textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior... -High temperatures in the upper 60s to low 70s Thursday cool slightly Friday and Saturday and bottom out Sunday in the upper 50s to mid 60s.

-A frontal system will bring 0.25- 0.5 inches of precipitation to the Interior from Fairbanks west Friday into Saturday. Another low entering the southwest Yukon increases chances of wetting rains slightly in the Upper Tanana Valley, although chances remain low.

-There are chances for an isolated thunderstorm or two each afternoon from Thursday through Saturday. The greatest probability and extent of thunderstorms is expected Friday afternoon, where isolated storms are possible across the entire Eastern Interior.

West Coast and Western Interior... -Relatively dry conditions expected Thursday ahead of a front Friday. This front moves across the West Coast Friday, and brings with it gusty winds, locally higher tides (no flooding is expected), and another round of moderate to heavy rainfall. -Rain totals of 0.75 to 1.5 inches expected along the Southern Seward Peninsula and Western Brooks Range.

-Northerly wind gusts through the Bering Strait increase Friday evening with gusts up to 45 mph possible. Winds diminish Saturday morning.

-Temperatures cool slightly following the front. Highs in the 50s to near 60 expected Friday through the weekend and into early next week.

North Slope and Brooks Range... -Isolated thunderstorms are possible in the Eastern Brooks Range and Arctic Plains Friday afternoon as a ridge shifts east into Canada.

-Temperatures cool into the weekend as a front passes over the North Slope. Expect highs in the upper 30s/low 40s after the front passes through, which will be Saturday west of Umiat and Sunday from Umiat east.

-A front sweeps across North Slope Friday and Saturday. It brings the potential for traces of snow, with 2-4 inches possible in the Northeastern Brooks Range.

SYNOPSIS

Broad, but weak, low pressure across the region keeps conditions cooler and showery into next week. A front moves west to east across Northern Alaska Friday into Saturday bringing increased rain and wind to the West Coast and chances of snow to the North Slope. The Eastern Interior slowly cools through Sunday with some isolated thunderstorms possible along higher terrain each afternoon/evening through Saturday. Forecast confidence is high in the overall pattern, but low in many of the finer details.

SHORT TERM /THROUGH SATURDAY NIGHT/

At the start of the forecast period, Thursday, the pattern is dominated by a large low pressure system over the Arctic Ocean northwest of Alaska and a pair of large region of high pressure in the North Pacific. A trough extends south from the Arctic low over most of Northern Alaska. Embedded in this trough are many smaller features that will influence the weather over the region through the next several days. The 2 largest of these features are a front approaching the West Coast from the northwest Friday and an upper level low at the bottom of the trough that moves from near Kodiak Island Thursday east and then north towards the Yukon by Saturday. Between these features lies expected weather for Thursday across the region. The larger pattern is easy to discern as cooler and showery, but many of the more specific details have become have become harder to forecast due to the presence of many smaller features. These smaller features become increasingly unpredictable as they interact with each other and makes many forecasting details such as the exact timing of precipitation or the range of possible rain totals much harder to nail down.

The front that moves east across the West Coast Friday will be more predictable in terms of timing, although there remains a large range of possible rain totals of 0.5 to 1.5 inches along the southern Seward Peninsula. Additional impacts include northerly winds gusting up to 45 mph through the Bering Strait and lows approaching freezing along the North Slope. As the front crosses the North Slope Friday through Saturday night light snow is possible. Given recent warm temperatures this snow will have difficulty sticking along the coast and is expected to quickly melt. The only place where notable accumulations are expected is in the Brooks Range where conservative ranges of 2 to 4 inches are possible across the Western Brooks Range. There is a much wider spread of possible values for the Central and Eastern Brooks Range where 1 to 5 inches is possible, but the more conservative estimates keep accumulations at 2 inches or less. There is also a very small, but non-zero chance for some periods of freezing drizzle along the Arctic Coast Friday night. The front pushes precipitation into the Western Interior by Friday afternoon and into the Central Interior by Saturday morning. As pressure decreases Friday and Saturday over the Eastern Interior increased instability allows for some isolated thunderstorms to form along the higher terrain of the Fortymile country.

