Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
046 FXAK69 PAFG 240102 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 502 PM AKDT Thu May 23 2024 .SYNOPSIS... Cool and wet conditions will continue through the weekend. A thermal low pressure trough from Chicken to Arctic Village will weaken tonight. A weakening occluded weather front stretching from Point Hope to Northway will weaken on Fri PM. A thermal low pressure trough devloping from Eagle to Tanana to Galena on Fri night will move south to Northway to McGrath on Sat. A cold front over the North Slope will push south over the Northern Interior on Sat and across the southern Interior on Sat night. Over the North Slope... The Arctic Coast will have flurries and fog through Fri, then get colder Fri night through Sun. Expect 4-6 inches of snow falling over the Eastern North Slope including the Dalton Highway mostly between Friday night and Sat night, with blowing snow over passes. Over the Eastern Interior... Scattered to numerous showers across the Eastern Interior will continue into Fri morning with showers becoming scattered to isolated on Fri and then more isolated on Sat and Sun. Expect wetting rain over most of the Interior between now and Fri, with some areas getting up to one half inch. Isolated thunderstorms between Chicken and Arctic Village will continue through this evening, with isolated thunderstorms between Eagle and Tanana on Fri. An upper level disturbance moving north to near Northway by 4am Fri will move to near Old Crow by 4pm Fri, and then move over NE AK Fri night and then dissipate Sat night. This will bring another band of moderate showers that move north along the ALCAN Border Fri and Fri night. Over the Western Interior and West Coast... Scattered showers across the Western Interior will continue into Fri with showers becoming more isolated Sat and Sun. The SW Interior will have numerous showers tonight and Fri. Isolated thunderstorms around Galena and Huslia will continue through this evening, with isolated thunderstorms between Tanana and Galena on Fri, and Isolated thunderstorms near McGrath on Sat. The West Coast has areas of fog with showers on the SW and NW portions tonight and Fri. The West Coast will see significant cooling and north winds of 25 to 35 mph from Fri night through Sat night. && .DISCUSSION... At 12Z, models initialize 10-20 meters too low on the 500 mb ridge that lies from the Yukon Territory across North AK to the Chukchi Sea. Models show similar solutions aloft through 4am Sat, then the NAM, ECMWF and Canadian Models take a low from the Eastern Arctic Coast southwest towards the Seward Pen while the GFS it an outlier keeping the low much further north. Favor the NAM, ECMWF and Canadian solutions aloft through Mon, but will adjust to keep tonight and Fri slightly more stable over the Northern Interior and North Slope due to the stronger than forecast ridge aloft. The long wave pattern consists of a trough over the Bering Sea and Western AK and a ridge over Western Canada and NE AK. A series of short wave troughs digging into the ridge from the south and late from the north will cause the long wave trough to moves east over Mainland AK on the weekend. This will keep Northern AK wet with cooling through weekend. The long wave trough then retrogrades back over the Bering next week as a ridge builds from NW Canada back over Northern AK next week. This brings gradual warming and drying next week. A short wave trough from the Bering Strait to SE AK will move to Point Hope to Northway by 4pm Fri, then weaken. A second short wave over SE AK will move north to near Northway by 4am Fri, to near Old Crow by 4pm Fri, and then move over NE AK Fri night and then dissipate Sat night. This will bring another band of moderate showers that move north along the ALCAN Border Fri and Fri night. A third strong short wave over the high Arctic will move over the Western Beaufort Sea Fri, over the Central North Slope on Sat, and over the Seward Pen on Sun. This will bring much colder air and strong NE winds to NW AK Fri night through Sat night, and to the West Coast of AK Sat into Sun. 850 mb temps range from +6 over the SE Interior to 0C along the Brooks Range and Central Interior, then to -6C over the Arctic Coast and Southwest Coast. Temps see little change through Fri, then cool 2-4 degrees C most areas Sat except that SW AK warm to near 0C. Sun all areas cool another 2-4C