Digging Out

Three days later, and I have just finished shoveling my way to the road. The drifting was as much as I recall here on the ridge. Anyway, since Saturday clear and cold with high pressure in control. Down to 31 below at Fairbanks Airport this morning, and 38 below at Goldstream Creek. A more pleasant 12 below here on the ridge, although it appears it will not get above zero today, which is not shabby for the last day of February.

That's a Gradient

Environment Canada's surface analysis valid 3PM AST. That is one whale of pressure gradient across Alaska. 1047 mb high in the northwest Bering and 979 mb low over Banks Island. Maybe it will be windy.

Howling winds

Possibly the most impressive wind observation thus far:

Umiat RAWS at 223PM AST

Temperature -1F, west winds 45 gusting to 62 mph. That's a whole lot of wind for Umiat.

Update:

At 7pm AST Friday the Fairbanks Airport reported a peak wind of 53 mph. This is the strongest wind gust in February since a gust recorded was installed in 1985, and one of strongest any time outside of a thunderstorm.

Winds Aloft

Here's a snapshot of the VAD winds early Friday afternoon from the Pedro Dome NexRad Radar, high atop Pedro Dome, northeast of Fairbanks.

This shows 40 kts of wind at 3000 feet MSL (that's only a few hundred feet above the elevation of the radar) increasing to 50 kts at 6000' MSL. The most recent winds are on the right of the graphic, courtesy of the WeatherUnderground

Windy

The attached plot of surface observations from 1pm AST Friday, though corase, shows it windy from the Bering Strait to the Yukon border as a decent surface low tracks eastward north of the Arcti Coast, supported by roaring winds aloft. The Prudhoe Bay area has had winds gusting to around 60 mph since around midnight. It had been very mild; high temperature of 33F at Deadhorse on Thursday, but temperatures are now falling rapidly.

Here in Fairbanks, it looks like 3-6 inches of snow overnight is the rule. Although windy, there is much less drifting than the storm Sunday and Monday, as the snow is denser and temperatures much milder.

Calm before the storm

A shallow inversion has held all day Thursday in Fairbanks, keeping temps down well below freezing. Above the inversion the winds are roaring, with 55 mph winds at 850 mb on the 3pm AST RAOB. The Snotel on Eagle Summit has sustained winds almost 30 mph as of 6pm. This will work down to the ground when the front comes through later this evening, when temps will jump up before falling all day tomorrow.

Storm winding down

The storm is winding down now. but not before producing a 53 mph gust at the airport, where the storm total snowfall is 18.5 inches. At the left is the 3pm Monday surface analysis from Environment Canada. The the big storm exiting Interior Alaska? That's right, there isn't one. This is the classic pattern for heavy snow in the Fairbanks area: high pressure over the north Pacific/western Gulf of Alaska and southwest winds aloft. Of course, they don't all come with this much wind.

Heavy Snow

Update:
24 hours ending 3pm AST, snowfall at Fairbanks Airport is apparent 17.1 inches. This is, I believe, the second greatest 24 hour snowfall of record, exceeded only in February 1966.

Snowfall observations coming in quite remarkable, Fairbanks south and eastward. In the North Pole area there are reports of 14 to 17 inches of new snow since Sunday morning. The North Pole climate station, in operation since 1968, only as one day in February with 10 or more inches of snow, so this might be a new record there. For locations with obs back that far, the snowfall of February 11-12, 1966, in which Fairbanks Airport measured 20 inches in 24 hours, is the greatest storm 24 hour event of record.

Other reports include
Perkins Landing 16.5 inches (NWS employee)
UAF West Ridge Coop: 12.5 inches
Chatanika Coop: 12.0 inches
Goldstream Creek: 10.7 inches
Keystone Ridge 7.5 inches (as of noon)

More to come

Late Winter Action

The third major storm in the past six days is racking the northwest coast of Alaska with blizzard conditions. The surface analysis at the left, valid 3AM Sunday AST, courtesy of Environment Canada, shows the low, weakening rapidly but still potent, along the Chukotka coast.

Here in the central Interior, snow alternating with clear skies has been the rule, though the snow Saturday did not amount to much. Of more note were low temperatures overnight. With a cold airmass in place, higher elevation temperatures were in the teens below and valleys 2o to 30 below.

Fairbanks Snow

A nice snow for Fairbanks late Thursday and early Friday.

Amounts mostly in the two to three inch range, though 5.3 inches here on Keystone Ridge. This happens sometimes on southwest flow aloft events, though often Chatanika will do well too. However, Chatanika reported a "mere" 2.6 inches this morning.

Diurnal Temperatures and the Sun

It is nearly eight weeks past winter solstice now, and sure is enjoyable to have more than twice the daylight of late December. However, the sun is still at quite a low angle: only about 13 degrees above the horizon at solar noon today. The result is that direct heating from the sun is still not the primary factor in temperature changes in Interior Alaska. The plot at the right shows the hourly temperatures for the past several days from here on Keystone Ridge, with the vertical lines marking midnight. On most days, the high or low temperatures have occurred close to midnight. There is of course nothing special about midnight. Whatever time you pick for the break in the climatological day will tend to have the extremes when solar heating is not an important driver of temperature changes.

