Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 240 PM EDT Mon May 07 2018 Valid 12Z Fri May 11 2018 - 12Z Tue May 15 2018 ...Guidance/Predictability Assessment and Preferences... WPC Alaskan medium range guidance was primarily derived from a composite blend of the reasonably clustered 12 UTC GFS/GEFS and 00 UTC ECMWF ensembles days 4-8, albeit cognicient of quickly growing forecast spread days 7/8. Manual forecast modifications were modestly applied to this composite solution to depict deeper low pressure systems offshore consistent with dynamic support aloft, but decreasing forecast confidence. ...Weather/Threat Highlights... An amplified pattern into the weeekend is highlighted by a warming ridge over the Alaskan interior/North Slope ahead of an unsettling AKPen/Bering Sea/SW AK closed low. WPC progs show a deep surface low pressure system with potential for high winds/waves and wrapping heavy precipitation in the region and sustained moisture inflow and enhanced coastal/terrain precipitation downstream to srn/sern AK. Uncertain lead low and shortwave energy there lift over the central and ern Gulf of Alaska and gradually weaken inland into the ridge position, along with their precipitation/weather focus. Flow amplitude gradually decreases into early next week in a transitional pattern with quickly degrading predictability. However, there seems to be a reasonably decent signal for deep low genesis and storm focus along/south of the Aleutians days 6-8. 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 Schichtel