January Post-Mortem

I've been meaning to post a brief analysis of January climate conditions over Alaska, especially in view of what proved to be a very misleading analog forecast for the month.  Here's what I wrote in December:

http://ak-wx.blogspot.com/2013/12/analog-seasonal-outlook.html

"While the uncertainty is great, and we can't have high confidence in this kind of forecast, the analogs suggest a cold January may be in store for Fairbanks."

However, January proved to be very warm over all of Alaska, with a prolonged chinook event in the second half of the month.  Daily mean temperatures were below normal on only four days in Fairbanks.  All-time records for January high temperatures were set in some locations, the state record was tied, and Nome and Barrow set very significant records as discussed on this blog.  Precipitation was well above normal at most locations, with notable exceptions being Fairbanks where the chinook effect prevailed, and Annette Island, which was close to the apex of the anomalous ridge; the third chart below shows the average 500 mb height anomaly for the month.

So what went wrong with the long-range forecast?  Well, in retrospect it was unwise to focus on just a single predictor (2013 conditions in Barrow) rather than also examining potential predictability from other sources.  A major influence on Alaska climate for some months now has been the unusually warm ocean temperatures in the northeast Pacific.  The maps below show (top) the sea surface temperature anomaly for January and (bottom) the mean temperature anomaly between the surface and 100m depth.  These are remarkably large anomalies over a large area and represent a major perturbation in the climate system.  The unusual ocean warmth has developed in tandem with a persistent circulation pattern that keeps bringing warm air to the same areas over the northeast Pacific, thereby reinforcing the ocean anomaly; and of course it's a positive feedback, as the unusual ocean warmth also reinforces the strength of the atmospheric ridge.  The persistent ocean anomaly seems to be at least part of the reason why a similar weather pattern keeps developing near and over Alaska: compare the third chart below, showing the October 500 mb height anomaly, to the January map above.

We can go all the way back to May 2013 and find a very similar ocean temperature pattern, as shown in the next two charts; and of course the summer brought record-breaking warmth to interior Alaska.  The northeast Pacific sea surface anomaly did go away for a time in the early fall, as colder air swept down and erased the surface warmth (third chart below), but a subsurface chart from September shows that there was still anomalous warmth lurking beneath the surface (fourth chart below) and the overall pattern remained unbroken.

In summary, the forecast failure for January was a good lesson that we should not rely too heavily on one analog predictor - especially one without a strong physical basis.  This is not to say that the Barrow analog was without value; but it seems the ocean conditions south of Alaska were a more potent factor and prevented the January climate from following the pattern of the Barrow analog years.

Fairbanks Temperature Update

The chart below shows recent daily mean temperatures in Fairbanks, compared to the 1981-2010 normal; the gray lines show the +/- 1 standard deviation range around the daily normal values.  The see-saw pattern that began in mid-November ended abruptly in mid-January, giving way to very unusual warmth that persisted for most of the rest of the month.

Below is the January climate summary, courtesy of NWS Fairbanks.  Note that the summary says that the 45 °F on the 24th was the "warmest temperature recorded at the airport during the month of January" - this refers to January 2014, not the all-time record for January, which is 52 °F (Jan 16, 2009).

PUBLIC INFORMATION STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE FAIRBANKS AK
624 AM AKST SAT FEB 1 2014

...MONTHLY WEATHER SUMMARY FOR FAIRBANKS ALASKA FOR JANUARY...

JANUARY 2014 WAS EXCEPTIONALLY WARM AND DRY IN FAIRBANKS WITH THE
AVERAGE TEMPERATURE FALLING BELOW NORMAL ON ONLY 4 DAYS...HOWEVER
WITH THE WARM TEMPERATURES CAME TWO FREEZING RAIN EVENTS OVER A 3
DAY PERIOD THAT CREATED HAZARDOUS DRIVING CONDITIONS AND CLOSED
MANY LOCAL SCHOOLS FOR TWO DAYS.

JANUARY STARTED WARM WITH AVERAGE TEMPERATURES 10 TO 20 DEGREES
ABOVE NORMAL FOR THE FIRST 9 DAYS...HOWEVER TEMPERATURES PLUMMETED
FROM 15 ABOVE ON THE 8TH TO 41 BELOW ON THE 12TH AND 13TH. 41
BELOW WAS THE COLDEST TEMPERATURE RECORDED AT THE AIRPORT DURING
THE MONTH OF JANUARY.

WARM TEMPERATURES RETURNED AGAIN TO THE INTERIOR BY MID MONTH.
A HIGH PRESSURE RIDGE ALOFT THAT STRETCHED FROM NEAR HAWAII TO
NORTHERN ALASKA ALLOWED A PROLONGED CHINOOK EVENT THAT LASTED
FROM AROUND THE 20TH TO THE 28TH OF JANUARY TO DEVELOP OVER THE
INTERIOR. AVERAGE TEMPERATURES WERE 20 TO 40 DEGREES ABOVE NORMAL
THROUGH THIS PERIOD. THE TEMPERATURE SOARED TO 45 DEGREES AT THE
FAIRBANKS AIRPORT ON THE 24TH. THIS WAS THE WARMEST TEMPERATURE
RECORDED AT THE AIRPORT DURING THE MONTH OF JANUARY. THE WARM
TEMPERATURES WERE NOT UNIQUE TO FAIRBANKS AS SEVERAL SITES ACROSS
THE INTERIOR SET RECORDS INCLUDING AN ALL TIME RECORD HIGH
TEMPERATURE FOR THE MONTH OF JANUARY OF 52 DEGREES AT DENALI
NATIONAL PARK HEADQUARTERS ON THE 26TH.

THE AVERAGE HIGH TEMPERATURE FOR THE MONTH OF JANUARY AT THE
FAIRBANKS AIRPORT WAS 16.4 DEGREES ABOVE ZERO WHICH IS 15.3
DEGREES ABOVE THE NORMAL HIGH TEMPERATURE OF 1.1 DEGREES ABOVE
ZERO. THIS RANKS AS THE 7TH WARMEST OF 106 YEARS OF RECORD. THE
AVERAGE LOW TEMPERATURE FOR THE MONTH OF JANUARY AT THE FAIRBANKS
AIRPORT WAS 1.1 DEGREES BELOW ZERO WHICH IS 15.8 DEGREES ABOVE
THE NORMAL LOW TEMPERATURE OF 16.9 DEGREES BELOW ZERO. THIS RANKS
AS THE 7TH WARMEST OF THE 107 YEARS OF RECORD. THE AVERAGE
TEMPERATURE WAS 7.6 DEGREES ABOVE WHICH WAS 15.5 DEGREES ABOVE THE
NORMAL AVERAGE TEMPERATURE OF 7.9 DEGREES BELOW.

0.22 INCH OF PRECIPITATION FELL AT THE AIRPORT DURING THE MONTH
OF JANUARY WHICH IS 0.36 INCH BELOW THE NORMAL PRECIPITATION OF
0.58 INCH. THIS RANKS AS THE 20TH DRIEST OUT OF 103 YEARS OF
RECORD. ONLY 2.5 INCHES OF SNOW FELL AT THE FAIRBANKS AIRPORT
WHICH IS 7.8 INCHES BELOW THE NORMAL JANUARY SNOW FALL OF 10.3
INCHES. WELL ABOVE NORMAL TEMPERATURES ALLOWED A HIGH PROPORTION
OF THE PRECIPITATION THAT FELL TO FALL IN LIQUID FORM FURTHER
REDUCING THE AMOUNT OF SNOW FALL. THE 2.5 INCHES OF SNOW THAT FELL
RANKS AS THE 12TH LOWEST AMOUNT FOR A JANUARY TOTAL SNOW FALL.

