Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 311 PM EDT Mon Aug 19 2019 Valid 12Z Fri Aug 23 2019 - 12Z Tue Aug 27 2019 ...Continued rain for the Panhandle... Upper pattern favors troughing over eastern portions of the mainland (around 140-150W) with zonal flow across the northeastern Pacific (50N) which will sustain the moisture plume into the Panhandle. There remain large timing/track differences with respect to a second system in this forecast period (Fri-Tue) on the heels of the lead/deeper system Friday. The former has a good consensus position/strength and a deterministic blend sufficed to start. The latter is expected to pass south of the area early next week (Sun/Mon) but was much quicker per the 00Z ECMWF while the 12Z GFS stalled it south of the Aleutians. 00Z Canadian represented a good middle ground in track/strength/timing which weakens it by Sunday south of the area, but mid-level flow would continue the rain chances for the Panhandle. For Sun-Tue, Canadian was likely too aggressive to drop a shortwave around the mean upper low in the Arctic through the Interior, so a trend toward majority ensemble weighting was used. Farther south, the ECMWF fell back into line with the consensus as a weak low likely lifts northeastward toward the Gulf in between high pressure centers to the WNW/ESE. Cyclonic flow will still dominate much of the mainland but remain westerly across the Panhandle with higher rain chances. Multi-day amounts may exceed several inches, on top of short range amounts from a prior system. 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 - Heavy rain across portions of the Alaska Panhandle, Thu-Sat, Aug 22-Aug 24. 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