Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 556 PM EST Sun Jan 12 2020 Valid 12Z Thu Jan 16 2020 - 12Z Mon Jan 20 2020 ...Overview... Closed high will migrate across the North Slope, through the Beaufort Sea, and into northwestern Canada near Banks Island late next week through the weekend. This will allow an upper low near Haida Gwaii to slip westward underneath the upper high and combine with westerly flow aloft out of the Bering Sea. Well below normal temperatures will slowly moderate next week over eastern/southeastern portions of the state. Precipitation will be below average outside the western Aleutians with a suppressed storm track until the end of the period. ...Guidance/Predictability Assessment... The 12Z GFS/ECMWF/Canadian/UKMET offered reasonable clustering with the 00Z ECMWF ensemble mean and 12Z GEFS mean to start the period, Thu-Sat, with high pressure retreating through the Yukon. Differences in the models related to the track and shape of the upper high as it morphs east-northeastward. Consensus approach served well with the latest guidance in good agreement into Saturday. Thereafter, ensembles show weakening of the upper high as lower heights take its place across the Gulf/Southcentral. There, with smaller embedded features, the models continue to struggle with how to track the shortwaves or weak upper lows. Trended toward an ensemble blend with a rather amorphous upper pattern that has lower predictability than the longer wavelength pattern to the east. System lifting out of the northeast Pacific may lift toward the Panhandle then perhaps curl back and weaken as another may fill in behind it next Sun/Mon, based on the forecast change in the upper pattern. ...Weather/Hazards Highlights... Much of eastern/southeastern Alaska, especially the Panhandle, will have lingering much below normal temperatures as arctic high pressure ~1040mb only slowly retreats into NW Canada. Above normal temperatures may be limited to the North Slope. Precipitation will be light late next week given the storm track well to the south, focused over the Aleutians as a system slides eastward Fri-Sat south of the island chain. By next weekend, ensembles suggest low pressure may lift northward just offshore the Panhandle but uncertain how much precipitation (maybe snow changing to rain) it may draw northward past about Sitka. Fracasso 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