textproduct: Fairbanks

SYNOPSIS

Wet and cool conditions are expected to persist for most of the region today, with the Interior and West Coast receiving rain and the North Slope receiving some light snow. Isolated thunderstorm chances linger around the Alaska Range and Alcan border near Northway for this afternoon. Thunderstorm potential is expected to diminish starting Monday afternoon. Winds are expected to pick up by tonight over the Interior and Southern Brooks Range with higher elevations seeing the strongest winds. Winds are expected to taper off by Monday night, with a pattern change beginning on Tuesday. Drier and warmer conditions will prevail starting Tuesday, with many locations south of the Brooks Range reaching highs in the low to mid 70s.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Moderate rain with pockets of heavy rain is possible today over the Interior with a widespread 0.25 to 0.75" expected from Fairbanks to Coldfoot, including the White Mountains and Koyukuk Valley. Showers are expected to taper off by Tuesday morning. Isolated thunderstorms are likely this afternoon over the Alaska Range, Central Interior, and Northway area as storms will initiate off of higher terrain.

- Southwest winds are expected to strengthen over the Interior and Southern Brooks Range by tonight, with gusts reaching up to 45 mph at higher elevations and 35 mph in valleys. These stronger gusts are expected to weaken by Monday night into Tuesday morning.

- A pattern change begins on Tuesday with warmer and drier conditions. High temperatures are expected to reach the low to mid 70s over most of the Interior and last through the week.

West Coast and Western Interior...

- Rain showers with a couple of thunderstorms develop Sunday afternoon. These could come with pockets of heavy rain, especially from Holy Cross northeast to Lake Minchumina.

- Gusty southwest winds are expected Sunday afternoon through Monday afternoon with gusts potentially upwards of 45 mph above 1500ft and 35 mph in Kuskokwim Valley.

- High temperatures are expected to hit the low to mid 70s by Tuesday of this week as a warm air mass brings calmer and drier conditions.

North Slope and Brooks Range..

- Below average temperatures are expected to persist through Tuesday on the North Slope with values mostly between 30 and 40 degrees through the week.

- Areas of light snow move into the region today with less than 1 inch of snow on the North Slope and 0.5 to 2 inches in the northern Brooks Range.

- Gusty southerly winds up to 45 mph and moderate rain are expected to develop in the southern Brooks Range today and persist through Monday evening before ending thereafter. Rainfall amounts of 0.25 to 0.50 inches are expected with localized higher amounts possible.

FORECAST ANALYSIS AND DISCUSSION

Sunday through Tuesday.

A low in the Gulf of Alaska along with a low in the Arctic support general troughing across most of Northern Alaska. A stationary front has been hovering over the Interior and will continue to bring precipitation in the form of rain to the Alaska Range, Tanana Valley, and the Northern Interior. The highest accumulations of liquid precipitation are expected just north of the Alaska Range, including the Fairbanks area, the Central Interior, and the Dalton Highway Summits. Between Fairbanks and the Central/Northern Interior, accumulations of 0.25" to 0.75" are likely from Sunday afternoon through Monday night. Surrounding areas are likely to receive less than 0.25" while higher elevations could see up to 1". However, models are showing uncertainty for exact rainfall amounts and the placement of the front will continue to be monitored throughout the forecast period. Any residual moisture is expected to move out of the region by Tuesday morning as it is pushed to the east by a high pressure system coming in from the west.

Ridging building in over much of Northern Alaska will influence a pattern change. Moist and cooler conditions will gradually become drier and warmer starting Monday night into Tuesday. Widespread ridging will raise high temperatures over the Interior and West Coast into the low to mid 70s by Tuesday afternoon. This shift is also supported by warm air advection from the west and southeast. In terms of thunderstorms, the ECMWF lightning flash density product shows the highest chance of convective storms over the Alaska Range, Western/Central Interior, and near Northway for Sunday afternoon as systems will tend to initiate off higher terrain. Following Sunday, chances for thunderstorms diminish as convective potential moves northward along the Alcan border starting Monday. However, a few isolated thunderstorms are possible over the Middle Kuskokwim Monday afternoon.

