textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 2)

While much of the fog is finally dissipating this afternoon, localized areas continue to impact portions of Southcentral this afternoon from the Mat-Valley down through the Anchorage Bowl and into the western Kenai Peninsula. Southcentral remains wedged between competing weather systems with high pressure between the two systems and a warm air inversion unwilling to let go of regional fog entirely. The expectation is for winds to increase over Southcentral through tonight, as a Gulf low sends an easterly wave into the Sound through tomorrow morning and a second low over the Aleutians lifts into Cook Inlet. Winds be strongest over the Eastern Turnagain Arm and also through Palmer and Wasilla where a Mat-Valley wind should gust as high as 30 to 35 mph for much of Thursday. The increasing winds will help remove any lingering fog while also bringing in warmer temperatures. The biggest challenge then in the short term is precipitation and precipitation type.

A quick round of a wintry mix will accompany the easterly wave tonight across the Chugach Mountains into Turnagain Pass and possibly into the Anchorage Bowl. Accumulations at the surface will be on the light side most locations only seeing a dusting, though up to 1 to 3 inches is possible along the Seward Highway from near Portage down through Turnagain Pass, Moose Pass, and Cooper Landing, transitioning to light mixed precipitation as snow levels rise. Roads could become slick through the morning hours. Downsloping winds over the Chugach Mountains should limit heavier precipitation to the Gulf Coast and Prince William Sound tonight and tomorrow, though the arrival of a low over the Alaska Peninsula into Cook Inlet will help moisture lift further northward into the Copper River Basin Thursday afternoon. Thompson Pass will likely remain all snow with a good 8 to 12 inches of snow accumulation forecast through Thursday night. Meanwhile, only an inch to perhaps 2 inches are forecast from Sutton to Mendeltna along the Glenn Hwy corridor.

Any precipitation that does fall further inland across Southcentral should be relatively light, with sprinkles being the likely outcome tomorrow morning for the Anchorage Bowl north into the Valley. It does appear that a brief window of freezing rain and a freezing rain/snow mix will develop across the Western Kenai Peninsula, Anchorage Bowl, and Mat-Valley during the morning hours on Thursday. Again, however, precipitation amount should be extremely light with little to no accumulations forecast as snow level rise to ~2000 ft. Slick road conditions, however, may be present during Thursday morning's commute.

Temperatures will continue to warm into the latter half of Thursday with daytime highs in the mid to upper 30s and the potential for some locations to see low 40s with the gustier winds. By Thursday afternoon precipitation should be largely all rain, and then, just as quickly as temperatures warmed, cold air advection on the backside of a departing low into interior Alaska should see temperatures cool and snow levels drop back to the surface Thursday night through early Friday. On Friday yet another trough is forecast to push into Southcentral and light snow chances will return to the region before temporary high pressure develops on Saturday with drier conditions and a break from unsettled weather.

BL

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

An omega block pattern will be in place at the start of the long term forecast period with a dying low in the Gulf of Alaska, building high pressure over the Bering Sea, and another low just south of the western Aleutians. The tight pressure gradient between the Bering high and Aleutian low will create a corridor of southerly winds up to storm-force through the western and central Aleutians Saturday night and Sunday. The low will track into the Gulf of Alaska for the first half of the week, setting up a rex block pattern with high pressure over the northern half of mainland Alaska and low pressure over the southern Alaska and the Gulf. Surface lows spinning up will likely bring elevated winds and precipitation to the Bristol Bay region, Kodiak Island, and the north Gulf coast Tuesday and Wednesday while the Copper River Basin and interior Alaska stays cold and dry.

AVIATION

PANC...For this afternoon and evening, the potential for fog will persist. However,a strong front will push into the coast tonight, but downsloping should keep the area dry and VFR. Northerly winds will also increase through the TAF period as a low pressure system approaches the Alaska Peninsula this evening and the southern Inlet Thursday morning. Wind shear is not expected at this time due to the strong down- inlet winds, but strong southeasterly winds are expected above 3000 to 4000 ft. Thursday has to potential to see a mix of precipitation-types that will be strongly dependent on the exact track the low takes up Cook Inlet late Thursday into Thursday night.