Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
994 FXAK69 PAFG 171028 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 228 AM AKDT Mon Jun 17 2024 .SYNOPSIS... Another warm day is on tap today for most of the Mainland with temps continuing to run above seasonal norms. Thunderstorm chances will once again favor higher terrain, although strong thunderstorms are forecast near the W Alaska Range to the Lower Yukon Valley today. Wednesday, strong thunderstorms will be possible from the Central Interior into the Upper Koyukuk Valley and Yukon Flats. Temps are cooling out west as an arctic trough digs south. && .DISCUSSION... Upper Levels and Analysis... A narrowing 567 ridge axis extends across the state of Alaska, from SE Alaska all the way to the West Coast. There is an anomalous 537 dam arctic low over the Chukchi Sea. There is a shortwave trough moving east across the Brooks Range with areas of elevated thunderstorms and showers. Some storms are also occurring over the Arctic waters as of 1 AM this morning. There is a broad 549 dam NPAC low spanning the Aleutian Chain with a weak shortwave trough moving across the AKPEN from Kodiak Island. Model Discussion... The numerical weather models are doing fairly well with the general pattern through midweek. The largest discrepancy is with a migratory shortwave trough currently over the AKPEN, which is projected to move north and interact with the arctic trough farther north. The models are showing fairly large dispersion by Tue afternoon with a whole slew of differing solutions, but the general trend in all models is to move things faster north by Tue afternoon, so this forecast will adjust for thunderstorm chances Tue to be nudged northward, faster. A blend of NAM nest and hi-res models was favored for winds. A blend of all models was favored for everything else. Central and Eastern Interior... Another warm day today with temps near 80 or slightly above for most of the S Interior and Yukon Flats. Thunderstorm chances are higher for the Yukon Flats, especially from Chalkyitsik north, but otherwise, more isolated thunderstorms today mainly over the higher terrain. Some storms will be strong along the W Alaska Range today, as well. The flow aloft turns southwest late this evening and some storms may drift north off the Alaska Range into parts of the Tanana Valley, and may continue overnight as showers. Tuesday, with the mid level flow turning more southwest and a weak front shifting north, widespread showers and thunderstorms are expected from the Central Interior highlands northward to the Upper Koyukuk and Yukon Flats, as well as the Fortymile Uplands and White Mtns. More isolated thunder activity will be possible from the Alaska Range to the Tanana Valley, but a few storms may be strong as CAPE/shear parameters look fairly respectable. Wednesday, it will still be on the warmer side with more isolated thunderstorm chances pretty much across the Interior as a southeast flow develops. West Coast and Western Interior... Dry and warm again today except strong thunderstorms late this afternoon over the W Alaska Range to the Lower Yukon Valley, with some storms producing a lot of lightning and potential hail. The area of thunderstorms expands Tuesday across the Interior to the Brooks Range, with fairly widespread thunderstorm chances, with the best chance from Galena northward, where some storms will be quite strong. Meanwhile, an arctic trough is digging south across the West Coast later today through Tuesday, bringing a chance of rain showers along the front, along with increasing north winds and cooler temps. The arctic low moves offshore Wednesday although showers may persist along with slightly cooler temps. Expect areas of stratus and some fog to move south with the arctic trough today and tonight across the NW Arctic, Seward Peninsula, and Bering Strait. North Slope and Brooks Range... A stout arctic low persists over the NW Arctic to Utqiagvik, with southwest winds and showers. There are even some elevated thunderstorms tonight as the leading upper disturbance moves east. Thunderstorms will continue along the front as it shifts to the E Brooks Range later today. Showers continue over the Arctic coast mainly from Utqiagvik west through Tue, with high pressure bringing back possible fog and stratus further east after a couple of nice days. Northeast winds increase along the coast Tue with another round of heavy showers with thunderstorms over the Brooks Range, with that general pattern persisting into Wednesday. Extended Forecast Days 4-7... The West Coast arctic low is drifting west Thursday with a low developing in the Gulf of AK, and a weak Interior ridge persisting over the Mainland. It does look like the far S Interior to AK Range will cool down with increasing chances for heavy rain showers and thunderstorms as easterly waves shift inland. Weak high pressure aloft will shift farther north and it should be warming across most of the remainder of the Mainland through the weekend, with the exception being the Arctic coast where temps remain seasonal. Coastal Hazard Potential Days 3 and 4...None. && .FIRE WEATHER... Scattered wet thunderstorms today over the Lower Yukon to the W Alaska Range along a thermal low, with another warm and hot day for most of the Interior. isolated Interior thunderstorms once again favor the higher terrain. Expect widespread upper 70s to low 80s with another day of lower to mid 20 percent min RHs. The thermal low shifts north Tuesday and a very active wet thunderstorm day is expected from the Central Interior highlands into the Upper Koyukuk and Yukon Flats, as well as the Fortymile Uplands. We are continuing with scattered wet thunderstorms north of the Tanana River to the White Mtns and into the Yukon Flats. Elsewhere, there will be isolated wet thunderstorm chances with southerly steering flow, but some may be strong in the late afternoon, from the Alaska Range to the Tanana Valley. Wetting rain chances are moderate over the Central Interior to W Interior Tue. Temps are slightly cooler Tue but still running above average over most of the Interior. A cold front shifting south along the West Coast tonight will bring much cooler temps for Tue from the Seward Pen north. && .HYDROLOGY... No current concerns as rivers over the N Slope are all trending downward. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...None. PK...None. && $$ Ahsenmacher