textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior...

- Following widespread wind gusts across the Interior of 30 to 50 mph, winds will gradually subside this evening as rain showers build in out of the west.

- Slightly cooler temperatures in the low to mid 50s expected Wednesday and Thursday as a shortwave moves southeast across the state from the Chukchi Sea, eventually warming back into the upper 50s/low 60s by Friday.

- A strong low pressure system tracks northeast towards the Chukchi Sea Thursday into Friday and ejects a warm front into the Interior Thursday afternoon. As this system moves farther inland, more widespread rain and gusty winds are expected across the Interior through Saturday evening. New rainfall amounts could range from 0.50" to 1.50".

West Coast and Western Interior...

- Rain showers continue through the day as a shortwave passes through from the west. Winds gusting up to 35 mph are possible through Wednesday evening.

- A strong low pressure system begins to track northeast towards the Chukchi Sea Wednesday afternoon and ejects a warm front into Western Alaska late Wednesday night into Thursday. As this system moves farther east Thursday into Friday, widespread rain and gusty winds are expected regionwide, with high surf and minor coastal erosion expected.

- High Surf Advisories are in effect Wednesday through Friday along the coast from the YK Delta to Kivalina for water level rises around 2 to 4 feet above the normal highest high tide line. High Wind Warnings have also been issued for St. Lawrence Island and the Bering Strait for wind gusts up to 65 mph.

- Storm total rainfall amounts will be around 0.50" to 1.50" regionwide with locally higher amounts in the Southern Seward Peninsula, southern slopes of the Western Brooks Range, and Kobuk/Noatak/Wulik River Valleys around 1.50" to 2.50".

North Slope and Brooks Range...

- A shortwave moving east from Siberia and into the Chukchi Sea will continue to support additional rain showers across the North Slope and snow showers at higher elevations of the Brooks Range Wednesday morning through Wednesday night.

- A strong low pressure system begins to track northeast towards the Chukchi Sea Wednesday afternoon and ejects a warm front towards the Lisburne Peninsula by early Thursday morning. As this system moves farther inland Thursday into Friday, widespread rain, gusty winds, and onshore flow is expected across the NW Arctic Coast where high surf and minor coastal erosion is expected.

- Storm total rainfall amounts will range from 0.50" to 1.00" regionwide, with higher totals in the Western Brooks Range around 1.50" to 2.50".

- High Surf Advisories have been issued for the NW Arctic Coast from Point Hope to Wainwright for water level rises around 3 to 5 feet above the normal highest high tide line. High Wind Warnings have also been issued for Point Hope to Point Lay for wind gusts up to 65 mph.

SYNOPSIS

Following peak gusts across the Interior of 30 to 50 mph today behind a cold front, our next system lifting north from the Western Bering Sea into Siberia and the Chukchi Sea remains on track to bring widespread rain and gusty winds into Northern Alaska. High Surf Advisories remain in effect from Hooper Bay to Wainwright across the West Coast, with High Wind Warnings in effect for St. Lawrence Island northeast through the Bering Strait to the Western Arctic Coast. As several rounds of rain and atmospheric river moisture build in, rainfall totals through Saturday will be widespread around 0.50 to 1.50 inches, locally higher around 1.50 to 2.50 inches for the Northwest Arctic Coast and Western Brooks Range region. Driest conditions will be farther east across the Yukon Flats and Upper Tanana Valley. Going into the weekend, fairly cool and wet weather with breezy conditions are expected to continue across much of the state with models hinting at the potential for yet another Bering Sea low to arrive later this weekend.

SHORT TERM

Today through Friday Night. The current forecast remains fairly on track with multiple shortwave features driving the pattern through midweek. Widespread wind gusts of 30 to 50 mph have been observed across the Interior today, with rain showers building in out of the west as the first shortwave tracks east. The Wind Advisory may need to be cancelled earlier dependent on how late continued mixing of the stronger 925 mb winds aloft. The second shortwave feature to note will be moving into the Chukchi Sea this morning. As this feature moves farther inland, it will support additional rain showers across the North Slope as well as snow showers at higher elevations of the Brooks Range through tonight. By early Thursday morning, this feature will have moved southeast into the Interior bringing an additional round of rain showers across the region. The majority of this rainfall will impact the Middle Tanana Valley north and west towards the Yukon Flats and AlCan border while the Upper Tanana Valley remains mostly dry due to downsloping effects from a building upper level ridge over the Alaska Peninsula. Additional rainfall amounts from this system will be between 0.10" to 0.25".

