Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 625 PM EDT Sun Apr 16 2023 Valid 12Z Thu Apr 20 2023 - 12Z Mon Apr 24 2023 ...Easing cold pattern to revive next weekend... ...Guidance Evaluation/Predictability Assessment... Recent models and ensembles have been offering more similar larger scale pattern evolutions for the coming week, bolstering forecast confidence to at least near normal levels overall, but still differ with the focus of small-mid scale embedded systems over time. A composite of generally compatible guidance from the 12 UTC GFS/ECMWF/UKMET/CMC seems to offer a good forecast basis Thursday into Saturday and the blend process tends to mitigate embedded system differences consistent with uncertainty. This solution also has good ensemble support during this period. Prefer to again change guidance preference away from the increasingly varied individual system depictions of the models toward the more run to run stable and compatible 12 UTC GEFS/ECMWF ensemble means later Saturday through early next week, but kept some model input for better definition. Ensembles and especially the models have trended toward a more amplified mainland upper trough/cold surface high pressure settling down over much of the state. Guidance is also trending toward an increasing interaction of this northern stream flow with lingering upper trough energies already over the Gulf of Alaska in this period that may allow an overall northward shift of Gulf lows that become generated. ...Overview and Weather/Hazard Highlights... Upper lows/troughs over the Arctic Ocean, through the mainland and additionally over the Gulf of Alaska are expected to remain roughly sandwiched between upper ridges centered both to the west and east of Alaska into early-mid next week. The pattern remains slated to become transitional mid-later next week as ridging to the west of the state reforms into a strong closed high to center near the Bering Strait, leading into an Omega-style blocking pattern over the state and vicinity as upper troughs increasingly become solidified all around the powerhouse closed upper high. Height rises downstream over the mainland mid-late week should allow temporary cold pattern easing. However, expect cold conditions of varying degrees may prove hard to fully dislodge for much of the state. There is a growing signal for a renewed cooling upper trough to dig southward down through the mainland by next weekend and to linger into the last week of April. The North Slope/Interior then South-central into Southeast Alaska would eventually become colder and unsettled again in this pattern. Farther south, there is a risk of deeper than expected Gulf of Alaska low developments to monitor given potentially potent, but quite uncertain energy interactions within a mean upper trough position held over the area. Periods of light to locally moderate precipitation will mainly be limited to Southeast Alaska. There is potential there for enhancement from next weekend into next week if the northward trend of guidance leads to a closer proximity of any of the uncertain Gulf of Alaska lows. Meanwhile, Late period low deepening and slow approach toward the Aleutians may also lead a wetter pattern for the area into early next week. 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