textproduct: Fairbanks

SYNOPSIS

The pattern change across Northern Alaska continues as the warmer and drier conditions earlier in the week have given way to rainier and cooler conditions through the end of the week, with an unsettled pattern looking to stick around into early next week. A front situated over the northeastern Interior this afternoon will continue to lift northeastward with scattered rain showers and breezy winds as a more organized low in the Bering Sea moves onshore into Southwest Alaska this afternoon and evening. Widespread rain and gusty winds will accompany this low as it tracks inland Thursday into Friday, as cooler temperatures settle in region-wide. Associated with the Bering Sea low, minor coastal impacts such as high surf are possible, but should remain minimal, overall. While any thunderstorm chances over the coming days will remain isolated in nature given the cooler airmass building-in, there is increasing confidence for primarily a rain/snow mix and a pocket or 2 of freezing rain for the mainly for portions of the North Slope and Brooks Range later in the day Thursday into Friday. As this mid-to- late week system shifts eastward Friday into Saturday, warmer and drier conditions will progressively build-in out of the west ahead of an arctic trough working southeastward out of the Chukchi Sea late Saturday into Sunday. This secondary system will support another round of rain/snow mix for the Brooks Range and North Slope and rain for areas to the south, along with breezy winds and subsequent cooler temperatures.

KEY MESSAGES

Central and Eastern Interior...

- A front situated over the far northeastern Interior Wednesday afternoon that has been continuing to bring some isolated to scattered rain showers is lifting northeastward and departing the region throughout the rest of the day as drier conditions continue to build-in out of the southwest. This drying trend will be short lived as widespread rain moves in for late Wednesday into Thursday, continuing through Friday morning as a Bering Sea low moves inland.

- Additional rainfall amounts through Friday are expected to be around 0.25-0.75" regionwide with locally higher totals around 1-2" in the Alaska Range and locally lighter totals around 0.10-0.25" in the Upper Tanana Valley around Tok and Northway.

- Cooler temperatures and breezy winds will accompany the aforementioned system, with highs in the 60s/70s today dropping to the 50s/60s for Thursday and Friday. Winds across the Interior will peak this evening into Friday with generally gusts to around 20-30 mph expected. Locally stronger winds will continue through Alaska Range Passes this evening through Thursday where Wind Advisories are in effect.

- Dry conditions will build-in out of the west on Friday into Friday night as best rain chances shift to the east of Fairbanks. Warmer temperatures will return over the weekend as highs rebound into the 60s/70s.

- An arctic front remains on track to work southeastward through the Interior Sunday into Monday with widespread rain, breezy winds, and cooler temperatures.

West Coast and Western Interior...

- A front lifting northeastward, exiting the Western Interior, has been continuing to bring some isolated to scattered rain showers. It will continue lifting northeastward throughout the day and exit the region ahead of a Bering Sea low that will be moving onshore later today.

- That Bering Sea low will move onshore into Western Alaska late today, bringing widespread rain and gusty winds through Thursday. The strongest winds will remain west/northwest along the West Coast, with the primary concerns continuing to center around high surf and minor coastal flooding. See the Coastal Hazard Potential discussion below for additional information.

- Water levels will rise a bit with each high tide tonight through Friday morning. A High Surf Advisory has been issued for the Yukon Delta coast region from 4pm today until 4pm Thursday for Water levels 1-2 ft above the highest high tide line. Localized beach erosion may occur. Fortunately, impacts are expected to be minor.

- Additional rainfall amounts through Thursday are expected to be around 0.25-0.75" regionwide with locally higher totals around 1-2" in the Alaska Range and 0.75-1.25" for the Upper Kuskokwim near McGrath and Nikolai, along with locally lighter totals around 0.10- 0.25" for the NW Arctic Coast and Kotzebue Sound region.

- Gusty winds will accompany this system as it moves inland, as temperatures hold relatively steady. Wind gusts will peak tonight into Thursday and Thursday night around 30-45 mph along the West Coast and 20-30 mph in the Western Interior.

- Dry conditions will build in out of the west on Thursday and continue through Friday. A much weaker low will move into Southwest Alaska on Saturday with isolated to scattered light rain showers possible.

