textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Key Messages:

* A Gulf low will continue to affect Southcentral Alaska through this evening.

* Multiple Winter Weather Advisories remain in place across Southcentral this afternoon through Tuesday afternoon.

* Blizzard Warning remains in place for Thompson Pass through noon Tuesday. * A Wind Advisory is in effect for Whittier, Portage Valley, and East Turnagain Arm through Tuesday morning.

* A High Wind Warning is in effect for Cordova through Tuesday morning.

A strong Gulf low positioned south of Seward overnight will move over the southern tip of the Kenai Peninsula as it begins to weaken through this morning. As the low moves west-northwest, its front, and a potent upper-level shortwave, are driving into Prince William Sound with copious amounts of moisture, warmer air, and strong winds.

Easterly winds peaked at 92 mph overnight at the Cordova Harbor along with gusts close to 70 mph across parts of Prince William Sound, 60 mph at Thompson Pass, 50 mph across the lower Matanuska Valley and Nikiski, and over 40 mph around Seward and Kenai. SNOTEL sites across the region indicate up to a foot of new snow for the higher elevations around Turnagain and Thompson Passes, while other reports indicate several inches of new snow along portions of the Richardson and Seward Highways through early this morning.

As the front drives farther into Prince William Sound and across the coastal mountains this morning, strong easterly winds will quickly ramp up through Passage Canal, Turnagain Arm, and across the Anchorage Hillside. A strong southerly wind will also likely move through Resurrection Bay and into Seward for a time this morning as the low moves inland to the west of town. Any snow lingering across the eastern Kenai this morning will change quickly to rain as the winds increase and temperatures warm into the mid 30s to lower 40s, pushing the snow level up above 2500 feet. For areas in the lee of the mountains, a persistent northeasterly surface winds has kept the precipitation at bay through the overnight hours. However, as the front drives inland, the atmospheric column will saturate, leading to mainly rain across the Mat Valley south to Kenai. A few pockets of freezing rain remain likely this morning for those areas less likely to see a strong wind (e.g. East Anchorage, Eagle River, Sterling). Even these locations, however, will eventually warm up above freezing.

Given the multiple weather impacts from this system, a number of winter weather and wind products have been issued for this event, so please see these products for more details.

By late Tuesday afternoon and evening, the Gulf low will weaken substantially with any lingering showers mainly confined to the coast. A second storm system looks to them move from the southeastern Gulf into the central or northern Gulf late Tuesday or early Wednesday with another round of gusty winds and showery precipitation for the Southcentral coast.

AB

AVIATION

PANC....VFR conditions are expected to prevail through the TAF period. Light rain will continue into the afternoon, with ceilings generally remaining above 4000 ft. Northerly winds will gradually shift easterly through the afternoon, increasing to around 10 kt with gusts up to 18 kt. Low-level wind shear will remain possible as stronger easterly winds around 35 kt persist at 2000 ft AGL.

Rain showers will taper off later this afternoon, with vicinity showers possible through the evening. Ceilings will gradually lift overnight, with VFR conditions continuing through Wednesday morning. Winds will shift back northerly and diminish overnight, becoming light and variable by Wednesday morning. Low-level wind shear is expected to diminish overnight as stronger winds aloft weaken.

-LM