textproduct: Anchorage

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

The long term begins on Sunday with a continuation of the amplified upper-level weather pattern consisting of a trough digging across the eastern half of the Bering and a ridge downstream extending the northeastern Pacific northward across the Al-Can border.

By Sunday, there is already some notable differences between the various deterministic model runs, although all do show a digging upper-level trough with its axis extended south over the Alaska Peninsula. The biggest difference is in the placement of two shortwave troughs embedded within the flow near the base of the longwave trough. The GFS has a more pronounced wave lifting north across western Alaska with the ridge downstream slightly stronger and more stationary. This lends to a second shortwave digging farther south across the AKPen and developing a much stronger surface low closer to Kodiak than the ECMWF and Canadian solutions which have a weaker wave and weaker, faster moving low in the Gulf.

By Monday, this upper-level wave is moving east toward the Alaska Panhandle. Again, guidance diverges on the exact track of the associated surface low, with the GFS solution keeping a stronger low centered over the central Gulf and the ECMWF and Canadian solutions showing a weaker low somewhere along northern Gulf coast between Cordova and Yakutat. Nonetheless, the result will be an increase in gap winds for the AKPen, Kodiak Island, and the BArren Islands in the wake of the low as colder air advects southeast from the eastern Bering.

By late Monday, expect a repeat of the weather pattern, with a transient upper-level ridge upstream moving over the state for late Monday into Tuesday as another area of low pressure develops near Kamchatka with its front moving quickly across the Bering Sea Tuesday and into Southwest Alaska for Wednesday as the amplified pattern becomes a bit more zonal.

AVIATION

PANC...A slight chance of isolated showers along the mountains is expected until this evening as the trough moves through the region. Otherwise, mostly cloudy with VFR conditions throughout the rest of the afternoon and overnight hours. Low stratus may develop in the Inlet tomorrow morning as high pressure builds in from the west, but if it does, it should be short lived with the April sun helping to break it up by late morning.