


Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
144 FXAK68 PAFC 181242 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 442 AM AKDT Fri Jul 18 2025 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today through Sunday)... The underlying pattern is not slated to change much this weekend as much of Southcentral continues to see a mix of clouds and sun along with seasonably warm temperatures through early next week. This morning, an upper level trough is moving from the Alaska Peninsula up into the greater Cook Inlet and Mat-Su region, spreading mostly mid to upper level cloud cover into all but the Copper Basin. Farther south, a weak low is developing just south of Kodiak Island along a slow moving frontal boundary lifting up into the southern Gulf. Similar to the last system a couple days ago, rain associated with the incoming front is very unlikely to reach just about any part of the Southcentral interior. Measurable rainfall will be confined mostly to the southern end of the Kenai Peninsula and Kodiak Island today as the upper level trough outruns the already weak Gulf low and front, which will cause the system to dissipate and lose upper level support well before it can make any headway past the Gulf coastline. Southerly gap flow will develop out of the Copper River Valley and Turnagain Arm today, but given the upper cloud cover and very weak coastal gradient, expect gap winds in both locations to remain fairly light today. From Saturday into Sunday, the northern periphery of a Pacific ridge will build into the southern Mainland, extending the already relatively warm and dry conditions for much of the region. The fly in the ointment hinges on the exact timing and trajectory of a series of weak shortwaves that could eject from a large Bering Sea low and ride around the ridge axis. Any stronger shortwave that can reach our area will threaten to bring periods of light rain at times for mainly the western half of Southcentral, particularly towards Sunday afternoon. However, it`s quite plausible that (just like what we observed with the past two disturbances) precipitation will fail to make it much past the Cook Inlet and Kenai Peninsula as supporting lift weakens while the upper ridge remains the dominant influence on surface conditions. Regardless of any rain chances, expect valley temperatures to become quite warm both Saturday and Sunday, with much of Anchorage and the Mat- Su Valleys approaching 70F for highs. In fact, parts of the Copper Basin could even hit 80 degrees on Sunday afternoon. -AS && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3: Today through Saturday)... A quasi-stationary, occluded Bering Sea low located roughly 275 miles north of Amchitka will continue to steer multiple waves of moisture and smaller low pressure systems into the Aleutians, Alaska Peninsula and Southwest Mainland through the end of this weekend. There is also a more compact low pressure system skirting just to the south of the Aleutian chain. Aloft, the flow around the Bering low is rather disorganized and noisy as multiple vorticity waves are being advected from the North Pacific, across the Aleutian chain, and into the Bering. This morning, a fast moving low pressure system situated between Chignik and Kodiak Island is quickly moving out of the region and into the Gulf of Alaska. Showers are expected to continue for a few more hours for the northern AK Pen and Kuskokwim Valley as the system departs. Due to the low formation south of the Central Aleutians, a stout southerly wind fetch has developed and is moving across the Eastern Aleutians, with small craft conditions expected for Dutch Harbor and Cold Bay. Friday afternoon to Saturday evening, southerly winds return for Bristol Bay as the low pressure system and its front move eastward. There is the likelihood of a prolonged period of onshore winds early Saturday afternoon through the late evening hours for the Southwest Mainland coast. The current thinking for precipitation is that an axis of moisture will move inland into the Kuskokwim coast and Bristol Bay areas, and then pushing more so into the Southwest interior on Saturday. As this low departs Sunday, widespread showers are expected across the Aleutians, Alaska Peninsula and Southwest Mainland. -AM/DJ && .LONG TERM FORECAST (Days 4 through 7: Monday through Thursday)... By Monday, the pattern will be initially directed largely by a weakening low pressure system over the northwestern Bering Sea and a large ridge developed over the southern Gulf of Alaska. Southwesterly flow across southern Alaska will persist due to the orientation of the aforementioned pressure system. This flow pattern will keep Southwest Alaska likely moist with plenty of cloud cover with air continuing to flow in from the Bering Sea. Through mid-week, the weak low in the northwestern Bering will dissolve, leading to the pattern being lead by the ridge in the northern Pacific. Shortwaves coming up and over the ridge will maintain the unsettled pattern along the Alaska Peninsula and into Southwest/Southcentral mainland Alaska. -CL && .AVIATION... PANC...VFR conditions will persist. Light winds this morning become southeasterly with gusts of 15-20 kt this afternoon and evening, then diminish overnight. Ceilings may drop to around 4000 ft early this morning but should increase above 5000 ft by late morning. && $$