Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 449 PM EST Sun Jan 19 2025 Valid 12Z Thu Jan 23 2025 - 12Z Mon Jan 27 2025 ...Heavy precipitation across portions of southeast Alaska and the Alaska Panhandle at times through next weekend... ...Storm-force winds for the upper Aleutians and lower Alaska Peninsula Thursday... ...Cooling Friday into Saturday, then sharply colder next Sunday and Monday... ...General Overview with Model Guidance Assessment... The general flow pattern features an approaching upper trough trying to shift and split around ridging across southeastern AK and northwest Canada. This should maintain periods of enhanced onshore flow across southeast AK and the AK Panhandle over the next week or so, keeping them wet. Detail issues appear to be resolving themselves, implying less uncertainty in the forecast. The pressures, winds, 500 hPa heights, fronts, PoPs, and QPF were primarily based on the 12z runs of the UKMET, Canadian, GFS, and ECMWF, with some 12z NAEFS/00z ECMWF ensemble mean included later on to deal with the usual detail issues, mainly cyclone progression timing. The remainder of the grids were based more towards the 19z NBM. This forecast philosophy was able to maintain a decent amount of continuity, with the main aspects being a more southern system south of AK and some slowing to the frontal progression across southeast AK. ...Weather/Hazards Highlights... The main story will be the periods of heavy precipitation across southeast AK and the AK Panhandle, with local amounts in the 4-8" range forecast, mainly in and around next weekend. As a deep cyclone (~982 hPa central pressure) moves through the Bering Sea and a surface high strengthens well south of AK and west of WA (~1045 hPa central pressure), a period of storm-force winds appears likely across the upper Aleutians, southern portion of the AK Peninsula, and possibly the southwest AK coast on Thursday. As the upper trough slowly edges into western AK, a prolonged period of light to moderate snow is possible from Wednesday into early Saturday; model spread here has shrunk a bit since this time yesterday. The eastern interior will be driest, more under the remnant ridging aloft. Due to the general amplified pattern over North America (ridge western continent and trough eastern continent), temperatures will be well above average across the state, with 20-40F warm anomalies common early on for the west & north with 15-30F positive anomalies common in eastern AK and the AK Panhandle early on/mid to late week. The warm anomalies initially erode slowly in the wake of the Pacific frontal passage, down to roughly 10-20F on Saturday, but then drop sharply in the wake of the Arctic/secondary front next Sunday and Monday which has a 1045+ hPa high pressure cell in its wake across eastern Siberia. Lows will fall into the -30Fs in spots next Sunday night with those same locations struggling to rise to -20F next Monday. Roth Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can also be found at: https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html