textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior... - Lows dropping into the the upper teens and lower 20's tonight will refreeze remaining surface moisture and slush, creating localized slick travel conditions through Wednesday morning.

- Precipitation returns from the west Wednesday afternoon and advances east overnight. A period of light freezing rain mixed with snow is possible into Thursday AM before transition to rain/snow showers Thursday.

- Strong winds will blow through the Alaska Range Passes Wednesday with the potential for localized blowing snow and reduced visibility through pass corridors.

- Noticeably warmer Friday with highs potentially near 40 degrees along with slight chances for rain/snow heading into the weekend.

West Coast and Western Interior... - Coastal rain and gusty winds continue into Wednesday morning as High Surf Advisories remain in effect tonight along much of the west coast.

- Heavy snow remain possible across the south slopes of the western Brooks Range through Thursday with the heaviest accumulations expected Wednesday night into Thursday morning.

- Elsewhere widespread rain is expected along the coast with a rain/snow mix over the western Interior Wednesday into Thursday with precip totals of 0.20 to 0.50 inches possible.

- Beyond Thursday: Remnants of Typhoon Champi approach Late Thursday and into Friday. A coastal Flood Watch is in effect for the Yukon Delta Coast as rising water levels, strong gusty wind, and additional precipitation move into the region.

North Slope and Brooks Range... - Persistent southerly winds of 15 to 25 mph will keep areas of blowing snow in place across the western and central Brooks Range through Thursday. Additional snowfall can be expected through Thursday morning resulting in localized travel impacts over the Dalton Highway Summits as well as Atigun and Howard Passes.

- Gusty winds will remain through Wednesday along the Northwest Arctic coastline. As winds shift to the southwest Thursday localized blowing snow will be possible for both Point Hope and Point Lay.

- Unseasonably mild temps (highs in the mid-to-upper 30's) will help maintain slight chances for rain/snow across portions of the Arctic coast with the potential for some light freezing rain Wednesday night for portions of the Northwest Arctic Coast.

SYNOPSIS

Clearing skies across portions of the Interior will allow for colder temps and a refreeze of surface moisture Tonight into Wednesday morning. Meanwhile, strong southerly flow remains in place across the west with coastal rain, high surf, and blowing snow across portions of the Brooks Range. As a front advances east Wednesday through Thursday additional rain/snow chances will push into the Interior along with the potential for strong gap winds through the Alaska Range passes. By late week the remnants of Typhoon Champi will allow winds to ramp up again along the west coast with localized coastal flooding concerns along the Y-K Delta coast while unseasonably mild air spreads northwards in advance of the system.

SHORT TERM /THROUGH FRIDAY/

An amplified longwave trough anchored over far eastern Russia and the Bering Sea continues to tap a deep fetch of moisture, driving higher precipitable water values towards western Alaska. Downstream, a transient shortwave ridge over the Gulf of Alaska looks to provide a brief window of subsidence across the Interior tonight. This ridge will flatten Wednesday as shortwave energy ejects out of the Bering Sea, dragging a cold front eastwards across the state through Thursday night.

Under building high pressure aloft tonight, clearing skies and light winds will foster strong radiational cooling over portions of the Interior. Boundary layer temps will drop into the upper teens and lower 20's triggering a widespread refreeze of standing moisture and slush, creating slick travel for the Wednesday morning commute. As the ridge axis shifts east Wednesday afternoon, robust low-to-mid level warm air advection will precede the advancing cold front. As a warm nose aloft at 850 mb overrides the shallow cold layer over the valley's, a period of light freezing rain or sleet could take shape Wednesday night over the central Interior lowlands, including the Fairbanks metro. Any precipitation looks to be light and will quickly transition to rain and snow showers by Thursday afternoon as boundary layer mixing increases. Meanwhile, a tight north-south surface gradient will drive strong cross- barrier flow through the Alaska Range passes. Southerly gusts to 65 mph through Isabel Pass looks likely Wednesday afternoon through Thursday morning.

Across the West Coast and Western Interior, persistent southerly to southwesterly flow ahead of the main trough maintains strong low level moisture convergence. Orographic lift over the western Brooks Range will sustain additional snowfall. Thus Winter Storm Warnings remain in effect in this area through Thursday afternoon. At lower elevations warmer temperatures will keep most of the precipitation primarily liquid with overall QPF values of 0.20 to 0.50 inches. As the surface front moves east Thursday afternoon a brief lull in the precipitation chances will set in ahead of the next system that arrives Thursday night.

