Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 558 PM EDT Sat Nov 02 2024 Valid 12Z Wed Nov 06 2024 - 12Z Sun Nov 10 2024 ...Deep low pressure systems could cause high winds across the Aleutians/Alaska Peninsula and southwest Mainland and enhanced precipitation in southern Alaska next week... ...Overview... A deep and broad upper low will position itself over the eastern Bering Sea and vicinity while the remnants of TC Kong-rey crosses the northern Pacific. The deep surface low will impact the eastern Aleutians/western Alaska Peninsula into Bristol Bay by Tuesday and move into the Lower Kuskokwim/Yukon regions by Wednesday, bringing high winds and heavy precipitation potential there, with heavy precipitation also spreading to its east across Southcentral to Southeast Alaska. Additional energy and surface low pressure are likely to move eastward through the northern Pacific and reinforce the trough pattern into midweek, with yet another surface low tracking similarly for late next week. This deepening and then reloading upper troughing over the Bering Sea southward into the Aleutians and northern Pacific should promote ridging developing across the eastern Mainland to Panhandle for mid- to later week, but troughing may finally reach those areas by next Friday-Saturday. Meanwhile the tight surface pressure gradient could cause strong easterly winds across the North Slope with some blowing snow. ...Guidance Evaluation/Preferences... Overall the latest model guidance is reasonably good agreement with the large scale pattern including the evolution of TC Kong-rey in the western Pacific as its remnants approach the Aleutians early next week. The broad and deep upper low and surface lows were clustered within the 12Z GFS/ECMWF/CMC/UKMET such that a near equal blend of the deterministic guidance was preferred. After the low bottoms out on Tuesday, it begins to fill/weaken into Wednesday, the start of the period. Upstream another fast moving shortwave trough and surface low will move through the northern Pacific mid-week, merging with the preexisting upper low into Thursday. A blend favoring the 12Z GFS/ECMWF worked through early Thursday, but then there is additional spread later Thursday into Friday with where the low ends up among deterministic models and ensemble members/means. Additional surface lows moving into the region complicate the forecast enough that by Days 7-8, the forecast favored a blend of the GEFS and ECENS means. ...Weather/Hazards Highlights... The deepening surface low moving from the northern Pacific northeastward is expected to cause high winds for the Aleutians and Alaska Peninsula on Monday and move into the Lower Kuskokwim and Lower Yukon regions given the strength of the low. Ahead of the low, precipitation including some heavy amounts will spread from the Alaska Peninsula and into the Southwest Mainland Monday, to Southcentral on Tuesday, and toward Southeast late Tuesday into Wednesday. The reloading upper low pattern should promote additional rounds of precipitation moving west to east across southern Alaska through late week. High wind and heavy precipitation hazards are outlooked on the Day 3-7 Hazards Chart for these threats. Meanwhile, rounds of snow showers are possible farther north through the period. A tight pressure gradient across the North Slope could also cause some breezy easterly winds and blowing snow there for potential for blizzard conditions, per coordination with the Fairbanks WFO. Finally, in coordination with WFO Fairbanks, there are chances for freezing rain on Tuesday and Tuesday night along the coast south of Shaktoolik and from the Yukon Delta inland to the Lower Yukon and McGrath. Most locations will see above average temperatures rising further as next week progresses, with the possible exceptions of the Seward Peninsula, parts of the higher mountain peaks, and the Panhandle showing cooler temperatures into midweek. In most cases the anomalies for morning lows should be greater than anomalies for daytime highs. High temperatures will generally be in the upper teens to 20s in the Interior and North Slope, with 30s and low to mid 40s in southern areas. Tate/Taylor Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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