textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Discussion:

The next round of precipitation has slowly been rotating westward across the Chugach Mountains and northern Kenai Peninsula during the overnight hours with rain showers transitioning to a mix and/or all snow for Portage, Turnagain Pass, Anchorage Bowl and up towards the Mat-Su Valley. Anchorage up through the Mat Valley were slow to saturate, but we are now seeing light to moderate snow spread across these areas. Some heavier bands of snow are also pushing west, and these bands will likely result in reduced visibility and some quick, but minor, accumulations. The Anchorage Bowl up through the Mat-Su Valley is still on track for up to 2 to 3 inches through Tuesday, with higher amounts looking to be focused near Portage and Turnagain Pass where up to 6 inches is possible (higher amounts at higher elevations). Most lower elevation coastal locations along the Gulf and Prince William Sound remain warm enough that precipitations has remained all rain, but Whittier and Valdez may see enough cold air work in to get a mix or period of light snow.

The overall pattern does not change much in the near term as an upper low near the Seward Peninsula ejects several shortwave troughs southward across Southwest Alaska and the AKPEN and into the Gulf. These lows will dip south towards the central Gulf before swinging back up towards the northern Gulf Coast. This will allow for continued unsettled weather for much of Southcentral this workweek. Persistent northerly flow on the west side of the trough will help to draw cooler air into the region and mostly snow showers for inland areas of Southcentral and rain or a rain/snow mix for many of the coastal Gulf zones.

- PP

LONG TERM FORECAST (Days 4 through 7: Thursday through Sunday)

The weather through the long-term will mostly be characterized by a mostly quiet pattern for the Bering Sea, Aleutians, and Southwest Alaska. In contrast, the Gulf of Alaska, Kodiak Island, and the mainland Southcentral Alaska coast will remain active.

Generally cooler weather is expected across mainland Southwest Alaska through through the long-term with the best chance of precipitation being on Thursday as an upper-level low originating near the Bering Strait region continues to drop southward across the Bristol Bay area. Any precipitation associated with this feature would be light and mostly in the form of snow across Southwest and the Alaska Peninsula (AKPEN). As this low dives down across the AKPEN and into the North Pacific through Thursday, this will help to enhance northerly winds through the the favored terrain, bays, and passes across the AKPEN Thursday afternoon and potentially persisting into the weekend as cold northerly flow continues across the eastern Bering and mainland Southwest. High pressure across the western and central Bering Sea looks to persist into the weekend as well. This high pressure also looks to help keep a lifting North Pacific low to the south of the Aleutians on Friday. Although easterly to southeasterly winds will pick up and be gusty at times, especially across the marine areas, most of the area is expected to remain dry. The one exception is that the front could briefly clip the Western Aleutians Friday before it weakens and the high pressure across the northern Bering moves south towards the area.

Meanwhile, across Southcentral and the Gulf of Alaska, confidence is relatively high that the weather pattern will remain active, especially across the coast and the Gulf. However, confidence is low on the exact tracks and timing of each Gulf low through the period. There is also higher confidence that most precipitation with the various Gulf systems will be along the coast with lighter precipitation inland. There are also hints that cold air will be present, even along the coast. Therefore, snow, especially during the nighttime hours will be possible. During the day, it will depend on how hard precipitation falls if snow is maintained as the main precipitation-type or not. While confidence is low for snow amounts this far out, there could be some surprisingly heavier snow amounts given the active pattern. Winter is not quite through yet.

AVIATION

PANC...MVFR conditions will likely prevail this morning as snow showers pass over the terminal accompanied by 5-10 kt northerly winds. IFR conditions also cannot be ruled out during heavier snowfall rates through the morning and afternoon. A low moving into the Prince William Sound tomorrow afternoon brings light southeasterly Turnagain Arm winds back into the picture, as well as more snowfall potential.

-AM