FXAK69 PAFG 191940

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
1140 AM AKDT Thu Jul 19 2018

Warming and drying over most of northern Alaska through the
Weekend and early next week.

The wet and windy weather of the last few days over northern
Alaska, especially the Brooks Range and the North Slope and the
cool and unsettled weather over the interior will transition to a
much warmer and dryer pattern through the weekend as the strong
low north currently located 400 nm north of Demarcation Point
moves north and east Friday and a strong ridge aloft and at the
surface builds north out of the Gulf of Alaska over mainland

Aloft a 500 mb a 510 DAM low 400 NM north of Demarcation Point
will continue to move north and east as a 580 DAM ridge builds
north out of the Gulf of Alaska over mainland Alaska through
Monday. The ridge builds north over the West Coast and western
Interior Friday and Saturday and then builds east over the central
interior and eastern interior Sunday and Monday. As the ridge
builds over the eastern interior expect southerly winds aloft to
generate a mountain wave along the northern slope of the Alaska
Range and combined with surface gradient building from the south
will produce a chinook that will enhance the warming and drying
over central and eastern interior as well as produce strong and
gusty winds near the Alaska Range beginning late Sunday and
continuing into Monday. The warm temperatures aloft will
effectively cap thunderstorm activity in the central and eastern
interior through Monday, however as a weak upper level trough
develops over the west coast and western interior over the weekend
expect scattered showers and isolated thunderstorms over the
western interior.

850 mb temperatures rise to around 10 celsius over the southeast
interior Friday and rise to around 13 celsius Saturday over the
central and eastern interior. Temperatures continue to rise at
850 mb to around 15 celsius on Sunday and Monday over the central
and eastern interior.

On the surface upper 70s to around 80 degrees are expected over
the central and eastern interior Friday with temperatures rising
into the lower 80s Saturday and Sunday over the central and
eastern interior. Shower and thunderstorm activity will be minimal
with the southerly down slope flow off of the Alaska Range
developing Saturday and continuing into Monday. As the surface
gradient increases between the southern side of the Alaska Range
and the northern Side of the Alaska Range expect gap winds to
develop along and near the Alaska Range passes Sunday afternoon
and evening. As stronger winds aloft push over the Alaska Range
Sunday night and Monday expect a weak mountain wave to develop
with gusty winds developing along the northern foothills of the
Alaska Range late Sunday and Monday.

The 12z model suite initialized well against the 12z surface
analysis and verified well against the 18z surface analysis. Model
spread is reasonable in the short range but increases rapidly in
the mid range as the models struggle with the transition from a
very progressive pattern to a pattern dominated by the strong
ridge developing over eastern Alaska, the Yukon and western

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


Fire weather concerns will increase over the next several days
over the central and eastern interior, especially along and near
the northern foothills of the Alaska Range Sunday and Monday.
Thunderstorm activity and attending lightning will be minimal with
a capped atmosphere over the central and eastern interior Friday
through Sunday. Temperature criteria for Red Flag conditions will
likely be met over most of the central and eastern interior
Saturday through Monday. The Yukon flats and Upper Tanana Valley
and areas near the northern foothills of the Alaska Range will
flirt with the Minimum Red Flag Relative Humidity Criteria Sunday
and Monday. The foothills of the Alaska Range will likely meet
Red Flag Criteria for wind Sunday and especially on Monday.
Continue to monitor.




Brisk Wind Advisory for PKZ235-PKZ240-PKZ245.


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