LOOKING AHEAD TO FEBRUARY WITH THE CLIMATOLOGICALLY COLDEST PART
OF WINTER BEHIND...AND AVAILABLE DAY LIGHT INCREASING AT NEARLY
SEVEN MINUTES PER DAY...A NOTICEABLE DIURNAL TEMPERATURE RANGE
WILL BE FELT...ESPECIALLY BY THE END OF THE MONTH. THE AVERAGE
HIGH TEMPERATURE AT THE FAIRBANKS AIRPORT INCREASES FROM 3 DEGREES
ABOVE ON THE 1ST TO 17 DEGREES ABOVE ON THE 28TH. THE AVERAGE LOW
TEMPERATURE INCREASES FROM 16 BELOW ON THE 1ST TO 10 BELOW ON THE
28TH. TEMPERATURES IN FEBRUARY HAVE RANGED FROM 50 ABOVE IN 1943
TO 58 BELOW IN 1947 AND MOST RECENTLY IN 1993. THE NORMAL
PRECIPITATION FOR FEBRUARY IS 0.42 INCHES. AVERAGE SNOWFALL IN
FEBRUARY IS 8.1 INCHES. AVAILABLE SUNSHINE INCREASES FROM 6 HOURS
AND 59 MINUTES ON THE FIRST TO 10 HOURS AND 2 MINUTES ON THE 28TH.

THE OUTLOOK FOR FAIRBANKS FOR FEBRUARY FROM THE CLIMATE PREDICTION
CENTER CALLS FOR EQUAL CHANCES OF ABOVE...NEAR NORMAL OR BELOW
NORMAL TEMPERATURES. THE CLIMATE PREDICTION CENTER IS ALSO
CALLING FOR EQUAL CHANCES FOR ABOVE NORMAL...NEAR NORMAL OR BELOW
NORMAL PRECIPITATION.

OBSERVED LAST MONTH...01/2014

                         OBSERVED   RANK
AVG MAX TEMP (F)             16.4   7TH WARMEST OF 106 YEARS
AVG MIN TEMP (F)             -1.1   7TH WARMEST OF 107 YEARS
AVG TEMP (F)                  7.6   7TH WARMEST OF 106 YEARS
TOTAL PRECIPITATION (IN)      0.22 20TH DRIEST OF 103 YEARS TOTAL
SNOW (IN)                     2.50 93RD SNOWIEST OF 104 YEARS

$$

CCC

December Anomalies

The maps below show the December climate anomalies for most of the first order observing stations in Alaska; as usual, the area of each circle indicates how unusual the month's conditions were, as measured by the anomaly in standard deviations for temperature and the percentile rank for precipitation (based on the 1981-2010 normals).

It was another warm and wet month in western and southwestern Alaska, and Cold Bay was anything but cold as it experienced its warmest December on record.  The annual average temperature for 2013 was also the warmest on record in Cold Bay.  However, December was colder than normal in the eastern half of the interior and in the southeast.  Fairbanks was relatively warmer and wetter than several other interior locations.

Barrow experienced an extraordinarily wet month again and broke the previous record for December precipitation by over 50%; in fact, December was the wettest calendar month ever observed in Barrow between November and February (inclusive).  Remarkably, three individual days in the month recorded precipitation greater than would normally be expected for the entire month of December.  2013 ended as the third warmest and third wettest year on record for Barrow.

 

2013 Review (NOAA)

Here's a nice summary of 2013 weather in Fairbanks, courtesy of the National Weather Service.  All in all, an extraordinary year from a meteorological perspective.

...2013 FAIRBANKS WEATHER REVIEW...

2013 WAS A HIGHLY VARIABLE YEAR WITH LARGE SWINGS IN TEMPERATURE
AND MOISTURE. FOR EXAMPLE JANUARY STARTED OFF WITH THE
TEMPERATURE REACHING 37 DEGREES ABOVE ON THE 14TH BUT FALLING TO A
BONE CHILLING 48 BELOW ON THE 27TH WHICH WAS THE COLDEST
TEMPERATURE AT THE FAIRBANKS AIRPORT IN 2013. FEBRUARY WAS THE
ONLY MONTH FROM JANUARY TO JUNE THAT ENDED UP AVERAGE OR WARMER.
MARCH BROUGHT A RETURN TO MUCH BELOW NORMAL TEMPERATURES AND ABOVE
NORMAL SNOWFALL. APRIL WAS EXCEPTIONALLY COLD AND SNOWY AND RANKED
AS THE 3RD COLDEST APRIL OF 108 YEAR ON RECORD. APRIL WAS ALSO THE
8TH SNOWIEST WITH THE SNOW PACK REACHING 25 INCHES ON THE NINTH.
MAY WAS AN EXCEPTIONAL MONTH THAT TRANSITIONED FROM ONE OF THE
COLDEST AND SNOWIEST SPRINGS IN RECENT MEMORY. IN FACT THE PERIOD
FROM THE 3RD OF APRIL TO THE 7TH OF MAY WAS THE COLDEST 5 WEEK
PERIOD FOR THAT PERIOD IN THE RECORDED IN HISTORY. THE SNOWPACK ON
THE 1ST OF MAY MEASURED IN AT A HEALTHY 17 INCHES AND REMAINED
THROUGH THE 12TH. WINTER WAS NOT QUITE DONE WITH FAIRBANKS AS
NEARLY ONE HALF INCH SNOW WAS MEASURED AGAIN ON THE 17TH AND 18TH.
MAY ENDED UP BEING OVER 5 DEGREES BELOW NORMAL DESPITE THE
TEMPERATURES SHOOTING INTO THE THE UPPER 70S AND MID 80S DURING
THE LAST WEEK WITH A DAILY RECORD OF 84 DEGREES SET ON THE 30TH.

2013 WILL BE REMEMBERED FOR ITS RECORD BREAKING WARM AND DRY
SUMMER. A REMARKABLE HEAT WAVE BAKED THE INTERIOR BEGINNING ON
THE 14TH OF JUNE AND CONTINUING WELL INTO JULY. THE WEEK OF 23RD
TO 29TH OF JUNE WAS THE WARMEST WEEK EVER RECORDED AT THE
FAIRBANKS AIRPORT AND MAY BE THE WARMEST WEEK OF RECORD AT ANY
LOCATION IN ALASKA. THE MERCURY SOARED TO 92 DEGREES BOTH ON THE
25TH AND THE 26TH. THE LOW TEMPERATURE OF 70 DEGREES ON THE 25TH
SET A MAXIMUM LOW TEMPEATRURE RECORED AND MAY BE THE HIGHEST
RELIABLE CALENDAR DAY LOW TEMPERATURE EVER RECORDED IN ALASKA.
JUNE RANKED AS THE 10TH DRIEST OF 101 YEARS OF RECORD. JULY
REMAINED HOT AND DRY AND HAMPERED FIRE FIGHTING EFFORTS ON SEVERAL
WILD FIRES ACROSS THE INTERIOR. THE METEOROLOGICAL SUMMER WHICH
IS THE 3 MONTH PERIOD FROM JUNE THROUGH AUGUST WAS THE SECOND
WARMEST ON RECORD AND THE 17TH DRIEST. THE MERCURY HIT 80 DEGREES
OR WARMER ON 36 DAYS DURING THE SUMMER OF 2013 SHATTERING THE
AVERAGE OF 11 DAYS. THE MERCURY REACHED 85 DEGREES ON 14 DAYS AND
REACHED 90 OR ABOVE ON TWO DAYS.

