textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Discussion:

An amplified ridge remains in place over the north-central Pacific and Bering Sea this morning with the Gulf low having shifted southwards overnight. The upper ridge axis will begin to bend eastwards over mainland Alaska with axis becoming more SW to NE oriented by Sunday morning. This will shift the main jet streak much further south into the eastern North Pacific. At the surface, the strong gradient along the coast will start to slacken today in response to the departing low and surface ridge shifting east. The strong gap flow winds that were ongoing yesterday for places like Valdez, Whittier, Seward, and the Mat Valley will gradually decrease today, though likely remaining breezy through this afternoon. Thompson Pass winds will also decrease, but remain gusty throughout the weekend. Temperatures have been slow to fall this morning given the gusty winds, but many areas are expected to start falling this morning as winds decrease and radiational cooling increases, especially over the Copper River Valley where temperatures should be able to fall into the negative teens and 20s. There may still be some occasional breezy winds over the Copper Basin which will allow for dangerous wind chills to develop this morning. As such, a Cold Weather Advisory remains in effect this morning for the Copper Basin and Thompson Pass where wind chills of 30 to 40 below are possible.

This cold spell will be short-lived as warmer air in the low-levels surges into the Bering Sea and Southwest Alaska then spreading into the Gulf and Southcentral by Monday morning, as a shortwave trough rides up and over the ridge. Looking ahead to the workweek, a short- wave moving out of Asia on Monday will drive southeastward toward mainland Alaska, helping to squash the ridge and push it off to the south. As a result, clouds and precipitation will move back into Southcentral Monday through Monday night. This looks like it will be a glancing blow, with a quick shot of snow before the short-wave rapidly exits to the Gulf. Arctic air will surge back in behind this system with another period of much colder temperatures and gusty off- shore gap winds by midweek. - PP

AVIATION

PANC...VFR conditions are expected to prevail through the period. Gusty northerly winds will gradually decrease to under 10 kts through early afternoon. Clear skies will give way to increasing mid and upper level clouds working in from the west by this evening.