textproduct: Fairbanks

SYNOPSIS

Scattered showers and isolated thunderstorms continue through the week across northern Alaska as broad scale troughing persists. A Bering Sea low sitting in Bristol Bay will work to tighten the pressure gradient over the Alaska Range allowing for strong southerly gap winds to develop this afternoon through Wednesday. Gusty east/northeast winds up to 55 mph will continue this morning across the Dalton Highway Summits before quickly decreasing this afternoon. Showers and thunderstorms are expected to increase in coverage over the Central/Eastern Interior by Thursday. Temperatures remain steady across the state with slightly warmer and drier weather possible early next week.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Isolated thunderstorms and scattered showers are expected to continue across most of the Interior throughout the week. The greatest chances for thunder will be in the higher terrain of the Eastern Interior through Wednesday afternoon.

- Gusty east/northeast winds continue across the Interior this morning with gusts reaching near 20 to 30 mph for areas north of Fairbanks. Stronger gusts up to 55 mph are possible across the Dalton Highway Summits through this afternoon.

- Southerly gap winds return to the Alaska Range passes this morning and continue into Wednesday. Gusts up to 55 mph are possible. Elevated fire weather concerns are expected near Delta Junction this afternoon.

- Showers and thunderstorm chances increase and become more widespread going into the weekend.

West Coast and Western Interior... - Scattered showers and isolated afternoon thunderstorms continue across the Western Interior and parts of the Seward Peninsula this week. Showers and thunderstorm chances gradually decrease and become more isolated going into the weekend.

- Gusty northeast winds continue across the West Coast today. The strongest winds are expected from St. Lawrence Island through the Bering Strait to the Lisburne Peninsula with gusts up to 35 to 45 mph possible. Winds should gradually diminish late tonight into Wednesday, but remain gusty around 20 to 30 mph through the end of the week.

- Patchy dense fog is possible across the West Coast each morning this week.

North Slope and Brooks Range... - Slightly cooler than normal temperatures continue across the North Slope with highs in the mid to upper 20s and lows in the upper teens. Highs will be in the low 40s across the northern Brooks Range and in the upper 50s to low 60s across the southern Brooks Range.

- East/northeast winds increase across the Arctic Coast through the morning with gusts up to 30 mph possible east of Point Barrow and up to 35 mph near Point Lay. Winds are expected to quickly weaken later tonight.

- Low clouds and patchy fog continue across the North Slope through most of the week. Gaps in the clouds become more common further west.

FORECAST ANALYSIS AND DISCUSSION

For Tuesday through Thursday night. Broad scale troughing continues over the state as a Bering Sea low settles into Bristol Bay early this morning. This low will work to tighten the pressure gradient over the Alaksa Range this afternoon with strong southerly gap winds expected through Wednesday. Due to dry and windy conditions near Delta Junction this afternoon, elevated fire weather concerns are possible. A lingering front ejected off the Bering Sea low will have made its way north towards the Brooks Range this afternoon, supporting isolated showers and thunderstorms across the Western Interior and higher terrain of the Central/Eastern Interior. Wetting rain chances decrease with these storms through Wednesday as PWAT values drop to around 0.30 inches and RH values drop into the 20 to 30% range across much of the region.

By Wednesday night, the Bering Sea low will have moved from Bristol Bay east into the Gulf of Alaska. As the low moves east, it begins to pull a large swath of moisture and shortwave energy south towards the Alaska Range. This will work to increase precipitation and thunderstorm chances over the Central/Eastern Interior Thursday and Friday. Additionally, winds across Interior Alaska will gradually decrease Wednesday through the weekend with winds from the Lisburne Peninsula south towards the Bering Strait remaining gusty at times. Temperatures are expected the hold steady across the state through the rest of the week with models hinting at a slight warm up sometime early next week.