TEMPERATURES IN AUGUST WERE ABOVE AVERAGE AND REMAINED VERY DRY
HOWEVER A SIGNIFICANT PATTERN CHANGE IN THE MIDDLE OF THE MONTH
BROUGHT A WELCOME BREAK FROM THE HOT TEMPERATURES AND DRY
CONDITIONS AND BROUGHT MUCH MORE FAVORABLE CONDITIONS FOR
FIREFIGHTERS FIGHTING THE MANY FIRES ACROSS THE LOCAL AREA. THE
FLIP FROM HOT AND DRY TO COLD AND WET WAS SIGNIFICANT AS MANY
OUTLYING AREAS REPORTED A HARD FREEZE WITH TEMPERATURES FALLING
INTO THE MIDDLE AND UPPER TWENTIES. THE LOW TEMPERATURE AT THE
AIRPORT FOR AUGUST WAS 34 DEGREES ON THE 25TH. COLD AND WET AND
YES SNOWY CONDITIONS REMAINED THROUGH SEPTEMBER. THE FIRST
SNOWFALL OF THE SEASON AT THE AIRPORT FELL ON THE MORNING OF THE
18TH WHICH WAS ABOUT 2 WEEKS EARLY. THE 123 DAYS BETWEEN THE LAST
SNOWFALL OF THE SPRING ON THE 17TH OF MAY AND THE 18TH OF
SEPTEMBER WAS THE 4TH SHORTEST SNOW FREE PERIOD AT THE FAIRBANKS
AIRPORT. ANOTHER SIGNIFICANT PATTERN CHANGE OCCURRED EARLY IN
OCTOBER WITH VERY WARM DRY CHINOOK CONDITIONS DOMINATING THE
MONTH. OCTOBER 2013 WILL BE REMEMBERED FOR ITS LACK OF SNOW FALL
AND LACK OF SNOW PACK ON THE GROUND. ONLY A TENTH OF AN INCH OF
SNOW HAD FALLEN AT THE AIRPORT THROUGH THE MORNING OF THE 31ST
WITH ONLY TRACE AMOUNTS FALLING AND MELTING ON SEVEN DAYS IN
OCTOBER. THE SNOW DEPTH AT THE AIRPORT REMAINED ZERO UNTIL THE
EVENING OF THE 31ST WHEN 0.6 INCHES OF SNOW FELL. SNOW DEPTH IS
RECORDED IN WHOLE INCHES SO THE 0.6 INCHES ROUNDED UP TO 1 INCH OF
SNOW COVER. THE LAST MINUTE SNOWFALL PREVENTED MATCHING A LONG
STANDING SNOW DEPTH RECORD FOR THE 31ST OF OCTOBER. THE LAST TIME
SNOW DEPTH ON THE 31ST OF OCTOBER WAS ZERO IN FAIRBANKS WAS IN
1925 AND IS THE ONLY OCCURRENCE OF ZERO SNOW DEPTH IN THE CLIMATE
RECORD. THERE HAVE BEEN 5 OCCURRENCES OF A TRACE SNOW DEPTH ON THE
31ST OF OCTOBER IN THE CLIMATE RECORD...THE LATEST OCCURRING IN
1962.

OF ALL THE WILD WEATHER IN FAIRBANKS IN 2013 THE ONE THAT WILL BE
TALKED ABOUT AND REMEMBERED THE MOST WAS THE ICE AND WIND STORM
OF 13 AND 14 NOVEMBER. A POWERFUL STORM MOVED OUT OF THE BERING
SEA AND INTO THE INTERIOR WITH VERY WARM TEMPERATURES AND
ABUNDANT MOISTURE WHICH FELL AS FREEZING RAIN AND SNOW ON THE
MORNING OF THE 13TH. WIDESPREAD FREEZING RAIN WAS REPORTED ACROSS
THE AREA CAUSING DIFFICULT DRIVING CONDITIONS AND MANY ACCIDENTS
REPORTED THE MORNING OF THE 13TH. MANY RESIDENTS REPORTED HAVING
TO PULL OVER AND SCRAPE OFF THE FREEZING RAIN THAT BONDED
INSTANTLY ON WINDSHIELDS. ICE ACCUMULATIONS OF ONE HALF INCH WERE
COMMON ACROSS THE AREA NOT ONLY ON ROAD SURFACES BUT TREES AND
POWER LINES AS WELL. 3.9 INCHES OF SNOW FELL DURING THE DAY AT
THE AIRPORT WITH 4 TO 6 INCHES OF SNOW FALLING IN THE HILLS. THE
SNOW ADDED TO HEAVY ICE LOADS ALREADY ON TREES AND POWER LINES.
THE MOST DESTRUCTIVE PORTION OF THE STORM CAME WITH THE WINDS THAT
BLASTED INTO THE AREA LATE IN THE EVENING ON THE 13TH AND
CONTINUING THROUGH THE 14TH. WINDS GUSTS PEAKED AT 55 MPH AT THE
AIRPORT AT 1239 AM ON THE 14TH AND WAS ONE OF THE STRONGEST WIND
GUSTS IN THE PAST DECADE. A WIND GUST OF 62 MPH WAS RECORDED AT
FORT WAINWRIGHT. WIND GUSTS IN THE 60 TO 70 MPH RANGE BUFFETED THE
HIGHER TERRAIN SURROUND FAIRBANKS OVERNIGHT. NUMEROUS TREES WERE
UPROOTED WITH SEVERAL REPORTS OF CAR AND ROOF DAMAGE. THE STORM
ULTIMATELY LEFT OVER 14000 PEOPLE WITHOUT POWER ACROSS THE
FAIRBANKS AREA...SOME AREAS DID NOT GET POWER BACK FOR NEARLY TWO
WEEKS. TEMPERATURES DROPPED TO 27 BELOW ON THE 19TH PROMPTING THE
OPENING OF WARMING SHELTERS FOR THOSE WITHOUT POWER ACROSS THE
FAIRBANKS AREA AND A DECLARATION OF A STATE OF DISASTER BY THE
FAIRBANKS NORTH STAR BOROUGH MAYOR ON MONDAY NOVEMBER 18TH.

Fairbanks 2013 Charts

Here are some preliminary charts depicting the 2013 year in Fairbanks. In terms of temperature, 2013 was the 20th warmest of the 84 years since 1930 with an annual temperature of 28.3°F. As will be detailed in a future post, by my chi-square metric, this was the most extreme year on record due to the very large number of days more than 2.0 standard deviations from the mean. For precipitation, the 10.65" was very near the normal and was the 41st most of the last 84 years.

Autumn Forecast Verification

Regular readers may recall that way back in August we discussed some long-range analog forecast indicators for September through November, based (only) on the warm, dry summer that occurred in interior Alaska.  It's always fun to go back and check long-range forecasts to see if there was any semblance to the actual outcome; so here we go.

Listed below are the main (though admittedly tentative) conclusions of the analog investigation, along with the corresponding outcome:

• Dry September in Fairbanks: incorrect  1.74" vs 1.08" 1981-2010 median precipitation.  Three-quarters of an inch of rain fell on one day, September 11.
• First 25 °F frost in Fairbanks earlier than normal: correct  Sep 20 vs Sep 26 1930-2012 median
• First 0.5" or greater snowfall in Fairbanks earlier than normal: correct  Sep 18 vs Oct 6 normal
• Wet September in Barrow: correct  1.29" vs 0.59" normal
• Warm October in Barrow, Fairbanks, and Anchorage: all three correct, much warmer than normal
• Warm November in Anchorage: correct but only barely, 21.9 °F vs 21.3 °F normal

The discussion also showed maps of the 500 mb height and sea-level pressure patterns that have historically been observed in September following warm, dry summers in Fairbanks.  Below is the observed September 500 mb height anomaly: this agreed very nicely with the forecast map, with one of the main features being low heights over the Chukchi Sea.

Finally, here's the observed sea-level pressure pattern from September; this doesn't show the same degree of correspondence with the analog forecast map, but nevertheless below-normal pressure occurred as expected over eastern Alaska and western Canada.

All in all, the forecast exercise was fairly successful and illustrates that simple statistical techniques can - if you're lucky - yield limited long-range predictability.  In the next week or so I'll put together another analog forecast based on the very wet, warm year that Barrow has observed.

November Anomalies

Below are maps showing the November temperature and precipitation anomalies at some primary observing stations across the state.  The area of each circle indicates how unusual the month's conditions were, as measured by the anomaly in standard deviations for temperature and the percentile rank for precipitation (based on the 1981-2010 normals).  In the temperature map, the circle in the legend indicates the size of a 1 standard deviation anomaly, and in the precipitation legend, the circle size corresponds to a precipitation total that was outside the range of observations in 1981-2010.

The monthly temperature averages were fairly unremarkable for most of the state, with the largest departure from normal being at Cold Bay (+1.4 SD) and McGrath (+1.1 SD).  Interior Alaska saw much above normal temperatures in the first half of the month, but colder than normal conditions emerged after mid-month.

Precipitation was well above normal over most of western, interior, and northern Alaska; Bettles had their third wettest November of record, Gulkana their fourth wettest, and Fairbanks their fifth wettest.  Barrow experienced yet another month of above-normal precipitation, the ninth in a row; the year-to-date precipitation in Barrow is now the third highest on record.

November Summary

Here's the November weather summary from the National Weather Service in Fairbanks.

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
530 PM AKST SUN DEC 1 2013

...MONTHLY WEATHER SUMMARY FOR NOVEMBER FOR FAIRBANKS ALASKA...

