textproduct: Fairbanks

SYNOPSIS

An anomalously strong low in the Arctic is bringing a very stout cold front through Northern Alaska. Moderate snowfall is continuing in the Brooks Range, where a winter weather advisory remains in place until 10 PM Monday. Ahead of the cold front spotty rain showers will continue across the Central and Eastern Interior. As this front moves southeast today through the Interior, it will bring a 6 to 8 hour period of moderate rainfall. Behind this cold front, skies will rapidly clear, and overnight temperatures will drop. The Northslope and Northwest Interior will drop in to the 20s, while the Interior temperatures will drop to the low to mid 30s. Wednesday afternoon temperatures will warm back up to a few degrees below normal, and are expected to gradually warm into the weekend.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Scattered showers will continue this morning ahead of a cold front later today. As this front moves over, steadier rainfall is expected with rain accumulations up to 0.15" possible.

- Behind this cold front, skies will begin to rapidly clear. With clear skies and colder arctic air, temperatures will begin to bottom out, with lows in the 30s Monday night and Tuesday night. Widespread frost is possible across the Tanana Valley, and the colder valleys could hit freezing.

- Gusty winds will continue across the Interior today with gusts up to 30 mph possible. Areas above 1500 feet could see wind gusts up to 45 mph.

- Temperatures will steadily warm starting Wednesday afternoon. This warming trend will take us to the low 70s by this weekend.

West Coast and Western Interior... - A cold front is moving through the region this morning, and will bring some scattered rain and snow showers. Behind this front conditions will quickly dry out, and skies will clear.

- This cold front is keeping northwesterly winds up to 35 mph going through today. These winds will begin to weaken Monday night.

- Colder and drier conditions on Tuesday will give way to a warming trend Wednesday onwards as temperatures return to more seasonable levels with highs rebounding into the 50s/60s/70s regionwide.

North Slope and Brooks Range.. - Light snow is continuing this morning across the Eastern Arctic Coastline, with heavier snow in the Brooks Range. In the Brooks Range there is a winter weather advisory for heavier snowfall with an additional 2 to 4 inches possible today.

- Another round of light snow is possible Monday night for Wainwright and Utqiagvik. Accumulations will be light with less than inch anticipated.

- Below normal temperatures will continue today with highs around 30 degrees. Tuesday will see a warming trend that will continue to the weekend. Temperatures along the Arctic coast will warm to the upper 30s and low 40s, while the Arctic Plains could see 60 degrees as soon as Thursday.

FORECAST ANALYSIS AND DISCUSSION

Today through Wednesday Night. An anomalously strong low in the high Arctic is ejecting a positively tilted trough into Northern Alaska. For context, that low is 506 decameters, and in early June that is -3.6 sigma. -3.6 sigma correlates to a roughly 0.03% chance of occurrence when compared to the mean. As the positively tilted trough gets ejected southeast towards the Interior, a cold front will accompany it. This will help to produce isolated to scattered showers along the front. The Upper Tanana Valley and Fortymile Country could see an isolated thunderstorm today, as temperatures will not be affected from the cold front. As the cold front drags eastward on Tuesday expect those thunderstorm chances to shift eastward towards the AlCan.

Behind the front skies will quickly clear, and cold and dry conditions will settle over Northern Alaska. Clear skies will allow for temperatures to plummet across Northern Alaska Monday night. In the Tanana Valley, the timing of the clearing skies will make the difference of having frost or not. Models are in fairly good agreement that skies will begin to clear around 3 am. This should be enough time for the inversion to quickly strengthen, and rapidly drop temperatures. This could allow for a brief period of frost. In the colder valleys you should expect frost, and possibly even freezing temperatures.

Tuesday will see the cold front linger across the Eastern Interior, as it begins to weaken. Tuesday night could see another round of frost development, but there is less confidence at this time for it. Much of the colder air that will be in Tanana Valley Monday night will be forced northward on Tuesday.

