Closing Up Winter

Here's a plot of the daily average temperature at Fairbanks since Oct 01. For what I usually refer to as "mid-winter", December through February, the mean temperature (through Feb 27) of -6.0F is a bit below normal (-4.7F through Feb 27). This will be coldest December through February since, get this, way back in 2008-09.

Wild Swings Update

Here's the updated plot of standardized daily temperature departures for this winter (through Feb 24) at Fairbanks. While not extreme this month, the persistent warmth follows the pattern established in November.

Arctic Sea Ice

Arctic sea ice is within a few weeks of it's maximum extent. Here is the Alaska-centered view from the University of Illinois's Cryosphere Today:

http://arctic.atmos.uiuc.edu/cryosphere/

Sea ice extent is much above normal, while on the European side of the Arctic it's much below normal.

Nice February Day

A lovely late February day at Arctic Village: sunny and 13 below at 1pm

Fluffy Snow

Keystone Ridge through noon Wednesday: 1.4inches of snow melted down to 0.03" water. Snow so fluffy you can see through it. :)

Another Morning, Another Inversion

Here's the morning sounding from Fairbanks, showing a strong inversion. At 9am, Goldstream Creek was -14F and Keystone Ridge +20F. Solar heating is increasing rapidly but is still not enough to come close to breaking the inversion. Yesterday the high temperature at Fairbanks was +11F, ten degrees lower than on Keystone Ridge.

More on the Wild Temperature Swings

The monthly mean temperature in January at the Fairbanks Airport was 30.8F lower than the December mean, This is the largest drop between December and January in the Weather Bureau/NWS era (since 1930). The change from October to November, 2011 of -37.1F was the third greatest since 1930. Depending on how the rest of this month turns out, it is entirely possible that the change from January to February will be in the top five greatest increases.

Clear Skies at Night, an Inversion's Delight

Clear skies overnight have allowed a strong inversion to develop this morning. At 8am, -10F in Goldstream Creek and +24F here on Keystone Ridge.

How Warm Has it Been?

The average temperature at the Fairbanks Airport the first two weeks of February was +5.6F. This is about 10 degrees above normal, but is only the 17th warmest first half of February of record. Temperatures are not expected to show overall much change the next few days, though low temperatures will vary in valleys depending on overnight cloud cover.

February Sunrise

A pretty morning Thursday at Mentasta Pass on the Glenn Highway, south of Tok. Photo from the FAA webcam.

Wicked Inversion

Here's the 3am AST Monday sounding from Fairbanks Airport, showing a very sharp surface inversion. That's a temperature of +4F at ground level, and +32F just 32 meters up. At 8am AST, the temperature at Goldstream Creek was -5F, while most of the hill elevation sites were reporting temperatures near +30F.

The Yoyo Goes On

Now that the next "warm phase" of the winter is well underway for Interior Alaska, here's an updated plot of standardized daily temperature anomalies at Fairbanks. For the most part, it's been either one or the other. Since November 1st, 54% of the days (55 out of 102) days have had an average daily temperature 1.0 or more standard deviations from the mean. If temperatures were normally distributed (which in general is not the case), we would expect about 32 such days. In the El Niño winter of 2009-10, Nov 1-Feb 10 had only 24 days ±1.0 standard deviation from the daily normal. Got all that?

The Carved Out Ridge

Here's the Monday 11am AST GOES-15 infrared image. This nicely show the high aloft centered over the Yukon (with a small low embedded near Watson Lake).

As the Winter Turns

Here's an updated plot of daily average temperatures this winter at Fairbanks. The mild weather now in place will be modulated in the valley by strong inversions when skies stay clear and winds stay light, at for the next couple of days. At 11am Monday, temperatures are near zero in the valleys and just above freezing at higher elevations. And the sun is shining.

Cold Snap at an End

Cold Snap 2012 has come to an end, with nearly all of northern Alaska now above zero. Here's a UCAR plot of observations from 11am AST Sunday. The only large area still below zero is the western North Slope. There is a typical inversion over much of the Interior. At 11am in the Fairbanks area temperatures were in the single digits above zero, while higher elevations were in the upper 20s and lower 30s.