NOVEMBER 2013 IN FAIRBANKS STARTED OFF MILD...BUILT TO WILD
CRESCENDO IN THE MIDDLE OF THE MONTH WITH SNOW...FREEZING
RAIN...RAIN AND ONE OF THE MOST DESTRUCTIVE WIND STORMS IN THE
INTERIOR IN RECENT MEMORY...BUT ENDED UP ON A CALM AND COLD NOTE.

THE AVERAGE HIGH TEMPERATURE AT THE FAIRBANKS AIRPORT WAS 15.4
DEGREES ABOVE WHICH WAS 4.5 DEGREES ABOVE THE NORMAL HIGH
TEMPERATURE OF 10.9 DEGREES. THE AVERAGE LOW TEMPERATURE AT THE
FAIRBANKS AIRPORT WAS 3.2 DEGREES BELOW WHICH WAS 2.5 DEGREES
ABOVE THE NORMAL LOW TEMPERATURE OF 5.7 DEGREES BELOW. THE AVERAGE
TEMPERATURE WAS 6.1 DEGREES ABOVE WHICH WAS 3.5 DEGREES ABOVE THE
NORMAL AVERAGE TEMPERATURE OF 2.6 DEGREES. NOVEMBER 2013 RANKS AS
THE 43RD WARMEST OF 109 YEARS OF RECORD.

NOVEMBER 2013 WILL BE REMEMBERED FOR A DESTRUCTIVE STRONG STORM
SYSTEM THAT MOVED ACROSS THE WEST COAST AND INTERIOR THAT BROUGHT
FREEZING RAIN DURING THE DAY ON THE 13TH AND DAMAGING WINDS EARLY
MORNING ON THE 14TH THAT LEFT NEARLY 14000 PEOPLE WITHOUT POWER
ACROSS FAIRBANKS...NENANA...AND NORTH POLE AREA AS WELL AS
UPROOTED NUMEROUS TREES. THIS STORM EVENT WAS DECLARED A STATE OF
DISASTER BY THE FAIRBANKS NORTH STAR BOROUGH MAYOR ON MONDAY
NOVEMBER 18TH WHEN TEMPERATURES DROPPED TO 27F BELOW ZERO ON THE
19TH AND AN ESTIMATED 800 RESIDENTS FROM GOLDEN VALLEY ELECTRIC
ASSOCIATION WERE STILL WITHOUT POWER. THIS STORM SYSTEM HAD
INITIALLY STARTED OUT AS SNOW BRIEFLY AT THE FAIRBANKS AIRPORT
BEFORE SWITCHING OVER TO A MIX OF FREEZING RAIN AND SNOW THROUGH
THE EARLY MORNING ON THE 13TH. AS WARMER AIR MOVED ALOFT OVER THE
COLD SURFACE...WIDESPREAD FREEZING RAIN WAS REPORTED ACROSS THE
GREATER FAIRBANKS AREA ON THE MORNING OF THE 13TH. ALTHOUGH
DRIVING CONDITIONS WERE DIFFICULT AND SEVERAL ACCIDENTS WERE
REPORTED ON THE MORNING OF THE 13TH...MANY COMMENTED MORE ISSUES
WITH THE RAIN FREEZING INSTANTLY ON THE WIND SHIELDS RATHER THAN
THE ICY ROADS. SEVERAL DRIVERS HAD TO PULL OFF THE ROAD TO REMOVE
THE ICE ON THE WIND SHIELDS DURING THE MORNING COMMUTE. SEVERAL
REPORTS OF A QUARTER OF AN INCH TO ONE HALF INCH OF ICE
ACCUMULATION. THE WINTRY MIX OF FREEZING RAIN AND SNOW CONTINUED
THROUGH THE DAY WITH TOTAL SNOW ACCUMULATIONS ON THE 13TH OF 3.9
INCHES AT THE FAIRBANKS AIRPORT. SEVERAL REPORTS ACROSS THE AREA
RANGED WITH 4 TO 5 INCHES OF SNOW WITH THE STORM SYSTEM. AS THE
WARM FRONT PUSHED TOWARDS THE GREATER FAIRBANKS AREA DURING THE
LATE EVENING OF THE 13TH...SNOW QUICKLY STARTED TO MELT AS THE
SOUTHEAST WINDS INCREASED TO SUSTAINED WINDS OF 15 MPH AND GUST OF
26 MPH AT 1000 PM RECORDED AT THE FAIRBANKS AIRPORT. ALONG WITH
THE INCREASING WINDS THE TEMPERATURES ALSO INCREASED FROM 22F TO
44F IN TWO HOURS BETWEEN 800 PM AND 1000 PM AKST. REPORTS OF POWER
OUTAGES AND BLOWN TRANSMITTERS WERE REPORTED BETWEEN 1100 PM ON
THE 13TH THROUGH 1 AM AKST ON THE 14TH. ALTHOUGH THE STRONG
SOUTHEAST WINDS STARTED AS EARLY AS 1000 PM AKST ON THE 13TH AND
CONTINUED THROUGH 1 PM ON THE 14TH...THE PEAK WIND GUSTS RECORDED
AT THE FAIRBANKS AIRPORT WAS 55 MPH AT 1239 PM ON THE 14TH. OTHER
AREAS SUCH AS FORT WAINWRIGHT RECORDED A PEAK WIND GUSTS OF 62 MPH
AT 1239 AM AND 101 AM ON THE 14TH AND EIELSON AFG RECORDED A PEAK
WIND GUST OF 49 MPH AT 137 AM ON THE 14TH. FROM THE COLLECTED DATA
FROM 1930 AT THE FAIRBANKS AIRPORT FOR WIND RECORDS... THE 55 MPH
WIND GUST IS STRONGEST PEAK WIND GUST FOR THE MONTH OF
NOVEMBER AND THE 4TH STRONGEST PEAK WIND GUST AT THE FAIRBANKS
AIRPORT WITH THE RECORD PEAK WIND GUST OF 63 MPH SET ON JULY 7TH
1990. AS PREVIOUSLY MENTIONED...NUMEROUS TREES WERE UPROOTED
WITH SEVERAL REPORTS OF CAR...ROOF...AND HOUSE DAMAGE. THERE WAS
ALSO REPORT OF A PIPER SUPER CUB AIRPLANE WITH THE WINGS SHREDDED
AND DAMAGE ALL OVER THE PLANE. IT TOOK OVER A WEEK FOR GVEA TO
RESTORE POWER TO CUSTOMERS AND REPAIR THE DOWNED POWER LINES DUE
TO UPROOTED TREE DAMAGE.

NOVEMBER ALSO HAD LARGE AND IN SOME CASES RAPID TEMPERATURE
SWINGS. THE WARMEST TEMPERATURE AT THE FAIRBANKS AIRPORT OCCURRED
ON THE 14TH WHEN THE TEMPERATURE SOARED TO 45 DEGREES AND SET A
NEW RECORD HIGH TEMPERATURE FOR THE DAY. THE LOWEST TEMPERATURE
OCCURRED ONE WEEK LATER ON THE 21ST WHEN THE TEMPERATURE DROPPED
TO 33 BELOW. WARM CHINOOK WINDS BLOWING THROUGH THE ALASKA RANGE
BROUGHT LARGE AND RAPID TEMPERATURE FLUCTUATIONS ACROSS THE
FAIRBANKS AREA. THE TEMPERATURE JUMPED 39 DEGREES FROM 25 BELOW TO
14 ABOVE IN LESS THAN 24 HOURS AT THE FAIRBANKS AIRPORT ON THE
21ST AND 22ND. THE TEMPERATURE JUMPED 53 DEGREES AT EIELSON IN 24
HOURS. BOTH OF THESE TEMPERATURE SWINGS PALE IN COMPARISON TO THE
TEMPERATURE CHANGE THAT OCCURRED AT HEALY WHERE THE TEMPERATURE
JUMPED FROM 41 BELOW TO 40 ABOVE...AN INCREDIBLE 81 DEGREE
SWING...IN LESS THAN 24 HOURS. AS THE WARMING CHINOOK FADED AT
HEALY THE TEMPERATURE PLUNGED 32 DEGREES IN 4 HOURS.

