Pattern Change Coming

I'll have a lot to say about the cold January stats, but in the meantime, a big, big change is on the way. Here's the Canadian GEM forecast valid Sunday morning, showing a big ridge aloft from British Columbia northwest in Interior Alaska. This is will a very mild pattern, though strong inversions will sometimes mask the warm airmass in valley bottoms.

Satellite Temperatures

Nice post today from the University of Wisconsin CIMSS blog on satellite derived temperatures over the past couple days in Interior Alaska.

http://cimss.ssec.wisc.edu/goes/blog/archives/9672

Slowwww Warming

Here's the plot of low level temperatures from Fairbanks. It continues to oh so slowly warm aloft. At 10am AST, Cleary Summit was up to -16F, and at 11am here on Keystone Ridge it was -22F. Meanwhile, at 11am, -50F at Fairbanks International.

More Cold

Updated:
Cooperative observations in the past 12 hours add more definition to the cold:

Low temperatures Saturday include:
Galena: -63F (cooperative observer, new record for date)
Clear Sky Lodge: -60F (on the Parks Highway near Anderson)
North Pole: -57F (cooperative observer)
Woodsmoke: -57F (near North Pole; cooperative observer)
Goldstream Valley Bottom: -55F

Low temperatures Sunday morning include:
Fort Yukon: -65F (cooperative observer)
Kandik River: -64F (cooperative observer)
Manley Hot Springs: -60F
Bettles: -60F (new record for date)
Chicken: -59F
Circle Hot Springs: -58F
Eagle: -57F (cooperative observer)
Goldstream Creek: -55F
Nenana: -54F
Eielson AFB: -52F
Fairbanks Airport: -51F
UAF West Ridge: -48F

Denali Park VC: -52F (RAWS)
Denali Park Airstrip: -49F
Denali Park Headquarters: -37F

Still Warming Aloft

The high temperature today was just 42 below at the Airport, the lowest daily high temperature since Jan 2, 2000. The afternoon sounding shows slow warming continuing aloft.

A Cool Yule, and then Some

Here's a plot of daily temperatures (high and low temperatures at the top and bottom of the bars) at the Fairbanks Airport since Christmas. Not Hot. So far Saturday, Airport has a high of -42F, low -50F

50 below at Fairbanks

The sunrise view from the Alaska Climate Research Center webcam Saturday morning. Fairbanks Airport has now been down to -50F. The first -50 temperature at the Airport since January 2006. Record low for January 28th is -60F set in 1933.

Serious Cold

Okay, now it's getting seriously cold.

Here's at NOAA-19 infrared, this capture from the UAF Swath Viewer. This B & W rendition has slightly higher contrast than the NWS Alaska Region HQ version:




Updated:
Low temperatures through 10am AST Saturday

Goldstream Creek: -54F
Fairbanks Airport: -49F
Eielson AFB: -47F
UAF West Ridge: -46F
Cleary Summit: -30F

CORRECTED
Elsewhere in Interior Alaska:
Fort Yukon: -63F (cooperative observer)
Husila: -63F
Tanana: -61F (not a record for the date: record low is -68F in 1933)
Bettles: -59F (new record low for Jan 28th)
Chicken: -59F
Bolio Lake: -57F (south of Delta Junction)
Kaltag -56F
Nenana: -53F

Here's the low level temperature plot for last three soundings from Fairbanks. Cold, though the airmass is starting to warm aloft:

More Cold

Scott Bachmeier sent a link to this false color infrared image from early Friday morning (I've reoriented the original image to be longitudinally centered over Alaska):

The purple colors are radiance derived temperatures -50C (-58F) and lower. Over mainland Alaska any temperatures this cold are surface temperatures. These are a bit lower than the surface observations. The difference comes from several different sources, the most of significant of which are satellite calibration and the fact that "surface observations", i.e. METARS, cooperative obs, etc are from thermometers exposed above the surface. Nominal exposure 1.5 to 2 meters above the ground, though some are routinely higher (SNOTEL, RWIS). The presence of the mid-winter snowpack makes the actual thermometer exposure something like 0.5 meters lower in most places north of the Alaska Range.
Skies cleared by mid-morning over Fairbanks. By Noon temperatures have been down to 41 below at the Airport and 42 below at Fort Wainwright and Goldstream Valley.

Now it's Getting Cold

The 320am NOAA-19 Polar Orbiter infrared image shows it is cold over the western Interior. Fairbanks is near one of the last remaining areas of clouds.

