textproduct: Fairbanks

SYNOPSIS

Active weather expected to continue across the state throughout the weekend. Low pressure is expected to expand eastward throughout the day, today, allowing scattered chances for thunderstorms across the Interior. Another area of low pressure will be working its way up the Aleutians throughout the weekend, allowing the gusty east/northwest winds to return by Monday night. This low is expected to set up around Bristol Bay, similar to the previous one, and will continue to allow for isolated showers and thunderstorms through the end of the weekend and into the early portions of next week.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Increasing chances for thunderstorms going into the weekend, around 30% in the Central and Northern Interior today and Sunday.

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

- Gusty east/northeast winds return across the Interior Monday night with potential gusts between 20 and 30 mph. - Strongest winds are expect along the Dalton Hwy Summits and higher elevations. - Another round of gusty, southerly gap winds through the Alaska Range passes possible late Monday night/early Tuesday.

West Coast and Western Interior... - Daily chance for Isolated showers are expected to continue throughout the weekend, along with slight chances for thunderstorms across the Western Interior during the evening hours.

- A slight warming trend is expected for northern portions of the West Coast throughout the weekend.

- Gusty east/northeast winds return across the West Coast Monday night with potential gusts between 30 and 40 mph. - Strongest winds are expect through the Bering Strait to St Lawrence Island and higher elevations.

North Slope and Brooks Range.. - Intermittent periods of mixed precipitation, including the chance for freezing rain/drizzle, for the northern slope with little to no accumulation expected.

- 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.

- Easterly winds increase across the North Slope Monday night with potential gusts between 30 and 40 mph.

FORECAST ANALYSIS AND DISCUSSION

Overall forecast continues to remain on track with little to no changes made since the previous discussion. At the start of the forecast period, the main pattern driver is a low that continues to weaken over Bristol Bay. This is what helped weaken the gradient across much of the Interior, today. A shortwave system will be moving westerly across the Gulf of Alaska, moving toward the southern portion of the Alaska Panhandle. Instability is expected to continue to increase across much of the Interior throughout the weekend, but the low will play a larger role on Sunday. With its westerly progression, this will allow for E/SE flow, aloft, to move easterly across the Interior, from the Yukon. Models are also showing some weak shortwaves embedded within the flow as some of the lingering energy, from the previous shortwave that moved across the SE Interior, moves back across the state from Canada. Additionally, the easterly flow across the state will be further enhanced by a upper-level ridge that will continue to strengthen over the Brooks Range throughout the weekend. Models continue to show the potential for a thermal trough to settle in under the upper-level ridge Sunday and slowly progress across the Interior. All of these components will work together to support thunderstorm development.

A separate upper-level ridge will begin building up over the Aleutians, behind the low that moves across the Gulf of Alaksa, by the end of the weekend. This will allow for the low that was previously over Bristol Bay to dissipate. Scattered showers and thunderstorms are expected to continue across the state through the start of next week. Meanwhile, another occluded low will be moving up the Aleutians Monday, setting up around Bristol Bay once again. With some areas of higher pressure building under the ridge over the Arctic, this low moving up will tighten the gradient across the state and increase the east/northeast wind speeds by Monday afternoon. With this next low essentially replacing the previous one, the overall pattern next week will be similar to the previous week. Temperatures will be around the seasonal normal and much of the Interior will see daily chances for isolated showers and thunderstorms.

FIRE WEATHER

Thermal troughing prevails across interior Alaska this weekend and focuses daily chances for afternoon/evening showers and thunderstorms. This trough axis shifts south toward an unseasonably deep Bering Sea low pressure system early next week. A disturbance embedded within the trough axis brings potential for a broad swath of wetting rains along and south of a line from Healy to Salcha to Chicken on Sunday. Dry east-northeast develop behind the trough axis across the northeast interior on Sunday then spread across most of the interior while increasing on Monday. There is potential for RH values below 25% combined with sustained winds >15mph across portions of the Yukon Flats on Monday, but temperatures are likely to stay in the mid-60s or well below the 75F threshold for RFW. This low also brings another round of gap winds to the Isabel Pass and Delta Junction area starting on Tuesday.

HYDROLOGY

Yukon River: The ice jam downriver from Holy Cross released Tuesday evening, allowing water levels to drop several feet. Downriver, this has resulted in water levels rising in Russian Mission. Minor flooding was observed during an overflight. Rising water levels and minor flooding were reported at Marshall on Friday. The Yukon River breakup front is likely along the stretch from Pilot Station to Mountain Village as of Friday afternoon. Reports were received of minor flooding at Marshall and moving ice at Mountain Village. Reports were also received, Friday night, of ice shifting near Emmonak.

The surge of water from the Holy Cross ice jam will increase ice jam and flooding potential for Marshall, Pilot Station, St. Mary's, and Mountain Village. With that said, a series of flood watches and warnings are in effect throughout the weekend. Additional watches have been issued further downriver to the YK- Delta coast.

Innoko: Reports from Shageluk indicate that the Innoko River has begun to backup due to high water in the area. Currently not expecting significant impacts.

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

To start the forecast period on Monday, warm temperatures in the low to mid 60s will be possible across the Interior and could last through the middle of next week. With high pressure in the Arctic and a low in the southeast Bering Sea, north to northeast winds will be likely on the West Coast and easterly winds across most of the Interior and North Slope. Sustained winds of 20 to 30 mph will be possible in prominent/exposed coastal locations such as St. Lawrence Island and on the the western tip of the Seward Peninsula, with weaker winds moving inland. Farther inland, the highest sustained winds will be in elevated areas across the Interior, with gusty easterly winds in the valleys, especially during periods of maximum diurnal heating. Southerly flow across the Alaska Range on the east side of the low will yield gap winds through the passes which could continue into Wednesday. The Bering Sea low will rapidly weaken moving into Wednesday, by which time its remnants will have drifted into the Gulf of Alaska. Interior winds will gradually decrease through the day, but shower and thunderstorm potential will linger across much of the Interior each day.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Flood Watch for AKZ825-826. PK...Brisk Wind Advisory for PKZ815.