Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 712 PM EDT Thu Apr 09 2020 Valid 12Z Mon Apr 13 2020 - 12Z Fri Apr 17 2020 ...Overview and model guidance... Upper ridging over the Gulf and Panhandle early next week will slowly weaken by the end of the week as the flow strengthens over the North Pacific and across the Beaufort/Arctic Sea. The models and ensembles have struggled with the several features over the northeast Pacific to start the forecast period due to slight changes in the shape/strength of the upper ridge to the east and how they either lift up and over or slip underneath the upper ridge. Consensus of the 12Z deterministic guidance again today (though a bit different than yesterday) should be a good starting point with a few detail differences in the system progression/depiction. By midweek, North Pacific system may slide more easterly before turning northeastward toward the Gulf before weakening/dissipating. That system may be a catalyst for the ridge breakdown, in concert with a stronger northern stream flow across the Interior than was shown yesterday. By the end of the week, ensembles still indicate a more robust system to approach the Aleutians, though the 00Z ECMWF ensemble mean was quicker than all the rest of the guidance. Preferred the slower 12Z GEFS mean with the GFS/ECMWF/Canadian. Farther east, unclear how the ridge breaks down or tries to hang on in pieces across portions of western Alaska, but a blended/consensus solution (such that it was) would allow for some ridging ahead of the Aleutian system next Thu/Fri but confidence is low given the spread. ...Weather/Threats Highlights... Rather wet few days for areas of the AKPEN and favored upslope regions of Kodiak Island eastward across the southern Kenai into Prince William Sound (with snow in marginally colder air). In-house ensemble-based QPF shows several inches (4-6") liquid equivalent over the 5-day period. Otherwise, rain/snowfall will be on the lighter side over the rest of the stateexcept for southwestern areas and along the cold/stationary boundary through the Interior. Along the North Slope, temperatures perhaps 10-25 degrees above normal (but still below freezing around Utqiagvik) will trend a bit cooler (back to typical mid-April values) as heights lower and the surface boundary settles across the Tanana Valley. Over southeastern areas, temperatures will generally be below normal as high pressure remains overhead or to the northeast and east. Fracasso Hazards: - Heavy precipitation across portions of mainland Alaska, Sun-Mon, Apr 12-Apr 13. - High winds across portions of mainland Alaska, Sun-Mon, Apr 12-Apr 13. - High winds across portions of the Aleutians, Tue-Wed, Apr 14-Apr 15. - Much above normal temperatures across portions of mainland Alaska, Sun-Wed, Apr 12-Apr 15. Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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