textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Key Messages:

- Gap winds return to Southcentral as ahead of a gale force front that will lift northeastward across the northern Gulf.

Discussion:

The low in the eastern Gulf is continuing to weaken in place as a band of rain showers moving around its northern periphery moves from east to west along the northern Gulf coast into Prince William Sound this morning. These showers will continue to spread west across the Gulf coast through the rest of this morning. By this afternoon, gap winds will start to increase, becoming breezy ahead of the incoming front that arrives to the western Gulf tonight.

While the parent area of low pressure remains in the Bering, models show the front lifting northeastward across the Gulf through the rest of the short term. Winds will reach Kodiak Island starting this afternoon and then spread north after midnight tonight. Coastal ridging is on track to build across the northern Gulf coast on Friday, which will lead to increasing gap winds for the Copper River Basin, Knik River Valley, and Turnagain Arm. For precipitation, rain chances increase later this evening for Kodiak Island and spread north across the northern Gulf coast overnight. Periods of locally heavy rain are possible with strong orographic lift. By Sunday morning, Seward, Cordova, Valdez, and east Turnagain Arm could see roughly one to three inches of rainfall. In contrast to coastal locations, southeasterly winds ahead of the front will create a rainshadow affect for the western Kenai, Anchorage Bowl, the MatSu, and Copper River Basin, keeping these areas mostly dry through Saturday morning. As the front continues north though, some of the energy could push moisture up Cook Inlet, bringing light rainfall to Kenai, Anchorage, and the MatSu Saturday afternoon. The pressure gradient will show signs of gradual relaxing Saturday night into Sunday, but strong winds will continue to push east to southeast winds into Prince William Sound.

As the east to west oriented pressure gradient maximizes along the Gulf coast from the coastal ridge Friday afternoon and the southeasterly winds from the front itself aligns with the Turnagain Arm, expect Turnagain Arm winds to increase here as well. Due to the parent low location out west signaling down-inlet flow, the Anchorage Bowl seems to be less of a concern than the Hillside, where at elevation wind gusts will be ticking upward of 50 mph. Overall consensus remains short of Wind Advisory criteria for the Hillside. Current forecast confidence is still in the medium range (50 to 60 percent) for Hillside wind gusts. Higher profile vehicles may struggle with those gusty winds on the Seward Highway along the Turnagain Arm, especially Friday afternoon into Saturday morning as the highway could become clipped with strong wind gusts. The low location out west will be a key factor in determining the extent of impacts from the Turnagain Arm winds.

-AM/Rux

LONG TERM FORECAST (Days 4 through 7)

An upper level stationary low over the Interior Mainland late this weekend causes a trough to dig into the Bering Sea through the middle of next week. This trough brings persistent northerly/northwesterly winds to the Central and Western Aleutians through mid-week. Additionally, the flow brings low pressure systems through this area Monday and Wednesday resulting in rounds of precipitation and gusty winds through the bays and passes. The exact track of the mid-week storm through the Aleutians is uncertain with the general consensus of a more southerly route looking likely at this time as winds turn more northerly. In Southwest Alaska, onshore flow and weak ridging sets up between the lows' passing.

For Southcentral, multiple lows are projected to enter the Gulf of Alaska bringing rain and wind to Kodiak Island and both the Eastern Kenai Peninsula and the Prince William Sound coasts from late this weekend and into the middle of next week. There are signals of a weak ridge in the Gulf of Alaska arrives late next Wednesday.

AVIATION

PANC...VFR conditions will persist through the TAF period. Light and variable winds early this morning become southeasterly around 12Z. Winds gradually shift more easterly through the day, with Turnagain Arm wind developing Thursday afternoon. Increasing mid- level cloud cover is expected tonight, though ceilings will remain VFR.

LM