Gale Warning 52, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
326 PM AKDT Sun May 10 2020

.SYNOPSIS...
Near record heat over Interior Alaska will persist into Mon, then
cool Tue as a front moves north into the Interior and West Coast.
This is causing rapid snow melt from the Brooks Range south, along
with rising water levels on rivers south of the Brooks Range and
numerous flood issues. See Hydro section for details. Cooling
across the Eastern Interior Tue through Wed will cause a reduction
in snow melt mid-week, but temps could rise above normal again by
the weekend.

Aloft...
A long wave ridge over Western Canada and Northern Alaska will
retrograde over mainland Alaska by Wed, and then weaken slowly. A
long wave trough over the Bering and Gulf of Alaska will persist
through Wed and then retrograde.

A short wave trough over the Beaufort Sea will move south over the
Eastern Arctic Coast on Mon and then dissipate Tue. This will
bring stratus and fog to the Arctic Coast from Utqiagvik east
tonight through Tue.

A weak short wave trough over the YK Delta will move to the Bering
Strait tonight then dissipate. There are isolated to scattered
showers with this.

A third and stronger short wave trough in the Gulf of Alaska will
move to the Western Alaska Range by 4pm Mon, to Bethel to Denali
by 4am Tue, and to the YK Delta to Ambler by 4pm Tue, then west to
the Dateline by 4am Wed. A surface trough and band of showers
will develop along this trough Mon and spread NW over Alaska with
the trough Mon night and Tue.

Surface...
An Arctic front along the Arctic Coast of Alaska will move along
the Brooks Range tonight and then persist into Tue. High pressure
north of the Arctic Coast of Alaska will build through Tue and
then persist into Wed. This will bring stratus and fog to the
Arctic Coast from Utqiagvik east tonight, then spread it south to
the Brooks Range Mon and persisting into Wed.

An occluded front over the NE Bering Sea will weaken tonight. This
is causing rain and SE winds 20-30 kt along the front over zones
213 and 214 which will diminish tonight.

A thermal low pressure trough just north of the Alaska Range will
persist through 4pm Mon, then move north on Tue night. This is
causing very warm conditions across the Interior now that will
persist into Mon, with highs in the mid 60s to near 80, warmest
south and east of Fairbanks. This is also causing S winds 15g30
mph through Alaska Range Passes now through this evening, and
again Mon PM. This is causing Ref Flag conditions over zones 222
223 and 226 now through 10 PM tonight, and will cause similar
conditions again Mon in those same areas.

A surface low developing near Mcgrath on Mon under the third short
wave trough mentioned above, will move to Norton Sound as a 1004
MB low by 4am Tue with a trough  from Nome to Tanana to Northway.
By 4pm Tue there will be a 1004 mb low near St Lawrence Island
with a trough from the Bering Strait to Ambler to Northway.
By 4am Wed there will be a 1007 mb Low near Gambell which will
move west on Wed. Expect showers likely along this low center,
with scattered showers along the trough over the Western
Interior and West Coast, with just isolated showers over the
Central and Eastern Interior. Expect winds to increase to 15g25
mph along this front and trough, but RHs will rise with the
trough as well on Mon night.

A low developing in the northern Gulf of Alaska Coast Tue into Wed
will pull cooler air south across the Eastern Interior Tue night
and Wed and turn winds north 15-20 mph.

&&

.DISCUSSION...
At 12Z, GFS and NAM verify 10-20 meters to low on the H500 high
located over NW Canada. The ECMF and Canadian verify better on
this feature. Expect that with ridge being a bit higher heights
than models indicate, that conditions under ridge will be a bit
warmer, and that the ridge will hold in place a bit longer than
models indicate. For this reason favor the EMCF and Canadian
model solutions through Wed, which maintains the ridge a bit more
strongly than the GFS and NAM. After that time there is still
disagreement about long wave retrogression over mainland Alaska,
and at this time looks like on agreement is on cooling towards
normal by the end of the week.

With Precip, the ECMF keeps the precip on Mon night and Tue
further West than GFS and NAM, which makes sense due to its
stronger ridge aloft. The ECMF also moves that precip of to the
West more slowly on Wed due to weaker flow aloft. Precip the ECMF
precip due its showing the stronger and more persistent ridge
aloft over the Interior.

At the surface models verified well at 15Z and show similar
solutions through Tue, with a the ECMF slightly slower moving
systems NW on Tue night and Wed. Favor the ECMF for Tue night and
Wed due to the better solutions aloft.

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

&&

.FIRE WEATHER...
A thermal low pressure trough just north of the Alaska Range will
persist through 4pm Mon, then move north on Tue night. This is
causing very warm and dry conditions across the Interior now that
will persist into Mon, with highs in the mid 60s to near 80, and
RHs 17-30%, warmest and driest south and east of Fairbanks. This
is also causing S winds 15g30 mph through Alaska Range Passes now
through this evening with similar conditions again in those areas
on Mon PM. This is causing Ref Flag conditions over zones 222 223
and 226 now through 10 PM tonight, and will cause similar
conditions again Mon in those same areas.

&&

.HYDROLOGY...
Very warm temperatures across the Interior are causing rapid snow
melt now that will last Mon from the Brooks Range south, then
cool closer to normal on Tue and Wed. River levels will rise
through Tue or Wed most areas, and remaining high through the
week. Most Eastern Interior Rivers are broken up, but break up in
the Northern and Western Interior will proceed rapidly in rivers
that remain ice covered.

Flooding is likely on the Chena River upstream of Moose Creek
Dam, and on the Salcha River. Flooding is occuring on the
Dietrich River and has closed the Dalton Highway at Milepost 206.
Flooding is possible on the Chatanika, Little Chena, Goodpaster,
and Fortymile Rivers. The Chena River downstream of Moose Creek
Dam will start to rise to a high level today, and remain high for
most of the upcoming week. Low areas along the Chena River, such
as the Steamboat Landing Subdivision, and bike paths under bridges
in Fairbanks have water flowing over them that will persist
through Wednesday.

On the Koyukuk River, the ice jammed at Bettles on Saturday but
no flooding occurred. The ice moved downstream of Bettles by
Sunday morning and the water level dropped. Ice jammed at
Allakaket Saturday night, and the water rose to several feet below
the bank. The the ice jam broke up at Allakaket and moved
downstream late Sunday morning, and the water level there dropped.
It is expected that the ice and high water will move downstream
to Hughes over the several days, and people in Hughes should be
alert for possible ice jams and rising water though Tuesday.

On the Kobuk River, ice remains in place in many locations. Ice
is expected to break up over the next week along the Kobuk River
along with rising water levels. People along the Kobuk River
should be alert for possible ice jams later this week.

The Buckland River had an ice jam near the village of Buckland on
Saturday. The river came out of its banks early Sunday morning
and caused minor flooding in Buckland. The jam broke Sunday
morning and moved downstream, and the water level dropped back
below bankfull. Due to the lack of ice upstream of the village of
Buckland, the threat of flooding there is over.

The Yukon River has broken up in most areas upstream of Galena,
but some areas of ice are still remaining between the Yukon River
Bridge and Tanana. Ice remains in place downstream of Kaltag.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning for AKZ222-AKZ223-AKZ226.

Flood Watch for the Chatanika, Goodpaster, Fortymile rivers
in zones AKZ222-AKZ223-AKZ224.

Flood Advisory for the Dietrich River

Flood Advisory for the Salcha River

Flood Advisory for the Chena River Upstream of Nordale Road.

Brisk Wind Advisory for PKZ225-PKZ230.

&&

JB MAY 20