Northern Alaska forecast discussion National Weather Service Fairbanks Alaska 348 am akdt Sat may 18 2013 Discussion... aloft...deep long wave trough over western Alaska extending from Kodiak to northwest of wrangel island continues to rotate eastward with axis over central Alaska Sunday evening. A weak short wave rounding the bottom of the long wave separates and continues east into the southern Yukon while most of the energy rotates northward into the Arctic as an upper level ridge builds into the southern Bering Sea Sunday and into southwest Alaska Monday. The upper level ridge continues to build into central Alaska into next week with a gradual warm up to more seasonal temperatures. Surface...very cold air mass for middle of may entrenched over western and central Alaska with very strong cold front moving east out of eastern Alaska into the Yukon at this time. Paor dropped from the low 60s yesterday afternoon ahead of the front to snow and the upper 20s this morning. Many locations in the western interior have dropped into the middle teens while low visible and snow with temperatures in the middle 20s are found across the central interior. Winter storm warnings hoisted for eastern Brooks range and eastern Alaska Range look to be on track with reports of nearly two feet of snow near Black Rapids Glacier in eastern Alaska Range. Over a quarter of an inch of snow fell at valley level in Fairbanks yesterday while reports of 1 to 2 inches fell in the hills above 1500 feet. Expect similar snow fall across the interior today with less than 1 inch in the valleys and 1 to 2 inches above 1500 feet. Winter weather advisories hoisted for zones 220...221...222...223 and zone 224 with another 1 to 2 inches of snow expected to fall today...especially above 1500 feet. Models...are in good agreement on main features in the short and middle terms however considerable model and run to run spread exists in the long term which reduces forecaste confidence to below normal. Gradual warming indicated into the middle of next week. && Fire weather... none && Hydrology... breakup in progress on the upper Yukon river and will proceed slowly over the next couple of days with unseasonable cold temperatures. More snow melt is expected next week as temperatures warm across the central and eastern Alaska. Flood Watch for ice jam flooding for the Yukon river for Circle City. && Afg watches/warnings/advisories... Winter Storm Warning for akz218-akz225-akz226. Flood Watch for akz220. Winter Weather Advisory for akz220-akz221-akz222-akz223-akz224. Brisk Wind Advisory for pkz200-pkz210-pkz220-pkz225-pkz230- pkz240-pkz245. && $$ Ccc may 13