Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
113 am akdt Friday Aug 1 2014
Upper air...deep upper low...507 dam at 500 mb...300 miles north
of Wainwright will weaken into a trough east of Demarcation Point
by noon Sat...then proceed eastward into Canada through Sat
night. A short wave trough will sweep across the northern half
of northern Alaska Friday evening through noon Sat. A weak residual
trough will persist over the central interior through Sat night.
Another short wave will sweep southeastward across the central
and eastern Arctic coast and eastern Brooks range sun. A very
strong upper level high centered west of St Matthew island will
weaken into a ridge over the western Bering Sea then northwestward
across Russia by Sun afternoon. Weak ridging will build across the
Alaska interior sun and persist into Monday.
Surface...a 1004 mb low 300 miles north of Wainwright will weaken
to a 1006 mb center 150 miles north of Demarcation Point by late
Friday night...then proceed rapidly eastward into Canada Sat. At
09z...cold front extends from deadhorse southward to the Alaska
Range then curving westward to the Point Lay area. The eastern
part of the front will be moving rapidly eastward into Canada
today. High pressure will persist over the north Gulf Coast and
the Bering Sea through Sat...weakening a few mb during the period.
A thermal trough will develop over the northern interior Sat and
persist through sun.
The cold front and the two short waves will bring rain to much of
the central/eastern interior...and the eastern Brooks range and
central/eastern Arctic coast.
Coastal hazard potential days 3 and 4...none
min relative humidity will likely be above 40 percent today and Sat. Some drying
and destabilization of the airmass expected sun. Isolated
afternoon and evening thunderstorms expected over parts of the
central and western interior sun...with the most unstable air
expected to be over the southwest interior. A secondary weak
maximum of instability over the interior Seward Peninsula Sun
afternoon and evening might produce a thunderstorm.
expected 48 hour rainfall amounts through Sat afternoon...0.25 to
1 inch over the eastern interior Arctic slope and Brooks range.
0.25 to 0.5 inch over the eastern Arctic coast. Over the southern
and eastern interior...0.25 to 1 inch. Since the rain will be
spread out over a 48 hour period...flooding is not expected but we
should see some general rises on rivers draining out of the Alaska
Range and northern Brooks range.
Rf Jul 14