Besides the messy and disorganized interactions of these shortwaves features, the most notable system to mention is a strong low over the Sea of Okhotsk moving northeast into the Chukchi Sea Wednesday into Thursday. As this system progresses eastward, it pushes a warm front across the state, first reaching the West Coast Wednesday evening, the North Slope by Thursday morning, and the Interior by Thursday afternoon. By Thursday night, a strong pressure gradient will have formed over Western Alaska as a 1040 mb high pressure in the North Pacific pushes against the 998 mb low over the Chukchi Sea.

This pattern helps to set up strong southwesterly flow that funnels an abundance of moisture into the West Coast from Northern Japan in the form of an atmospheric river. As a result, widespread rain, strong gusty winds, and onshore flow will impact Western Alaska through early Saturday morning. High Surf Advisories remain in effect through late Friday night from the YK Delta coastline north towards the NW Arctic Coastline for water levels 2 to 5 feet above the normal high tide line. Localized beach erosion may occur as well, however flooding is not expected. The highest rainfall amounts will range from 1.50" to 2.50" and will mainly impact the Southern Seward Peninsula, the southern slopes of the Western Brooks Range, and the Kobuk/Noatak/Wulik River Valleys. More on this will be discussed in the Coastal Hazard and Hydrology sections.

As the low moves farther east going into Friday, more widespread rain will make its way into the Interior, but exact rainfall amounts are a bit uncertain for now. Storm total rainfall will be highly dependent on how the North Pacific high moves/shifts and where areas of downsloping will work to keep parts of the Interior a bit drier than surrounding areas. Otherwise, mostly wet and active weather persists going into the weekend with models hinting at yet another low pressure system moving into the Bering Sea later into the weekend.

No major changes were made to the forecast today. We have updated hazard timing and the forecast remains on track.

LONG TERM

Saturday through next Wednesday. The extend begins on Saturday, with the arctic low tracking northeast through the Beaufort Sea, and the sustained ridge moving east out of Alaska. As these systems progress, the previous pressure gradient between them will begin to weaken. As a result, wind gusts will begin to decrease Saturday through early Sunday morning.

During this time, westerly winds are expected for the Interior, and any areas north of this region. The Northwestern Coastline will likely see gusts between 30 to 40 mph throughout Saturday, and see them dropping off by early Sunday morning. The North Slope has the potential to reach between 35 to 45 mph, and weaken closer to Sunday afternoon/evening. Along the Interior wind gusts are expected to be slightly weaker, ranging between 20 to 30 mph at the start of Saturday, and trailing off into early Sunday morning.

Precipitation throughout Saturday to Sunday will be relatively uniform, ranging between 0.2" to 0.6" for most of the Central West Coast and Interior, with areas north of the Brooks Range likely receiving 0.1" to 0.3". Higher elevations have more potential to receive heavier amounts of rainfall, ranging upwards to an 1.25".

Continuing with the extended on Sunday morning, a new pattern will begin to develop throughout our area. A ridge will begin to orient itself over Alaska on Sunday, and progressively track east through Monday. At the same time a low pressure system will begin to move north into the Bering Sea. This system will then track towards Alaska Tuesday, and likely fully reach the West Coast on Wednesday morning.

The confidence has increased in the track of this coastal storm, due to better model agreement then shown previously. Both the ECMWF and GFS ensemble models show this low pressure system traveling north from the tropics and reaching the Bering Sea roughly around a similar time. Along with general track agreement, both models are showing similar solutions with an atmospheric river extending towards Alaska during the same time of this storm.

Given this model agreement, there is reasonable confidence that this upcoming storm may bring moderate to heavy amounts of precipitation along the West Coast of Alaska, as well as some hydrological impacts. Confidence in precipitation remain high at this time, but exact amounts are still uncertain with this storm. Due to model uncertainty in the low tracks we have low confidence on the potential for strong winds and coastal impacts. Current model guidance suggests a gale force low, will impact southwest Alaska with marginal coastal impacts. This pattern will continue to be monitored over the next couple of days.

COASTAL HAZARD POTENTIAL

A developing Siberian low is quickly moving northeast towards the Chukchi Sea setting up southwesterly flow across the West Coast. This low will bring gale force winds into Norton Sound and Kotzebue Sound. With these strong winds and long fetch of the winds we will see water rises across the West Coast. For much of the coastline we could see rises of 2 to 5 feet with the highest rises from Elim to Unalakleet. These 2 to 5 feet rises across the West Coast has led us to issue High Surf Advisories across the Coastline from Hooper Bay to Point Lay. While no flooding is expected localized beach erosion may occur.

