Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 610 PM EDT Sun Aug 09 2020 Valid 12Z Thu Aug 13 2020 - 12Z Mon Aug 17 2020 ...Guidance Evaluation and Preferences... A mostly progressive pattern will continue across the northern Pacific later this week into next week with a storm track along 50-55N. Models have been wavering on how to evolve the Aleutian system Thursday into the Gulf (either in a couple pieces or with embedded waves) which has slowed or quickened the frontal progression. The parent low progression (and then the triple point progression) have been a bit more stable. The 12Z ECMWF/Canadian/UKMET were close to the 00Z ECMWF ensemble mean and not too far from the 12Z GEFS mean but the GFS was quicker into the Gulf (not implausible but at least noticeable). Opted to rely mostly on the 00Z ECMWF ensemble mean rather than keep wavering quicker/slower due to the hard-to-predict smaller-scale features that will modulate the frontal evolution. This still maintained the front on an eastward trajectory into the Panhandle Saturday. Another system is still progged to enter the Bering at that time, moving eastward next Sun-Mon. To the north, guidance has trended a bit stronger with an upper trough through the Arctic/Beafort with a weak front at the surface scraping the North Slope. ...Weather Highlights/Threats... Main system Thu/Fri will bring showers/rain and breezy conditions to the AKPen initially then to the east thereafter. Expect light to modest rainfall into the AKPen as the triple point redevelops late Thu into Fri. Some locally heavier rainfall is possible on southeast-facing and terrain-enhanced areas over Kodiak, but overall rainfall will be modest. Some showers will spread across Southcentral but the system will be pretty far to the south. Some modest to heavier rain could push into the Panhandle, though the higher precipitable water values (>1.25") may stay near/south of the new triple point and warm front, mainly over the southern Panhandle. Daytime temperatures will be cooler than normal along southern/southeastern coastal areas but warmer than normal over the Interior and especially western/southwestern areas as upper ridging noses in atop the Gulf system. Cooler than normal temperatures are forecast for the North Slope/Brooks Range. Overnight mins will generally be a bit milder than normal. 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 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