Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
792 FXAK68 PAFC 121244 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 444 AM AKDT Wed Jun 12 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)... A stacked low south of Kodiak Island will slowly move east over the next few days while high pressure building over the interior mainland of Alaska. Easterly flow with embedded shortwaves, has brought precipitation across the area moving east to west and only a few isolated showers remain this morning. Rainfall chances will return late morning over the Copper River Basin and spread west along the Alaska Range to the Susitna Valley. A few hit and miss showers will remain possible for the Kenai Peninsula, Anchorage, and the Matanuska Valley. The building ridge over the interior will push those chances a little more southward as it scatters out tonight through Thursday. Residual moisture with showers however will linger for the Copper River Basin and the mountain foothills of the Central Chugach Range. Friday, the low will have moved east and upper level flow will become northerly with higher pressure to the north and west and lower pressure to the east. The pressure gradient will decrease, weakening upper level, northerly flow through the weekend. Skies will become partly to mostly clear, warming temperatures in low elevations to the upper 60s to mid 70s. An embedded shortwave looks to dip south through Copper River Basin which could promote thunderstorms Friday afternoon. There is a possibility for thunderstorms to develop over the Matanuska and Susitna Valley Friday evening too, though chances are expected to be more isolated. Flow is going to weak though, so any thunderstorms that develop would be slower moving. The shortwave slightly bends westward for this weekend, increasing the likelihood for thunderstorm development to spread into the Susitna and Matanuska Valleys, the south and western portions of the Copper River Basin, and even in portions of the Anchorage and Kenai Peninsula area. rux && .SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)... Light rain showers will linger through this morning across the Kuskokwim Valley and Bristol Bay and will taper off into this afternoon. A benign pattern sets up over Southwest for the rest of the week as high pressure ridging moves in. By Friday, the chances of convective activity return to the Western Alaska Range. A low developing west of the Western Aleutians will push south of the Aleutian Chain through late week, eventually stalling in the North Pacific south of Adak. This will bring rounds of rain showers and small craft winds to the Western/Central Aleutians through the end of the week. && .LONG TERM FORECAST (Days 4 through 7) Saturday through Tuesday... High pressure looks to persist across the eastern Bering, the Alaska Peninsula, and western mainland through most of the long- term period. However, as with cases in the past, the GFS wants to break the ridge down too quick on Sunday while the other guidance has the ridge persisting. Therefore, the GFS seems to be an outlier at this point. Additionally, the ensembles of the GFS also have a similar solution to the deterministic GFS while the ensembles of the other deterministic guidance do indeed have the ridge persisting. All-in-all, odds favor warmer and drier weather over southwest through the long-term with the occasional easterly wave moving through to help induce diurnal scattered showers. Odds favor cooler and unsettled weather over most of the Aleutian Chain with low pressure dominating in the North Pacific. The high pressure over the western mainland looks to nudge eastward through Sunday and provide mostly dry and warm weather to Southcentral for that time. Diurnal showers will be possible for the interior locations of Southcentral and perhaps even thunderstorms if enough instability builds with day-time heating. Confidence then decreases dramatically for the Sunday night through Tuesday timeframe as guidance has different solutions on the orientation of the ridge and how fast or slow the ridge might break down. Thus, forecast uncertainty remains on the high side for Southcentral during the second half of the long-term. && .AVIATION... PANC...Expect generally light southerly flow and dry conditions. VFR ceilings will tend to remain greater than 5000 ft this afternoon, though light showers are possible through the TAF period which may briefly lower ceilings to MVFR. Rain showers are most likely this afternoon and evening. Rain chances decrease heading into Thursday. Quesada && $$