Winter Weather in Nern P.w. Snd, Alaska

Alaska 511 (Department of Transportation) reported blowing and drifting snow through Thompson Pass from MP 18 to MP 30 on the morning of October 26th. A nearby DOT surface observing site recorded winds gusting to 30 knots (35 mph).

A low pressure system moved over the Kuskokwim Delta on the evening of October 25th before turning southeast and moving over Bristol Bay by the morning of October 26th. As the upper-level energy of the system continued eastward, it initiated the development of a triple-point low over the northwestern Gulf of Alaska, which eventually tracked into Southeast Alaska.

Together, these systems contributed to a variety of winter weather across southern mainland Alaska, including widespread snowfall on October 25th and 26th, though some precipitation fell as rain along the coast of Bristol Bay and for a time on the southern Kenai Peninsula. The heaviest snow fell over the western Kenai Peninsula as the low over the Kuskokwim Delta pushed moist southwesterly flow up Cook Inlet while an upper-level shortwave rotated through, creating a band of heavier precipitation. The triple point low in the northern Gulf of Alaska contributed to blowing snow through Thompson Pass as a result of an enhanced pressure gradient due to its presence drawing cold air through the pass out of the Copper River Basin. Additionally, low pressure in the Gulf of Alaska combined with cold advection on the back side of the system to produce high winds through gaps in the Alaska Peninsula.