textproduct: Fairbanks

SYNOPSIS

Broad troughiness continues over the Bering. This is allowing for daily chances for isolated showers across much of the West Coast and the Interior. High pressure holds strong over the Arctic which will keep the cooler temperatures and low ceilings over the North Slope over the next couple of days. Another low will move inland from the northern Gulf of Alaksa, bringing a line of showers across the Interior throughout the day, today, and into tomorrow. Another, more pronounced low will move along the Aleutians, setting up around Bristol Bay sometime Thursday morning. An abundant amount of energy is associated with this low and will wrap a series of shortwaves into the Central Interior and West Coast over the next couple of days. In addition, southerly flow will be set up over the Alaska Range as these shortwaves move north, setting up the potential for another round of gusty winds through the Isabel and Windy Pass on Thursday. The upper-level trough will slowly elongate eastward through the end of the week which will slightly increase the chances for isolated thunderstorms through the start of the weekend.

KEY WEATHER MESSAGES

Central and Eastern Interior... - An increased chance of precipitation today as a system moves north across the Interior. This will set up daily chances for isolated showers and a non-zero chance for a thunderstorm or two. - Chances for thunderstorms become more scattered across the Central Interior by Friday afternoon.

- Seasonably warm temperatures are expected to continue across the Interior through much of the week.

West Coast and Western Interior... - Gusty S-SE winds are expected to continue across the West Coast through with an upper-level shortwave passage. Thunderstorm chances continue for portions of the Western Interior.

- Showery conditions are expected along the Lower Yukon and Yukon Delta regions throughout the week. Light showers expected today with heavier showers possible on Thursday. These showers will be mostly rain, especially nearer the Western Interior, but some periods of snow and light wintry mix are possible near St. Lawrence Island and the Bering Strait Coast.

North Slope and Brooks Range.. - Breezy northeasterly winds along the Western North Slope weaken slightly and shift more easterly. E to ENE winds 15 to 25 mph are expected across the Arctic Coast through the rest of the day.

- Diurnal showers along the southern portion of the Brooks Range are expected to continue through the week. Little to no precipitation is expected for the North Slope

- Chilly temperatures persist with highs in the 20s and lows in the teens along the North Slope. A gradient of temperatures across the Brooks Range with highs in the 50s to near 60 along the southern slopes and low 40s for the northern slopes.

- Low clouds and areas of fog persist across the Arctic Coast and will likely remain through much of the week, especially along the Eastern Arctic Coast.

FORECAST ANALYSIS AND DISCUSSION

Isolated showers continue across portions of the Central Interior and West Coast as the remnants of a shortwave move NW over the Norton Sound. Another low continues to work its way into the northern portion of the Gulf of Alaksa. Models continue to show agreement in this low setting up between the 150 and 140 degree longitude line, which will be a good setup for wrap around precipitation into the Interior. Meanwhile, a more pronounced low will be work its way up the Aleutians, entering Bristol Bay Thursday morning. Ahead of this low, a warm front will swing across the YK-Delta late tonight into early Thursday morning. However, some isolated showers may continue to linger across the West Coast throughout the day, today. Cold air will continue to be advected from the north across the Bering, which will allow for mixed precipitation chances to continue St. Lawrence Island and the Bering Strait.

This new low over Bristol Bay will eventually take over as the main driver for the broad troughiness across much of the state. With this, a series of shortwave will wrap around this low which will allow daily chances for scattered showers and isolated thunderstorms to continue across much of the state through the end of the week. A more pronounced line of energy will begin to work its way north, by Thursday, as it stretches from the YK-Delta to the Eastern Interior. This will help tighten the gradient and allow for another round of gap winds through the Alaska Range on Thursday. The main bulk of the energy will work its way into the Kuskokwim valley on Friday, setting up the next chance for scattered, afternoon thunderstorms. The best chance for storms, Friday, will be across the Central and Western Interior.

Looking over the North Slope, high pressure continues to linger off the northern Arctic Coast. Cooler temperatures, breezy east winds, and low cloud ceilings are expected to continue as the overall pattern is not expected to change much over the next few days.

