Area Forecast Discussion

KEY MESSAGES

Central and Eastern Interior... - High winds through the ALaska Range Passes will continue to diminish as we head into the overnight hours. Winds will stay elevated a bit longer through Isabel Pass than Windy Pass.

- Heavy mountain snow across the Alaska Range will continue this evening affecting travel along portions of the Parks Highway as well as the Richardson Highway south of Trims Camp through Saturday.

- Downsloping winds north of the Alaska Range should help keep Fairbanks and much of the valley floor mostly dry through the short term.

- Unseasonably mild conditions continue into Saturday with highs of 10 to 15 degrees above normal. A cool down will follow Sunday into Monday as a front brings temps back down closer to seasonable norms.

West Coast and Western Interior... - Strong northerly winds wind through the Bering Strain and into the NW Bering will slowly diminish overnight, Allowing for high surf advisories along parts of the Yukon Delta Coast to expire on time.

- Widespread precipitation should transition to mainly snow overnight and into Saturday for the western portions of the state. Through Saturday snowfall totals will exhibit a range of 1 to 5 inches (elevation dependent) across the Seward Peninsula, north towards Kivalina, and the Western Brooks Range.

- A passing cold front will bring drier and colder conditions over to wrap up the weekend before another approaching Bering Sea low returns warmer than normal temps, gusty winds, and additional precipitation to the region early next week.

North Slope and Brooks Range... - Snow spreads across the region through Saturday with generally lighter accumulations for coastal and lower elevations with anywhere from 1 to 3 inches of accumulation. Higher totals of 4 to 8 inches are possible for higher passes including Atigun Pass and western Brooks Range.

- Gusty north to northwest winds along the Western Arctic Coast will produce areas of blowing snow and localized visibility reductions through Saturday.

- Unseasonably mild conditions persist through Saturday with highs in the upper 20's to low 30's before a gradual cooling trend sets in Sunday and into early next week.

SYNOPSIS

The remnants of ex-Typhoon Champi will continue to track eastwards from the SE Bering into the northern Gulf over the weekend. As this system continues to weaken, strong winds and heavy snow through the Alaska Range will subside. Likewise high surf and strong northerly winds through the Bering will also slowly ease up. Snow will fall the next couple of days across portions of the West Coast and through the Brooks Range up onto the North Slope. An area wide transition to more seasonable temperatures takes place behind a passing front later in the weekend. Meanwhile another storm likely enters the Bering next week, which could bring another round of active weather going forward.

SHORT TERM /THROUGH MONDAY/

An active synoptic setup continues across Northern Alaska the first half of the weekend before a regime shift towards cooler, more seasonable air arrives Sunday into Monday. The primary synoptic feature driving current weather is the decaying remnant low of ex-Typhoon Champi, currently tracking southeastward through the Southern Bering enroute to the northern Gulf. A tight surface gradient remains established early this afternoon between this feature and higher pressure over western Canada. Guidance continues to indicate cross-barrier flow with enhanced southerly gap flow through the Alaska Range passes. By early Saturday morning, gradients will be relaxing as the low slowly fills, helping to bring wind speeds down substantially by Saturday afternoon.

In tandem with the the wind gradient, a strong plume of sub- tropical moisture riding the eastern periphery of the system continues to impinge on the southern slopes of the Alaska Range. Moderate to strong upslope flow will continue to sustain heavy mountain snow into Saturday before eventually winding down. Conversely, downsloping and rain-shadowing north of the Range will keep the Fairbanks bowl and lower Tanana Valley mostly dry.

By Sunday, broad upper level troughing and post frontal cold advection will overspread the Interior from the west. Model soundings show 850 mb temps dropping to around -5C to -8C, which will help to collapse the thermal ridge that has been in place, thus driving surface temperatures back a little closer to early November norms by late weekend. To accompany the cooling trend, building weak surface high pressure will result in drier, subsident conditions allowing for a rather quiet finish to the weekend.

