Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
183 FXAK69 PAFG 212231 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 231 PM AKDT Sat Sep 21 2024 .SYNOPSIS... There is a weak arctic shortwave over the area, which has allowed for some cooler temperatures and continued rain showers for the lower elevations, and snow showers for locations around and above 1000 ft, and even down to near the valley floor for locations north of the Brooks Range. These will continue to weaken and taper off by tomorrow for most of the Mainland as there will be more of a persistent northeasterly winds across much of the region with relatively drier conditions. There will be a strong low pressure system moving into the Gulf by later tomorrow and through the mid part of next week, which will help to increase the chance of shower activity. This will also increase gap flow winds for the passes of the Alaska Range, but these winds should remain below criteria. More more impressive system moving into the Gulf towards next weekend could result in more impactful conditions, depending on the track of the low, otherwise overall weak arctic waves passing to the north with an overall active pattern will keep the chance of showers in place throughout the rest of the week. && .DISCUSSION... Upper Levels and Analysis... Weak arctic troughing over the Mainland and a strengthening low to the south moving into the Gulf, will keep weak instability in place. Deterministic models are beginning to resolve the major shortwave and associated low pressure system moving into the Gulf better over the previous runs, which has the center undergoing cyclogenesis just south of the Alaska Peninsula. The Canadian has this deepening the most of all of the models, at around 965 dam (the others around 970 to 975 dam). The general consensus of the models has the low moving into the northern Gulf and weakening as it does, hugging the coastline as it does, with the propagation slowing down as it nears the Prince William Sound by Tuesday morning. The gradient from this still looks to be weak enough so that gap flow through the passes (Windy and Isabel) should not be of concern. Depending on the development and track of another major shortwave trough nearing the Gulf the following weekend, there could be more in the way of impacts to the region, although at this time there appears to be too much in the way of inconsistencies between the models to deem either of them reliable. A weak arctic trough will still be present over the North Slope through the rest of the week and keep things generally unsettled. Central and Eastern Interior... Showers, and snow showers, possibly down to the valley floor for areas north of the Brooks Range with minor accumulations, will continue to be possible through the rest of this weekend. Lingering showers, and snow above 1000-2000 ft, will continue to diminish tomorrow, with only spotty rain/snow showers still continuing to be possible through early next week. The low pressure to the south will bring in some wrap around moisture over the eastern Interior around the mid part of next week and will help to enhance shower activity around that time. It will also increase gap flow winds for the passes, although at this time, it appears that these winds will remain below criteria. West Coast and Western Interior... It will be generally dry with persistent northeasterly wind flow and colder air advection in place. There could be a few isolated snow showers possible through the early part of next week, with an increase of snow shower activity towards the end of next week as another arctic wave moves overhead. North Slope and Brooks Range... Anaktuvuk Pass has been receiving a couple of inches already since this morning, and areas of central to west Brooks Range will continue to see several inches more through tomorrow morning. Snow showers are also expected to continue through tomorrow morning for the central and eastern Brooks Range, where anywhere from 6 to 12 additional inches of snow is expected for the higher elevations. Weaker snow shower activity over the North Slope will begin to diminish going into tomorrow. Overall on and off shower activity will continue to be possible through the early part of next week, with a slight uptick going into the later part of the week since there will be another weak arctic wave looks to be moving overhead by then. Extended Forecast Days 4-7... Depending on the track and intensity of a major shortwave trough entering the Gulf towards next weekend, there could be more significant impacts to the region. Otherwise, general arctic troughing will remain in place with another weak wave propagating over the region by later in the week, which will keep the chance of rain/snow showers in place through the rest of the week, especially for the central and eastern portions of the Mainland. Coastal Hazard Potential Days 3 and 4...None. && .HYDROLOGY... None. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Winter Storm Warning for AKZ809. PK...Small Craft Advisory for PKZ801-817-854. Small Craft Advisory for PKZ850-851. && $$ Steward