Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 654 PM EST Sun Feb 19 2023 Valid 12Z Thu Feb 23 2023 - 12Z Mon Feb 27 2023 ***Strong low pressure system to track across the Bering Strait on Thursday, bringing strong winds and periods of snow and coastal rain to western Alaska*** ...Model Guidance/Predictability Assessment... The 12Z model guidance initially has a good overall depiction on the large scale weather pattern through the end of the week, with the normal level of mesoscale differences. There is excellent agreement on the ridge axis from the Gulf to the eastern mainland through Friday, and then the ridge breaks down by the weekend. Going forward to next Saturday, the CMC differs more with the handling of a separate storm system across the southern Gulf and stronger than the GFS/ECMWF. The fronts/pressures forecast was primarily derived from the GFS/ECMWF along with some CMC/UKMET for the first half of the forecast period, and then increasing the percentage of the ensemble means to about 50% by next Monday. ...Pattern Overview and Weather/Hazard Highlights... An amplified ridge axis over the eastern mainland and the Gulf on Thursday is forecast to break down going into Friday and then a broad trough sets up over the state going into the weekend. By early next week, the ridge axis attempts to rebuild over the eastern Aleutians and the southwestern mainland. Meanwhile, the dual-low pressure system is forecast to cross over the Bering Strait on Thursday and then lift northward over the Arctic by the end of the week, and a weaker storm system develops over the northern Gulf for the weekend and slowly drifts southeastward. Another organized storm system may enter the Bering Sea region by next Monday. The track of the surface lows across the western Bering is forecast to produce warm frontal snow across portions of western mainland Alaska for the middle to end of next week, and strong gusty southerly winds across western coastal areas of the state. There may even be some rain for portions of southwestern Alaska on Thursday where highs manage to get into the 35 to 40 degree range. Several inches of snow is likely for many inland locations. This storm system will also lead to a surge of well above normal temperatures by late February standards, with highs potentially running 20-35 degrees above average across central and western portions of the mainland for Thursday and Friday. This will equate to temperatures possibly getting above the freezing mark in some of these areas. Colder weather is forecast to make a return by the weekend as the cold front heralds an end to the unseasonably mild conditions. Hamrick 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