Area Forecast Discussion
Issued by NWS Fairbanks, AK

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902
FXAK69 PAFG 270003
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
403 PM AKDT TUE JUL 26 2016

.DISCUSSION...

The 26/12Z deterministic models are in good agreement through
Friday,  then some spread among the ECWMF, GFS, and CanadianNH
thereafter in regards to the cold, Arctic upper level trough that
is advertised to dig southward over Northern Alaska. The 26/12Z
ECMWF is a bit more progressive with moving the upper level trough
east and a bit more aggressive bringing colder H850 temperatures
south and over the West Coast. The 26/12Z CanadianNH and GFS lag
behind the operational ECWMF solution, keeping the trough axis
over the West Coast this weekend.

Several shortwaves are progged to move east over the North Slope
through the rest of the week. The first will arrive over the
Chukchi Sea Coast tonight and quickly weaken as it moves east.
Wednesday night into Thursday morning, a second and stronger short
wave will round the base of a digging trough from the high Arctic
and will move onshore over the northern Chukchi Sea and Western
Arctic coasts then quickly move east over the North Slope. The
aforementioned Arctic trough will swing southeast and over the
west coast Saturday night into Sunday morning, then proceeded
inland Sunday. A vertically stacked low will move out into the
Gulf of Alaska from the Alaska Peninsula and Kodiak tonight with a
shortwave moving north and over the Alaska Range and the southern
Interior late tonight into Wednesday.

At the surface, a weak pressure pattern will remain over Interior
Alaska through Thursday with westerly to southwesterly flow
developing on Friday. Several weak surface lows will form over the
Chukotsk Peninsula and then move east over the Chukchi Sea and
Arctic Coast through Thursday.

Eastern and Central Interior: One more warm day in the 70s across
the area before a transition to a wetter, cooler, unsettled
pattern for the latter half of the week and into the weekend.
Isolated thunderstorms are expected over much of the Southern
Interior this evening, then over parts of the southwestern,
central, and northern interior Wednesday afternoon and evening. An
increase in convective activity is expected as the aforementioned
upper level trough enhances thunderstorm activity. More widespreadshowers
are likely Wednesday and Thursday.

Western Alaska: Latest model guidance suggest that Western Alaska
will be in a cooler and wetter pattern developing Wednesday as the
aforementioned starts to dig south over Northern Alaska. There is
the potential for significant rainfall over parts of the west
coast and western interior Wednesday afternoon through the
weekend. Some details need to be ironed out in the deterministic
models as there is some differences, especially after late
Thursday in regards to the progression of the upper level trough
advertised to move south. This will have to be monitored over the
next several days. Meanwhile, areas of fog will persist over the
Bering Sea and Chukchi Seas tonight.

North Slope and Arctic Coast: Increasing clouds along the western
Arctic Coast tonight and eastern Arctic Coast Wednesday as the
first in a series of several shortwaves approaches the area. Fog
will also develop and spread east along the Arctic Coast over the
next couple of days. Rain is likely along the western Arctic Coast
Wednesday and Wednesday night and will spread east along the
Arctic Coast Wednesday night. Chances for rain will continue
across the North Slope through the rest of the week.

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

&&

.FIRE WEATHER...
Minimum RH values will increase over the Northern Interior
Wednesday as all other areas remain above 40 percent. By Thursday,
minimum RH values are expected to be above 40 percent over all of
Northern Alaska. Winds should remain light, except for possible
gap winds in the Alaska Range passes through the rest of the week.
Isolated thunderstorms are expected over much of the Interior in
the afternoon and evening hours through Thursday.

&&

.HYDROLOGY...
Rivers and streams in the Chena and Tanana basins will continue to
fall slowly over the next few days. Minor flooding ongoing
upstream of Nordale Road including the Steamboat Landing
subdivision with the flow through Fairbanks still being regulated
to less than 12,000 cfs at Moose Creek dam. Also, high ground
water levels along the Tanana River will fall slowly over the next
several days. Some streams in the eastern Alaska Range may still
be running at elevated levels as a result of the recent rainfall.
There is a possibility of heavy rain in western Alaska Range from
Denali southwest on the weekend that will need to be monitored but
is still very uncertain at this point in time.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Flood Advisory for the Chena River upstream from Nordale Road.


&&

$$
LTH
EXTENDED RF JUL 16



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