Flash Flood Warning 1, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
333 PM AKDT Fri Jun 23 2017

.DISCUSSION...
Overall, the models are in good agreement out through the weekend. The
main forecast challenges in the short term will be strong winds
along the northwest Arctic Coast and convection in the Interior.

Aloft, at 500 mb, the current pattern has a ridge centered over
the Yukon Territory extending into eastern Alaska with trough
situated over the western half of the state.

At the surface, a 985 mb low currently sits near 83N 178E with a
trough extending to Wrangel Island. A surface ridge stretches
from the Chukotsk Peninsula south into Bristol Bay. This ridge
combined with the aforementioned low will will create a tight
pressure gradient across the Chukchi Sea Coast on Saturday. The
pressure gradient will relax on Sunday with the low moving to the
north and surface high building northward across the state. A weak
thermal trough stretches from Eagle to Mcgrath. The thermal
trough will move to the east on Saturday to stretch from Eagle to
near Denali Park withe upper ridge building in out west.

North Slope and Brooks Range: Gusty winds are expected to develop
tonight along the Chukchi Sea Coast. The strongest winds will
likely stay offshore; however, wind gusts up to around 50 mph are
possible near Point Lay on Saturday. With the strong winds
elevated surf is expected to develop tonight along the Chukchi Sea
Coast and will continue into Sunday morning. The strong winds may
cause previously shorefast ice to break off causing the ice to
quickly move to the northeast. At this point the ice movement does
not look to cause any major issues to land; however it is not out
of the question that some ice could move up on shore . Elsewhere
along the Actic coast, some isolated showers and thunderstorms east
of Barrow this evening. A weather front with bring showers to
areas from Barrow west Sunday evening.

Central and Eastern Interior: Isolated thunderstorms along the
thermal trough today and Saturday. This evening the isolated
thunderstorms will generally be limited to areas south and east
of a line from Chalkyitsik to Circle to Fairbanks to McGrath with
scattered thunderstorms east Chicken. Some of the thunderstorms
tonight may produce small hail, brief gusty winds and heavy
downpours. On Saturday isolated thunderstorms will be limited to
areas south and east of a line from Circle to Fairbanks to
McGrath. On Sunday with the ridge building in there will be a
general clearing trend and any isolated thunderstorms will
generally be limited to areas south and east of a line from Eagle
to Tok. Current guidance shows an increase of several degrees
between Sunday and Monday with the ridge building in and clearing
skies combined with warmer air moving in aloft.

West Coast and Western Interior: Gusty winds expected tonight
into Saturday for areas north of Cape Krusenstern with elevated
surf. Some isolated thunderstorms today southeast of a line from
Lake Minchumina to Marshall Isolated thunderstorms tomorrow
will generally be southeast of a line from Lake Minchumina to
McGrath. Thunderstorm and shower activity will diminish for Sunday
with the ridge building in.

Coastal Hazard Potential Days 3 and 4...but see North Slope
section above for more immediate concerns. .

&&

.FIRE WEATHER...
A Red Flag Warning has been issued until 10 PM today for
areas east of Chicken for abundant lightning combined with dry
fuel conditions. This evening the isolated thunderstorms will
generally be limited to areas south and east of a line from
Chalkyitsik to Circle to Fairbanks to McGrath to Marshall with
scattered thunderstorms east of Chicken. On Saturday isolated
thunderstorms will be limited to areas south and east of a line
from Circle to Fairbanks to McGrath. On Sunday with the ridge
building in there will be a general clearing trend and any
isolated thunderstorms will generally be limited to areas south
and east of a line from Eagle to Tok.

Relative humidity values in the low 20 percent range are expected
this evening for parts of the Yukon Flats into the Southeastern
Brooks Range. Elsewhere, relative humidity values will remain
above 30 percent for remainder of the forecast areas. In the
areas with relative humidity values below 25 percent temperates
will be in the low to mid 70s. With sustained winds remaining
under 15 mph there are not any Red Flag concerns in these areas
at this time.

