textproduct: Fairbanks

SYNOPSIS

Wet and windy conditions will be the primary weather focus for much of western and Interior Alaska over the next several days. A storm system in the Bering will continue to tap into a deep stream of moisture and bring it north into the Western and eastern Interior through at least early Sunday. Meanwhile the North Slope is still feeling a lot like winter with colder temps and occasional snow showers as a separate system slowly tracks east across the Beaufort. By late weekend both systems will begin to loosen their grip on the region, but more unsettled weather will be possible heading into next week.

KEY MESSAGES

Central and Eastern Interior...

- Widespread rain will continue to push into the region this afternoon and into this evening as a warm front approaches from the southwest.

- Rainfall is expected to be moderate to heavy at times overnight tonight into Friday and again Friday night into Saturday as an Atmospheric River associated with a low in the Bering continues to supply deep moisture to the Western and Central Interior.

- Total rainfall of 1.00 to as much as 2.50 inches of rain will be possible over the course of the next few days. This represents annual return intervals of up to 10 or even 25 years for some locations.

- Local main stem rivers will see significant rises, but should be able to handle the expected excessive rainfall. However smaller streams and rivers that feed the main stem rivers could experience minor flooding.

- Despite the deep moisture push, portions of the Upper Tanana Valley and Fortymile region may remain mainly dry.

- Warmer conditions are expected in the days to come, especially in areas where the rain is less intense.

West Coast and Western Interior...

- Rainfall coverage diminishes along the West Coast later tonight as an atmospheric river moves east of the area. However, parts of the Western interior will continue to see periods of moderate rainfall through Saturday.

- Current rainfall along the west coast will likely amount to between 0.50 to 1.00 inches across Western Alaska through tonight, with locally higher totals at St. Lawrence Island up to around 1.25 inches.

- S/SW winds along the Yukon Delta coast and into the Norton Sound will diminish somewhat in speeds to between 20 and 30 mph. However do to a long fetch of these southerly winds through the Bering, water levels are expected to continue to rise, especially for the Norton Sound where High Surf Advisories remain in effect through Saturday morning.

- Water levels could potentially reach 2 to 4 feet above the normal high tide, with highest levels expected around Golovin and Elim Friday morning. A secondary water level rise is expected Saturday morning around the time of high tide.

North Slope and Brooks Range...

- Winter's chill will remain for another day or so as a low north of the Arctic coastline continues to bring bands of mainly light snow to portions of the North Slope.

- The warm front associated with a low in the Bering will reach the western and central Brooks Range tonight and early Friday. Widespread mainly light precipitation is expected with it's arrival.

- Snow will develop at higher elevations, but the moisture plume is expected to shift eastwards with time, allowing for most of the snow over the Brooks Range to shift eastwards as well. Accumulations should remain rather light ranging from 1 to 3 inches depending on elevation.

- Temperatures will hold steady through the first half of the weekend, with highs in the 30s/40s and lows in the 20s/30s. High elevations of the Brooks Range tonight could drop to around 10-20F with wind chills down around 0-10F.

SHORT TERM /THROUGH SUNDAY NIGHT/

While an upper low over the eastern Beaufort continues to supply some light snow showers for the Arctic coastline and North Slope, it is expected to continue slipping east as surface high pressure settles into the central Beaufort, helping to settle things down across the north for a few days. However a stubborn upper low spinning out over the western Bering continues to provide lot's of impactful weather for areas from the Brooks Range south and west.

The general circulation around the Bering low in concert with upper ridging that has built into southcentral Alaska is bringing a steady southwest flow pattern to much of western and central Alaska. Initially this is being realized at the surface as a warm front that reached the Seward Peninsula around daybreak today with widespread light to moderate precipitation and should be impinging on the Brooks Range as early as tonight. While pockets of heavier rainfall will continue along the frontal boundary itself, the primary focus for sustained significant rainfall will be along an Atmospheric River that is attached to the warm front. Satellite imagery continues to show a healthy AR stretching from about 35 degrees latitude northwards over Bristol Bay and into the western Interior as of this writing.