Big Swings

Here's a plot of hourly temperatures at Keystone Ridge since Wednesday. Find the time of frontal passage. The drop from 25F at 8pm to -1F at 10pm was accompanied by only a slight breeze: enough to tinkle the wind chimes, but that's about it.

January Cold Stats

Here's an abridged version of the statement highlighting the monthly records. The full version (for a while) is here.

NOAK49 PAFG 012052
PNSAFG
AKZ216-218>225-227-020915-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
1146 AM AKST WED FEB 1 2012

...JANUARY 2012 WAS A RECORD OR NEAR RECORD COLD MONTH FOR MUCH OF
CENTRAL AND WESTERN ALASKA...

ALL OF NORTHERN ALASKA WAS UNDER THE INFLUENCE OF A VERY COLD AIR
MASS FOR NEARLY ALL OF JANUARY. THE GREATEST TEMPERATURE DEPARTURES
FROM NORMAL OCCURRED ACROSS THE WESTERN INTERIOR WHERE THE SKY WAS
MORE PERSISTENTLY CLEAR...WHICH ALLOWED STRONG INVERSIONS TO FORM
AND TEMPERATURES REMAINED VERY LOW FOR A PROLONGED PERIOD OF TIME.
MANY COMMUNITIES ALONG THE WEST COAST AND ACROSS THE WESTERN
INTERIOR HAD THE COLDEST OR ONE OF THE TOP FEW MONTHS ON RECORD.
THE DURATION OF THE COLD WEATHER WAS MORE NOTABLE THAN THE
ABSOLUTE MINIMUMS...AS RELATIVELY FEW DAILY RECORD LOW TEMPERATURES
WERE SET AT LOCATIONS WITH MORE THAN 50 YEARS OF WEATHER
OBSERVATIONS.

AT NOME...THIS PAST JANUARY WAS THE COLDEST ON RECORD. THE
AVERAGE TEMPERATURE OF -16.6 DEGREES EASILY EXCEEDED THE OLD
RECORD OF -15.2 DEGREES THAT OCCURRED IN 1989. THIS WAS NOT QUITE
THE COLDEST MONTH OF RECORD...AS FEBRUARY 1990 HAD AN AVERAGE
TEMPERATURE OF -17.2 DEGREES. FOR COMPARISON...THE NORMAL
TEMPERATURE FOR NOME DURING JANUARY IS 5.2 DEGREES ABOVE ZERO. THE
LOWEST TEMPERATURE OBSERVED DURING THE MONTH WAS 40 BELOW ON THE
5TH. THIS WAS THE FIRST 40 BELOW READING AT NOME SINCE 1999.
TEMPERATURE RECORDS AT NOME DATE BACK TO 1907.

AT KOTZEBUE...JANUARY 2012 WAS THE SECOND COLDEST SINCE 1929. THE
AVERAGE TEMPERATURE OF -22.6 DEGREES IS THE COLDEST SINCE 1934...
WHEN THE AVERAGE TEMPERATURE WAS -27.7 DEGREES. CONTINUOUS
TEMPERATURE RECORDS AT KOTZEBUE DATE BACK TO 1929. THE LOW
TEMPERATURE OBSERVED DURING THE MONTH OCCURRED ON THE EVENING OF
THE 31ST WITH A LOW OF 45 BELOW. THIS WAS THE COLDEST TEMPERATURE
OBSERVED AT KOTZEBUE SINCE 2006.

AT GALENA...JANUARY 2012 GOES DOWN AS THE COLDEST MONTH OF
RECORD. THE AVERAGE TEMPERATURE OF -32.6 DEGREES SURPASSED THE
-31.4 DEGREES IN 1971. THE LOWEST TEMPERATURE THIS MONTH WAS 65 BELOW
OBSERVED ON THE 29TH. NOT ONLY WAS THIS A DAILY RECORD LOW...BUT
IT WAS THE 3RD LOWEST TEMPERATURE EVER OBSERVED AT GALENA. THE
ALL-TIME LOW WAS 70 BELOW BACK IN JANUARY 1989. THERE WERE ALSO
FOUR CONSECUTIVE DAYS WITH A LOW TEMPERATURE OF 60 BELOW OR COLDER
ON THE 28TH THROUGH THE 31ST. THIS WAS ONLY OUTDONE ONCE...IN
1989...WHEN THERE WERE SIX CONSECUTIVE 60 BELOW DAYS AT GALENA.
WEATHER RECORDS AT GALENA DATE BACK TO 1942.


