890 FXAK68 PAFC 050004 AFDAFCSouthcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 404 PM AKDT Sat Oct 4 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...
A warm front that moved up into the Gulf this morning is now beginning to slow down and stall out as it approaches the Gulf Coast this afternoon. Easterly winds up to gale force are developing out ahead of the front, with the strongest winds currently centered over the Barren Islands. A shield of moderate rainfall moving out ahead of the front has now spread into the Prince William Sound region, while steady rain that fell earlier today across the Cook Inlet and Mat Valley region is tapering off for now in the wake of a subtle shortwave passage. Gap winds that were strong, erratic and gusty across the Mat Valley and much of Anchorage earlier today are weakening and turning northerly as a down-inlet pressure gradient develops north of the front stretched across the Gulf. However, southeast winds gusting up to around 50 mph or so across the Anchorage Hillside are set to continue well into tonight.
The outlook for the rest of the weekend will continue the same theme of moderate, steady rain along the coast and more intermittent rainfall for interior valleys with passing shortwaves lifting up between a deepening trough out west and a strong upper ridge over the eastern Gulf. By Sunday night, a more potent, negatively-tilted shortwave will lift up past Kodiak Island into the Kenai Peninsula and northern Gulf. This will send a pulse of more intense rainfall across much of Southcentral as it lifts north through Monday morning. The heaviest rainfall amounts with this next round will still be focused where southerly flow upslopes into terrain, especially near Prince William Sound. Models diverge in terms of how quickly the trough progresses northeast on Monday as the upper level pattern becomes notably more complex. However, the progression is consistent enough to say with confidence that winds will become westerly (as strong as gale force) over the Gulf as more steady rainfall tapers off to showers across most of Southcentral through Monday evening.
For Tuesday, a strong upper ridge is expected to build back overhead as the system moving through for Monday exits into the Yukon and Southeast. Things should dry back out for the most part as well, except across the Talkeetnas and near Broad Pass where moisture streaming in along an atmospheric river extending from the Bering into the Interior wrings out moisture via upslope flow. Following a brief cool down on Monday, temperatures will also begin to trend warmer once again.
-AS
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.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3)...
A fast-moving low crosses the Aleutians into Bristol Bay just east of King Cove this evening bringing continued rain and strong winds through tomorrow afternoon. High pressure builds in the North Pacific and a Kamchatka low moves eastward this upcoming week causing persistent southwest wind flow, heavy rain and coastal impacts for the entire region; especially coastal Mainland.
Overnight, a 992 mb low currently south of Unalaska moves over the Aleutians just west of Cold Bay and crosses into Bristol Bay late tomorrow morning before moving onshore tomorrow afternoon near Dillingham. Northwesterly wind speeds through the gaps and passes of the Eastern Aleutians and Alaska Peninsula increase during this time frame ranging from 35 to 45 knots. Winds begin to decrease tomorrow afternoon as a weak ridge builds into the area.
A Kamchatka low moves eastward through the Bering Sea early next week. Also, a 1038 mb high in the North Pacific Monday evening builds to 1040 mb by Tuesday morning staying fairly stationary through mid- week. This will bring persistent southwesterly flow around its northern periphery; primarily from Adak northeastward to Nunivak Island Tuesday into Wednesday morning. Integrated Water Vapor Transport (IVT) shows this flow will tap into tropical moisture from the Pacific Ocean. This moisture, referred to as an Atmospheric River, will bring heavy rain, from points east of Adak to the Mainland Tuesday through Thursday of next week. Southwesterly wind gusts associated with this stream of moisture will result in widespread gale to storm force winds in the Bering Sea. Of note, this prolonged period of southwesterly flow could cause impacts to coastal areas of the Mainland; from Kipnuk to Quinhagak next Tuesday and Wednesday.
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.LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)...
High pressure will dominate south central Alaska through the end of the work week. By next weekend, a weakening front stretching across the western half of the state, will help develop low pressure that will bring rains back into the region. While still a week out, precipitation type will be something to watch. Termination Dust should continue it`s descent down the mountains. At this time, most of lower elevation should remain rain. Temperatures are definitely cooling, so this aspect will need a keen eye to remain on it.
Out west... low pressure in the western Bering will sling a front across the Aleutians through Friday. This weather system will have a deep tap of moisture (roughly 40N) and should bring abundant precipitation to the Aleutians and west coast into the weekend. The deep southerly flow will rebound temperatures. Upper level high pressure over the state will help to deflect any approaching western Pacific system from impacting the coast. Friday and into the weekend, in what looks like a rinse and repeat of the current weather system, another WNPac low will ride the ridge north into the western Bering. Another front is expected to drive east across the Aleutian Chain and AKPen into Sunday. Continued unseasonably warm and wet weather will continue through the extended forecast.
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.AVIATION...
PANC...The main challenge will continue to be the winds, both at the immediate surface and for low level wind shear. By late this afternoon, the surface winds should with to a northerly direction as opposed to the southeasterly winds that varied wildly in speed earlier in the day. While the surface winds will be northerly, the winds aloft will remain from the east-to-southeast 20 to 30 kt. The level this wind switch occurs will range anywhere between 500 and 2500 ft above the surface so we are expecting the low level wind shear to continue into Sunday.
Periods of light rain will occur through the night and into Sunday morning. VFR conditions are expected to persist in spite of the rain, though the ceiling heights could drop into the 3500 ft to 5000 ft range anytime through Sunday afternoon.
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NWS AFC Office Area Forecast Discussion