&&

.HYDROLOGY...
No concerns at this time.&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning for AKZ224.

Small Craft Advisory for PKZ220.

Gale Warning for PKZ225-PKZ230-PKZ235.
&&

JUN 17

Special Weather Statement
National Weather Service Fairbanks AK
239 PM AKDT Fri Jun 23 2017

AKZ201-202-242245-
Western Arctic Coast-Northern Arctic Coast-
Including Wainwright, Atqasuk, Point Lay, Cape Lisburne, Barrow,
Alaktak, Pitt Point, and Nulavik
239 PM AKDT Fri Jun 23 2017

...Strong Winds and Elevated Surf Saturday...

Elevated surf is expected to develop tonight along the Chukchi
Sea Coast and will continue into Sunday morning. Strong
southwesterly winds will develop tonight continuing into early
Sunday morning. The strongest winds are expected to remain
offshore; however, gusts of 45 mph are possible along the coast.
The strong winds may cause previously shorefast ice to break off
causing the ice to quickly move to the northeast. At this point
the ice movement does not look to cause any major issues to land;
however, it is not out of the question that some ice may wash up
on the shore. Individuals with interests along the coast should
prepare for the potentially elevated surf conditions this weekend
by moving property away from the coastline. Boaters in the area
should be aware of hazardous boating conditions.

Special Weather Statement
National Weather Service Fairbanks AK
548 PM AKDT Fri Jun 23 2017

AKZ220-222>226-240800-
Yukon Flats and Surrounding Uplands-Middle Tanana Valley-
Deltana and Tanana Flats-
Upper Tanana Valley and the Fortymile Country-Denali-
Eastern Alaska Range-
Including Fort Yukon, Venetie, Central, Circle, Stevens Village,
Beaver, Chalkyitsik, Birch Creek, Circle Hot Springs,
Eagle Summit, Twelvemile Summit, Fairbanks, Fort Wainwright,
Eielson AFB, Ester, North Pole, Moose Creek, Two Rivers, Fox,
Chatanika, Chena Hot Springs, Sourdough Camp, Salcha,
Delta Junction, Fort Greely, Harding/Birch Lake, Dry Creek,
Dot Lake, Healy Lake, Tok, Tanacross, Eagle, Tetlin, Northway,
Alcan, Chicken, Boundary, Healy, Denali National Park,
Carlo Creek, Kantishna, Mentasta Lake, Black Rapids,
Donnelly Dome, Trims DOT Camp, Eagle Trail, and Mineral Lake
548 PM AKDT Fri Jun 23 2017

...Strong Thunderstorms with Hail, Strong Winds and Brief Heavy
Rain Today in the southern Interior...

Thunderstorms across the southern Interior of Alaska are
producing hail, winds gusting to 30 mph, and brief heavy rain.
Hail may be up to one half inch in size, and rain fall amounts
may be up to three quarters of an inch. The thunderstorms are
isolated over most of the southern Interior including Fairbanks,
but are scattered in the Upper Tanana and Fortymile Country near
the Canadian Border which includes Tok, Northway, Chicken and
Eagle. The thunderstorms are short lived, but will continue to
develop over the southern Interior through midnight, and may last
past midnight near the Canadian Border.

The town of Eagle had a thunderstorm from 3 to 4 pm today with
hail lasting for over one half hour. By the time the storm was
over, an inch or more of hail was covering the ground. Some of
the hail was one half inch in diameter. Eagle also had winds
gusting to 25 mph, and had over sixty-six hundredths of an inch
(0.66) of rain from that storm. A long time weather observer in
Eagle reports that they have not had a storm like this since the
1970s.

Another round of significant thunderstorms is expected Saturday
in the Fortymile Country and Upper Tanana Valley including Tok,
Northway, Chicken and Eagle.

JB