Scientific Forecaster Discussion
000 FXAK69 PAFG 221338 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 438 AM AKST Wed Nov 22 2017 .DISCUSSION... Models...Better agreement in the short term out to 48 hours or so with the latest solutions. Some disagreement on what the surface low near the Arctic Coast will be doing beyond 48 hours. Will be using more of an equal blend with the exception of leaning toward the GFS for the wind fields. The 22/00Z solutions did initialize okay against the 22/06Z surface analysis for positions and central pressures. Coastal Flood guidance has done well and most areas will see falling sea levels through the day today. Aloft...at 500 hpa...A 504 dam low 150 nm northwest of Point Lay will remain stationary, then move east. The associated shortwave extends southeast over Bettles to Paxson to Cordova this morning and will move east to over the Yukon Territory by late this evening with a 504 dam low developing over the Eastern Arctic Coast and trough extending west to the stationary low. A 508 dam low will develop over St Matthew Island this morning and move over Nunivak Island early this evening at 504 dam, then dives southeast over Kodiak Island by Thursday morning. A weak ridge lies from a 589 dam high in the North Pacific south of Kodiak Island over the Kenai Peninsula then northwest to the Seward Peninsula this morning and will pull south and move east to lie South over the Alaska Range and east of Cook Inlet by Thursday morning. A ridge over the Western Bering Sea will move to the Eastern Bering Sea and extend northeast over the Seward Peninsula Thursday morning, and by Thursday afternoon will lie over most of the West Coast and Western Interior south of the Brooks Range and east of the Chukchi Sea. The ridge will work east and south, but weaken significantly Thursday night and dissipate Friday morning. By Friday morning troughing will be over the eastern Half of the state with a 510 dam low over Nuiqsut, and Ridging will moving be over the Eastern Bering Sea, Chukchi Sea, and West Coast. At 850 hpa...Temperatures over the forecast area generally -11C to -16C. Surface...Strong low that was over the Western Chukchi Sea yesterday has moved to 100 nm northwest of Point Lay at 980 mb and will become stationary as it weakens through tonight before moving slowly east. Weak high pressure continues over most of the Central and Eastern Interior with a 1009 mb high in the Upper Yukon Valley in the Yukon Territory. A 976 mb low has moved to 100 southwest of St Matthew Island this morning and will move to Nunivak Island this evening at 969 mb. A relatively tight pressure gradient around the low will move over the Lower Yukon Delta this afternoon and east to south winds will increase from Nome south and southwest of Ruby. Ridging over the interior will persist as the low over the Arctic moves east over the coast through Friday, and th low over Nunivak Island moves southeast and merges with a low in the Western Gulf of Alaska Thursday afternoon. A strong weather system will move to the west coast Friday night. Arctic Coast and Brooks Range...Blizzard to near Blizzard conditions continue over the Western Brooks Range and Northwest Arctic Coast. Peak winds reached almost 90 mph from the storm but are diminishing as the low weakens just offshore. Conditions will be improving through the day. Expect periods of low clouds and snow through the day, with accumulations up to 5 inches, but generally 1 to 3 inches. Locally blowing snow will reduce visibility after Blizzard conditions end. Strongest winds will be west of Point Barrow with southwest winds gusting to 60 mph near Point Lay this morning. Temperatures slightly cooler. West Coast and Western Interior...Blizzard conditions primarily north of the Seward Peninsula this morning will diminish through the day. However, a rapidly moving low in the Bering Sea will move to Nunivak Island this evening spreading Blizzard conditions to the lower Yukon Delta by this afternoon as winds ramp up with gusts to 70 mph around Cape Romanzof and gusts to 60 mph around Marshall. The remainder of the Delta will have winds gusting to around 45 mph. Heavy snowfall can be expected in the lower Yukon Delta as well with 6 to 12 inches of snow. Temperatures slightly warmer today, then cooling. Central and Eastern Interior...Cloudy conditions will prevail today with light snow or flurries, then decreasing clouds this evening with falling temperatures. Snowfall today up to 2 inches. Winds light and variable. && Coastal Hazard Potential Days 3 and 4...Models still bringing a storm to the Bering Strait Saturday that has the potential to produce high surf along the southern Seward Peninsula, and the Chukchi Sea Coast north of Cape Espenberg. && Extended Forecast days 4 to 7...Better agreement in the guidance for the mid and extended periods with the latest solutions. Expect high pressure building over the Arctic, and Central and Eastern Interior with cooling temperatures. Lows on the weekend falling into the 20s below or colder, then warming a bit to start the week. No new snow expected in the interior through the middle of next week. && .AFG WATCHES/WARNINGS/ADVISORIES... Coastal Flood Warning for AKZ207-AKZ211. Coastal Flood Advisory for AKZ209. Winter Storm Warning for AKZ212. Blizzard Warning for AKZ201-AKZ205-AKZ207-AKZ213-AKZ214-AKZ215. Heavy Freezing Spray Warning for PKZ200-PKZ220-PKZ225-PKZ230- PKZ235. Gale Warning for PKZ200-PKZ210-PKZ225-PKZ230-PKZ235. Brisk Wind Advisory for PKZ240-PKZ245.