PRECIPITATION THAT FELL AT THE FAIRBANKS AIRPORT TOTALED 1.74
INCHES WHICH WAS 0.67 INCHES ABOVE NORMAL AND RANKS AS THE 5TH
WETTEST OF 99 YEARS OF RECORD. NOVEMBER 2013 WAS ALSO SNOWY WITH
17.6 INCHES OF SNOW FALLING AT THE AIRPORT WHICH IS 4.4 INCHES
ABOVE THE NORMAL NOVEMBER SNOW FALL OF 13.2 INCHES. NOVEMBER 2013
RANKS AS THE 15TH SNOWIEST OF 98 YEARS OF RECORD. SNOW ON THE
GROUND STARTED WITH ONLY A TRACE ON THE 1ST BUT HAD GROWN TO 12
INCHES OF SNOW ON THE GROUND BY THE 29TH.

LOOKING AHEAD TO DECEMBER...THE AVERAGE HIGH TEMPERATURE DROPS
FROM 7 ABOVE ON THE 1ST TO 2 ABOVE ON THE 31ST. THE AVERAGE LOW
TEMPERATURE DROPS FROM 11 BELOW ON THE 1ST TO 16 BELOW ON THE
31ST. IN THE LAST 108 YEARS...DECEMBER TEMPERATURES HAVE VARIED BY
120 DEGREES IN FAIRBANKS...FROM A HIGH OF 58 ABOVE IN 1934 TO A
LOW OF 62 BELOW IN 1961. AVERAGE SNOWFALL IS 12 INCHES BUT HAS
BEEN AS MUCH AS 50.7 INCHES IN 1984 TO AS LITTLE AS A TRACE IN
1969. DECEMBER IS THE DARKEST MONTH OF THE YEAR WITH POSSIBLE
SUNSHINE DECREASING FROM 4 HOURS AND 35 MINUTES ON THE 1ST TO THE
ANNUAL MINIMUM OF 3 HOURS AND 42 MINUTES ON THE WINTER SOLSTICE.
BY THE 31ST POSSIBLE SUNSHINE INCREASES TO 3 HOURS AND 59 MINUTES
GAINING 17 MINUTES ALONG THE LONG CLIMB BACK TO THE MIDNIGHT SUN
ON THE SUMMER SOLSTICE IN JUNE.

THE OUTLOOK FOR FAIRBANKS FOR DECEMBER FROM THE CLIMATE PREDICTION
ENTER CALLS FOR EQUAL CHANCES OF ABOVE NORMAL...NEAR NORMAL OR BELOW
NORMAL TEMPERATURES. THE CLIMATE PREDICTION CENTER IS ALSO CALLING
FOR EQUAL CHANCES FOR ABOVE NORMAL...NEAR NORMAL OR BELOW NORMAL
PRECIPITATION.


OBSERVED LAST MONTH...11/2013

                         OBSERVED   RANK
AVG MAX TEMP (F)             15.4   37TH WARMEST OF 109 YEARS
AVG MIN TEMP (F)             -3.2   44TH WARMEST OF 109 YEARS
AVG TEMP (F)                  6.1   43RD WARMEST OF 109 YEARS
TOTAL PRECIP (IN)            1.74   5TH WETTEST OF 99 YEARS
TOTAL SNOW (IN)             17.60   15TH SNOWIEST OF 98 YEARS

$$

CCC/MAK

October Summary

Here's the October summary from the National Weather Service in Fairbanks:

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
852 AM AKDT FRI NOV 1 2013

...OCTOBER 2013 WEATHER SUMMARY FOR FAIRBANKS ALASKA...

THE WEATHER FOR OCTOBER 2013 IN FAIRBANKS WAS DOMINATED BY WARM
AND DRY CHINOOK CONDITIONS AS A LARGE RIDGE FORMED OVER EASTERN
ALASKA. UPPER LEVEL WINDS AROUND THIS RIDGE DIRECTED MULTIPLE LOW
PRESSURE SYSTEMS WITH SUBTROPICAL ORIGINS NORTH OVER THE ALASKA
RANGE CREATING MULTIPLE EPISODES OF CHINOOK WARMING AND DRY
CONDITIONS ACROSS THE INTERIOR. THE 1ST OF OCTOBER WAS THE ONLY
DAY THAT THE AVERAGE TEMPERATURE WAS BELOW NORMAL. THE 4TH OF
OCTOBER AVERAGE TEMPERATURE WAS RIGHT AT NORMAL. EVERY OTHER DAY
IN THE MONTH WAS ABOVE NORMAL WITH THE THE AVERAGE TEMPERATURE ON
THE 28TH OF OCTOBER WARMING TO AN INCREDIBLE 31 DEGREES ABOVE
NORMAL. THE HIGH ON THAT DAY OF 51 DEGREES WHICH SET A NEW DAILY
HIGH TEMPERATURE RECORD FOR THAT DAY. THIS BROKE THE OLD RECORD
OF 48 DEGREES SET IN 1923. THE HIGHEST TEMPERATURE FOR THE
MONTH WAS 57 DEGREES WHICH OCCURRED ON BOTH THE 18TH AND THE 19TH
IN CONJUNCTION WITH A SIGNIFICANT CHINOOK WIND EVENT IN THE ALASKA
RANGE. THE LOWEST TEMPERATURE FOR THE MONTH WAS 16 DEGREES ABOVE
AND OCCURRED ON THE 26TH. OCTOBER 2013 RANKED AS THE 3RD WARMEST
OF 109 YEARS OF RECORD AND WAS THE 40TH DRIEST OF 103 YEARS OF
RECORD WITH ONLY 0.59 INCHES OF PRECIP FALLING AT THE AIRPORT. THE
PALTRY 0.70 INCHES OF SNOW THAT FELL IN OCTOBER WAS 10.1 INCHES
BELOW THE NORMAL SNOW FALL OF 10.8 INCHES. THIS RANKED AS THE
100TH SNOWIEST OCTOBER OF THE 104 YEARS OF RECORD...OR IT RANKED
AS THE 4TH LEAST SNOWY OCTOBER ON RECORD.

THE AVERAGE HIGH TEMPERATURE AT THE FAIRBANKS AIRPORT WAS 44 DEGREES
WHICH WAS 12 DEGREES ABOVE THE NORMAL HIGH TEMPERATURE OF 32 DEGREES.
THE AVERAGE LOW TEMPERATURE AT THE FAIRBANKS AIRPORT WAS 28 DEGREES
WHICH WAS 12 DEGREES ABOVE THE NORMAL LOW TEMPERATURE OF 16. THE AVERAGE
TEMPERATURE WAS 36 DEGREES WHICH WAS AN INCREDIBLE 12 DEGREES ABOVE
THE NORMAL AVERAGE TEMPERATURE OF 24 DEGREES.

OCTOBER 2013 WILL BE REMEMBERED FOR ITS LACK OF SNOW FALL AND LACK
OF SNOW DEPTH ON THE GROUND. ONLY A TENTH OF AN INCH OF SNOW HAD
FALLEN AT THE AIRPORT THROUGH THE MORNING OF THE 31ST AND ONLY
TRACE AMOUNTS HAD FALLEN AT THE AIRPORT ON SEVEN OTHER DAYS. WITH
A VERY WARM GROUND AND WARM CHINOOK WINDS WHAT LITTLE SNOW FELL
QUICKLY MELTED ALLOWING ZERO SNOW DEPTH ON THE GROUND THROUGH THE
30TH OF OCTOBER. SNOW DEPTH AT THE AIRPORT REMAINED ZERO UP UNTIL THE
EVENING OF THE 31ST WHEN 0.6 INCHES OF SNOWFALL IN THE AFTERNOON
AND EVENING. SNOW DEPTH ON THE GROUND IS ROUNDED TO THE NEAREST
INCH SO THE 0.6 INCHES OF SNOW ON THE GROUND ON THE EVENING OF
THE 31ST WAS RECORDED AS A SNOW DEPTH OF 1 INCH FOR THE 31ST.
THE LAST MINUTE SNOWFALL PREVENTED MATCHING A LONG STANDING SNOW
DEPTH RECORD FOR THE 31ST OF OCTOBER. THE LAST TIME SNOW DEPTH ON
THE 31ST OF OCTOBER WAS ZERO IN FAIRBANKS WAS IN 1925 AND IS THE
ONLY OCCURRENCE OF ZERO SNOW DEPTH IN THE CLIMATE RECORD. THERE
HAVE BEEN 5 OCCURRENCES OF A TRACE SNOW DEPTH IN THE CLIMATE
RECORD...THE LATEST OCCURRING IN 1962.

