Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 330 PM EDT Wed Jul 24 2019 Valid 12Z Sun Jul 28 2019 - 12Z Thu Aug 01 2019 The 00Z ECWMF and GFS have more amplitude than previous runs and are fairly clustered with there means; however, in general, the latest guidance still has an appreciable amount of variability and spread. The CMC is nearly 180 degrees out of phase by Monday and remains so through the rest of the forecast. Again, the shortwave tracking from the Alaska Peninsula across the Gulf to the Southeast and a westward drifting Arctic ridge near the beginning of the extended is the most agreeable aspect of the forecast. From Monday onward the means maintain the eastern Siberia upper low west of the spread. To maintain continuity in this below average confidence forecast, this issuance began with 00Z ECWMF/GFS at 70 percent with 30 percent using the EC/GEFS means, 50/50 split by Monday and 100 percent means by the end. This approach maintains the forecast of a North Pacific warm front lifting toward/to the western Aleutians while a modest surface ridge covers the Bering. Meanwhile there is a hint of a weak trough aloft settling over the Gulf of Alaska with modest low pressure over the northern Gulf. A brief period of enhanced rainfall is expected across the southern Coast and across the Southeast as the shortwave/surface low crosses the Gulf of Alaska this weekend. Otherwise a fairly broad area will see some precipitation potential for one or more days during the period but with low confidence in location/timing specifics due to the uncertainty in flow details aloft and corresponding surface evolution. Rausch/Campbell 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