Winds from the south/southwest are likely to strengthen in the Interior and Southern Brooks Range beginning late Sunday morning and continuing through Monday night. Sustained winds are expected to remain around 10 to 20 mph with gusts reaching up to 45 mph. While the strongest winds will reside at the highest elevations, gusty winds could mix down to the surface in some areas. While a break from gusty winds is anticipated following Monday night, a second ramp up of north/northwesterly winds is likely to begin over most of the Brooks Range starting Wednesday evening in the extended forecast.

FIRE WEATHER

A brief period of quiet weather gives way Sunday afternoon as the potential for isolated thunderstorms shifts northward, bringing a slight chance of isolated convective activity to the Tanana Valley and Central Interior, while a 40 to 50 percent chance of showers and thunderstorms is expected to linger across the Fortymile Country and Upper Tanana Valley. Widespread wetting rains are forecast to intensify Sunday night through Monday afternoon as a front lifts north and interacts with an incoming trough, driving precipitation chances up to 50 to 70 percent and chances of wetting rain between 40 and 80 percent across the Central Interior, White Mountains, and southern Brooks Range.

Surface winds on Sunday morning will start light and variable before shifting out of the west/southwest and strengthening through Monday afternoon. Elevations above 1500 feet along the Dalton Highway and White Mountain summits are likely to see sustained winds between 10 and 20 mph, with gusts approaching 35 mph, while passes along the eastern Alaska Range will contend with southerly winds between 10 and 20 mph, gusting between 40 and 50 mph. Interior valleys are expected to see lighter late-afternoon winds from the southwest between 5 and 15 mph with gusts peaking between 20 and 30 mph.

Maximum temperatures across the Interior valleys are likely to remain seasonable, reaching the upper 50s to mid 60s, while minimum relative humidity values drop into the 30 to 40 percent range for most areas. However, pre-frontal drying will cause minimum relative humidity values to decrease to around 30 percent across the Yukon Flats and Upper Koyukuk Valley ahead of the rain on Sunday. Under rain and thick cloud cover on Monday, temperatures should be limited to between the low 50s to low 60s across the Central Interior. Clearing along the Canadian border will allow temperatures to climb into the mid 60s in the Fortymile Country and Upper Tanana Valley, driving minimum relative humidity values down into the 20 percent range. This sets the stage for a seasonal shift Tuesday into Wednesday as a ridge builds over the state, clearing skies and driving temperatures into the mid to upper 70s and minimum relative humidity values into the teens to 20 percent range across the Interior valleys.

HYDROLOGY

No major concerns on the hydro front.

Sagavanirktok River: Some overflowing is occurring; however, breakup along the Sag River has not begun yet. High temperatures are expected to increase to around the mid to upper 30s and even low 40s on Monday with low temps in the 20s and 30s (north to south). Tuesday and Wednesday appear to be the warmest days with highs in the 30s to near 40 along the coast and low 50s towards the northern Brooks Range. Temperatures will then dip back down later in the week, exact values are uncertain. Near the Sag River source on the north Brooks Range, high temperatures could reach the mid 50s from Monday to Wednesday, with snow levels reaching upwards of 4000 ft. Again, temperatures look to cool going into the late week but continue to be above freezing.

EXTENDED FORECAST DAYS 4-7

For Wednesday through next Saturday.

At the start of the extended forecast Wednesday, the pattern remains dominated by a large region of high pressure over the Bering Sea, a large low in the Gulf of Alaska, a ridge in western Canada, and a very large low near the North Pole. Northern Alaska remains stuck between these features at least until Thursday before they may begin to shift. As the low in the Gulf shifts east it suppresses the ridge in Canada and will cause conditions to change. The most likely outcome is gradually increasing temperatures across the Interior under a slowly shifting pattern, but there is a chance that the high in the Bering shifts towards the Gulf and warms the region more rapidly. Late this week into next week, it is possible that the low over the North Pole shifts further south and moderates temperatures with more periods of showers.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. PK...None.