LOOKING FORWARD TO NOVEMBER...THE AVERAGE HIGH TEMPERATURE DECREASES
FROM 18 DEGREES ON THE 1ST TO 7 ABOVE ON THE 30TH. THE AVERAGE LOW
TEMPERATURE DECREASES FROM 3 ABOVE ON THE 1ST TO 11 BELOW ON THE
30TH. THE AVERAGE DAILY TEMPERATURE DECREASES FROM 11 ON THE 1ST TO
2 BELOW ON THE 30TH. OVER THE LAST 108 YEARS THE TEMPERATURES HAVE
RANGED FROM 54 DEGREES ON THE 25 IN 1936 TO 54 BELOW ON THE 29TH
IN 1909. NOVEMBER AVERAGES 0.67 INCHES OF PRECIP WITH ALL OF THAT
FALLING AS SNOW IN MOST YEARS...HOWEVER RAIN EVENTS DO HAPPEN AS
MANY WILL REMEMBER THE CRIPPLING ICE STORM IN NOVEMBER OF 2010.
NOVEMBER AVERAGES 13.2 INCHES OF SNOW. POSSIBLE SUN LIGHT CONTINUES
TO DECREASE AT ABOUT 6 MINUTES PER DAY...FALLING FROM 7 HOURS AND
48 MINUTES ON THE 1ST TO 4 HOURS AND 45 MINUTES ON THE 30TH.

THE OUTLOOK FOR FAIRBANKS FOR NOVEMBER FROM THE CLIMATE PREDICTION
CENTER CALLS FOR EQUAL CHANCES OF ABOVE...NEAR NORMAL OR BELOW
NORMAL TEMPERATURES. THE CLIMATE PREDICTION CENTER IS ALSO CALLING
FOR EQUAL CHANCES FOR ABOVE NORMAL...NEAR NORMAL OR BELOW NORMAL
PRECIPITATION.




OBSERVED LAST MONTH...10/2013

                         OBSERVED   RANK
AVG MAX TEMP (F)             44.0   5TH WARMEST OF 109 YEARS
AVG MIN TEMP (F)             28.2   3RD WARMEST OF 109 YEARS
AVG TEMP (F)                 36.1   3RD WARMEST OF 109 YEARS
TOTAL PRECIP (IN)            0.59   40TH DRIEST OF 103 YEARS
TOTAL SNOW (IN)              0.70   100TH SNOWIEST OF 104 YEARS

$$

CCC

The Definition of The Seasons

When does winter informally begin in Fairbanks, or Anchorage, or Juneau? Is it the same date for all cities or are there difference? I have always argued that the seasons, especially here in Alaska, do not neatly correspond to strict climatological or astronomical definitions. In addition, the seasons are not all the same length. Winter certainly lasts longer in Barrow than in Anchorage.

After thinking about the idea of seasonal definitions for a while (see First Snow Date, and First Sub Freezing High Temperature) I have finally come up with a first draft of seasonal definitions for Alaska. Coincidentally, Rick gave this some thought last January and came up with some suggested criteria. One of his ideas was to use a running mean of temperatures as a threshold value to transition from one season to the next.

Since every location, from Barrow, to Adak, to Ketchikan, receives freezing temperatures and snow, it is only natural to use those criteria to define the winter season. But what about summer? For this first iteration, only temperatures are used. The beginning of winter is arbitrarily defined as the first day that a 5-day average of the daily temperature is under 30°F. The last day of winter is the last day that a 5-day average of the daily temperature is under 30°F. The beginning of summer is arbitrarily defined as the first day that a 5-day average of the daily temperature is over 55°F. The last day of summer is the last day that a 5-day average of the daily temperature is over 55°F. Spring is defined as the time period between Winter and Summer and Fall is defined as the period between Summer and Winter.

There were 142 stations used in the analysis. Each of them contained (relatively) complete records between 1980 and 2012. Of that 32-year period, at least 15 were necessary for inclusion in the analysis. For some North Slope stations, there were years when so Summer occurred by these definitions.

I promise, this is the last one of these for a while!

Click on Image to See Animation of Seasons (~3.1Mb)

Click HERE to see the complete list of dates for all 142 stations

A list of the individual files:

• August 1st
• August 15th
  
• September 1st
• September 15th
• October 1st
• October 15th
• November 1st
• November 15th
• December 1st
• December 15th
• January 1st
• January 15th
• February 1st
• February 15th
• March 1st
• March 15th
• April 1st
• April 15th
• May 1st
• May 15th
• June 1st
• June 15th
• July 1st
• July 15th

August and Summer Anomalies

The maps below show the August and climatological summer (June-August) temperature and precipitation anomalies for select observing sites in Alaska.  Red and green circles indicate above-normal temperature and precipitation respectively, while blue and brown circles indicate below-normal, relative to the 1981-2010 mean (temperature) and median (precipitation).  The size of the circles shows how far the anomalies departed from average, with larger circles indicating more unusual conditions.

For August, it's remarkable that every location experienced above-normal temperatures, although none of the anomalies was extreme: the highest standardized anomaly was at Cold Bay, where August mean temperature was 1.4 standard deviations above normal.  Both Cold Bay and Kodiak received more rainfall than in any August between 1981 and 2010, although neither location broke a record relative to the long-term history.

 

For the summer period of June through August, all locations were warmer than the 1981-2010 mean except for St Paul Island, which fell victim to the colder than normal Bering Sea temperatures.  Most locations were more than 1 standard deviation warmer than normal, and Gulkana temperatures were 2.2 SD above normal.  Interior and southeastern locations were much drier than average under the influence of the persistent ridge, but many coastal locations on the west side of the ridge were wet.  Barrow has seen above-median precipitation every month since March and had one of their wetter summers on record.

The Perils of Exposure

Deep Cold started off in 2010 as a way that I could share Interior and northern Alaska weather and climate factiods and analyses with friends and colleagues without clogging up their email inboxes.

As anyone who has read the blog can plainly see, I never get into second order attribution of events. I have done a few posts on climate variability, mostly in regard to PDO, which, being nothing more than a way to characterize North Pacific sea surface temperature anomaly patterns, is an important factor in Alaska (south of the Brooks Range) decadal-scale climate.

Readership has always been tiny. The blog received enough comments to know that a few folks had found the blog useful. Typical page views were in the 15 to 45 range. This is so tiny that I wound up using the blog as a place to "store" graphics, typically plots of some data or another, so that I could get to them regardless of where I was at or what computer I was on, suspecting that they would be of minimal interest to anyone else.

As my personal circumstances changed, I had less time for posting, and after some thought, I invited a couple of folks to contribute to Deep Cold who are very knowledge about high latitude weather and climate and have insights and analytical skills complimentary to my own. As a result, the blog now has more frequent posts and more the content is "beefier". And the small readership seemed to agree.

So it was with great dismay that a well known political website picked up a short post on record low temperatures over the weekend.  In three days this blog had nearly a quarter million page views, more than five times the total in the previous three years combined.

More importantly, the record cold post was swamped with comments that had nothing to do with Alaska weather and climate. Personal attacks on politicians have nothing to do with Alaska weather and climate and are not welcome here, nor is this a blog about climate change. A as a result I turned off comments.  There are a myriad of websites that cater to those. This is not one of them.

I'm interested in Alaska weather and climate and I'm interested in having a blog that addresses that. It would be nice if a few of the quarter million visitors stick around because they are interested in the same things, but this is not the place for political arguments. If you're interested in Alaska weather and climate for its own sake, then thanks for visiting Deep Cold. 

July anomalies

Below are a couple of maps showing the July temperature and precipitation anomalies at observing locations across Alaska.  The format was inspired by Rick's practice of comparing anomalies to the width of the local historical distribution; this allows a more meaningful comparison between locations with widely differing climates.

