textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:)

Satellite imagery at 4 AM this morning shows an area of low pressure near Chenega and associated occluded front both moving northeast toward the coast. An upper-level shortwave associated with the surface features has pushed inland over the coastal mountains and is helping drive a resurgence in precipitation across Cook Inlet and the Susitna Valley as the southeasterly cross-barrier flow quickly weakens and downsloping wanes.

Winds are beginning to wind down as both the surface low and pressure gradient between the collapsing coastal ridge and the strong Bering low weaken. Observed peak winds ranged from 30 to 45 mph across much of the Anchorage Bowl and Matanuska Valley, 45 to 60 mph through Turnagain Arm, and 50 to 75 mph for the Upper Hillside of Anchorage and Eagle River. It will remain breezy behind the front, with gusts ranging between 15 and 25 mph.

Winds will also remain gusty through Thompson Pass this morning with periods of heavy snow through mid-morning. A Winter Weather Advisory is in effect for the top of the pass through 10 AM for blowing snow and significantly reduced visibility.

As for precipitation, totals for this storm have generally been between 1" and 2.5" along the coast with upwards of an inch of precipitation in the Susitna Valley. Higher elevations of the Kenai and Talkeetna Mountains have seen as much as 2.5" to 3.5" inches. Snow totals have also been impressive, with SNOTEL sites in Hatcher Pass reporting up to 20" of new snow (Gold Cord Mine: 10" and Snowbird Glacier: 20") with this storm.

Widespread rain and high elevation snow showers will become more scattered as these feature continue to lift north and weaken through the day. Persistent south to southwest flow aloft, however, combined with weaker shortwaves embedded within the southwesterly flow and moving across Southcentral, will keep conditions rather unsettled through Monday. The best chance for showers and higher rainfall (and mountain snowfall) totals through Monday will be along the coastal mountains and along the south and west facing foothills of the Talkeetnas and Alaska Range.

-TM

LONG TERM FORECAST (Days 4 through 7)

The long term forecast starts off with a strong low in the North Pacific tracking south of the Alaska Peninsula. The low will bring strong northerly gap winds in the Unalaska and Alaska Peninsula starting Wednesday. The winds will be further enhanced by cold air advection. As the low tracks into the Gulf of Alaska on Thursday, strong easterly winds impact Kodiak and the gap regions around the island. A barrier jet may also set up along the Southcentral Coast. The strength of these winds will depend of the track and strength of the low, which are somewhat uncertain at this point. Rain and snow at higher elevations will push into Southwest and coastal Southcentral Alaska with this low. Friday sees the low weaken as it continues its track eastward. Wind speeds will diminish in both Southwest and Southcentral Alaska as the low moves east and weakens. Rain and snow will become more scattered as well. Meanwhile, ridging develops over the Bering, leading to calmer winds and potentially low stratus or fog. Saturday sees the remnants of Koguma and Nolo potentially merge with the low, leading to an increase in rainfall and winds, but this will be mostly east of Southcentral towards the Juneau area. There is still plenty of uncertainty with these scenarios, so the forecast will be clarified as time progresses.

-JAR

AVIATION

PANC...Upper level waves moving over the terminal will bring a return of gusty southeasterly to southerly winds, as well as frequent rain showers, through this evening. Given models' timing and placement differences with the weak waves moving through, confidence is low with the timing of rain showers. Still, current thinking is that showers will prevail through much of the day, with a period of lower rain chances (about 40 to 50 percent) in late morning/early afternoon between two distinct waves. Ceilings will likely be predominantly MVFR through tomorrow morning, with improvements to VFR (but still below 5000 ft) between rounds of rain showers.