By late Thursday night, the extratropical transition of former Typhoon Champi will be complete as it's core tracks into the southern Bering. Although the storms center is expected to remain south of our region, an expanding wind field will trigger a surge in easterly to southeasterly coastal winds Thursday night. Building high surf will initiate rising water levels along the Yukon Delta Coast ahead of the main precipitation shield. As such a Coastal Flood Watch has been issued for late week from Kotlik to Hooper Bay. In addition another round of strong gap winds through the Alaska Range passes will be developing late Thursday and into Friday with the potential for gusts as high as 60 to 70 mph.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

Ex-typhoon Champi is set to weaken throughout Friday and into Saturday before moving east into the Gulf of Alaska. The upper level low (which also weakens, becoming more of a longwave trough by Saturday), frontal band, and warmer airmass associated with Champi shifts east into the Interior Friday and Saturday. Precipitation will primarily fall as rain in Interior valleys on Saturday, though southerly Chinook flow will ensure that little to no precipitation makes it to the ground in the Central and Eastern Interior from Fairbanks east. Weak troughing lingers over the western third of the state through Sunday afternoon/evening, supporting lingering shower activity in the region. Snow levels do eventually drop towards the surface Sunday as the warm airmass associated with Champi moves to the southeast.

Forecast confidence decreases as we look ahead to next week. There is a potential for another low pressure system in the Bering early next week, but as is often the case in the 6-7 day time frame, forecast confidence is low. One of the features that will affect the low's track is a ridge (or lack thereof) over the Eastern Aleutians/Alaska Peninsula. The ECMWF ensemble solutions favor a much stronger ridge, which would keep the low in the Central Bering, at least initially. The GFS ensemble solutions depict this ridge much weaker, which would keep the low closer to the Aleutians and well south of the Yukon Delta Coast. We will continue to monitor this system as it develops.

Coastal Hazard Potential... As our most recent coastal storm exits to the north, attention turns to the remnants of Typhoon Champi which looks to track into the Bering Sea by Thursday morning. With current guidance placing the storm center just south of Nunivak Island. Broad coastal flooding concerns across the West Coast remain fairly limited due to a forecast track that will take the storm to our our south. The primary exception is Hooper Bay, where model guidance indicates water levels rising 4 to 6 feet above the normal high tide line Thursday evening. Elsewhere along exposed sections of the West Coast shoreline, high surf, gusty winds, and moderate to at times heavy rainfall can be expected Thursday into Friday.

HYDROLOGY

Repeated rounds of moderate-to-heavy precipitation will keep rivers and streams along the west coast and Seward Peninsula elevated through the week, with the highest hydrologic impacts focused near Nome. An incoming frontal boundary tapping into an atmospheric river, followed by the remnants of Typhoon Champi late in the week, will maintain persistent rain and high- elevation snow accumulations across western regions.

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Storm Warning until 4 PM AKDT Thursday for AKZ813-814. High Surf Advisory until 4 AM AKDT Wednesday for AKZ815-817- 818-820>822-824-825. Coastal Flood Watch from Thursday morning through late Friday night for AKZ825. Dense Fog Advisory until 2 PM AKDT this afternoon for AKZ840- 841-844. Wind Advisory from 7 AM Wednesday to 7 AM AKDT Thursday for AKZ847-849. MARINE...Small Craft Advisory until 1 PM AKDT Wednesday for PKZ801-806- 858. Small Craft Advisory until 6 PM AKDT Wednesday for PKZ802-803- 805-808>810-852-853-855. Small Craft Advisory until 10 PM AKDT this evening for PKZ804- 816-817-851. Small Craft Advisory from 7 AM to 6 PM AKDT Wednesday for PKZ804. Small Craft Advisory from 4 PM to 6 PM AKDT Wednesday for PKZ806-816-817-854. Small Craft Advisory until 4 PM AKDT Wednesday for PKZ807-811- 856-857. Brisk Wind Advisory from 10 AM to 4 PM AKDT Wednesday for PKZ809. Small Craft Advisory until 1 AM AKDT Wednesday for PKZ812. Small Craft Advisory until 7 AM AKDT Wednesday for PKZ850. Small Craft Advisory from 10 AM to 1 PM AKDT Wednesday for PKZ850. Gale Warning until 4 PM AKDT this afternoon for PKZ851. Small Craft Advisory until 10 AM AKDT Wednesday for PKZ854.