In the first map (temperature), the area of each circle shows the magnitude of the standardized anomaly, which is calculated as (July mean - 1981-2010 mean)/(1981-2010 standard deviation).  The second map (precipitation) depicts the significance of the precipitation anomaly by using the rank of the July total compared to the 30 July totals in the 1981-2010 period; so the largest possible circle is obtained when the July total is either smaller or larger than any in the 30-year period.  If the July total falls in the middle of the historical distribution, the circle has zero radius (i.e. precipitation was close to average).

The numbers at the observing locations show the actual values for the mean temperature and total precipitation.

Fire Season Takes Off

The cold spring greatly retarded the fire season: as of Friday, May 31 only 665 acres had burned. That changed over the weekend, as the season roared to life: Monday morning Alaska Fire Service was calling 32,600 acres burned. Most of that was in Southwest Alaska, where the Doestock Creek fire, south of Aniak, was over 18000 acres. There were several staff fires southeast of Tok, with the Bitter Creek fire threatening to close the Alaska Highway. Here's the AFS plot of "active fires" from Tuesday early morning, bearing in mind that active means "not declared out" and that many of these are 0.1 acres or less. The lack of fires in the northern Interior reflects the lack of lightning thus far this season.

Oh What a May It Was

Hard to know how to present all the notable events of May 2013, so when in doubt, put up a chart. Here's a plot of the daily mean temperature at Fairbanks in May.

Only six seven days the entire month were within one standard deviation of normal. On to the highlights:
In the Weather Bureau/NWS era (starting 1930)

• 10th coldest May
• Latest date (May 18th) of record with a daily high temperature below 40ºF and daily mean  below freezing
• Three daily record low temperatures and two record low max temperatures
• Winter snowpack melt-out of May 11 is the second latest of record
• 18 days with daily low temperatures of  ≤32ºF is most in May since 1964
• Green-up of West Chena Ridge as seen from UAF on May 26th is latest since observations began in 1974 and probably latest since 1964
• The 47 consecutive days with daily mean temperature below normal appears to be a record for such a streak, though it is not a record for consecutive days with departure of the same sign (53 days in a row in autumn 2002 above normal)
• Lowest April-May of record (mean temperature 31.3ºF)
• Fourth lowest March-April-May of record (mean temperature 23.2ºF)

On the warm side:

• Daily record high of 84ºF tied on the 30th
• Five days with highs in the 80s ties for second greatest such days in May (record is seven days in 2011)
• First time ever in May with five straight days of highs 82ºF or higher (thanks to reader Brian for this one)

April 2013 in Fairbanks

There is a lot of Alaska weather going on...but we'll try and take it one piece at time.

So, for Fairbanks for April, the mean temperature of 18.0ºF makes this solidly the coldest April since 1924 and the third coldest of record. Only 1924 (14.8ºF) and 1911 (17.4ºF) are colder. For all Interior locations with data from 1924, that month is still the coldest April of record.

The high temperature for the month of 48ºF makes this the first April since 1972 when the temperature failed to get to 50ºF or higher. Two daily record lows were set: 15 below on the 12th and 2 above on the 28th. The record on the 28th was especially notable as only twice as the temperature been lower than this so late in the season. The monthly low of 21 below on the 11th was not a daily record, but was the lowest April temperature since 1992. Daily mean temperatures were below normal every day after the 3rd. Which of course calls for a standardized anomaly plot:

Eight April days had daily anomalies 2.5 or more standard deviations below normal, and the monthly mean of 18.0ºF is a whopping 2.8 standard deviations below the 1981-2010 mean. The mean temperature for March and April combined of 12.5ºF is the coldest since 1972.

Snowfall totaled 9.9", while well above normal, made this only the 4th snowiest April since 1990. Far more unusual was the snowpack; outside of urban areas the snowpack has compacted some but has not really started to melt out at all. At the Airport, the snow depth of 18" on the 30th was the greatest end of April snow cover since 1937. This is not too surprising considering that the accumulated thaw degrees through the end of April is a paltry 3, fewer even than 1924 and 1911; 1937 had just one thaw degree day through the end of April, the lowest of record.

Tomorrow I'll try and gin a some analysis of why it was so cold in April.

February Summary

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
733 PM AKST FRI MAR 1 2013

...FEBRUARY WEATHER SUMMARY FOR FAIRBANKS ALASKA...

FEBRUARY WAS A FAIRLY QUIET MONTH IN FAIRBANKS. MILD WEATHER
EARLY IN THE MONTH AND AGAIN THE LAST COUPLE OF DAYS ALMOST
EXACTLY BALANCED OUT A SPELL OF COLD WEATHER AFTER MID-MONTH. AT
THE FAIRBANKS AIRPORT...THE AVERAGE HIGH TEMPERATURE FOR FEBRUARY
WAS 10 ABOVE AND THE AVERAGE LOW WAS 13 BELOW. THE MONTHLY AVERAGE
OF 1.4 BELOW WAS ALMOST EXACTLY NORMAL. THE HIGH FOR THE MONTH
WAS 29 DEGREES ON THE 9TH...WHILE THE LOWEST TEMPERATURE AT THE
AIRPORT WAS 43 BELOW ON THE 19TH.

FOR THE FOUR MONTHS OF NOVEMBER THROUGH FEBRUARY...THE AVERAGE
TEMPERATURE AT THE FAIRBANKS AIRPORT WAS 7.7 BELOW...NEARLY FIVE
DEGREES BELOW NORMAL. THIS WAS THE COLDEST NOVEMBER THROUGH FEBRUARY
SINCE 1998-99. THERE WERE A TOTAL OF 15 DAYS WITH A LOW
TEMPERATURE OF 40 BELOW OR LOWER...A BIT ABOVE THE LONG TERM
AVERAGE OF 11 SUCH DAYS BUT TWO LESS THAN LAST WINTER. IN
CONTRAST...THE AVERAGE TEMPERATURE FOR THE FIRST TWO MONTHS OF
2013 WAS 2.1 BELOW...WHICH IS MORE THAN TWO DEGREES ABOVE NORMAL.

SNOWFALL WAS LIGHT BUT FREQUENT THE FIRST THREE WEEKS OF THE
MONTH. TOTAL SNOWFALL WAS 10.7 INCHES...OVER A THIRD MORE THAN
NORMAL FOR FEBRUARY. THE SNOW MELTED DOWN TO 0.48 INCHES OF
WATER...WHICH IS ABOUT 15 PERCENT ABOVE NORMAL. SNOW DEPTHS AT THE
AIRPORT ROSE TO AN EVEN TWO FEET ON THE 22ND BEFORE SETTLING BACK
TO 22 INCHES BY MONTHS END. AS OF THE END OF FEBRUARY...TOTAL
SNOWFALL FOR THE WINTER STOOD AT 50.5 INCHES...WHICH IS ABOUT SIX
INCHES BELOW NORMAL.

LOOKING AHEAD TO MARCH...TEMPERATURES CLIMB SHARPLY AS THE SUN
RISES HIGHER AND HIGHER IN THE SKY EACH DAY. AVERAGE DAILY HIGH
TEMPERATURES INCREASE FROM 18 DEGREES ON THE FIRST TO 34 DEGREES BY 
THE 31ST. AVERAGE LOW TEMPERATURES START OFF MARCH AT 9 BELOW BUT
RISE ABOVE ZERO BY THE 21ST...AND THEN UP TO 8 ABOVE BY THE 31ST.
OVER THE PAST 108 YEARS MARCH TEMPERATURES IN FAIRBANKS HAVE
RANGED FROM 56 ABOVE IN 1994 TO 56 BELOW IN 1911. MARCH IS...ON
AVERAGE...THE DRIEST MONTH OF THE YEAR. NORMAL PRECIPITATION IS
0.25 INCHES OF LIQUID FROM AN AVERAGE OF 4.9 INCHES OF SNOW. IN
SOME YEARS THE WINTER SNOWPACK BEGINS TO MELT DURING THE LAST WEEK
OF MARCH IN URBAN AREAS...THOUGH TYPICALLY THAT DOES NOT OCCUR
UNTIL APRIL.

DURING MARCH...POSSIBLE SUNSHINE INCREASE BY NEARLY SEVEN MINUTES
EVERY DAY...AND REACHES 13 HOURS AND 33 MINUTES BY THE END OF THE
MONTH.  

