Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 132 PM EDT Thu Jul 18 2019 Valid 12Z Mon Jul 22 2019 - 12Z Fri Jul 26 2019 A more amplified pattern with time is forecast across the region, driven by a deep layer cyclone/upper trough progressing slowly across Siberia. Downstream of this feature, a stable Rex Block pattern takes hold extending from Alaska/Yukon (closed deep layer high) into the northeast Pacific (closed deep layer low). Broadly, the guidance is agreeable but detail issues continue to cloud the picture. A compromise of the 00z ECMWF, 00z UKMET, 06z GFS, 12z GFS, 00z ECMWF ensemble mean, and 00z NAEFS mean was used through the period, with increasing weight of the ensemble means with time to help deal with the forecast uncertainty. Confidence is increasing in this scenario, but remains no better than average where uncertainty is greatest near the Bering Sea/Aleutians/AK peninsula mid next week. Mild to warm temperatures are forecast for the state this period -- temperatures remain on pace for record warmth for the month of July across south-central AK. North and Northwest AK have the highest rain chances this weekend (where moderate to heavy rainfall is expected) before the low moving eastward through the northeast Pacific increases rain chances for southwest AK Sunday/Monday and southeast AK and the AK panhandle Tuesday into next Thursday. One to two inches of rainfall, with locally higher amounts in preferred topography, is expected in association with the northeast Pacific cyclone. Roth 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