Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 228 PM EDT Mon Jun 11 2018 Valid 12Z Fri Jun 15 2018 - 12Z Tue Jun 19 2018 ...Deep extratropical low threat associated with former Tropical Storm Maliksi... ...Guidance Assessment and Weather Highlights... Latest models and ensembles agree that the flow will amplify over the northeast Pacific and Alaska/western Canada later this week downstream of former western Pacific tropical storm Maliksi. Maliksi is now off the coast of Japan and is subsequently slated tp eject into the westerlies. A deep extraropical low associated with Maliksi is expected to track eastward across the north Pacific over the next few days, then lift northward toward the AKpen Thursday into the weekend. This poses a significant maritime threat of high winds and rough seas/weather. Heavy precipitation will also work into the AKpen and southwest/southern Alaska as deep layered moisture feeds ahead of the deepened low with a history of deep tropical moisture intrusion. Farther north, mid-later week arctic trough/low and height fall energy digs southward over the north slope and northwestern interior. Expect post-frontal cooling and an unsettled weather pattern with scattered precipitation that should become more widespread with overall flow amplification. Guidance remains varied with the extent of northern stream amplification though and is especially problematic with potential southern stream phasing issues as the deep extratropical low associated with the former Maliksi lifts through the AKpen into southwestern AK and up into western Alaska later period. WPC progs show potential for some phasing and an enhanced cooled northern AK and interior weather threat given expected organization and moisture. Overall, the WPC product suite was mainly derived from reasonably well clustered 12 UTC GFS/GEFS mean and 00 UTC ECMWF/ECMWF ensemble mean days 4-6 before switching to just the means later day 6 into day 8 (Sun-next Tue) amid growing forecast spread and uncertainty. Manual adjustments were applied to ensure the extratropical low associated with Maliksi was sufficiently deep given support aloft/tropical history. Schichtel WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can be found at: http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif www.wpc.ncep.noaa.gov/alaska/akmedr.shtml http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html