With the north Pacific ridge continuing to shift a bit to the southeast, this AR is expected to tilt more to the east, thus placing the highest available moisture content over portions of the central Interior Friday and Saturday. This is a trend that models latched onto a couple of days ago and continue to advertise. Current ECMWF EFI (Extreme Forecast Index) products indicate that the heaviest rainfall associated with the AR across the Interior will primarily focus along a line that stretches from McGrath northwards to Bettles and eastwards to near the Fairbanks metro area. It appears as if the heavy rainfall will occur Thursday night into Friday morning with a secondary push across the same area Friday night into Saturday morning. 48 hour QPF values of well over 1.00 inch to as much as 2.50 inches will be possible through Saturday afternoon.

Aside from the heavy rain threat, there is still the issue of stronger winds associated with the Bering low as well. It appears as if the strongest winds through the Bering and into Norton Sound are subsiding as the flow becomes more southerly. However this is resulting in mainly onshore flow that will continue to result in high water levels along the west coast, especially northern and eastern Norton Sound. More on this is found below in the "Coastal Hazard Potential" section.

Coastal Hazard Potential...

A low in the Bering will continue to allow for sustained southerly flow through the north Bering into the Norton Sound for the next couple of days. Due to the long fetch of southerly winds over open water, water levels could rise 2 to 4 feet above the normal high tide line in the Norton Sound, and 1 to 2 feet above the normal high tide line along the Yukon Delta Coast. Water levels are expected to peak Friday morning and again during the period of high tide Saturday morning. As a result we have issued a High Surf Advisory for coastal areas of the eastern Norton Sound where guidance is showing the highest water level rises at this time.

LONG TERM /MONDAY THROUGH THURSDAY/

The active and unsettled weather pattern is expected to continue across Northern Alaska through midweek as the ridging currently situated over the southeast shifts further east into Canada. The movement of the low allows for a broad area of troughing to develop over the state, with multiple embedded shortwaves and remnant fronts circulating through the overall pattern. With each passing shortwave, showers will return bringing more moisture into Northern Alaska. Attention then shifts to a new low pressure system that is expected to work its way into the Bering Sea from the Pacific, bringing strong winds and elevated waves. The landfall of this new low is where the greatest uncertainty currently lies with current model runs forecasting a track that is expected to make landfall in the southern YK Delta. A low track further south would reduce potential impacts for the Norton Sound and West Coast, however should the low track further north, potential for coastal erosion could occur with strong winds driving higher waves to the coast. Stay tuned for updates.

FIRE WEATHER

After a chilly morning temperatures are slow to rise across the Southeastern Interior this afternoon. This afternoon a ridge will begin to settle into the region bringing warmer temperatures, drier conditions, and a brief stint of gusty gap winds. The southerly gap winds will begin to ramp up west to east across the Alaska Range with the Tok Cutoff seeing winds begin around 4PM this afternoon. Today was anticipated to be driest day, but with southerly gap winds lagging behind, minimum RH values may struggle to get below 40%.

A low pressure in the Bering Sea is bringing a warm front sweeping up and over the aforementioned ridge bringing moderate to heavy rainfall to the Central Interior and parts of the Fortymile Country. Over the next few days we could see 0.5" to 2.5" of rainfall across the Central Interior. Unfortunately the ridge is expected to remain over the far Southeastern Interior keeping the Upper Tanana Valley and the Fortymile Uplands dry.

This pattern will continue for the next few days as the low in the Bering brings reinforcing shortwaves of energy. As the ridge eventually weakens and gets pushed off to the east Saturday afternoon, a weak shortwave trough will move through the far southeastern Interior. This trough could produce enough instability

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Surf Advisory from 10 PM this evening to 11 AM AKDT Saturday for AKZ822-824. MARINE...Small Craft Advisory until 4 PM AKDT this afternoon for PKZ806- 854. Small Craft Advisory until 1 AM AKDT Friday for PKZ807>810-855- 856. Small Craft Advisory until 6 PM AKDT Friday for PKZ811-857. Small Craft Advisory from 7 PM this evening to 6 PM AKDT Friday for PKZ812-858. Small Craft Advisory from 1 PM to 6 PM AKDT Friday for PKZ814. Brisk Wind Advisory from 4 PM to 6 PM AKDT Friday for PKZ814.