As of 7a Friday, lows include:

Tanana 56 below
Hulsia: 56 below
Galena Airport: 53 below
Kaltag: 50 below

More to come…

Really Cold on the North Slope

FAA webcam image from Barrow Tuesday after with thin ice fog and 35 below:

Low temperatures so far Tuesday:

Barrow -45F
Deadhorse Airport: -50F
Umiat RAWS: -59F
Ikpikpuk River: -59F
Nuiqsut: -62F

Near Record Cold January in the Works

Here's an updated plot of daily mean temperatures thus far this winter (through January 23rd). The winds and clouds the past few days have kept temperatures up near normal. Through Monday (the 23rd), the mean January temperature at the Fairbanks Airport is -25.0F. The rest of the month looks to average at least this cold, and probably colder. This will be one of the coldest Januarys of record.

Colder Air Moves in, Temperature Warms 30 Degrees

Here's a plot of the low level temperatures from Friday morning and Sunday morning. The airmass overall has cooled a bit, but the wind has mixed down to the valley floor in many area. The miracle of mixing. Here are the 8am Temperatures from Friday and Sunday:
Fairbanks Airport -33F -4F
Keystone Ridge +2F -10F

The Way Inversions Die

Here's a plot of temperatures and winds from Fort Yukon Saturday. Fort Yukon is an AWOS and reports a full observation every 20 minutes. When the winds broke through the inversion, the temperatures rose 29 degrees inside of 20 minutes.

Mid-Day Image

Nice infrared image from 1pm Thursday from the NOAA-19 Polar Orbiter showing lots of clouds on the North Slope and pushed up into north side of the Brooks Range (note the wavy looking clouds near the crest). Clear skies prevail again over the Interior and West Coast.

Inversion's Growing

Here's the 3pm sounding from Fairbanks. The inversion is growing. Temperatures above 2300' MSL have approached 0F today, and I expect overnight there will be 40 degrees or more between rural valley bottoms and higher elevations. High today at Fairbanks Airport has been -35F; Clearly Summit -3F. Here at Keystone Ridge the temperature has risen from -18F at 3pm to -10pm at 5pm, all without any evident breeze.

How Cold has January Been?

Through the first 16 days of January, the average temperature at the Fairbanks Airport was -25.8F, almost 18 degrees below normal. Temperatures over the next week look to continue to be cold, though nowhere near records for any given day. A reasonable guess would be that by January 24th the average temp for the month will be similar to the current value. What happens thereafter is yet unknown, but temperatures this month will almost certainly finish up being far below normal. So how unusual is this?

Well, in recent years, reasonably unusual. Since 1976, there have been five calender months with an average temperature lower than 20 below: January 2006 (-22.0F), February 1990 (-21.7F), January 1989 (-21.3F), December 1980 (-24.0F) and February 1979 (-25.3F)

So, while the current cold spell is unusual, it is in no sense "unprecedented", even in the context of post-pipeline era Fairbanks, when there is an undeniable urban effect on Fairbanks temperatures, at least in ice fog situations. If anything is unusual, it's the lack of extremely low temperatures, not just in Fairbanks (low so far a paltry -48F) but anywhere in the Interior. Even the 58 below at Chicken is not excessive by their standards. There has only been one or two daily record low temperatures set (at Galena); most places have not even been close. With a comparatively moderate airmass aloft, that situation does not look to change the before the weekend at the earliest.

Not Much Change

Here's the 9am AST Monday surface analysis from NWS Anchorage, showing a big high covering much of mainland Alaska. The coldest weather this afternoon is in the eastern Interior, where afternoon temperatures barely cracked 40 below. Sunday morning the cooperative station at Chicken reported the lowest official temperature thus far this event, 58 below.



The soundings from Fairbanks shows very little change in near surface temperatures between 3am and 3pm AST Monday. Temperatures at the higher elevation stations have approached 10 below today, while valleys have been stuck near 30 below.

Cold with Growing Inversion

Here's the lowest kilometer of the morning sounding at Fairbanks: the inversion is growing. Notice that right off the surface the inversion is not super sharp, showing the effects of the ice fog. The nearly constant temperature between 300 and 600 meters is interesting. There is not much wind in this layer, but above that, where temperature warm to almost 0F, there are west winds around 20 mph.


Overnight lows include:

Goldstream Creek: -51F
Woodsmoke PWS -49F (near North Pole)
Fairbanks Airport: -48F (both Saturday evening and since midnight, the lowest temperature since February 2008)
UAF West Ridge: -42F

Lows from cooperative observations reported Saturday evening included 54 below at North Pole and 48 below at Goldstream Valley Bottom.

Updates on the Cold

Here are a couple of updates from the past couple days. Temperatures are about as stable as can be with clear skies and light winds here on Keystone Ridge. The low of 33 below is the lowest temperature here since Jan 2, 2009 when the low was also -33F.

The afternoon sounding from Fairbanks shows the warming compared to Friday afternoon is underway above 450 meters AGL and will be progressing down in the next day (note that there may be an encoding error in the surface temperature on the 3pm Saturday sounding). This will result in an increasingly strong valley based inversion. The high this afternoon at the Fairbanks Airport was 39 below.