Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 717 PM EDT Mon Apr 18 2022 Valid 12Z Fri Apr 22 2022 - 12Z Tue Apr 26 2022 ...Guidance/Predictability Assessment... The latest guidance seems to continue to have a decent handle on the overall upper level flow pattern over Alaska during the medium range period. This features a deep upper closed low/surface low initially south of the Aleutians on Friday, which should drift slowly eastward into the Gulf and weaken somewhat as it lingers through early next week with a building and blocky ridge to it's north and east. The guidance seems to handle this feature better today, with only some insignificant differences in placement. A general deterministic model blend worked well for this system. Meanwhile, upstream, a couple of systems should cross the Kamchatka Peninsula and dissipate into the western Bering Sea. There are some lingering uncertainties on timing each of the systems, but most notably the 12z GFS is much farther north to redevelop the first low bringing it into the Arctic, while both the ECMWF and CMC (with support from the ensembles) suggest the low will drift into the western Bering Sea and dissipate. As such, the emphasis for todays forecast was placed more on the ECMWF with smaller contributions from the CMC (which shows issues in the Arctic early on as well) and the GFS. The second half of the forecast period featured increased usage of the ensemble means which helped to mitigate the uncertainties. At least half of the deterministic models were used even through day 8 though due to better than average agreement and for some added system definition. ...Overview Weather/Hazard Highlights... The low pressures system into the Gulf will continue to bring gusty winds and rough seas to parts of the Aleutians and Alaska Peninsula at the end of the week, with some lingering precipitation as well. Ahead of the low, moisture should direct northward along the attendant cold front to support enhanced and locally heavy precipitation (lower elevation rain/mountain snow) across parts of the Southern Coast and eventually eastward into the Panhandle this weekend and early next week as the system weakens but the general low circulation lingers. The western Aleutians may see some precipitation as well as a weakening cold front approaches early next week. Elsewhere, much of the Interior and North Slope regions should remain dry, with temperatures mostly above normal and trending warmer through the period. Southern regions, from the Aleutians to the Panhandle, should remain near or below average owing to increased clouds and precipitation. Santorelli Hazards: - Heavy precipitation across portions of the Alaska and Kenai Peninsulas, Sat, Apr 23. 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