Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 324 PM EDT Fri May 03 2019 Valid 12Z Tue May 07 2019 - 12Z Sat May 11 2019 Ensembles still show upper ridging currently south of the Gulf of Alaska to remain in place through most of next week, but have now all shifted to show the ridge breaking down around next Friday. The deterministic models have also showed this trend (or likely have led the way of their ensembles) but with increased spread in the surface waves along the wavy front moving slowly eastward through the Gulf. Trying to time/track these embedded features has been difficult and preferred to rely on a best consensus of the 12Z GFS/00Z ECMWF and their ensemble means given the changes of the weaker features. Still expect several waves of low pressure to ride northward along the boundary into, at first, southwestern Alaska then into Southcentral before the whole front finally moves eastward into the Panhandle around next Friday. This would allow the next system to move toward the Aleutians next Fri/Sat but the ensemble spread was large. Consensus approach yielded a position near the forecast yesterday which was prudent for now. To the north, non-ECMWF models take the small upper low in the Yukon near or into far northeastern Alaska before turning back to the east, and preferred to maintain this thinking rather than the westerly track of the 00Z ECMWF. Temperatures will increase over most of the state but high temperatures may be tempered over Southcentral due to the cloud cover. Precipitation will focus over the western side of Cook Inlet eastward to Prince William Sound but with a bit more progression eastward later in the week than indicated yesterday. Still, locally heavy rain may be possible (elevation snow) especially Tue/Wed dependent on the orientation of the lower/mid-level flow and track of surface waves along the front. In-house ensemble suggests 3-5 inches (local max 6"+) over the eastern Kenai peninsula into PWS. Fracasso Bullet points from the WPC Days 3-7 Hazards chart can be found at: https://www.wpc.ncep.noaa.gov/threats/threats.php - Heavy precipitation across portions of mainland Alaska, Tue-Wed, May 7-May 8. 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