textproduct: Fairbanks

SYNOPSIS

Light snow showers track east across the state today but any accumulations should remain relatively minor. Rain and/or freezing rain may mix in at times across the YK Delta and in communities along and just north of the Alaska range. Above average temperatures persist today and tomorrow, especially along the west coast where highs will hover around the freezing mark. High pressure building into the state keeps conditions relatively benign for the week ahead. Watching next weekend and beyond for another round of arctic air, especially for the eastern Interior.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Southerly gap winds across the Alaska range decreasing throughout the day today

- Light snow showers traverse the interior from west to east. Freezing rain or rain may mix in at times near the Alaska range.

- Above average highs in the teens to lower 30s persist

West Coast and Western Interior...

- Snow showers continue over the southern Seward Peninsula today and Western Brooks range, while the rest of the west sees drying conditions through the day

- Much drier and mild going into the beginning of next week with temperatures in the 20s and 30s

North Slope and Brooks Range...

- Snow showers continue north of the Brooks range and along the Arctic coast

- Increasing westerly winds along the arctic coast tonight may lead to blowing snow and reduced visibility

- Much colder air returns by Tuesday through the rest of next week as winds shift back to the east. Blowing snow and reduced visibility possible again on Tuesday.

FORECAST ANALYSIS AND DISCUSSION

Satellite imagery shows an occluded low in the Bering with a N-S boundary stretching across Western Alaska this morning. Southerly flow along the boundary is advecting pacific moisture northward all the way to the Western Brooks range resulting in snow showers across the west coast and western Interior. Weak downsloping off the Alaska range and southwesterly warm air advection aloft has resulted in a sharp low level inversion and warm nose less than 2000ft agl as confirmed by 12z soundings. Warmer air and rising surface temperatures within the YK Delta has already resulted in freezing rain and rain mixing in at times and should continue through the day and the area of precipitation tracks east. Best chance for any mixed precipitation will be in the YK delta this morning, then spreading east toward the Alaska range later today. Expect mainly snow with little to no p-type issues further north. Upslope on the southern facing slopes of the Seward Peninsula and Brooks range may result in heavier snowfall rates and higher accumulations. As ridging builds in behind the boundary, low level flow becomes more southwesterly then westerly, cutting off the better moisture advection northward but also lessening winds and downsloping off the Alaska range. This should result in the boundary bringing lighter snow showers to the eastern interior and Fairbanks area this evening and tonight. Wet bulbing of the warm nose aloft and weakening downslopiong will keep P-type mainly snow around Fairbanks.

Mid and upper level ridging builds over the state tonight and tomorrow setting the stage for a much quieter week ahead, with only very few exceptions. The main storm track, which has been aimed right at Western Alaska, becomes oriented more towards Siberia and then eastward over the high arctic, keeping the majority of the state dry and mild. With origins over the Pacific, the incoming airmass keeps well above average temperatures in place with widespread highs in the 20s and 30s above zero.

The only active regions to watch will be the Arctic coast where, right at the top of the ridge, where a stronger westerly low level jet sets up by Monday. A tightening pressure gradient from high pressure over the interior and lower pressure in the high arctic increases westerly winds to 20-30 mph along the arctic coast, potentially leading to periods of blowing snow and reduced visibility, but also keeping the much milder airmass in place.

May also see an increase in the Tanana Valley Jet Monday into Monday night as higher pressure settles into the Yukon and a E-W pressure gradient sets up. Added gusty winds to the Delta Junction area to account for this.

EXTENDED FORECAST DAYS 4-7

Ridging aloft and surface high pressure become the dominant weather influence across the majority of Northern Alaska into the extended. This pattern supports continued mild winter temperatures in the teens to 30s above zero across the state due to such anomalously high 500mb heights and 850mb temps for this time of year. Mid range guidance has been consistent with a weak upper level shortwave disrupting the ridge midweek; however since 500mb anomalies are so strong for this time of year, do not think there will be much of an impact to sensible weather at the surface other than some increase in clouds across the south and west.

The one exception to the benign weather may be across the arctic coast this week as they will be positioned at the top of the ridge where upper level shortwaves within the main flow may bring periodic chances for snow, winds, and low visibility. Confidence on timing, track, and strength of these passing waves is low at this time; however many mid to longer range models show this occurrence.

Upper ridging slowly shifts westward through the week before becoming NW-SE oriented from Siberia to the West Coast by the weekend. At the same time, troughing and a much colder airmass advect westward into the Interior. The long term forecast shows a cooling trend across the state late weekend into next week with another period of temperatures in the 0 to -30 range, especially for the eastern interior. West coast holds onto the warmer air a few days longer than areas further east as they remain under the influence of the ridge. Will have to watch for a strong E-W temperature gradient across the state. With higher pressure now moving over the Chukchi sea and lower pressure over the interior, easterly gap winds may significantly increase by this weekend.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Weather Advisory for AKZ851-852. PK...Brisk Wind Advisory for PKZ801-802-810-855-856. Brisk Wind Advisory for PKZ812-813-858-859. Brisk Wind Advisory for PKZ814-860. Brisk Wind Advisory for PKZ815. Brisk Wind Advisory for PKZ816. Brisk Wind Advisory for PKZ850. Brisk Wind Advisory for PKZ851-854-861.