textproduct: Fairbanks

SYNOPSIS

Active albeit low-impact weather brings cool and damp conditions through Monday night before ridging brings sunny and warmer weather to Northern Alaska on Tuesday through Thursday. Southwest winds increase through tonight and turn more southerly on Monday before becoming light and variable Monday night. These southerly winds will gust up to 35 mph in the valleys and up to 45 mph above 1500 ft this evening through Monday morning. South winds gusting up to 50 mph are also expected for the Alaska Range passes. Higher elevation locations are expected to receive quite a bit of rain this afternoon through Tuesday with localized amounts around 1 inch in the vicinity of the Ray Mountains and the south-central Brooks Range. Thunderstorm potential stays low for the entire forecast period, but a few strikes are expected near the Alaska Range today and near the Ogilvie Mountains on Tuesday. Clouds clear out on Tuesday resulting in a stretch of sunny, warm, and dry weather for Tuesday through Friday with many locations south of the Brooks Range reaching highs in the upper 60s to mid 70s.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Isolated thunderstorms are occurring further southeast this afternoon over the Upper Tanana Valley and adjacent highlands as storms develop over the higher terrain and track easterly.

- Rain is expected across the north-central interior this afternoon through Monday night with widespread rain amounts around 0.25" near and north of Fairbanks and locally higher amounts approaching 1" possible at higher elevations of the Ray Mountains area.

- Southwest winds gusting up to 45 mph at higher elevations and 35 mph in valleys tonight through Monday afternoon. Southerly gap winds up to 50 mph are also expected through the Alaska Range passes.

- A pattern change begins to sunny skies allows for warmer temperatures reaching the low to mid 70s over most of the Interior valleys begins on Tuesday and continues through at least Thursday.

West Coast and Western Interior...

- Rain showers with a few embedded thunderstorms develop this afternoon, especially from Holy Cross northeast to Lake Minchumina.

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

- Light winds and sunny skies return on Tuesday allowing for warmer temperatures with highs in the low to mid 70s.

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 Friday.

- Areas of light snow move into the region today with less than 1 inch of snow on the North Slope and up to a few inches for higher elevations of the northern Brooks Range, including Atigun Pass.

- 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. Rainfall amounts of 0.25 to 0.50 inches are expected with localized higher amounts possible.

FORECAST ANALYSIS AND DISCUSSION

Sunday night through Tuesday night.

An energetic Arctic 500 mb shortwave dropping southeast across the North Slope today interacts with a warm front lifting north from a Gulf of Alaska low through Monday. This phasing interaction results in an unseasonably cloudy and wet pattern across the central interior with EFI guidance values >0.95 and a shift of tails up to 2 in the vicinity of the Ray Mountains. Ensemble means indicate localized 2-day rainfall totals in excess of an inch in the higher terrain north of Tanana (Ray Mountains). The thunderstorm chances are highest this afternoon and evening with steadier, more stratiform rainfall expected on Monday. Thunderstorms are generally expected to be short-lived today. On the North Slope and above elevations above about 3000ft in the Brooks Range, temperatures will be cool enough for precipitation to fall as snow. There may be a few inches of slushy snow accumulations at Atigun Pass with less than an inch across the North Slope.

In addition to rainfall, southwesterly winds increase along and south of the warm front with valley locations gusting up to 35 mph. The Alaska Range passes may gust up to 50 mph and higher elevations across the central interior including the Steese Highway and White Mountain summits are forecast to gust to around 40 mph. Winds become light and variable Monday night and Tuesday as ridging builds eastward from Siberia, shifting the remnant Arctic low east into Canada. This allows for clearing skies on Tuesday and sunshine on the long June days is forecast to allow temperatures to warm to around 70F across most of the interior. The only possible exception is near the AlCan border east of Fork Yukon where an afternoon shower or thunderstorm is possible. These warm, dry, and sunny conditions are expected to continue through at least Thursday.

FIRE WEATHER

The Western Brooks Range and adjacent Kobuk Valley have been the driest areas so far this spring and there don't appear to be any substantial rain chances during this forecast period. In that area breezy west winds continue through this evening ahead of a period of light and variable winds expected on Monday with southerly winds increasing on Tuesday ahead of the next cool front. Breezy north to northwest winds are expected behind the front on Wednesday and Thursday.

Despite plenty of recent rainfall another area of potential concern is the Upper Tanana and Yukon Valleys, especially in the vicinity of Isabel Pass. Southerly winds gust up to around 50 mph through Isabel Pass continue into Monday before diminishing during the afternoon and evening. These winds stay south of Delta Junction until Monday morning then diminish for the entire pass by Monday evening. Relative humidity values drop to around 25% for Delta Junction and down to around 20% near Eagle and Northway. Marginal RFW conditions can't be ruled out, but it's a low confidence/low probability potential at this time.

Across the remainder of the interior, a wet and cloudy pattern prevails in most places through Monday before clouds and rain chances diminish on Tuesday. Gusty southwest winds accompany these rain chances, especially at higher elevations, but winds also mix down into the valleys during the afternoon/evening hours. Ridging builds across the entire interior late Monday into Tuesday resulting in decreasing winds and sunny skies. This will be the warmest stretch of weather so far this warm season, with Wednesday being the warmest day. Light winds support deep mixing to >7 kft and min RH values dipping below 25% across most interior valleys. A weak cool front moves through Wednesday night and Thursday results in decreasing upper level heights and a return to the persistent troughing pattern we've frequently seen this spring.

Thunderstorm chances remain low for most of the forecast period with the greatest chances this afternoon, generally closer to the Alaska Range. A few strikes are possible on the periphery of the precipitation shield on Monday, but a more stratiform/widespread showery regime limits instability. Lightning chances ramp up again on Tuesday across the Eastern Yukon Flats and adjacent AlCan border as the upper level disturbance shifts out of the area.

HYDROLOGY

No changes from the previous hydro forecast discussion.

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 Thursday through next Sunday.

On Thursday, the warmer temperatures and clear weather provided by the ridge over Alaska will become moderated by a large arctic low which meanders southwest from the Canadian Archipelago. The low's impact will be felt most immediately on the North Slope, where maximum temperatures along the coast will struggle to get above freezing through the rest of the extended. Areas farther south along the Slope will be warmer, peaking in the 40s to near 50s near the Brooks Range, but will still drop below freezing overnight. Smaller features embedded in the low will result in occasional light precipitation north of the Brooks Range.

South of the Brooks Range, the interaction between the arctic low and high surface pressure over Siberia will strengthen winds along the West Coast. In particular, northwest winds into Kotzebue Sound and north winds off the Brooks Range into the Kobuk Valley will serve to dry the northwest Interior, which is currently the driest part of the state and which won't receive much meaningful precipitation in the short term. Generally northwesterly winds across the Northwest Interior and West Coast will varying in strength through the week as a series of small disturbances track southeast throughout the extended.

The weakening ridge will allow a low in the Gulf of Alaska to bring bring slight chances for showers in the southeast Interior Thursday evening. Chances for precipitation remain low and mostly on the southern edges of our area as lows traveling east along the Aleutians and into the Gulf look to stay far enough south to limit impacts. The combination of a cooler airmass and cloudier conditions will moderate temperatures back into the 60s in the Interior.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

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