with all but the YK Delta and Upper Tanana Valley colder than 0C. With precipitation models show similar areal coverage but differ some on where and how much heavy precip will fall. Will use a blend of the NAM, ECMWF and Hi Res for areal coverage and amounts. Highlights are: Scattered showers over the Northern and Eastern Interior with numerous showers from Fairbanks SE this afternoon and evening, which will move north to Bettles to Eagle by early Fri, then taper off on Fri PM. Expect 0.25 to 0.50 inch of rain in this band through Fri. There could be high amounts but very uncertain at this time. Numerous showers developing near Eagle on Fri AM will move north to Old Crow by Fri PM, and then over NE AK Fri night and Sat. This will drop 0.25 or more liquid along the ALCAN Border Fri into Sat and over the Eastern North Slope Fri night into Sat night. This could drop 2-4 inches of snow over the Eastern North Slope Fri night into Sat night. Coastal Hazard Potential Days 3 and 4...None. && .FIRE WEATHER... Cool and wet conditions will continue through the weekend. A thermal low pressure trough from Chicken to Arctic Village will weaken tonight. A weakening weather front stretching from Point Hope to Northway will weaken on Fri PM. A thermal low pressure trough devloping from Eagle to Tanana to Galena on Fri night will move south to Northway to McGrath on Sat. A cold front over the North Slope will push south over the Northern Interior on Sat and across the southern Interior on Sat night. Scattered to numerous showers across the Eastern Interior will continue into Fri morning with showers scattered to isolated on Fri. Expect wetting rain over most of the Interior between now and Fri, with some areas getting up to one half inch. Scattered showers across the Western Interior will continue into Fri with showers becoming more isolated Sat and Sun. The SW Interior will have numerous showers tonight and Fri. Isolated thunderstorms between Chicken and Arctic Village and around Galena and Huslia will continue through this evening. Fri will have isolated thunderstorms between Eagle, Tanana and Galena. Isolated thunderstorms near McGrath on Sat. An upper level disturbance moving north to near Northway by 4am Fri will move to near Old Crow by 4pm Fri, and then move over NE AK Fri night and then dissipate Sat night. This will bring another band of moderate showers that move north along the ALCAN Border Fri and Fri night. && .HYDROLOGY... The break up front is now moving through the Yukon Delta. Ice has jammed up near Emmonak and water has risen rapidly there. Water is now rising fast at Emmonak and is flooding low lying areas, including the road to the airport. The staff gage at the power plant now reads 2 ft. No structures are flooded as of 8am Thursday, but that could change as water continues to rise. Flooding is expected soon at Alakanuk and Nunam Iqua. Water can rise rapidly. A flood Watch remains for Kotlik where ice has also jammed up with high water, but no flooding was occuring this morning. There is still as risk of flooding at Kotlik should the ice shift and push water towards the town. People in all these areas should move themselves and their valuables to higher ground. The water levels on the Porcupine River at Old Crow rose dramatically last weekend due to heavy snowmelt and remain high. This high water is expected to reach Ft Yukon between today and Friday, with water levels peaking at Ft Yukon over the weekend. This high water will gradually fill sloughs and swales east of Ft Yukon late this week and could bring flooding into Ft Yukon this weekend with high water continuing into next week. A flood watch is valid for Ft Yukon through next week Wed. Rivers on the North Slope are beginning to flow with water flowing over ice with some open water areas. Melt over the North Slope will taper off over the weekend as much cooler weather moves over the area. Temperatures will warm gradually over the North Slope next week and start melt water flowing into river again. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Flood Warning for AKZ825 Flood Watch for AKZ825. Flood Watch for AKZ833. PK...Small Craft Advisory for PKZ801-850. Gale Warning for PKZ811. Small Craft Advisory for PKZ812-857-858. Heavy Freezing Spray Warning for PKZ812-858. Small Craft Advisory for PKZ816. Small Craft Advisory for PKZ851. Small Craft Advisory for PKZ854. Brisk Wind Advisory for PKZ856. && $$ JB