649 FXAK68 PAFC 281339 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 539 AM AKDT Sun Sep 28 2025 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)... A low in the middle of the southern Gulf will allow for rain showers to persist for the rest of today across the northern Gulf. To the north is an upper level trough that is phasing with one of the Gulf's easterly wave. Some locations across the Matanuska Valley, Anchorage, and the Copper River Basin have started to clear out this morning as high pressure slowly fills in from the west and east. Cloud cover remains for the Susitna Valley and northwestern portions of the Copper River Basin where this trough is phased. Temperatures started to decrease where skies cleared up this morning, however northerly flow across west Anchorage along with a band of measurable rainfall late this past evening has made frost development in Anchorage more difficult. While frost cannot be ruled out for some locations this morning, the focus shifted to chances for fog. Fog has been observed in the Matanuska Valley and the Copper River Basin and low stratus near Kachemak Bay. The upper level trough over Southcentral is expected to stretch apart as the Gulf low pushes southeastward, allowing for skies to clear as higher pressure builds across the area. Some clouds could linger for parts of the Copper River Basin Monday as the arctic trough slowly makes its way east. Widespread clearing is likely by Monday night through Tuesday and chances for frost will be remain possible. Northerly winds will also increase, especially through terrain gaps on Monday. Winds weaken Tuesday and weather should remain quiet for the day. Tuesday night, clouds increase ahead of the next front that arrives for midweek. Models differ with the timing slightly, but Southcentral can expect widespread rainfall to return sometime Wednesday. && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3: Today through Wednesday)... The Bering continues to be active as a front pushes through. The Pribilof Islands and the Eastern Aleutians are currently seeing rainfall and gusty winds due to the front. The front will quickly weaken by this (Sunday) afternoon before reaching the southwest mainland, dissipating by tonight. A weak low will form over the Alaska Peninsula Monday morning as the front dissipates and the upper trough moves through. There is some uncertainty with the strength of the weak low, but it is not expected to increase wind speeds significantly with winds likely staying below small craft. The low will also bring light rainfall to the Alaska Peninsula. Meanwhile, the mainland will remain under the influence of a ridge, meaning drier and calmer conditions. Due to clearer skies associated with the drier air, the mainland can expect low temperatures in the mid to lower 20s this morning. Temperatures will remain cold on Sunday night as well, with lows likely dropping to the mid 20s. Monday slows everything down as a ridge builds into the Bering. Precipitation chances and wind speeds will decrease across the Aleutian Chain as more stable conditions arrive from the ridge. South-southwest flow means that temperatures in the Aleutians will stay on the warmer side due to warm air advection. The southwest mainland will have similar conditions, except with light and variable winds at the surface. Tuesday brings about a change as a large centered near the Bering Strait allows for small craft winds to infiltrate from the Pribilof Islands to the Kuskokwim Delta. The winds will be south-southwesterly over the Kuskokwim Delta Coast. Water levels will rise along the Kuskokwim Delta Coast from these winds, but coastal flooding potential is low as of now. Continue to monitor the forecast for updates regarding the potential for coastal flooding. A wave of rainfall will also affect the aforementioned areas. Moving into Wednesday, a low will move south of the Aleutian Islands, but gusty small craft winds will likely just skim the Andreanof Islands before heading southeast. There could also be some gap winds in the Eastern Aleutians/Alaska Peninsula, but this is more uncertain. -JAR && .LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)... A somewhat disorganized pattern is in store for the Bering on Wednesday of next week, with a broad upper trough situated over the Bering Strait and a pair of smaller waves moving just south of the Aleutians and also into Southwest Alaska. Rain should be ongoing across Southwest Alaska as a shortwave and front move inland from the Bering. The shortwave continues into Southcentral late Wednesday into Wednesday night, likely bringing showers into the Susitna Valley and Kenai Peninsula. After this occurs there is more uncertainty in the long range forecast, though deterministic models are in surprisingly good agreement. As the upper trough over the Bering Strait finally kicks out into the Brooks Range on Thursday, a new upper trough is forecast to take its place. Meanwhile, a North Pacific low emerges into the Western Aleutians. The combination of the two features should amplify the pattern with a longwave trough taking shape over the Bering while high pressure ridges from the Gulf of Alaska into Southcentral. This will see a greater likelihood of drier conditions for Southcentral to start the following weekend. However, shower chances will expand in coverage, becoming widespread across the Bering, Aleutians, and Southwest Alaska by Friday, with activity spilling into Southcentral late Saturday. BL && .AVIATION... PANC...Light north winds will persist through the TAF period. The biggest short term challenge involves potential for fog or low stratus to develop as higher clouds break up this morning. IFR conditions or lower will be possible if fog does manage to form, but this is beginning to look a bit less likely thanks partly to the 5 to 10 kt wind persisting on the west side of town. If fog does develop in the next few hours, expect lower cigs/visibility to be temporary, with conditions improving by late this morning as increasing solar heating helps warm and mix out any fog/stratus. && $$