Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 747 PM EDT Sun Jun 26 2022 Valid 12Z Thu Jun 30 2022 - 12Z Mon Jul 04 2022 ...Overview... Warm upper ridging over much of the mainland and Panhandle may persist into the latter part of the week, but gradually shift eastward as a couple of upper lows move in from the west. The large scale trough to the west of the state and a low/pressure frontal system will spread increasing rain chances generally from west to east across Alaska as the latter part of the week progresses. Areas influenced by the troughing, particularly southwestern Alaska, should also see cooling temperatures, but warmer than normal temperatures may persist in eastern Alaska through next weekend. ...Guidance Evaluation/Predictability Assessment... Recent model guidance continues to show an upper low embedded within longwave troughing initially in the Bering Sea Thursday and an upper high centered over the eastern mainland, with good clustering. This upper low's track has changed somewhat compared to guidance a day or so ago, with a more northerly track rather than northeasterly. The 12Z ECMWF may be fast once again in lifting this low northward. Overall this has led to a signal for more of the eastern part of the state to see continued ridging through next weekend. However, another energetic shortwave coming in south of that low will also be a factor. Model guidance indicates this energy should pass near/over the Aleutians around Friday and make its way into the Gulf of Alaska by the weekend, potentially closing off a low there. The GFS and CMC and 00Z ECMWF were fairly well clustered with the timing and placement considering the forecast lead time, while the newer 12Z ECMWF was slower than consensus. Though some models happen to agree, this aspect of the forecast remains uncertain. The WPC forecast blend incorporated the the 06Z/12Z GFS and 12Z UKMET and CMC along with the 00Z and 12Z ECMWF. As usual, increased the ensemble mean guidance for the latter part of the period. ...Weather and Hazard Highlights... Temperatures will continue to be rather warm across much of the state Thursday under the upper ridge, generally 10-15F above normal. With a slower eastward track of the ridge, central and eastern parts of Alaska should remain warm through the end of the week, but beginning Friday southwestern Alaska should cool to below normal for high temperatures, and near to below average highs are forecast to spread northeastward into early next week, though current indications are for lows to be around to above normal. The far eastern mainland and parts of the Panhandle may stay above average into next weekend as the ridge stalls. Just ahead of the trough and a surface low pressure/frontal system, moisture will increase given the southerly flow and lead to rainfall chances first for the Aleutians Thursday and then spreading into the western mainland and Alaska Peninsula Thursday-Friday and Southcentral Alaska Saturday, with perhaps lessening amounts through the eastward progression. Showers are possible elsewhere with lighter rainfall amounts across much of the mainland. The North Slope may see episodes of light precipitation if a front to the north gets close enough to the region. Tate 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