High pressure will begin to build over the Bering Sea and Western Canada on Wednesday. This will bring us quieter and warmer weather. This pattern shift will be talked about in more detail in the Extended Forecast Discussion.

FIRE WEATHER

A cool, windy, and wet day is on tap for much of Interior Alaska today. Ahead of an approaching cold front, scattered showers are continuing across the Central and Eastern Interior. These showers are likely not producing wetting rains, but on southwest facing slopes there is a higher chance that they could be due to upslope mechanics. The main area for thunderstorm concerns will be in the Upper Tanana Valley and Fortymile Country. As the cold front moves southeast across the Interior, it will bring widespread light showers. Locations above 1500 feet should see wetting rains with this storm, but the valleys will struggle to receive wetting rains. Temperatures will struggle to get into the 60s today, with the exception of the Upper Tanana and Fortymile Country. The only areas of concern for RH will be the Upper Tanana Valley, with RH values in the upper 20s.

Temperatures will continue to drop Tuesday, but with clear skies and dry air aloft, the minimum RH values will also be dropping. Near critical RH values are possible across the Western and Central Interior Valleys. Winds will weaken overnight Monday, so while RHs will be a concern on Tuesday, the winds should not be. Looking ahead to the middle of the week, we will see a warming trend begin and the minimum RH concern slowly shift eastward.

HYDROLOGY

No changes from the previous hydro forecast discussion.

Sagavanirktok, Colville, and Kuparuk Rivers

Below normal temperatures continue across the North Slope, with APRFC's breakup map showing some open to mostly open water on the Sag, Colville, and Kuparuk Rivers outside of immediately along the Arctic Coast where mostly ice remains in place. Fresh Eyes on Ice reports indicate that there could be some minor ice jams forming near the coast, but impacts remain limited at this time and is more just backing up water.

Colder temperatures will remain in place through early next week with warming temperatures expected Tuesday onwards. By as soon as Thursday and Friday, highs in the 50s and 60s will be in place across the Arctic Plains with 30s/40s along the Arctic Coast. This will likely accelerate snowmelt and lead to rises on North Slope rivers. With the recent cooldown and drop overall in most river levels, this will likely give enough room for new snowmelt to join the channels and help mitigate any significant flooding concerns at this time. Stay tuned.

For the latest breakup information, visit weather.gov/aprfc.

EXTENDED FORECAST DAYS 4-7

Thursday through next Monday. The expansive Arctic upper low will loosen its grip over northern Alaska on Wednesday as high pressure ridges over Canada and the Aleutians begin to merge, introducing a notable warming trend that will support above normal temperatures across western Alaska and the Interior through the weekend. This will act as a dirty ridge due to a persistent remnant low lingering in the Gulf, keeping cloud cover around and fueling daily scattered showers and isolated thunderstorms across the region as minor shortwaves propagate through the flow. High confidence ensemble guidance indicates that the primary Canadian ridge will set up along or just west of the CONUS West Coast late next week. This positioning leaves room for an anchored low pressure system near the Alaska Peninsula or western Gulf of Alaska to maintain southerly flow and enhanced moisture advection into much of mainland Alaska. This synoptic regime will reinforce a return to summerlike weather across the Interior with widespread showers, thunderstorms, and a prolonged period of temperatures ranging from the mid 60s to the mid 70s, while coastal regions remain cooler with highs in the 50s and 60s along the West Coast and 40s to 60s from the North Slope to the Brooks Range.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Weather Advisory for AKZ809. PK...Small Craft Advisory for PKZ804. Small Craft Advisory for PKZ806. Gale Warning for PKZ808. Gale Warning for PKZ809. Small Craft Advisory for PKZ810. Small Craft Advisory for PKZ812-858. Brisk Wind Advisory for PKZ813. Brisk Wind Advisory for PKZ855. Brisk Wind Advisory for PKZ859.