- An arctic front remains on track to work southeast through Western Alaska late Saturday into Sunday with widespread rain, breezy winds, and cooler temperatures.

North Slope and Brooks Range..

- A front will continue to lift northeast towards the Eastern Arctic Coast this afternoon into tonight with scattered to widespread showers and isolated thunderstorms. Small pockets of light freezing drizzle will also be possible along the Arctic Coast from Utqiagvik to Point Lay.

- A low moving into Western Alaska from the Bering Sea will move into the Interior this afternoon through Thursday, meeting a colder airmass situated over the High Arctic. Steadier rain will move into the Brooks Range on Thursday as colder air pushes south, supporting a transition to a rain/snow mix with isolated pockets of freezing rain. Storm total snowfall accumulations Thursday through Friday morning could be 3 to 5 inches, however with surface temperatures above freezing, the snow is not anticipated to stick to the road.

- The bulk of precipitation expected through Friday is expected to remain focused in the Brooks Range, Central/Eastern Arctic Plains, and Eastern Arctic Coast. Precipitation totals around 0.25-0.75" are expected in the Brooks Range, with around 0.10-0.40" for eastern portions of the Arctic Plains and Coast. Locally lighter totals around a T-0.10" are expected for the Central and Western Arctic Coast and Western Arctic Plains.

- Gusty winds will accompany this system as it passes over the North Slope, as temperatures see a cooling trend. Wind gusts will peak out late Thursday into Friday with up to around 30-45 mph regionwide, strongest in the Brooks Range and around Kaktovik.

- Warmer and drier conditions later in the day Friday into Saturday will be short lived as an arctic front remains on track to work southeast into far Northern Alaska late Saturday into Sunday with a rain/snow mix, gusty winds, and cooler temperatures.

FORECAST ANALYSIS AND DISCUSSION

Today through Friday Night.

Our primary forecast attention is transitioning to the low approaching in the Bering Sea. The latest CAMS and ensemble models remain in good agreement on the track and intensity of this system, showing it maintaining a similar strength of around mid-990s mb as it tracks northeastward toward the Norton Sound. The low pressure center is expected to make landfall in the Interior Norton Sound overnight tonight into early Thursday morning, as widespread rain and gusty winds have been building into Western Alaska throughout the day today & will continue into into tonight. Rain and wind will shift east into the Interior this afternoon into tonight & Thursday, as broad upper level troughing encompasses Northern Alaska. A front stalled over the High Arctic will get wrapped into the broad circulation Thursday into Friday, as colder air from the Chuckhi and Beaufort Seas meets a warm and moist airmass over the Interior with the North Slope and Brooks Range in between. This setup will remain conducive for precipitation to favor a rain/snow mix in the Central/Eastern Brooks Range and Eastern Brooks Range where small pockets of freezing rain/drizzle will also be possible. Storm total snowfall accumulations could be 3 to 5 inches, however with surface temperatures above freezing, the snow is not anticipated to stick to the road. Even ahead of this front dropping south, temperatures hovering around freezing from Utqiagvik to Point Lay today combined with the frontal boundary and low stratus could lead to small areas of light freezing drizzle. Pertaining to the aforementioned pockets of freezing drizzle, it is important to note that these areas have been experiencing warm temperatures for quite some time. So, SFC temps are relatively warm, making chances for significant freezing rain/freezing drizzle unlikely. Following an active thunderstorm day yesterday with over 2000 cloud to ground lightning strikes in Alaska and the Yukon, thunderstorms will trend to being much more isolated over the coming days as cooler temperatures and a more stable airmass work to suppress the bulk of convection.

Drier conditions will build in west to east Thursday into Friday across Northern Alaska as a ridge of high pressure shifts inland from the Bering Sea following the exiting low. Precipitation totals through Friday have remained consistent with previous forecasts, showing a broad 0.25-0.75" across much of Northern Alaska as driest locations including the NW Arctic Coast and Upper Tanana Valley around Tok and Northway pick up around a T-0.25". Locally higher amounts around 1-2" will also be possible in the Alaska Range. When it comes to potential wintry precipitation across the North Slope and Brooks Range, warm ground temperatures should limit accumulations with the exception to that being higher elevations of the Brooks Range including Atigun Pass which could see light snow amounts of a few inches to accumulate. With respect to freezing rain/drizzle amounts, expect those to remain light and focused along the Arctic Coast.