FIRE WEATHER

A low pressure system is expected to linger over Northern Alaska. This system plays a large role in supporting strong easterly winds over higher terrain in the Northern Interior. A High Wind Warning is in effect for the Dalton Highway Summits through this afternoon for gusts up to 55 mph possible. Additionally, strong southerly winds are expected for the Eastern Alaska Range and Delta Junction where a Wind Advisory will be in effect beginning early this morning through Wednesday afternoon for gusts up to 55 mph. Minimum relative humidity values are expected to be within the upper 20s to low 30s percent range at Delta Junction this afternoon. These drier conditions combined with the strong southerly winds could create elevated fire weather concerns.

Scattered rain showers are expected to persist for most of Northern Alaska throughout the week. Rain is likely to be accompanied by isolated thunderstorms in the afternoons over most of the Interior and Western Seward Peninsula as storms will tend to initiate off of higher terrain. Minimum relative humidity values are expected to be the driest over the Tanana Valley and surrounding areas in the upper 20s to lower 30s percent today and Wednesday afternoon, with recovery into the 40s percent range by Thursday. High temperatures south of the Brooks Range will remain in the upper 50s to low 60s throughout the week.

HYDROLOGY

Yukon River: At 10pm AKDT Monday, the River Watch Team observed the breakup front moving downstream past Emmonak and Alakanuk with a 30 mile run of thick bank to bank ice and high water upstream. There are reports that Kwig Pass is jamming up at the mouth and that water will begin backing up into Emmonak. The high water has caused flooding in upstream areas in conjunction with this ice run. Residents should take precautions now and continue to monitor the situation closely.

Flood warnings have been cancelled for Holy Cross, Russian Mission, Marshall, Mountain Village, and Pilot Station. Flood warnings were issued for Emmonak and Alakanuk. A Flood Warning remains in effect for St. Mary's. A Flood Watch remains in effect for the Yukon Delta.

Emmonak: As of 745pm, local observers report water is rising steadily with ice only moving in the middle channel. Expect continued steady rises through this morning. If ice stops completely, water levels will rise faster. Local officials advise that the Emmonak High School is a safe place if residents should need to relocate.

Alakanuk: As of 4pm, River Watch observed a run of 20 to 30 miles of heavy ice and high water moving towards the village. Local observers reported minor flooding is occuring, primarily on the south river bank. Expect continued steady rises through this morning. If ice stops completely, water will rise faster. There was a partial jam noted at the South Mouth with Casey Channel and the Alakanuk Slough as the primary outlets for ice to pass.

Nunam Iqua: As of 2pm, River Watch observed a partial jam near the South Mouth. Ice was primarily flowing through the Casey Channel. Another 20 to 30 miles of heavy ice and high water is expected to make water levels rise through this morning. Residents should take precautions and monitor.

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

Friday through Monday. At the start of the extended forecast period late Thursday, the pattern is that of broad troughing centered around a low in the Gulf of Alaska. Ridging in Canada and high pressure over Siberia wear at the trough and cause it to shift somewhat unpredictably over the weekend. There is a great deal of forecast uncertainty regarding how the pattern evolves early next week. The most likely outcome currently is remaining within this broad troughing pattern keeping temperatures slightly moderated with afternoon showers and isolated thunderstorms possible each day. A less likely, but more dramatic solution begins building the Canadian ridge farther into Alaska which would lead to a warmer and drier pattern. Current ensemble estimates do not have the potential ridge being very strong, meaning that strong lows moving through the pattern could more easily shift it should a ridge begin developing. Case in point, generally unsettled weather will continue for Northern Alaska through the weekend with daily showers/storms focused in the Interior as drier conditions prevail along the coasts, and temperatures hold steady regionwide before warming up early next week.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ849. Wind Advisory for AKZ837. Flood Watch for AKZ825. High Wind Warning for AKZ832. PK...Small Craft Advisory for PKZ806-811-812-817-850-854-857-858. Brisk Wind Advisory for PKZ807-810-816. Brisk Wind Advisory for PKZ814-815. Brisk Wind Advisory for PKZ851. Small Craft Advisory for PKZ853. Gale Warning for PKZ856. Brisk Wind Advisory for PKZ860-861.