textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior...

- Conditions will trend predominantly dry through Sunday, with rain lifting northward once more through the latter half of Monday.

- Patchy Fog is likely Sunday morning. - Temperatures will trend warmer into Monday for most areas, with highs in the 50s/60s and lows in the 30s/40s. Temperatures cool somewhat Tuesday onwards, but remain above freezing overnight

West Coast and Western Interior...

- A series of lows entering Southwest Alaska and lifting north will bring steadier rain chances to the Yukon Delta and Norton Sound region on Sunday, before lifting northeast Monday into Tuesday to encompassing all of Western Alaska.

- Southwest winds will pick up on Wednesday ahead of a strong low and atmospheric river moving into Western Alaska late Wednesday into Thursday. This system will bring widespread rain, gusty winds, and onshore flow, with the potential for high surf and minor coastal flooding. Stay tuned for additional updates.

- Temperatures will hold steady through midweek, with highs in the 40s/50s to low 60s with lows in the 30s/40s.

North Slope and Brooks Range...

- Widespread low stratus and areas of fog persist.

- Conditions will trend drier for Sunday into early Monday outside of very isolated showers, with another front lifting north throughout the day Monday into the Brooks Range with rain showers, especially for the NW Arctic Coast.

- Temperatures will hold steady or see a warming trend through midweek with highs in the 40s/50s and lows in the 30s/40s, colder across higher elevations of the Brooks Range.

SYNOPSIS

The Pacific storm track continues to remain fixed squarely over Northern Alaska, bringing system after system to our doorstep through the upcoming week. The widespread rainfall from the most recent system has finally come to an end as the atmospheric river responsible has finally left the area, leaving lingering low clouds and pockets of fog in its wake. The active weather pattern looks set to continue however, as additional systems move up from the SW and into the Interior. The next low will move N out of the Alaska Peninsula and over the Seward Peninsula through Monday, keeping chances of rain in the forecast for the western interior and coast through early next week. Hot on its heels a new system moves in from the SW, bringing a surge of rain and breezy conditions which will spread across the area Tuesday. Another shortwave moves in rapidly behind it, keeping chances of rain in the forecast on Wednesday. Ridging briefly starts to rebuild across the Gulf of AK and the Eastern and central Interior Thursday, before crumbling in the face of a fairly strong Bering Sea low and its corresponding fronts Friday into Saturday.

SHORT TERM /THROUGH TUESDAY/

A brief lull in the rain has settled across much of the Interior, as the remnants of an atmospheric river move off into the Arctic Ocean. In the system's wake, saturated ground has provided a foundation for patchy fog which has developed through the early morning hours across parts of the central and eastern interior.

The pause in the rainfall will not last long however with satellite and radar showing the next low already knocking at our door. This low will encounter significant difficulties remaining cohesive as it moves north, as partial phasing with a weak warm front originating in the western Bering Sea will result in the system functionally splitting in two. The mid- level circulation and the best dynamic support will move E into the Gulf of AK, while a portion of the low level circulation will move due North through Monday, ultimately reaching the Seward Peninsula and bringing chances of rain for Sunday and Monday across the West Coast and Western Interior. While some chances of rain cannot be ruled out for the Tanana Valley, southerly flow over the Alaska Range will encourage downsloping, keeping precip chances for FSNB on the lower side. The southerly flow will support moderate Chinook winds in the vicinity of Isabel Pass, with gusts of 40-45 mph anticipated in parts of the eastern AK Range on Tuesday.

By early Tuesday, this low will have been supplanted by a stronger system moving out of the SW and making landfall over the Kuskokwim Delta. Deterministic guidance is in good agreement on this system being fairly weak (around 995 to 1000 mb), but with fairly abundant moisture support and a prevailing SW flow pattern, rainfall will spread across the area reaching from the central and eastern interior through the NW Arctic Coast.

Immediately in the wake of this system, a weak ridge will begin building across south/central on Wednesday, steering a shortwave over its axis and directly over northern Alaska, bringing still more chances of rain. The silver lining with all of these systems being the continued injections of warmer subtropical air keeping snow levels above 4k ft for most places, and cooler autumn conditions held at bay - at least for now.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Weather conditions continue to remain inclement, with confidence growing that a respectable strength storm system on Thursday and Friday could bring with it high surf and the potential for some minor cold flooding.

In the wake of a shortwave which moved through on Wednesday, a ridge builds over the Alaskan Interior, before moving east on Thursday. As the ridge moves E through AK, a fairly strong 975-985 mb low is expected to move over NE Siberia. The low itself looks to have respectable dynamics, with moisture support from the subtropics alongside a ~145kt jet streak along its eastern flank.

All of this will result in SW flow along the low's flank racing up across the Bering and into the West Coast. While the low's distance from the state will prevent any truly spectacular sustained winds, do still think that there will be a period of 20-30kt winds along a considerable fetch of the Bering Sea from late Wednesday through Friday. This will drive a surge of water which will impact parts of the W Coast, particularly areas along Norton Sound and potentially along the Kuskokwim Coast. At this time, think that this could result in the potential for high surf, or even minor coastal flooding for a few locations. We will provide updates as confidence grows in the final storm track and strength.

Otherwise, the system itself will bring a fast moving plume of moisture across Northern AK. Some significant differences in precip totals remain, with the Euro and its Ensemble showing significantly less precip for the central interior owing to a stronger anticipated ridge, while the GFS and its ensemble bring more moisture into the central and eastern parts of our area as they break down the ridge more quickly. Given the usual overaggressiveness that deterministic models and ensembles have when it comes to breaking down ridges, think that the EURO likely has a better grasp on rainfall potential in this case. Either way, periods of rain and breezy conditions will last through the weekend, with the initial system being reinforced by another shortwave moving up through the latter half of the weekend.

Coastal Hazard Potential...

Confidence is growing in a respectable strength 975-985 mb system which will move over NE Siberia Thursday and Friday. Strong SW flow near the surface of 25-30kt sustained could bring elevated chances of high surf, and potentially even minor coastal flooding to parts of the West Coast. Currently anticipate that the best chances for elevated surge levels will be around Norton Sound and for the Kuskokwim Delta area, with heights of 3-5 ft possible. Stay tuned for additional updates.

FIRE WEATHER

Most of northern Alaska continues to enjoy periods of wetting rainfall through the foreseeable future, with temperatures reaching the mid to upper 50s or lower 60s, and relative humidities remaining fairly elevated. The one exception is the upper Tanana Valley and forty mile country, where generally drier conditions have prevailed, and will for the most part continue to prevail barring some scattered showers. The best chances of more appreciable wetting rain for this area would likely be late Tuesday into Wednesday, when a wind shift from the W or NW could allow some moisture from the central interior to move further east. Minimum RH values of between 45-55% are expected through Monday for the forty mile country area, before increasing to 60%+ Tuesday and Wednesday.

HYDROLOGY

Rivers and streams have risen in response to a recent atmospheric river, but have remained below bankful. Rainfall totals through the first half of the week will be low enough that flooding concerns are not anticipated.