textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior... - Freezing overnight temperatures yield slick travel conditions Wednesday morning as wet and slushy spots from Tuesday become frozen.

- Precipitation builds into the region from west to east Wednesday night into Thursday morning. Liquid accumulations will be between a T-0.25". Higher accumulations are expected north and west of Tanana.

- Southerly gap winds through the AK Range Passes strengthen Wednesday morning and stay elevated through late Wednesday night gusting upwards of 65 mph. Winds strengthen again Thursday afternoon and continue through Saturday morning with gusts up to 80 mph possible in the Eastern AK Range.

- Temperatures remain above seasonable norms in the mid/upper 30s through Friday before cooling into the mid/upper 20s over the weekend.

West Coast and Western Interior... - Rain/snow showers continue across the West Coast this morning, moving east into the Western Interior Wednesday afternoon/evening. Rain is expected during the day with a transition to snow overnight and above 1500 feet.

- Moderate snowfall accumulations between 4 to 6 inches are expected across the southern slopes of the Western Brooks Range through late Wednesday night.

- A brief break in precipitation is expected Thursday morning before remnants of Typhoon Champi bring a return of widespread rain/snow showers to the region Thursday night through Friday.

- Impacts from Champi remain fairly minor with the exception of Hooper Bay where water levels 2 to 4 feet above the normal high tide line and minor flooding of low-lying areas are expected. A Coastal Flood Advisory is in effect from Thursday morning through late Friday night.

North Slope and Brooks Range... - Gusty winds and slight chances for a rain/snow mix at times will continue along the Chukchi Sea Coast through Thursday afternoon from Utqiagvik west. Snow chances are highest farther east, with rain more likely farther west.

- Heavy snow is expected in the Western Brooks Range through Thursday afternoon, with accumulations between 8 to 18 inches. Another round of snowfall will move in from the southwest Thursday night through Friday morning with an additional 8 to 12 inches possible over the Central Brooks Range.

- Temperatures remain seasonably warm through Saturday with highs in the low/mid 30s and lows in the low/mid 20s.

SYNOPSIS

A rainy start to the morning can be seen across the West Coast today as a front moves through the area. This front will gradually move east through Wednesday bringing widespread precipitation to much of the Interior Wednesday night into Thursday. Fairly light accumulations are expected in the FNSB, with most precipitation falling as rain during the day, transitioning into snow overnight and above 1500 feet. Remnants of Typhoon Champi bring yet another round of widespread precipitation and gusty winds to Western Alaska beginning Thursday morning/afternoon. As a result, showers build into the Western Interior from the southwest through Friday while winds strengthen and gust up to 60 to 70 mph through the AK Range Passes Thursday evening through Saturday morning.

SHORT TERM /THROUGH FRIDAY NIGHT/

The forecast remains on track with a ridge of high pressure currently sitting over Prince William Sound and a decaying low over Siberia. A front associated with the aforementioned low continues to progress eastward this morning as it gradually embeds itself within a shortwave trough. Because this front is tapping into atmospheric river moisture extending all the way down from around 30N, widespread moderate to heavy precipitation will impact the West Coast through Wednesday night. Due to temperatures in the upper 30s and low 40s across the region, rain is expected at the surface with snow above 1500 feet. Farther north, moderate to heavy snowfall will impact the southern slopes of the Western Brooks Range where 6 to 12 inches is expected near Red Dog Mine and up to 18 inches are expected at elevation. Periods of blowing snow may develop at times where winds gust up to 35 mph. Towards the overnight hours Wednesday, the front moves farther east into the Interior where liquid precipitation accumulations will generally range from a T- 0.25". The highest accumulations are expected to the north and west of Tanana, as well as within the Central Brooks Range. Ahead of the front's arrival, southerly gap winds through the Alaska Range Passes strengthen with gusts up to 65 mph expected. A Wind Advisory remains in effect from 7 AM Wednesday through 7 AM Thursday.

Looking towards Thursday, the West Coast experiences a brief break in precipitation before another round of showers moves in from the southwest as remnants of Typhoon Champi move into the Bering Sea. Previous model guidance had this system tracking farther north and with each model run has progressively shifted its track farther south. As a result, impacts from this storm remain much more marginal than originally anticipated, with the YK Delta coastline feeling the most effects. With that being said, a Coastal Flood Advisory is in effect for Hooper Bay from 7AM Thursday through 1 AM Saturday for water levels 2 to 4 feet above the normal high tide, beach erosion, and flooding of low-lying areas/buildings. Otherwise, as the storm moves farther east through the day Thursday, strong southerly flow sets up over the state, with a nearly 8 to 10 mb gradient set up over the AK Range. With a gradient that strong, we expect to see winds quickly strengthen again with gusts up to 60 to 70 mph possible through Saturday morning. Otherwise, as mentioned earlier, precipitation will gradually build in over the state from the southwest, pulling in quite a bit of tropical moisture with it. This abundance of moisture will help to yield snow accumulations of 8 to 12 inches in the Central Brooks Range, while the rest of the Central and Eastern Interior remains fairly dry due to downsloping effects. Similarly, because of strong southerly flow in place over the past few days, temperatures across the state remain above seasonable norms but will gradually cool going into the weekend as broad troughing sets up over the state.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

At the start of the extended forecast period, Saturday, the pattern continues to shift to broad troughing. A strong low pressure system in Bristol Bay continues to shift southeast towards the Gulf of Alaska. Gusty east to northeasterly winds across the West Coast and Interior weaken Saturday. Rain and snow showers dissipate across the West Coast and Interior Saturday and Sunday.