The Southeastern Interior will be the least affected by this front remaining relatively warmer and drier than the rest of the region.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

At the start of the extended forecast period, Sunday, the pattern remains dominated by the upper level low over the Arctic Ocean and higher pressure in the North Pacific. The front that passed over the region earlier in the weekend will have reached the Gulf of Alaska and formed into a more distinct low. Between systems in the Bering the Pacific high pushes higher pressure north creating some weak ridging over the West Coast. A brief break in rainy weather is expected for the West Coast and Western Interior late Saturday into early Sunday before the next system starts moving towards the West Coast.

This next system moves through the West Coast as another low that rotates around the larger Arctic low. Model confidence on the timing, strength, and exact position of this system is low to moderate. This system will bring another wave of cooler, wetter, conditions to the West Coast and Western Interior, but there is a significant range of potential values for how wet it will get and how far into the Interior the rain will get. There is high potential for gusty south to southeast winds for the West Coast and its waters and periods of moderate to heavy rain along south and southwest facing slopes throughout the West Coast and Western Interior, but the range of possible values is too wide to be able to narrow in on other potential impacts.

Coastal Hazard Potential... A very weak Bering Sea storm will bring higher waters to the Eastern portions of Norton Sound Friday morning during high tide. This storm could bring an additional 1 to 2 feet of water above the mean high water mark. This could create some minor beach erosion, but no flooding is expected with this system.

FIRE WEATHER

Primary fire weather concerns remain across portions of the Upper Tanana. However, this area has seen a few showers over the last 12 hours. This was from a weak front moving NE ahead of an elongated NW- SW oriented trough that stretches from the Chukchi to the northern Gulf of Alaska. At the base of this axis, a well defined low will continue to move east across the northern Gulf Thursday night into Friday. Meanwhile, another low will begin to shift SE out of Siberia on Friday, which will help with the progression of the low in the Gulf. Throughout the day on Friday, the gulf low will begin to shift more northerly and progress across the southeastern Portion of the Interior. This will allow for a brief period of SE flow to set up across Eastern Alaska, which could lead to isolated thunderstorms during the afternoon. Temperatures are expected to remain between 60 and 70 degrees through much of the weekend. The driest values will continue to be along the Upper Tanana, although not as dry with expected values around 35 percent.

On Saturday, the low from Siberia will continue to shift SE across the YK Delta and replace the previous low that was situated over the northern Gulf. The associated surface low will also bring a series of fronts across the Interior which could provide a chance wetting rain for areas west of the Dalton and the Parks Hwy. The trough will continue to push east throughout the day, bringing isolated to scattered showers across the Upper Tanana Saturday night into Sunday. Although the chances for wetting rain decrease farther SE. Westerly flow will set up across the state by the start of next week. This will allow for scattered showers to continue across the state as a series of shortwaves move across. In addition, this will also bring cooler temperatures which will help moderate some of the fire weather concerns.

HYDROLOGY

Despite recent heavy rainfall across portions of the Central Interior and Brooks Range, rivers and streams have not seen significant rises in water levels. While some smaller creeks and streams could still reach bankfull with additional rainfall through , no flooding is currently anticipated. An additional 0.5" to 1.0" of rainfall is possible Friday and Saturday across the Koyukuk and Middle Yukon Valleys. This rainfall could keep the water levels elevated in the smaller creeks and streams.

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. MARINE...Small Craft Advisory from 10 AM to 4 PM AKDT Friday for PKZ801. Small Craft Advisory from 4 PM to 6 PM AKDT Friday for PKZ806- 807. Small Craft Advisory from 1 PM to 6 PM AKDT Friday for PKZ817- 854.