textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Key Messages:

- Gusty winds will continue through the extended forecast. Peak timing for this next round is Wed afternoon through Thu morning. Winds diminish for a brief period between Thu night through Fri morning. Winds increase again Fri night with lower confidence with how long those winds will remain elevated. - Cold temperatures and wind chills are expected to persist until at least the end of this week. A cold advisory is currently in effect through Fri afternoon for the Copper River Basin and through the Thompson Pass area.

- You can reduce your risk of hypothermia or frost bite by protecting your skin from exposure and wearing appropriate clothing while outdoors. Keep emergency supplies with you in your home and while traveling whenever possible. Consider wearing your cold weather gear while you are driving longer distances through frigid temperatures. Know the signs of hypothermia and check on others.

Discussion:

The forecast remains on track with a blocking ridge stubbornly nestled over the Bering Sea. Northerly flow with a broad upper trough remains across mainland Alaska and into the Panhandle and Canada. Shortwave troughs will remain the key player in the timing and amplification of the winds and cold air across Alaska, including Southcentral.

Winds calmed down across Southcentral Alaska this past afternoon including in the Matanuska Valley. Due to the lower winds and another push of cold air from the north, low temperatures have cooled into the negatives and single digits across Anchorage, the Mat-Su Valley, and the Kenai Peninsula. The Copper River Basin including Glennallen to McCarthy and Thompson Pass saw overnight temperatures of minus 40F and colder. Due to these very cold conditions, the Cold Weather Advisory has been extended until 4 PM Friday and now includes Thompson Pass.

A weaker upper trough is moving into Southcentral this morning. Expect wind speeds to increase later today through gap areas including Valdez and around Kodiak Island. Since midnight, winds have markedly increased through Seward and Whittier/Passage Canal. The Matanuska Valley will also see increased winds, but these will not nearly be as strong as the previous event. Gusts of 40 to 50 mph will be possible though. Anchorage and the Kenai Peninsula will likely be breezy with gusts to 25 mph possible. These effects will last through Thursday morning. Temperatures will remain very cold as the Arctic air mass remains in place.

For Friday night, another stronger upper trough descends into Southcentral. There are slight differences with the spatial extent of this trough that would influence the resulting impacts. With reasonably high confidence however, the wind speeds will once again crank up throughout Southcentral. The Matanuska Valley could see gusty winds with this trough. The Valdez gaps including Valdez itself is another area that could see gusty winds. This trough could potentially bring stronger and more prolonged winds than what we are expected to experience later tonight into tomorrow morning. Cloud cover will likely increase with this event, so temperatures across the area could be relatively warmer, especially in the Copper River Basin. However, another push of cold air is expected Saturday and our weather regime is appearing to stick around a bit longer.

Rux/JAR

AVIATION

PANC...VFR conditions and light northerly winds will persist. Northerly winds will increase to 10 to 15 kt this afternoon through mid-day tomorrow before decreasing tomorrow night.