AT MCGRATH...THE AVERAGE TEMPERATURE OF -28.5 IS THE COLDEST MONTH
OF RECORD. THE PREVIOUS RECORD WAS -27.5 DEGREES IN JANUARY 1989.
THE LOW TEMPERATURE IN JANUARY WAS 55 BELOW ON THE 4TH. WEATHER
OBSERVATIONS HAVE BEEN MADE AT MCGRATH SINCE 1939.

AT BETTLES...THIS PAST JANUARY ENDED UP AS THE COLDEST ON RECORD.
THE AVERAGE TEMPERATURE OF -35.6 DEGREES SURPASSED THE OLD RECORD
OF -34.0 IN 1971. THE LOW TEMPERATURE FOR THE MONTH WAS 61 BELOW
ON THE 31ST. THREE OF THE LAST 4 DAYS OF THE MONTH HAD A LOW
TEMPERATURE OF 60 BELOW...AND ALL THREE WERE NEW DAILY
TEMPERATURE RECORDS. THESE WERE THE FIRST 60 BELOW TEMPERATURES AT
BETTLES SINCE FEBRUARY 1999. WEATHER RECORDS AT BETTLES DATE BACK
TO 1951.

AT TANANA...THIS PAST JANUARY WAS THE COLDEST IN OVER A HUNDRED
YEARS WITH AN AVERAGE TEMPERATURE OF -32.6 DEGREES. ONLY 1906 WITH
AN AVERAGE TEMPERATURE OF -36.6 DEGREES WAS ANY COLDER. THE LOW
TEMPERATURE FOR THE MONTH OF 61 BELOW WAS OBSERVED ON THE 28TH.
ALTHOUGH NOT A RECORD...IT WAS THE FIRST TIME THE TEMPERATURE HAD
DROPPED TO 60 BELOW OR LOWER SINCE 1993.

AT DENALI NATIONAL PARK HEADQUARTERS...THIS WAS THE COLDEST
JANUARY SINCE 1933...WITH AN AVERAGE TEMPERATURE OF -18.6 DEGREES
AND IS 22 DEGREES BELOW NORMAL. THE LOWEST TEMPERATURE WAS 41 BELOW
ON THE 25TH. WEATHER OBSERVATIONS HAVE BEEN MADE AT DENALI
NATIONAL PARK HEADQUARTERS SINCE DECEMBER 1922.

AT FAIRBANKS...JANUARY 2012 WAS THE FIFTH COLDEST ON RECORD WITH AN
AVERAGE TEMPERATURE OF -26.9 DEGREES...WHICH WAS 19 DEGREES BELOW
NORMAL. IT WAS THE COLDEST JANUARY AT FAIRBANKS SINCE 1971...AND
RANKED ONLY BEHIND 1906...1934...1966 AND 1971. THE COLDEST
TEMPERATURE OBSERVED WAS 51 BELOW ON THE 29TH. TEMPERATURE RECORDS
AT FAIRBANKS START IN SEPTEMBER 1904.

EAST OF THE FAIRBANKS AREA THIS WAS GENERALLY ONLY THE COLDEST
JANUARY SINCE 2004, AND ON THE NORTH SLOPE...TEMPERATURES IN JANUARY WERE CONSIDERABLYBELOW NORMAL BUT WERE NOWHERE NEAR RECORD COLD.

$$
CB/RT FEB 12

The Way Cold Snaps End

Furiously warming aloft since mid-day Tuesday. The morning sounding tells the story. At 6am Wednesday, Cleary Summit+3F, Fairbanks Airport -34F