Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 616 PM EST Sun Mar 01 2020 Valid 12Z Thu Mar 05 2020 - 12Z Mon Mar 09 2020 ...Overview and Guidance/Predictability Assessment... The most recent model guidance continues to advertise average to above average agreement and continuity for the synoptic features during the days 4-8 Thursday-Monday period across the region. An amplifying upper trough, anchored by a closed low likely to be tracking near the Kenai Peninsula very early Wed, should progress southeastward with time and encourage a similar path for one or more surface lows over the Gulf of Alaska/Northeast Pacific. 12Z guidance now has trended toward a deeper surface low offshore southeast Alaska at the start of day 4 (Thursday). That system is quickly replaced by upper level ridging and a brief window of high pressure before another deeper shortwave trough approaches the Aleutians and southern Bering Sea. Model guidance then has converged on the idea that the upper level energy and surface low diverts southeastward late in the week and early next weekend. Following that period, there is reasonable agreement that an anomalously deep upper level low moves into the portions of the Bering Sea with deep southwesterly flow through the Aleutians. At the surface, a fairly deep low is forecast to move across the northern Bering Sea toward St. Lawrence Island and across the western mainland. The WPC blend leaned heavily on the deterministic runs of the 12Z ECMWF/UKMET/GFS/CMC for day 4-6 where there was excellent agreement and run to run continuity. Beyond that time frame, given increasing model spread, higher inclusion of the 12Z GEFS mean and 00Z ECENS mean was incorporated, but there was still some considerable weights of the 12Z ECMWF/GFS included through day 8. ...Weather Highlights/Threats... Corresponding to the progress of low pressure over the Gulf/northeastern Pacific, precipitation over the southeastern corner of the mainland and Panhandle should gradually decrease in coverage and intensity from northwest to southeast during the latter half of the week. An area of precipitation and brisk winds will accompany the system expected to affect the Aleutians/Bering Sea and parts of the Alaska Peninsula around Thu-Fri. The system likely to track into the western/northern Bering Sea next weekend should bring a broad shield of moisture and large area of brisk to strong winds across the Aleutians/Bering Sea and eventually into the mainland. Some locations in the southwestern half of the mainland will see the best potential for focused precipitation by the latter half of the weekend. The change in pattern over the course of the period will lead to a pronounced warming trend from initially well below normal temperatures. The North Slope region should be first to see readings rebound to the above normal side of the spectrum, followed by warmer air spreading from west to east over central/southern areas. Rausch/Taylor 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