Coldest morning of the Winter

It a chilly one:

The low of 44 below this morning at Fairbanks is the lowest temperature of the season. The high temperature Monday of 20 below is the latest date in the winter with a high of 20 below or lower since 1990.

Other lows include:

East Fort Wainwright: -44F
Eielson AFB: -44F
Goldstream Creek: -43F
UAF West Ridge: -37F

The Weather Underground personal weather stations in the North Pole area are in the mid 40s below.

Temperatures have been VERY SLOWLY moderating at higher elevations, with the temperature at 10am here on Keystone Ridge at -19F, up about 8 degrees from late Monday afternoon.

February Sunshine

Sunny and 24 below on at Bettles on Valentines Day afternoon.

Cold morning

Updated

Some clouds moved in early morning hours Monday, which moderated valley temperatures. But hills remained cold.

31 below here on Keystone Ridge early this morning is the lowest temperature since Jan 2, 2009.

Other higher elevations minimum temperatures include:

Eagle Summit SnoTel: -35F
Cleary Summit RWIS: -28F
Caribou Peak RAWS -28F
Parks Highway RWIS: -26F (near FNSB boundary)
Chatanika River RAWS: -28F (ridge NW of Murphy Dome)

From Weather Underground personal weather stations:
Chena Ridge (1000'MSL): -29F
Skyline Drive (1200;MSL): -27F

Valley min temperature included -43F at both Goldstream Creek and the Fairbanks Airport.

Colder, then warmer

Here is a plot of the observed 1000-850 mb thickness for the past few days (blue) and the forecast from the GFS for the next few days (red). Thickness is a measure of the mean temperature of a layer of air, in this case roughly the lowest 4500 feet. From this I would expect tonight will be the coldest night in the area. Temperatures will start to rise in earnest during the day Monday, and in the hills will probably be rising steadily for a couple days. Nighttime valley temperatures will depend in part on when clouds move in.

Cold morning

A cold Sunday morning in Interior Alaska, and in a few places the coldest of the winter so far.

In the Fairbanks area, lows in the teens and 20s below in the hills, and 30s and 40s in valleys.

Some specifics (thru 9am) include:

Chicken: -54F
Chandalar Lake: -54F
Coldfoot: -51F (from the NRCS SnoTel station)
Bettles: -50F
Fort Yukon Airport : -49F
Fort Yukon Coop: -46F
Huslia -45F


In the Fairbanks area:
Eielson AFB: -44
Fairbanks International Airport: -43F, lowest of the season
East Fort Wainwright: -40F
UAF West Ridge: -34F
Chatanika: -33F
Keystone Ridge: -22F
Clearly Summit: -18F

North Pole area in the mid -40s from the WeatherUnderground home weather stations.

Continued Cooling

The airmass has continued to cool over the central Interior. In Fairbanks-land this morning, temperatures are in the teens below in the hills and 20s below in the valleys. Cooler farther west, with some 40s below showing up. But for the first half of February, its pretty tame. This morning's GOES infrared image shows more clear skies over the Interior than Friday, but still some clouds in the east.

Morning View

This (Friday) morning 's Polar Orbiter infrared image from 4am shows clear skies over the western Interior, where temperatures are in the 20s and 30s below (-33F at Galena at 8am). Farther east, clouds and temperatures zero to 10 below (-5F at Fairbanks International). Even in a cold air mass, clouds matter.

Cooling off

After a week of fairly quiet weather, much cooler air, possibly the coldest of the winter, is moving into Interior Alaska. This is a deep cold airmass, as can be seen in the upper air data from Thursday afternoon compared to Wednesday afternoon, with big temperature falls above 500 meters AGL. Since then it has continued to cool, with the 9pm AST temperature here on Keystone Ridge down to -9F, making this the first day this month with a subzero temperature (here on the ridge).

Blazing sunshine

Sunny afternoon at Lake Minchumina. Photo from the FAA.

Strong Inversion

A pretty strong inversion this morning, with temperatures in the teens below in the valley and teens above in the hills. As the RAOB shows, there is very mild air up above 800 meters above valley level, but that will not be able to make it down.

Snow Thursday

A nice little snow Thursday in Fairbanks-land

Totals include:
North Pole: 1.2 inches
Fairbanks Airport: 1.5 inches
UAF West Ridge: 1.8 inches
Goldstream Creek: 1.9 inches
Aurora: 2.0 inches
East Farmer Loop: 2.4 inches
Keystone Ridge: 3.3 inches

January Recap

Overall a mild month; the average temperature at the airport of -6.0F almost 4 degrees above normal. Here on the hill, average temperature of +8.6F, making the mean inversion only a little stronger than normal. Plot is of the daily high and low temperatures at the Airport: Mild early and late, cool in the middle of the month.