FXAK68 PAFC 190045 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 445 PM AKDT Mon May 18 2026 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Tonight through Thursday)... The key message of the forecast for the next few days is: expect more of the same, with a persistent cool, cloudy, and windy pattern (and wet in some areas). Starting with the analysis, a high amplitude trough and large vertically stacked low are centered over the Bering Sea. Southern AK is right at the exit of the trough, with fast moving features ejecting out of the trough and northward across mainland AK. A short-wave trough over the western Gulf is elongating and weakening as it approaches Southcentral this afternoon. This is producing light intermittent rain along the coast, but expect rain to become steadier as the trough nears this evening. Meanwhile, mostly cloudy skies prevail across inland areas of Southcentral, with a few showers driven by weak surface-based instability. A surface ridge along the Gulf coast is building inland as a weak trough approaches, leading to another day of gusty southeasterly gap winds. Looking upstream, a compact vertically stacked low is crossing the Alaska Peninsula into Bristol Bay, with a frontal system and associated wind and rain tracking toward Kodiak Island and the western Gulf. As the low continues to Southwest AK tonight, a trailing short-wave and the surface frontal system will lift northward across the western Gulf tonight and to Southcentral tomorrow. This will bring steadier and heavier rain to the coast. Strong low level southeasterly flow will become a bit more southerly as the short-wave lifts northward across Southcentral tomorrow. Thus, downslope flow will weaken and there could be a brief period of light rain from the western Kenai to Anchorage and the Matanuska Valley tomorrow morning. There is higher confidence in steady rain overspreading the Susitna Valley Tuesday morning. Inland areas of Southcentral will dry out later in the day Tuesday. By this point in time the long-wave trough will have shifted over mainland AK. A steady stream of short-waves will maintain rain along the Gulf coast and Prince William Sound. A weak surface low will track out of the Pacific and across the Gulf Tuesday night through Wednesday as another stronger short-wave crosses Southcentral. While this has looked like a no-doubter for continued rain along the coast, models have trended wetter across all of Southcentral for Wednesday. The best corridor of rain looks to be from Prince William Sound to the Copper River Valley, though light rain could extend all the way west to the western Kenai Peninsula, Anchorage, and the Mat-Su. Low level flow will lighten ahead of the surface low, so upslope/downslope will not be a factor in the rain forecast. Southcentral will dry out Wednesday night, but a new Bering low will send a frontal system toward Kodiak and the western Gulf Wednesday night into Thursday, as the active weather pattern continues. -SEB && .SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS (Days 1 through 3)... The deep upper-level trough and vertically stacked low over the Bering continues to be the dominant weather feature and driver of the overall weather pattern for much of the region. A stout jet streak embedded in a zonal jet south of the Aleutian Chain, combined with a vigorous upper-level shortwave just south of the eastern Aleutians. These features are driving the dynamics responsible for the rapid development of a gale-force surface low getting ready to cross the Alaska Peninsula just east of Cold Bay this afternoon. This low will continue to track into western Bristol Bay tonight, moving onshore near Togiak overnight and into the Y-K Delta Tuesday morning, weakening rapidly as it races away from the jet and loses upper-level support. Conditions will deteriorate overnight along coastal and across interior Bristol Bay as rain and gusty easterly winds develop out ahead of the surface low. In its wake, the rain will become more showery as winds shift and become gusty out of the south with these showers and gusty winds moving into the Y-K Delta through Tuesday along with the low. The aforementioned vertically stacked low will redevelop southwest of the Pribilofs on Tuesday as another upper-level shortwave deepens over the Bering Sea. This feature will extend a cold front across the eastern Bering, lifting toward the southwest coast by late Tuesday with another round of gusty southerly winds and rain showers. The northeasterly jog of these features is in response to a slight amplification of the longwave pattern as a transient ridge builds over the western half of the Aleutians and a new surface low develops well south of Attu, at the triple point of an occluded Kamchatka Low. This new low will moves eastward, along the Pacific side of the Aleutians, with its front moving over the Adak and Atka by early Wednesday morning. This low is expected to deepen to a sub 980mb gale-force low by Wednesday morning as it moves toward Atka, likely moving over the southern Bering just east of town late Wednesday. As its front tracks east, expect strong southerly winds along the warm front, with the potential for westerly storm-force gusts wrapping underneath the low. The front will then reach the Southwest coast by Wednesday night with the front and parent low continuing to track northeast and weakening through Thursday. -TM && .LONG TERM FORECAST (Days 4 through 7: Friday through Monday)... A broad upper level low anchored over the Bering Sea looks to continue to remain in place through the long term. Several shortwaves rotating around this low across the western Bering, North Pacific, and into the Gulf will continue to support the active pattern and unsettled conditions across much of southern Alaska through this weekend. Models are in good agreement to begin the long term period as the late week low in the eastern Bering pushes inland into Southwest Alaska, spreading rain chances across much of the region from the Gulf into Interior Southwest and Southcentral heading into the weekend. This system will be quickly followed by a series of two subsequent low pressure systems lifting out of the North Pacific, with the first being this weekend and the second early next week. Models begin to slightly differ on the exact timing and northward progression of each of these lows, but the ensemble mean consensus generally has the lows tracking south and along the Aleutian Chain and into the Gulf. Elevated winds accompanied by light to moderate rainfall with each system can be expected along the Aleutians and Alaska Peninsula before pushing into the Gulf, with the heaviest precipitation expected along the immediate Gulf coast. && .AVIATION... PANC...As a front moves through the Gulf of Alaska the next 36 hours, rain showers at the terminal are likely from 15Z to 19Z Tuesday. Gusty southeasterly winds are expected to continue through most of this time too with wind gusts ranging from 30 to 35 knots into 15Z Tuesday. && $$