interior. Leeside troughing will
weaken for periods before the next wave moves through, then
strengthen expect winds to increase for 10 to 12 hours as those
waves move through the area.

North Slope and Brooks range...winds increasing across the area
this afternoon will produce some blowing snow reducing visibility
through the evening, with improving conditions across the area
tonight. Northeast to southeast winds will be increasing to 20 to
35 mph with some gusts to 45 mph locally. Strongest winds will be
west of Point Barrow. Winds will diminish Wednesday morning over
most of the area. Areas of fog developing over the northwest coast
this evening and spreading to the central coast, west of
deadhorse, by Wednesday morning. Snow spreading to the northwest
coast tonight as well with a mix of rain and snow possible in the
Brooks range around Anaktuvuk Pass. Snow spreading to the
remainder of the coast by Wednesday afternoon. Snowfall amounts
will generally be less than 2 inches.

West Coast and western interior...windy, cloudy, rainy, snowy, and
generally just kinda yucky over the area most of the next 24 to
36 hours. Dry slot behind the front will bring some relief to a
few areas, but not for any extended time. Strongest winds this
afternoon and evening diminishing from the south tonight, then
increasing a bit Wednesday as another front spins through the area
during the day. East to southeast winds this evening at 15 to 25
mph with gusts to 50 mph locally. Southeast winds 15 to 25 mph
tomorrow with gusts to 40 mph locally. Expect a mix of rain and
snow depending on the time of day with mainly snow in the
overnight hours, except south or Norton Sound it will be mainly
rain through Wednesday then mix back to snow as colder air wraps
into the area. Snowfall amounts will vary widely, and locally.
The higher elevations in the Nulato Hills, bendeleben mountains,
and Baird Mountains will get 2 to 6 inches of new snow, with
lesser amounts at the lower elevations. Temperatures will be
cooling slowly as cold area wraps around the low.

Eastern and central interior...Chinook winds will keep most of the
Tanana Valley in the dry slot north of the Alaska Range, with
precipitation redeveloping from the Yukon River North. Strong
south winds near the Alaska Range in excess of 70 mph will
diminish tonight, but remain gusty to around 45 mph through
Wednesday night. Winds over the summits will continue to gust to
around 40 mph through Wednesday night as well. Mainly snow north
of the Yukon river, but it may mix with rain during the evening,
and Wednesday afternoon. Snow along the south slopes of the Brooks
range with 2 to 4 inches expected. Special upper air sounding
around Delta Junction this afternoon showed winds from 3000ft to
4000ft from the south at 73 knots.


Coastal hazard potential days 3 and 4...none.


Fire weather...near red flag conditions continue near the Alaska
Range. Strong winds will diminish from 70 mph gusts, but remain
gusty to 45 mph through Wednesday night. Relative humidity values
will fall through Friday, then rebound some on the weekend into
the 30s. High temperatures in the in the 40s through the weekend.
Outside the Tanana Valley minimum relative humidity values above
30 percent and winds in the valleys 5 to 15 mph. There is slight
chance of thunderstorm activity west of Fairbanks Wednesday and


Extended forecast for days 4 to 7...a low pressure system moving
across the being sea will spread a mix of snow and rain to the
West Coast Friday night as it moves to the lower Yukon Delta at
990 mb Saturday morning. This will also bring a chance of showers
to interior locations Saturday and Sunday, but mainly north of
Fairbanks as another fairly strong Chinook winds event across the
Alaska Range brings south winds gusting 40 to 60 mph to the north
slopes and adjacent areas. Expect temperatures near seasonal
normals across the forecast area. In the central interior highs
will be in the upper 40s to lower 50s, with overnight lows around


Afg watches/warnings/advisories...

Wind Advisory for akz217-akz219-akz220-akz221-akz222-akz224-

Winter Weather Advisory for akz218.

High Wind Warning for akz223-akz225-akz226.

Small Craft Advisory for pkz200-pkz210.

Heavy freezing spray warning for pkz210.

Brisk Wind Advisory for pkz215-pkz220-pkz225-pkz230-pkz235-


National Weather Service Glossary of Abbreviations