Alaska Extended Forecast Discussion National Weather Service College Park MD 642 PM EDT Mon Jul 28 2025 Valid 12Z Fri 01 Aug 2025 - 12Z Tue 05 Aug 2025 ...Late week Aleutians/Alaska Peninsula Heavy Rain and Enhanced Wind/Wave Threat... ...Overview... The primary upper flow features to affect Alaska from late this week into early next week will be a slow to dislodge closed low/trough over the Gulf of Alaska, ridge re-building over the Interior/North Slope and closed low/trough emergence over the Aleutians/Bering Sea. The latter will support development of a well organized southern Bering Sea surface low pressure system into late week/weekend whose energies and triple-point low developments translate slowly work downstream to the Gulf of Alaska to kick/replace the aforementioned lead Gulf of Alaska closed low going into early next week. This emerging system track offers an uncertain long fetch moisture connection to current West Pacific Tropical Storm Krosa to monitor for system efficiency. ...Guidance Evaluation/Preferences... Model and ensmeble forecast clustering have overall improved, bolstering forecast confidence for much of this period. The WPC forecast was mainly derived from a blend of the 12 UTC ECMWF/Canadian/UKMET models and GEFS/ECMWF/Canadian ensemble means. This blend shows a slow transition of a blocky pattern and a building well downstream moisture connection to current West Pacific Tropical Storm Krosa. There are still uncertainties in the forecast that include the shape and strength of upper ridging building over the Interior/North Slope to monitor. The broad blend process used should act to mitigate lingering smaller scale variances as consistent with individual predictability while manual edits act to maintain/deepen offshore surface low pressure system strengthes with favorable support. ...Weather/Hazards Highlights... Expect much above normal temperatures across especially the Interior/North Slope where some spots may reach 80F by late week given and with anticipation of favorable upper ridge development. To the south, moisture and waves rotating around the northern periphery of a well offshore Gulf of Alaska closed low position offers periodic rounds of light to locally enhanced precipitation from Southeast to SouthCentral Alaska inland to the Alaska Range. Meanwhile upstream, a plume of heavy rain in unsettled flow will overspread the Aleutians and into the Bering Sea into later this week. The main focus should then work into the western Alaskan Peninsula as a deepened low pressure system enhances winds/waves and draws in enhanced moisture with a connection to Krosa. The main low is forecast to settle in the southern Bering Sea into the weekend. Triple point lows will transition with more uncertainty downstream into the Gulf of Alaska from the weekend into early next week to slowly spread enhanced rain and unsettled flow over the Gulf to coastal southern and Southeast Alaska. Schichtel 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