Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 546 PM EDT Thu May 14 2020 Valid 12Z Mon May 18 2020 - 12Z Fri May 22 2020 ...Guidance/Predictability Assessment... The WPC medium range Alaskan product suite was mainly derived from a composite of reasonably well-clustered guidance from the 12Z ECMWF/UKMET/Canadian Mon-Wed in a pattern with above average forecast predictability. The 12Z GFS was notably quicker against a slower trend in the rest of the guidance with the Pacific system moving along the Aleutians next Tue-Fri. For next Thu-Fri, the 12Z ECMWF/Canadian offered reasonable details to the 12Z GEFS/00Z ECMWF ensemble means as the system slowly moves eastward. Over the rest of Alaska, weak troughing over the interior will gradually give way to rising heights as the Bering/Aleutian system passes east of 170W. The Panhandle will have a lead system push through the region around Tue where the 12Z GFS was a bit closer to the larger ECMWF-led consensus but still just a bit quicker. Thereafter, northern edge of high pressure will move into the area. ...Weather/Hazard Highlights... Lead and subsequent system over the Aleutians will bring rounds of precipitation to the island chain into the AKPen and southwestern areas, where heavy rain is possible during the week. Breezy conditions will surround the low, which could be as strong as the low 980s mb or so. Southerly flow later in the week along with the triple point over the AKPen may enhance rainfall over Kodiak and south-southeastward facing terrain. Temperatures may stay just below average along the North Slope with an easterly fetch over the water. Areas south of the Brooks Range may be above average with less cloudiness and slightly above average 850mb temperatures (>0C). Coastal areas may see below average temperatures on cloudier/rainier days, especially over the AKPen and Southcentral nearer to the coast. 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 Hazards: - Heavy precipitation across portions of southern coastal areas of Alaska, Tue, May 19 and Thu, May 21. 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