Holy Cold Front, Batman

It's not every day a real live cold front comes through. Here are the hourly temperatures from Keystone Ridge. The big plunge was accompanied by a quick burst of snow; 1.8 inches between 2pm and 4pm.

Fairbanks above 0F

The temperature made it above 0F this (Thursday) morning at the Fairbanks Airport for the first time since Dec 4th. The 25 straight days in a row remaining at or below zero is not a record, but is the longest such streak since 1977, when it didn't get above zero between November 23rd and December 19th, 27 straight days.

Super Cold Siberia

Playing catch-up here: Oymyakon, in eastern Siberia and a perennial cold spot, had a low temperature on Christmas Eve of -75F. The high temperature the 23rd was -69F. That's cold. Even by their lofty standards. This might be exceeded early next week if it clears out.

Nome Sunshine

End of the year sunshine on Anvil Mountain, looking north from the Nome Airport, 115pm Wednesday. Photo from the FAA.

Pattern Change on the Way

The long chill is coming to an end. This mornings GFS (1200 UTC run) shows 2011 starting off with a significant Chinook. More to come.

Christmas Heat Wave

As of noon Fairbanks Airport is up to -1F...the warmest temperature since Dec 4th. Closer to the Alaska Range, where skies have remained clear, it's still in the 20s below at valley level.

Morning Inversion

This morning's inversion is pretty steep, even by Fairbanks standards: 13.6C (25F) degrees in the lowest 100 meters. The Airport dipped to -40F before the clouds arrived, the fourth -40 day of the month.

Balmy Hills

204p, Thursday, almost sunset photo from Delta Junction, from the FAA.

Meanwhile, back at the Ranch, at 7pm Thursday:
North Pole -44F
Eielson: -42F
Fairbanks: -37F
Cleary Summit: -10F
Keystone Ridge: -8F

Shallow Sloped Inversion

A shallow slope to the inversion Wednesday, thanks to some clouds and flurries. Here on the ridge, this might wind up as the first day of the winter with a high temperature in the double digits below.

Persistent Inversion

The persistent strong inversion, rather than any extremely cold airmass. The inversion has not been broken by any significant storms, with only 2.5 inches of snow thus far this month at the Airport. The plot shows the lows at the Fairbanks Airport and Keystone Ridge. Notice that here on the ridge it is yet to hit 20 below.

High level heat

One of the characteristics of a polar airmass in winter is the fact that the warmest temperatures in the troposphere often occur far above the ground. This morning's RAOB from Fairbanks has a nice illustration of this. The warmest temperature in the sounding is 9200 feet (2800 meters) above the ground.

The big six-oh

Updated: Noon at Fort Yukon: sunny and 58 below.

The AWOS at the Fort Yukon airport reports -60F this morning, after a high temperature of -56F Friday. That's just like winter. Only colder.

Black Stratus again

"Black stratus" is the in-house jargon term for low-topped status or stratocumulus that appear darker than surrounding ground on conventional infrared satellite imagery over Interior Alaska in winter, as the cloud tops are warmer than most of the ground. This mornings' NOAA-19 POES image shows a slug of clouds that moved into the eastern Interior from the Yukon Thursday night. Underneath the clouds, valleys are mostly 15 to 30F below this morning. Elsehwere, mostly 30 to 45F below, except on the Yukon Flats, which appear in this image as obviously "whiter", i.e. colder than most other clear valleys. Fort Yukon AWOS reports 56 below this morning, the lowest of the season. The Beaver Creek and Chalkytsyik RAWS temperatures have stopped reporting, but they are probably around -60F.

First 40

Fairbanks Airport made 41 below Wednesday evening, the first 40 below of the season. Most of the North Pole area was in the mid 40s below, though KJNP reported 52 below, 5 degrees colder than Woodsmoke, which makes you say hum...

Subtle Changes

The afternoon RAOB at Fairbanks shows significant cooling between about 100 and 300 meters, with no change at the surface and a little warming above 300 meters above the valley floor. Although narrow, the 200 meters of cooling is where most of the hill-dwellers live.

50 below sunshine

The noon sun peaks above the ice fog at Beaver, on the Yukon River. Temperature around 50 below.

All Valleys Not Equal

It's another inversion plot, you say. Yet it is not so.

Two valley station, Fairbanks Airport, and the Angel Creek RAWS, near 53 Mile Chena Hot Springs Road. Both valley bottom locations. The difference: terrain orientation. Fairbanks Airport is ringed by hills on three sides. Angel Creek is in a narrow valley that tends to funnel any northeast pressure gradient. The result is a persistent breeze right to the valley floor that largely busts the inversion. Go past Angel Creek and the road makes a braod curve into Chena Hot Springs and, presto, the wind (usually) drops off and the temperature dips.

Cold Morning

Updated Lows
Coldest morning of the season thus far in most valleys around Fairbanks-land. The Airport has been down to 39 below, Fort Wainwright and Eielson AFB 42 below, and some of the North Pole area places in the mid-40s below. Strong inversion (of course), with elevations above 1000' MSL 10 to 15 below. Overnight low at Keystone Ridge -9F with enough of a breeze to drive the wind mill.

Arctic Village

44 below and a fiery sky at Arctic Village Sunday afternoon. Fort Yukon AWOS was down to 53 below, the lowest reported temperature in the state.

First 50

Fort Yukon has the first 50 below of the season in Alaska (I think). The AWOS had 53 below, the RAWS 52 below, the SnoTel 55 below. Take your pick, all three platforms are on the grounds of the Fort Yukon Airport. The Fort Yukon coop observer, who does not live at the Airport, had 50 below.