As the end of the short-term period rolls in, models are showing the potential for a shortwave to peel away from the main low and work its way east across the Gulf. Doing this will help stretch out the trough farther east, potentially setting up easterly flow across portions of the Interior by the start of the weekend. A set up like this would be favorable for isolated to scattered thunderstorms across the Interior throughout the weekend.

FIRE WEATHER

The overall pattern remains mostly the same through much of the week with a low in the Bering Sea and ridging over Western Canada. This pattern will continue to support broad southerly flow across the region. Downsloping effects will work to keep most of the Central and Eastern Interior dry and warm with a few afternoon rain showers possible tomorrow. Increased chances for precipitation return this weekend as an influx of moisture is brought into the Interior. Accumulations should remain light with localized higher amounts expected in southwest Alaska, the Brooks Range, and where thunderstorms are present. Although chances are low, a non-zero chance for lightning is possible Friday afternoon through Sunday afternoon across portions of the Interior, Brooks Range, and Yukon Flats. Expect high temperatures in the 60s and lows in the 40s through the week, with min RH values ranging between 20 to 30% in the Central and Eastern Interior and 30 to 40% in the Western Interior.

The greatest fire concern this week will be near Delta Junction as strong southerly gap winds strengthen again on Thursday due to a tightening pressure gradient over the Alaska Range. Expect sustained winds 25 to 35 mph gusting as high as 60 mph possible. Winds will gradually weaken throughout the day Friday before subsiding by Saturday morning. Although min RH values are expected to be a bit higher on Thursday (around 30%), critical fire weather conditions may still develop in Delta Junction Thursday afternoon. The biggest limiting factor for this will be temperatures and whether or not highs in the mid to upper 50s can dry out the atmosphere enough to reach an min RH value of 25% or lower during the afternoon. Therefore, we will continue to monitor the situation throughout the day tomorrow.

HYDROLOGY

Yukon River: The breakup front on the Yukon has passed Russian Mission. As of Monday evening, an ice jam 10 miles downstream of Russian Mission remains in place mostly unchanged. A Flood Warning remains in effect. Extensive flooding of the lower portion of Holy Cross community was occurring Tuesday, including the Holy Cross runway. Water remains high on the Yukon upriver from the breakup front due to snowmelt and the Yuki Ice Jam release. Water has inundated the road to the airport at both Grayling and Holy Cross. Flood warnings remain in effect.

The ice jam located downriver of Russian Mission is made up of about 3 miles of large intact ice sheets extending from Roosevelt Island to Seven Mile. River Watch overflew the ice jam at noon Tuesday and again at 5pm and saw no change. About 60 miles of chunk and pan ice extend from the head of the jam upriver past Holy Cross. The most extensive flooding is occurring at Holy Cross and in the lowlands between Holy Cross and Anvik. Most large Yukon River ice jams during recent years decay, erode and fail within a few days. The current jam at Russian Mission is going on day 3.

Chena: The Chena River continues to respond to warmer temperatures with higher elevation snowmelt leading to rivers running higher than normal, but likely remaining below action stage.

Additional Information: Visit www.weather.gov/aprfc for the latest hydro information.

Please report observed flooding to local emergency services, law enforcement, or to the National Weather Service when you can do so safely..

EXTENDED FORECAST DAYS 4-7

High pressure in the Arctic will allow for persistent easterly winds to blow along the Arctic coast and northerly winds along the West Coast through the weekend. Scattered showers will be possible across most of Northern Alaska from Saturday into the weekend, with isolated thunderstorms possible among these showers in the Interior, especially in western areas. Generally warm conditions will persist throughout the period south of the Brooks Range, with highs in the 50s and 60s. The West Coast will likely see highs in the 30s and 40s, with 20s and 30s on the North Slope. Additional showers will be possible across Northern Alaska early next week ahead of another potential system in southwestern Alaska.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ837-849. Flood Watch for AKZ826-830. PK...Small Craft Advisory for PKZ801-850.