Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 604 PM EST Wed Feb 19 2025 Valid 12Z Sun Feb 23 2025 - 12Z Thu Feb 27 2025 ...Overview... Latest guidance shows a fairly persistent mean ridge aloft extending over the mainland from the Panhandle and western Canada, most likely weakening a bit during the weekend but rebuilding by Monday-Wednesday. Meanwhile shortwave energy over the North Pacific will support multiple surface lows reaching into or near the Gulf of Alaska, most likely providing the best precipitation focus over the Panhandle and to some degree the Southcentral coast. These lows combined with Arctic high pressure will keep most of the mainland within the surface gradient. Parts of the North Slope may see brisk winds as a result. Another area of low pressure should wobble over the Bering Sea before eventually weakening, and finally the northern periphery of a much deeper storm reaching the north-central Pacific by next Wednesday may affect the Aleutians. ...Guidance Evaluation and Preferences... Models are fairly agreeable on day 4, save for the 00z ECENS. The 12z GFS has an amplified shortwave approaching the panhandle while the other guidance keeps that energy farther upstream over the Gulf. Mean troughing over the Bering Sea is captured well by the 12z envelope of guidance on day 5. The 12z GFS appears to have a more amplified ridge over the mainland than the 12z ECMWF/CMC. The Canadian begins to diverge noticeably from the EC/GFS by day 6, while the Canadian ensemble resembles the ECE/GEFS means with respect to the upper low in NW Russia as well as two shortwaves propagating through the N. Pacific into the Gulf of Alaska. The non-12z CMC guidance all capture the deep upper low over the N. Pacific reasonably well on day 7. The Canadian has more of a progressive and amplified solution than the rest of the models. By day 8 the Euro and GFS model suites along with the Canadian ensemble appear to be in good agreement on the timing and intensity of the N. Pac. upper low. The GFS is slightly weaker with the aforementioned system. ...Weather/Hazards Highlights... Expect the Panhandle to see the highest precipitation totals during the period, in association with one or more surface waves forecast to track into the Gulf. Some of this activity should extend back into the Kenai Peninsula and Prince William Sound area. Most precipitation will likely be in the form of rain over the southern Panhandle and along the coast while the higher elevations see snow. A better defined system that may track into the Gulf by next Wednesday could produce a somewhat more pronounced moisture focus. Some localized areas could see several inches or more of liquid over the five-day period but totals probably will not reach hazardous criteria on a daily basis. Precipitation will be lighter away from the coast with the only potential focus of note being a weak front through the southern interior portions of the state. The gradient between persistent high pressure over the Arctic and the surface lows over the northeastern Pacific/Gulf will produce some brisk winds, in particular across parts of the North Slope. Forecast wind speeds are currently not high enough to merit depiction on the Days 3-7 Hazards Outlook but will be worth monitoring in coming model cycles. Finally, the northern periphery of the deep storm forecast to reach the central Pacific by next Wednesday may bring brisk winds and some precipitation to the Aleutians. Effects will be sensitive to the exact latitude of the storm. The mean upper ridge across most of the state will keep temperatures well above normal through the period over most areas, with some locations across especially southwestern and southern Alaska possibly seeing daytime highs up to 20-30F above normal. Parts of the North Slope could see one or more days with temperatures closer to normal. Kebede/Rausch 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