Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
275 FXAK69 PAFG 012013 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 1213 PM AKDT Mon Jul 1 2024 .SYNOPSIS... Ridging aloft is weakening and the shift in the pattern is beginning as temps are falling over the S Interior. Southwest winds increase through Wednesday and will become quite blustery, especially over the N Interior, with gusts over 30 mph. These winds should also begin to result in improvements in wildfire smoke over the Interior, although some smoke may filter into the valleys the next couple evenings. Rain and cooler temps begins to move in Wednesday evening across the Interior, and will continue through the week. Gale force winds and rain will also impact the West Coast, and will bring some elevated water levels from Norton Sound to the Chukchi Coast. && .DISCUSSION... Upper Levels and Analysis... A remnant skinny ridge aloft persists over the Interior, stretching from the Norton Sound to the E Interior. There is a 548 dam upper low over the AKPEN with another mobile low over E Siberia. There is a departing 523 dam low over the Arctic moving departing to the east across the Canadian Archipelago. Light rainfall and showers is occurring over parts of the Tanana Valley in association with a subtle easterly wave aloft and a deformation zone. Smoke has improved over the Interior due to this rainfall as well as increasing southwest winds aloft. Model Discussion... Models are in good agreement and a blend of all models was favored. We favored NAM nest hi-res winds for the strong southwest winds expected the next couple of days. For rainfall, we favored a blend to the GFS. Central and Eastern Interior... Rain showers over the S Interior will continue on and off through Tuesday morning. Isolated thunderstorms this afternoon will develop over the higher terrain and drift southeast, some may make it into the valleys as well. Heavier rain showers are most likely over the Fortymile and E AK Range. Southwest winds this afternoon will continue to ventilate smoke off the the northeast,but some will likely move into the Interior valleys overnight, however, it should not be as dense as the last few days. Tuesday, showers in the morning taper and southwest winds are becoming breezier than today, 15 to 20 mph across most locations, but 20 to 25 mph over the N Interior with gusts to 35 mph. A few mountain showers with isolated thunderstorms will still be possible over the E Interior, but overall, it will be drying out with tomorrow being the final near or above seasonal norms. Wednesday, temps fall again and winds are peaking from the southwest 15 to 30 mph, gusting to 40 mph over the N Interior and Yukon Flats. Light rainfall is moving south and will reach the Alaska Range by the evening. Heavier rainfall is moving into the Interior by the evening of the 4th of July. West Coast and Western Interior... Rain showers and isolated thunderstorms will continue moving across the Yukon Valley and into Norton Sound and then fall apart by tonight. More afternoon isolated thunderstorms are possible over the Interior and up to the W Brooks Range, otherwise, it will be another warm day with temps overall in the 70s, but a few degrees cooler than yesterday. Attention turns to a strong gale force front moving to the NW Arctic early Tuesday morning, and then shifting inland Tuesday evening. This front will bring a continuous period of southwest winds to 25 to 35 mph and periods of rainfall through the weekend. Rainfall amounts will be 2 to 4 inches over the SW brooks Range with a general 1 to 2 inches elsewhere, by late weekend. In addition, expect elevated water levels of 2 to 3 feet and high wave action along the West Coast, from Norton Sound to the Chukchi coast. Temps are trending down quite a bit through the week. North Slope and Brooks Range... High pressure along the coast is weakening which has allowed for some sun to peak through along the coast. Expect an isolated thunderstorm over the Brooks Range through this evening. Tuesday is a big change with a fast moving front shifting east, bringing southwest winds 15 to 30 mph and rainfall, which will move from the NW Arctic and reach the E Arctic and Brooks Range by Tue night. There will be a break in rainfall with intermittent showers Wed night into Thursday before more rainfall commences into Friday. Rainfall amounts will range from 2 to 4 inches over the W brooks Range to 0.5 to 1 inch elsewhere, with 1 to 2 inches over the E Brooks Range. Extended Forecast Days 4-7... Friday onward, there will be continued westerly flow moving onshore and inland, which means bouts of rainfall will continue through the weekend. By early next week, the flow pattern will amplify and rainfall may shift back west, which could allow for some light Interior ridging over the ALCAN to bring temps back up a bit, but overall, it does not look like a return any hot and dry for a while. Coastal Hazard Potential Days 3 and 4...Strong southwest winds to gale force will bring elevated water levels of 2 to 3 feet above the normal high tideline from Norton Sound to the Chukchi coast beginning Tue and lasting into late week. && .FIRE WEATHER... Very active fire weather conditions remain in place through Wednesday, as the upper ridge axis breaks down and the flow becomes more westerly. Today, expect the first day of southwest winds to develop by this afternoon, with 5 to 10 mph across most of the Interior. Isolated wet thunderstorms with an area of widely scattered thunderstorms are possible from the White Mtns to the Fortymile Uplands. Rain showers this morning have put down some light wetting rains and have also dampened temps across the Tanana Valley and toward the AK Range. Steering winds will be northwest this evening over the Interior highlands, so some storms may move off the higher terrain into the valleys. Fairly significant fire weather conditions begin Tuesday which is drying back out some with increased southwest winds of 10 to 15 mph over most of the Interior, and 15 to 20 mph over the N Interior, and 15 to 25 mph with gusts near 35 mph over the Yukon Flats and Upper Koyukuk Valley. Critical fire weather conditions look likely over the northern half of the Interior, as temps will be around 75 to 80, and minimum RH in the upper 20s to near 30 %, thus a red flag warning is now in effect for the N Interior zones from the Dalton Hwy east. The gradient continues to increase overnight, thus winds will only weaken partially and likely remain mixed out from the Fairbanks area northward. Winds on Wednesday are stronger yet, with widespread 15 to 20 mph, and 20 to 25 mph and gusts to near 40 mph over the Yukon Flats and Dalton Highway corridor, and into the S Brooks Range slopes. However, temps are falling and precipitation will be possible by Wednesday afternoon in the form of rainfall, so minimum RH looks to be higher, into the upper 30 to mid 40 % range. The onset of wetting rains looks fairly low through Wednesday, with increasing chances by Wednesday night, and high chances on Thursday and Thursday night. The lone holdout will be the Yukon Flats which will see downslope drying and little in the form of rainfall. && .HYDROLOGY... Glacial fed rivers including the Tanana are slowly rising as warming temperatures lead to increased high elevation snowmelt and glacial melt. Beginning next week around Wednesday, heavy rainfall will move across the W Brooks Range with 2 to 4 inches of rainfall through next weekend, with 0.75 to 1.5 inches over parts of the Interior. Expect river rises with this amount of water across the Mainland. Expect significant rises on rivers draining the Brooks Range including, but not limited to, the Wulik, Kobuk, Noatak, and Koyukuk Rivers and smaller creeks and streams. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Red Flag Warning for AKZ911-932-933. PK...Small Craft Advisory for PKZ802-803-808-852. Small Craft Advisory for PKZ804-809-855. Small Craft Advisory for PKZ805. Small Craft Advisory for PKZ806-807-812-858. Brisk Wind Advisory for PKZ810. Small Craft Advisory for PKZ811-816-817-854-857. Small Craft Advisory for PKZ850-853. Small Craft Advisory for PKZ851. Small Craft Advisory for PKZ856. Brisk Wind Advisory for PKZ859-860. && $$ Ahsenmacher