Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 312 PM EDT Wed May 29 2019 Valid 12Z Sun Jun 02 2019 - 12Z Thu Jun 06 2019 Flow over the high latitudes will feature a blocking pattern with slowly moving features. On Sun 02 Jun a slowly moving upper low is forecast to be centered south of the central Aleutians roughly near 52N 161W. The 00Z-06z suite of guidance (ECMWF/Canadian) clustered fairly well together and close to the ensemble means (00Z ECMWF ensemble mean and 06z GEFS Mean/00z Canadian mean). The consensus of these solutions stayed close to the prior forecast/ continuity through Sunday 02 June. As the low drifts south, an upper ridge drifts south across mainland AK. The 12z GFS was a few hours faster than the pack and given the least weighting in the forecast. The majority of models have kept yet another upper low north of Wrangel Island and retrograde the circulation west with time. The 12z GFS becomes an outlier by strengthening the low and developing a second sfc circulation. Consequently, more weighting was give to the ECMWF/Canadian models and their ensemble means. On next Tue 04 Jun the models mostly show a new cyclone developing in the northern central Pacific to the southwest of the lower Aleutians. There are latitude differences with the 06z-12z GFS north of the low positions/track vs the further south 00z ECMWF/ECMWF Ensemble Mean/Canadian . There is above average agreement on the development of a low and increasing clustering, minus the 12z GFS. Given the typical fast GFS bias in moving closed lows too quickly, greater weighting to the 06z GEFS/00z ECMWF Ensemble means should bias correct the forecast. Temperatures will average above normal in northern AK and the warm core spreads south in tandem with the upper ridge, reducing coverage of cool areas as next week progresses. Rainfall will generally be light but locally moderate in favored areas in windward terrain and coastal areas of the Kenai down into the Panhandle this weekend. Scattered showers are expected near a residual low level boundary in interior southern AK each day. Petersen 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 No significant hazards are expected over Alaska during this forecast period. 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