A Wind Advisory remains in effect for the Eastern Alaska Range north of Trims Camp along the Richardson through 7 PM Thursday. The current brief lull in the winds during the daytime hours today will ramp back up into this evening and Thursday morning as that low in the Bering Sea approaches. This Wind Advisory has been expanded to include the Windy Pass area from this evening into Thursday morning. Winds with the Bering Sea low will peak as the low tracks over the state, with peak gusts along the coast around 30-45 mph and around 20-30 mph in the Interior with locally higher spots. See the Coastal Hazard Potential section below for details on what we are expecting with this wind for our coastal communities along the West Coast from the Yukon Delta north to the Kotzebue Sound.

Coastal Hazard Potential Days 1 through 3...

A Special Weather Statement remains in effect for potential coastal impacts tonight to Friday morning from a Bering Sea low. Latest model guidance is coalescing on a more southerly track towards the YK Delta region as well as minor storm intensification to around the mid 990s mb is expected before moving ashore into Norton Sound. This system will likely bring widespread moderate to heavy rain along the coast with gusty west/northwest winds up to 45 mph (40 kts) this afternoon through Thursday night. Minor coastal impacts such as high surf for the Yukon Delta, Norton Sound, and areas north of the Bering Strait are possible. Water levels will rise slightly with each high tide tonight through Friday morning. The highest water level rises will be in Eastern Norton Sound, around 1 to 3 feet above the normal high tide line. General water level rises around 0.5 to 1.5 feet are expected from Golovin to Nome. A High Surf Advisory has been issued for the Yukon Delta coast region from 4pm today until 4pm Thursday for Water levels 1-2 ft above the highest high tide line. Localized beach erosion may occur. Water will approach the road to the Hooper Bay Airport, but should not inundate the airport or the road. Fortunately, significant impacts are not anticipated. We will continue to update as necessary. In the meantime, the West Coast from the Yukon Delta to Kivalina should continue to monitor the latest forecasts. Stay tuned to weather.gov/fairbanks for the latest updates.

EXTENDED FORECAST DAYS 4-7

SATURDAY THROUGH WEDNESDAY

Saturday evening an arctic cold front will dig south towards the North Slope. This cold front will bring 850 mb temperatures ranging from 0C to -7C with the coldest temperatures in the Brooks Range. There is some slight timing differences between the models, which could make precipitation types messy. The current expectations would be precipitation starts as rain during the day, and during the overnight hours it transitions to snow. Snow accumulations would be light due to surface temperatures well above freezing, but with gusty winds, blowing snow could be a concern.

As this cold front moves into the Interior on Sunday, another round of widespread precipitation and gusty winds are possible. Behind the front a weak ridge will build across the Interior from the Bering Sea. This would help to bring temperatures back to near normal as early as Monday. While a ridge builds across the Interior, low pressure will remain over the Northwest Arctic. This would create a tight pressure gradient, keeping gusty northwesterly winds and cooler temperatures in the Northwest Arctic.

Through the middle of next week, model guidance has not been in good agreement. The GFS/GEFS solutions would keep troughing over a majority of the mainland. This trough would keep us locked into a cooler and wetter pattern through at least Thursday. The ECMWF and the ECMWF ensemble as well the Canadian Ensembles show a ridge developing over Mainland Alaska, keeping temperatures more seasonable.

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ849. High Surf Advisory for AKZ825. PK...Gale Warning for PKZ801-850. Gale Warning for PKZ802-806. Small Craft Advisory for PKZ803. Small Craft Advisory for PKZ804-805-852-856. Small Craft Advisory for PKZ807. Small Craft Advisory for PKZ808>810-855. Small Craft Advisory for PKZ816-817. Small Craft Advisory for PKZ851. Small Craft Advisory for PKZ853. Small Craft Advisory for PKZ854.