By late Monday a messy pair of strong low pressure systems move into the Southern Bering Sea. These two storms are of roughly equal strength at first, around 960 millibars, and rotate around each other as they move east along the Aleutians. This is a very messy system with uncertain impacts. Which of these two storms becomes more dominant will end up determining impacts for the West Coast. Most models are currently suggesting that the easternmost of the two lows with better access to warm, moist air is more likely to become dominant. This would keep impacts farther south and limit Coastal impacts for the West Coast from Hooper Bay north. There are some model solutions that are suggesting that the westernmost low will be able to strengthen enough in the Bering Sea to instead become dominant. This would cause the more eastern storm to rotate north towards the West Coast bringing additional wind, rain, and water impacts to portions of the West Coast and Western Interior. We will continue to monitor the development of these messy storm systems and update as the forecast becomes more certain.

Away from the coast, the shifting trough/ridge axis is expected to lead to warming over the eastern portions of the state early next week. Storm impacts will be more limited over the Central and Eastern Interiors.

COASTAL HAZARD POTENTIAL

Water levels slowly receed through the end of the week. The next storm to approach the West Coast will be the remnants of Typhoon Champi. Since yesterday, the expected storm track for this storm has shifted even farther south with it now moving towards Bristol Bay Thursday through Friday. The most recent guidance places the track 200 miles south of Nunivak Island which will significantly weaken all expected coastal impacts from this storm system for areas from Hooper Bay north. The Coastal Flood Watch for Hooper Bay has been downgraded into a Coastal Flood Advisory for water levels peaking in the 2 to 4 foot range above the normal high tide line with the Thursday high tide. The more southerly track will limit water levels elsewhere along the coast with most of the Norton Sound and Yukon Delta Coast only seeing 1 to 3 feet of rise above the normal high tide line with the Thursday high tides.

Another messy pair of storms move through the southern Bering Sea early next week which could bring coastal impacts back to portions of the West Coast. This is a very disorganized system with high uncertainty in its development once it reaches the Bering Sea. Most model guidance currently suggests that the storm will be well to the south of Nunivak Island which would significantly limit impacts once again. There are, however, enough ensemble members showing more northerly tracks that could cause some coastal impacts that these storms cannot be dismissed. We will continue to monitor their development and update the forecast as confidence improves.

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. A 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 Watch from Thursday evening through Saturday morning for AKZ812. Winter Storm Warning until 4 PM AKDT Thursday for AKZ813-814. Coastal Flood Advisory from 7 AM Thursday to 1 AM AKDT Saturday for AKZ825. Wind Advisory until 7 AM AKDT Thursday for AKZ847-849. MARINE...Small Craft Advisory until 1 PM AKDT this afternoon for PKZ801- 806. Small Craft Advisory from 4 AM to 6 AM AKDT Thursday for PKZ801-814-850-851-859-860. Small Craft Advisory until 7 PM AKDT this evening for PKZ802- 803. Small Craft Advisory until 10 PM AKDT this evening for PKZ804. Small Craft Advisory until 10 PM AKDT this evening for PKZ805- 809-852-853. Small Craft Advisory from 4 PM this afternoon to 4 AM AKDT Thursday for PKZ806-854. Small Craft Advisory until 4 PM AKDT this afternoon for PKZ807. Small Craft Advisory from 7 PM this evening to 6 AM AKDT Thursday for PKZ807-856. Small Craft Advisory until 4 AM AKDT Thursday for PKZ808-855. Brisk Wind Advisory from 1 PM to 4 PM AKDT this afternoon for PKZ809. Small Craft Advisory until 6 AM AKDT Thursday for PKZ810. Small Craft Advisory until 4 PM AKDT this afternoon for PKZ811- 856-857. Small Craft Advisory from 10 PM this evening to 6 AM AKDT Thursday for PKZ811-812-857-858. Small Craft Advisory from 1 AM to 6 AM AKDT Thursday for PKZ813. Brisk Wind Advisory from 4 AM to 6 AM AKDT Thursday for PKZ813- 814. Small Craft Advisory from 4 PM this afternoon to 10 PM AKDT this evening for PKZ817. Small Craft Advisory until 7 AM AKDT this morning for PKZ850- 858. Small Craft Advisory from 10 AM this morning to 1 PM AKDT this afternoon for PKZ850. Small Craft Advisory until 10 AM AKDT this morning for PKZ854. Brisk Wind Advisory from 1 AM to 6 AM AKDT Thursday for PKZ859.