textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Discussion:

The area of low pressure that brought the strong winds and rain to the Southcentral coast overnight has moved over Lake Iliamna and is now rapidly weakening this afternoon. As such, winds have diminished significantly throughout this morning, with a few lingering gusts around 25 mph this afternoon from the Mat-Su down across northern Cook Inlet.

While the low has moved inland to the west, two distinct troughs over the region is allowing for shower activity to persist across Prince William Sound and the Kenai Peninsula. The first of these troughs is positioned along the immediate coast from Cordova to the Alaska Panhandle and is being pulled westward, embedded in the southeasterly flow ahead of the main trough. The second trough, is situated just east of Kodiak Island and is nearly stationary this afternoon as the attendant upper-level trough elongates and stalls with a negatively tilted trough axis extending from the southwest Alaska coast to Kodiak Island.

The upper-level trough will lift north and move over Southcentral by early Thursday morning as a second feature moves in from the North Pacific, taking its place. A continued southeasterly flow will allow showers to persist over the coastal mountains, with a few scattered showers pushing inland over the mountains Thursday morning as the trough moves through. Much like the previous night, temperatures will fall to around freezing around the Willow area, and perhaps across east Anchorage, allowing for the potential for some isolated pockets of very light freezing rain. Any wintry mix of precipitation that does fall north and west of the coastal mountains should once again be short-lived as temperatures quickly warm above freezing by mid-morning Thursday.

Showers taper off Thursday afternoon as the troughs weaken and lift farther north, resulting in an upper-level col or a weak transient ridge building over interior Southcentral through Friday.

By Thursday afternoon, another North Pacific low will deepen as it lifts north into the Central Gulf. As of this morning, models continue to keep the bulk of the impacts from this low over open and coastal waters along the northeast Gulf with very little working into Southcentral. The low will then retrograde back to the west, nearing Middleton Island on Friday and near Prince William Sound by Saturday...bringing increased chances for precipitation along the coast and increased winds over the near- coastal waters.

- TM/PP

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

Minor changes from previous discussion. A broad upper trough will be established from the eastern Bering into the eastern Gulf through midweek. Several disturbances and surface lows will travel along the upper longwave trough then the flow will be directed south of much of the Aleutian Chain and then northeastward into the eastern Gulf of Alaska. Southwest Alaska will be the focus for more active weather from Saturday into early next week, though coastal showers, elevation snow, and periods of gusty gap winds appear likely for the Gulf coast, especially the Prince William Sound region. Further inland, drier and cooler conditions remain favorable. Out west, persistent northerly flow will be common across the Bering with scattered convective showers possible as well as elevated gap winds through the Aleutian Chain.

AVIATION

PANC...VFR conditions are expected to continue through the period. Winds will remain generally out of the north at 5-10 kts. Some very light rain is possible (20-30% chance) this afternoon if showers make it over the mountains as cross barrier winds weaken. Even if they do make it over, no reduction to flight category is expected.