THE FORECAST FOR MARCH FROM THE CLIMATE PREDICTION CENTER CALLS
FOR INCREASED CHANCES OF SIGNIFICANTLY BELOW NORMAL TEMPERATURES
AND SLIGHTLY INCREASED CHANCES OF ABOVE NORMAL PRECIPITATION.

$$
RT MAR 13

Fairbanks January Summary

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
835 AM AKST FRI FEB 1 2013

...JANUARY MONTHLY WEATHER SUMMARY FOR FAIRBANKS ALASKA...

JANUARY 2013 WAS A ROLLER COASTER OF INTERESTING WEATHER.

THE MONTH OF JANUARY BEGAN UNSEASONABLY WARM...OVER 30 DEGREES
ABOVE NORMAL ON THE 1ST OF THE MONTH. TEMPERATURES FELL BACK TO
NEAR NORMAL GRADUALLY THROUGH THE 10TH OF THE MONTH...UNTIL
UNSEASONABLY WARM SOUTHERLY FLOW PUSHED BACK INTO THE INTERIOR BY
THE 12TH. THE WARM AIR PLATEAUED ON JANUARY 14TH WHEN THE
FAIRBANKS AIRPORT REACHED 37 DEGREES. THE WARM AIR WAS ACCOMPANIED BY A
SWATH OF RAIN AND SNOW WHICH CAUSED WIDESPREAD TRAVEL HEADACHES
THROUGHOUT THE FAIRBANKS AREA. AT THE AIRPORT...0.15 INCHES OF
RAIN FELL...THE GREATEST JANUARY RAINFALL SINCE 1963. IN THE NORTH
POLE AREA...SOME PLACES RECEIVED OVER ONE THIRD OF AN INCH OF
RAIN...AND THROUGHOUT THE AREA MANY ROADS REMAINED ICE COVERED AT
MONTHS END. FOLLOWING THE RAIN...TEMPERATURES COOLED BUT REMAINED
ABOVE NORMAL MOST DAYS UNTIL STAGNANT ARCTIC AIR MOVED IN ON THE
25TH. THE THERMOMETER PLUMMETED TO THE 40S BELOW FOR THE FIRST
TIME OF 2013 ON JANUARY 25TH. THE COLD SPELL OF LATE JANUARY DID
NOT LAST LONG BUT THERE WERE SEVERAL DAYS WHERE AIR QUALITY
EXCEEDED THE EPA HEALTH LIMITS FOR FINE PARTICULATE
POLLUTION...AIDED BY THE USUAL STEEP TEMPERATURE INVERSIONS IN THE
FAIRBANKS BOWL.

OVERALL...THE AVERAGE JANUARY TEMPERATURE WAS 2.7 BELOW. THIS IS
5.2 DEGREES ABOVE NORMAL AND MADE THIS THE MILDEST JANUARY IN
FAIRBANKS SINCE 2002. THE MAXIMUM TEMPERATURE FOR THE MONTH
OCCURRED ON THE 14TH WHEN THE FAIRBANKS AIRPORT REACHED 37
DEGREES. THE MINIMUM TEMPERATURE OF 48 BELOW WAS REACHED ON
JANUARY 27TH...WHICH TIES THE 48 BELOW REACHED ON DECEMBER 17TH
FOR THE LOWEST TEMPERATURE OF THE WINTER SO FAR.

JANUARY ENDS WITH A TOTAL OF 14 DAYS WITH TEMPERATURES OF 40
BELOW OR LOWER AT THE FAIRBANKS AIRPORT. FAIRBANKS HAS NOT REACHED
50 BELOW THIS YEAR...THOUGH SOME TYPICALLY COLDER PLACES
HAVE...INCLUDING LOWS OF 54 BELOW IN TWO RIVERS...52 BELOW AT
NORTH POLE AND 50 BELOW AT GOLDSTREAM CREEK.

PRECIPITATION FOR THE MONTH OF 0.79 INCHES WAS 0.21 INCHES ABOVE
NORMAL FOR THE MONTH OF JANUARY. DESPITE THE ABOVE NORMAL
PRECIPITATION AMOUNTS...SNOWFALL FOR JANUARY OF 9.9 INCHES WAS
ALMOST EXACTLY NORMAL. SNOW DEPTH INCREASED TO 19 INCHES BY THE END
OF JANUARY.

WITH THE CLIMATOLOGICALLY COLDEST PART OF WINTER BEHIND...FEBRUARY
PROMISES TO DELIVER MORE NOTICEABLE DIURNAL TEMPERATURE RANGES AS
THE MONTH PROGRESSES AND THE REGION GAINS OVER 3 HOURS OF POSSIBLE SUNSHINE
BETWEEN THE 1ST TO THE 28TH. AVERAGE TEMPERATURES INCREASE FROM 6
BELOW TO 4 ABOVE BY THE END OF THE MONTH. THOUGH ONLY A 10 DEGREE
AVERAGE INCREASE...THE NORMAL HIGH TEMPERATURES BY THE END OF THE
MONTH IS 17 ABOVE. NORMAL SNOWFALL IN FEBRUARY IS 8.1 INCHES...THOUGH
HISTORICALLY FAIRBANKS HAS OCCASIONALLY RECEIVED DAILY SNOWFALLS
IN EXCESS OF TEN INCHES...MOST RECENTLY IN FEBRUARY 1996 AND
2011.

THE FORECAST FOR FEBRUARY FOR FAIRBANKS FROM THE CLIMATE
PREDICTION CENTER CALLS FOR INCREASED CHANCES OF SIGNIFICANTLY
ABOVE NORMAL TEMPERATURES. 

$$

JM/RT

Ted Fathauer (1946-2013)

My friend, colleague and former boss Ted Fathauer unexpectedly died late Sunday evening at his home in Fairbanks, just three weeks after retiring from the Weather Service. For those on Facebook,  here is the NWS Alaska Region Facebook Tribue to Ted:

http://www.facebook.com/rthomanjr/posts/428668320537438?ref=notif&notif_t=like

RIP Ted

One More Round of Interior Alaska Seasons

Okay, before moving on to actual numbers, here's my personal "integrated" seasonal definitions for Fairbanks-land. By integrated, I mean this takes into account astronomics, climate and events.

• Early Winter: establishment of the permanent winter snow cover in October until mid-November. Roads are regularly icy and skies often quite cloudy. Most precipitation is snow but drizzle or very light rain from shallow clouds not that uncommon.
• Core Winter: the dark time of year, mid-November until the end of January: potential for extreme inversion and of course deep cold. 
• Late Winter: February through very early March: more sunshine, less snow. Daytime inversions weaken from the rapidly increasing solar heating but do not completely break without other forcing.
• Early Spring: very early March until sustained melting commences, typically early April. Often clear for days on end and breezy even in town. The time of year to get out and "play in the snow".
• Late Spring: early April until early to early to mid May: active snow melt and break-up. Ends at green-up. The sloppy season; crud emerges from the snow. Not the finest time in Fairbanks, but all the daylight is a delight after the dark winter.  Precipitation of any kind uncommon.
• Early Summer: green-up until start of the deep convective season, typically early to mid May until very early June. Very light brief showers common.
• High Summer: peak of the convective season, very early June until early-mid July. Highest frequency of hot days, and often all the rain comes as showers or thunderstorms.
• Late Summer: the stratiform rain season, typically mid July to mid-late August. Often condensed to "August" in general conversation in Fairbanks, i.e. "it always rains for the Fair". Highest frequency of fog.
• Early Autumn: late August until mid-late September: return of darkness at night, colors in trees and undergrowth. Ran frequency drops way down from late summer. The quintessential "crisp frosty nights and gorgeous sunny days" time of year (my personal favorite these days, just ahead of Late Winter).
• Late Autumn: mid to late September until establishment of permanent winter snow cover. Changeable weather, most common time for "snow in the hills, rain in the valley" kind of weather. Increasing darkness yet all is brown: harder to see moose by the road without some snow cover.

So obviously these definition are generalizations and in some years differ. For example, in 2004 there never was a late summer in that a sustained period with regular stratiform rain never occurred. The super high aloft help almost all month and helped keep the record wildfire season going until in snowed in September.