textproduct: Anchorage

LONG TERM FORECAST (Days 4 to 7, Sunday through Wednesday)

By Sunday morning, heavy rainfall will be ongoing for the northern Gulf Coast and small-craft to gale force winds will be present throughout the Gulf around an occluding low. Further away from the low, lighter showers are likely across the western Susitna Valley and portions of the AKPen, with more isolated showers across the rest of Southcentral and Southwest. With strong cold air advection behind the low, snow levels will have dropped to around 2000 feet across Southwest Alaska and the AKPen and around 4000-4500 feet across Southcentral by Sunday morning. At higher elevations, especially across Southwest Alaska, precipitation Sunday and onwards likely falls as snow. In the eastern Bering through the Aleutians and AKPen, northwesterly winds up to small-craft force are likely ongoing Sunday morning due to cold air advection on the west side of the low.

While the upper level low remains over the Gulf, the surface low looks to move into the coast by Sunday afternoon and rapidly weaken once onshore. Winds significantly decrease Sunday night around the Gulf as the pressure gradient weakens. Even as the low weakens, northwesterly gap winds will persist through the AKPen and eastern Aleutians. Though it appears the strongest winds will be Saturday into Sunday, constant cold air advection will allow northwest winds to persist at or near small- craft force through Monday evening. With the weakening low, showers should taper off for Southwest Alaska by Monday afternoon. Due to winds upsloping in the AKPen, showers likely persist there through Tuesday. Given continuous cold air advection, snow levels drop further on Monday to around 1000 feet across Southwest, 1500-2000 feet in the AKPen. Places above elevations mentioned will likely receive some snowfall, especially if precipitation persists into Monday. Since Southcentral is closer to the low, precipitation will persist there longer. The heaviest precipitation will be Sunday into Monday morning along the northern Gulf Coast with lighter precipitation inland as the low moves onshore. This means rain below 4000 feet and snow above 4000-5000 feet. With the low weakening, precipitation should slowly taper off at lower elevations by Monday afternoon while persisting at higher elevations through Tuesday morning. Cold air advection begins to drop snow levels Monday to around 2500-3500 feet. For places above 2500-3500 feet, any precipitation that lingers Monday and onwards likely falls as snow. Additionally, below average temperatures will allow for many places across Southwest and Southcentral to drop below freezing for this first time this fall.

Troughing looks to persist across Mainland Alaska through Tuesday as the upper low remains stationary over the Gulf. Remnants of the surface low should move away from Southcentral by Tuesday afternoon, tapering off any lingering precipitation along the coast. Mean ensembles show another potential low entering the western Bering and western Aleutians Tuesday into Wednesday, which may bring more rain and wind there. There also is some potential for post-tropical activity to make its way to the western Aleutians between Tuesday-Wednesday. Confidence with either solution is currently low, and details will become more clear in the coming days. Otherwise conditions look to be relatively benign across most Southern Alaska Tuesday into Wednesday.

- PA

AVIATION

PANC...Winds remain southerly with occasional gusts up to 15 or 20 kts likely through this evening. VFR conditions will prevail through the period, though ceilings could lower to around 4,000 ft tonight as light rain showers develop around the area. A steadier rain moves over the terminal by early Friday morning with increasing chances (50-60%) of MVFR ceilings and visibility.