High Wind in Alaska, August 1, 2017

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
255 PM AKDT Mon Jul 31 2017

.SYNOPSIS...
Aloft...
A long wave ridge over NW Canada and eastern Alaska will weaken
very slowly through Wed then rebuild slowly from Thu into the
weekend. A long wave trough over NE Russia and the Bering Sea
will persist through the weekend. There will be several short wave
troughs moves northeast across northern Alaska in this flow.
This pattern will keep the West Coast and western Interior wet,
the North Slope in changeable weather with a series of rapidly
moving systems, while the Eastern Interior remains relatively warm
and dry and today and Tue and again Thu.

A moderately unstable airmass of the eastern Interior combined
with a weak short wave trough from Bettles to Denali is producing
isolated thunderstorms over the eastern Interior. The short wave
will move east to the Alcan border by midnight and most thunderstorms
should diminish by then.

Several much stronger shorts waves will move northeast over
Northern Alaska through Thu and all will have surface weather
fronts associated with them which will be discussed below.

Surface...
A 998 mb low 200 nm northwest of Point Hope will move to 200 nm
northwest of Barrow as a 996 mb low by 4am Tue, to 300 nm north of
Prudhoe Bay as a 996 mb low by 4pm Tue and then continue moving
northeast. There are south winds 25 mph gusting to 40 mph in the
southeast quadrant of this low that will spread north with the
low. We have strong wind headlines for the West Coast that will
end this evening, and other strong winds in NW Alaska and the
Brooks Range for tonight and Tue.

An occluded front stretching from the low to Point Hope to the
Yukon Delta will move to Prudhoe Bay to Bethel be 4am Tue, to
Inuvik to Old Crow to McGrath by 4pm Tue, to Inuvik to Eagle to
Tok by 4pm Wed, and then dissipating. Significant rain along and
just east of the front will spread east into the central Interior
Tue and into the eastern Interior Wed. Expect 0.5 to 1.0 inch with
this front in the West Coast and Western Interior.

An Arctic Cold front stretching from the low west into Siberia
will move to Point Hope to a 1007 mb Low near Anadyr by 4am Tue.
By 4pm Tue the cold front will move to Nuiqsut to a 1006 mb Low
near the Bering Strait then south. By 4pm Wed the Low will move
to 150 nm north of Prudhoe Bay as a 1006 mb low with the cold
front stretching from Prudhoe to McGrath then continue moving
east and dissipating Wed night. Expect another 0.5 to 1 inch with
this front. Could see totals between now and Wed of 2 to 3 inches
in south Slopes of the West and Central Brooks Range.

A third low will move north into the central Bering Sea Wed and
into the northeast Bering Sea on Thu. This will bring another
batch of rain to the West Coast on Thu along with 25 kt winds.

&&

.DISCUSSION...
Models show similar solutions through Wed with slight differences
showing up on Thu. Differences become much larger over the
weekend over the Arctic Coast so will lean more towards the ECMF
and Ensemble means for the weekend.

Coastal Hazard Potential Days 3 and 4...None.

&&

.FIRE WEATHER...
Isolated thunderstorms across the Eastern Interior through this
evening. Conditions becoming more moist in the eastern Interior
through Wed then drying again Thu into the weekend.

&&

.HYDROLOGY...
Between 0.5 and 1.5 inch of rain expected over the West Coast and
Western Interior through Wed am with 2 to 3 inches in the south
slopes of the Brooks Range in zones 208 217 and western 219. This
will cause high water in Rivers draining in the West Coast of
Alaska this week but no flooding seen at this time. Small streams
may rise to near bank full by Wed.

Flood Advisory continues for the 5.3 mile Tetlin Road. The Tanana
river is high and has spread water into low areas near this this
road. High water on the Tanana is expected to for several more
days so water will remain over this low section of road through
Friday and likely into the weekend.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory for PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-
PKZ230-PKZ235-PKZ240-PKZ245.
&&

JB JUL 17