Late Sunday and into Monday, guidance once again shows a Bering Sea low tracking towards the Aleutians. While this feature will push yet another thermal ridge and enhanced wind field into the Y-K Delta, mid-level ridging across eastern Alaska should keep the precipitation and any significant impacts well south and west of the Interior domain through at least the early part of next week.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

The extended begins with a weak ridge set up over Northeastern Alaska. Tuesday, a new low pressure system in the Bering Sea will begin to track southeast, gradually weakening as it travels along the Alaska Peninsula through Wednesday. Although there still remains disagreement in the track of this system, most of the current model guidance supports the storm moving through Bristol Bay/Northern Gulf Wednesday night/Thursday morning. However, regardless of which track the models agree upon, this system will likely remain weak. This will result in most of the impacts associated with this storm to be limited to isolated to scattered snow showers, gap winds, and gusty offshore winds along the West Coast/Western Interior.

As we approach the middle of our extended period on Wednesday, another storm looks to be approaching. This rapidly moving secondary low pressure system will pass through the Gulf Thursday morning, and then trend north, crossing through Mainland Alaska on Friday. Currently there is high confidence in this storm reaching the Gulf by the end of next week. However, there is still model disagreement on the strength and location of this storm during this timeframe. Similarly to the previous system, the impacts associated with this storm will likely remain outside of our area, getting blocked by terrain in southern Alaska. With this storm there is potential for another round of isolated snow showers throughout Alaska, but will likely be brief and light. Along with the potential for snow, strong northerly winds are possible within the Bering Strait, which may lead to some elevated seas and minor coastal impacts. These storms will continue to be monitored throughout the week.

COASTAL HAZARD POTENTIAL

Impacts along the west coast due to ex-Typhoon Champi will continue to diminish heading into the weekend as the system tracks into the Northern Gulf and weakens. Looking ahead to next week, another low enters the Bering and will bring the potential for additional coastal impacts depending on the track. At this time confidence in the forecast track and strength of this system remains low. However the situation will continue to be monitored going forward.

AFG WATCHES / WARNINGS / ADVISORIES

AK...High Surf Advisory until 1 AM AKDT Saturday for AKZ825. Wind Advisory until 7 AM AKDT Saturday for AKZ837-849. Wind Advisory until 4 PM AKDT this afternoon for AKZ847. Winter Weather Advisory until midnight AKDT tonight for AKZ848. Winter Weather Advisory until 7 AM AKDT Saturday for AKZ850. MARINE...Small Craft Advisory from 7 PM this evening to 6 PM AKDT Saturday for PKZ801. Small Craft Advisory from 7 PM this evening to 4 PM AKDT Saturday for PKZ802. Small Craft Advisory from 4 AM to 1 PM AKDT Saturday for PKZ803. Small Craft Advisory from 10 PM this evening to 7 AM AKDT Saturday for PKZ805. Small Craft Advisory until 6 PM AKDT Saturday for PKZ806-807- 854-856. Gale Warning until 10 PM AKDT this evening for PKZ806-817-854. Gale Warning until 4 PM AKDT this afternoon for PKZ807. Gale Warning from 7 PM to 10 PM AKDT this evening for PKZ807. Small Craft Advisory from 4 AM to 4 PM AKDT Saturday for PKZ808-855. Small Craft Advisory from 10 AM to 1 PM AKDT Saturday for PKZ809. Small Craft Advisory until 4 PM AKDT Saturday for PKZ810-850- 853. Small Craft Advisory until 4 AM AKDT Saturday for PKZ811. Small Craft Advisory until 7 PM AKDT this evening for PKZ814- 860. Gale Warning until 7 PM AKDT this evening for PKZ816-851. Small Craft Advisory until 7 AM AKDT Saturday for PKZ816-851. Small Craft Advisory until 10 AM AKDT Saturday for PKZ817. Gale Warning from 10 PM this evening to 1 AM AKDT Saturday for PKZ850-853. Small Craft Advisory from 1 AM to 1 PM AKDT Saturday for PKZ852. Small Craft Advisory until 1 AM AKDT Saturday for PKZ857.