With the strong southwesterly winds continuing for roughly 48 hours, there will be multiple high tide cycles that will be elevated. Waters will begin to rise Wednesday and will peak Thursday night for the communities along the Norton Sound and the Y-K Delta Coastline. The higher waters are expected to continue through Friday. For communities along Kotzebue Sound and then the NW Arctic Coastline waters will rise early Thursday morning and peak Friday morning. The higher waters for this region will continue into Saturday.

FIRE WEATHER

Due to multiple rounds of precipitation, past and future, there are no fire weather concerns for the West Coast and North Slope, though gusty southwest winds will persist for these areas through the rest of the week.

Gusty southwest winds across the Interior peaking this afternoon will be the main story today due to a front passing through the area. Widespread gusts 30 to 40 mph are expected with stronger gusts possible at higher elevations. Isolated to scattered rain showers will be possible overnight into Thursday morning. Areas across the Yukon Flats and Fortymile Country will be drier through the week compared to other areas in the Interior. Friday will likely feature slightly warmer temperatures in the Upper Tanana Valley due to downsloping as well as slightly lower min RHs. Saturday should return to status quo.

HYDROLOGY

A strong low is moving into the Chukchi Sea late Wednesday night and will be accompanied with an atmospheric river extending to the tropics. This atmospheric river will help to produce 72 hour rainfall totals of 0.5" to 2.5" for most of Northern Alaska. The wettest areas will be the Southern Seward Peninsula and the south slopes of the Western Brooks Range will be the wettest. Friday and into Saturday the front that brought the moderate to heavy rainfall will drape and stall across the northern slopes of the Alaska Range. This could help to produce 0.75" to 1.5" of rainfall in 24 hours from Denali Park to the White Mountains including the FNSB. This rainfall wouldn't produce any flooding impacts, but could create rapid rises in the smaller tributaries.

In the Western Brooks Range and Northwestern Interior particularly the Kobuk, Noatak, and Wulik a hydrologic outlook has been issued. With the continued periods of heavy rainfall in the region the smaller streams will be more vulnerable to see bankfull conditions and rapid rises. No flooding in this region is expected.

Across most of Northern Alaska the mainstem rivers are low and this next round of moderate rainfall is not expected to create any flooding hazards. However, on the smaller creeks and streams could see rapid rises and/or bankfull conditions. Recreators should be prepared for rapidly changing water conditions in the smaller tributaries.

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Surf Advisory from 10 PM this evening to 4 AM AKDT Saturday for AKZ801-802. High Wind Warning from 4 AM Thursday to 4 PM AKDT Friday for AKZ801. High Surf Advisory until 4 AM AKDT Saturday for AKZ815>818. High Surf Advisory until 10 PM AKDT Friday for AKZ820>822-824- 825. High Wind Warning from 10 PM this evening to 4 PM AKDT Friday for AKZ820-821-827. Wind Advisory until 10 PM AKDT this evening for AKZ831>846. MARINE...Small Craft Advisory until 4 PM AKDT this afternoon for PKZ801>803-805-850-852-853. Small Craft Advisory from 1 AM to 6 PM AKDT Thursday for PKZ801-802-807-850-853-854-856. Small Craft Advisory from 7 PM this evening to 6 PM AKDT Thursday for PKZ803-816-817-851-852. Small Craft Advisory until 7 PM AKDT this evening for PKZ804. Small Craft Advisory from 10 PM this evening to 6 PM AKDT Thursday for PKZ804>806. Gale Warning from 7 AM to 10 AM AKDT Thursday for PKZ806. Gale Warning from 1 PM to 6 PM AKDT Thursday for PKZ806-810. Gale Warning from 10 AM to 6 PM AKDT Thursday for PKZ807-811. Small Craft Advisory from 10 AM to 6 PM AKDT Thursday for PKZ808-855-858. Small Craft Advisory from 7 AM to 6 PM AKDT Thursday for PKZ809-811-857. Small Craft Advisory from 4 AM to 6 PM AKDT Thursday for PKZ810. Small Craft Advisory from 1 PM to 6 PM AKDT Thursday for PKZ812. Gale Warning from 7 AM to 4 PM AKDT Thursday for PKZ817. Gale Warning from 7 AM to 6 PM AKDT Thursday for PKZ856. Gale Warning from 4 PM to 6 PM AKDT Thursday for PKZ857.