Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 644 PM EST Sun Mar 02 2025 Valid 12Z Thu Mar 06 2025 - 12Z Mon Mar 10 2025 ...A series of lows may bring enhanced precipitation and gusty winds into coastal areas of Alaska late this week into early next week... ...Overview... At the start of the period Thursday, an upper low will be centered near Nunivak Island embedded within a deep trough that could continue to amplify as Arctic energy feeds in. Ahead of this upper trough, surface lows and moist Pacific inflow will allow for precipitation to spread across Southcentral and Southeast Alaska through late week, and enhanced winds are possible especially over maritime areas depending on the details of surface lows. The mean southerly flow will also lead to widespread above normal temperatures. The upper trough pushing through should then flip the pattern, cooling temperatures closer to normal and lessening precipitation amounts. By late week into next weekend, mean upper ridging will track through the Aleutians/Bering Sea, while another upper/surface low moves into the Bering Sea behind it and spreads winds and precipitation to the Aleutians and toward the western and southern Mainland early next week. ...Guidance Evaluation and Preferences... Model and ensemble guidance is in generally good agreement with the pattern described above. Guidance struggles more with the smaller scale details of the embedded vort maxes and surface lows though. By Friday, recent models are still supporting a possibly moderately deep surface low in the northeast Pacific. The ECMWF shows the low closest to the southern coast near the Kenai Peninsula in the Gulf, while other models generally have the low farther south but east closer to the Panhandle Friday-Saturday. GFS runs also indicate a separate low farther west in the vicinity of Kodiak Island, which many GEFS members also support, and the WPC forecast today showed that secondary low initially as a frontal wave. There is also model spread in how fast the low weakens; today the GFS is the slowest to do so. The WPC forecast tried to take a middle ground approach with the low position(s) but they remain uncertain and will impact the wind forecast. Models are in good agreement in principle with the trough deepening and shifting east, while an upper ridge pushes through the Aleutians Friday-Saturday. There is fairly good consensus upstream for an upper low and potentially a strong surface reflection to move across the western Bering Sea next weekend and early next week. The ECMWF and EC ensemble mean were generally farther north with the low track than the GFS/CMC and their means, so there is still timing/placement spread despite the agreement in this low's existence. The 12Z CMC and CMC ensemble mean eventually became faster than consensus in pushing the upper low east by early next week and was not favored. The WPC forecast favored a blend of mainly deterministic models early in the period. As the period progressed, increased the proportion of ensemble means to just half by Day 7 and more Day 8. ...Weather/Hazards Highlights... Multiple surface lows and sufficient moisture with Pacific inflow will produce moderate to locally heavy precipitation along the southern coast of the state from the Kenai Peninsula and Prince William Sound and spreading into Southeast Alaska Thursday into Friday with possibly a more consolidated surface low. Precipitation chances, at least for enhanced amounts, are forecast to slowly lessen into the weekend as the trough aloft pushes through. The northern Pacific and vicinity surface lows may also cause periods of moderate to strong winds for the Gulf and perhaps even spreading into coastal areas Thursday-Friday. The details will depend on uncertain surface low magnitudes and tracks. Periods of light snow are possible farther north across much of the Interior through late this week. Additionally, northerly flow on the backside of the lows may produce gusty winds channeling through the Bering Strait to St. Lawrence Island and possibly cause some maritime hazards or perhaps localized blizzard conditions. The deep layer northerly flow is also likely farther south across the Aleutians to Alaska Peninsula Thursday-Saturday behind the trough, which could cause gap winds in favored areas. Then by next weekend, the next low approaching the Aleutians will lead to strong southerly winds and precipitation chances there ahead of the cold front, with potentially strong westerly winds behind. By early next week precipitation chances could spread into the Alaska Peninsula, Y-K Delta, and into Kodiak and the Kenai Peninsula. Much of Alaska will remain much milder than normal through late week. The Mainland can expect temperatures 10 to 25 degrees above average with highs well into the 30s in Anchorage and Fairbanks Thursday. Southeast Alaska can expect temperatures generally 10 to 15 degrees above normal. Temperatures may decrease a bit Friday, but cooler weather with closer to normal temperatures will reach much of the state over the weekend with the northerly flow behind the trough. 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