Saturday, October 4, 2014

September Anomalies

The September 2014 temperature and precipitation anomalies for a number of Alaska observing locations are shown in the maps below.  As in previous similar posts, the area of the colored circles indicates (for temperature) the anomaly in terms of standard deviations or (for precipitation) the percentile rank relative to the 1981-2010 period.




All southern and western locations were warm relative to normal, which is no surprise given the unusual warmth in the waters of the Bering Sea and Gulf of Alaska.  St Paul Island recorded by far its warmest September on record (1949-present), and remarkably the month was warmer than the average August in that location - and August is the warmest month of the year on average.  August 2014 was also the warmest August on record on St Paul Island.  Cold Bay also saw its record-breaking warmth continue, with the warmest September on record (1950-present).

September was much wetter than normal in Fairbanks, but only because of the deluge at the beginning of the month; surprisingly Big Delta, McGrath and Bettles were all drier than normal.

As far as I know, the lowest temperature observed in the state in September was 6 °F at the new Ivotuk CRN site, observed on both the 5th and 26th.  The Chicken COOP reported 8 °F on the 25th, 26th, and 27th.  One might think that it is unusual for no sub-zero temperatures to be reported anywhere in the state in September, but in fact the normal statewide minimum September temperature is above zero.  The chart below shows the statewide temperature extremes in September between 1950 and 2013.


Finally, here's the Fairbanks September weather summary from the NWS.

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
708 PM AKDT WED OCT 1 2014

...MONTHLY WEATHER SUMMARY FOR SEPTEMBER FOR FAIRBANKS ALASKA...

SEPTEMBER 2014 STARTED OFF WET AND COOL FOR THE FIRST WEEK AND
THEN TRANSITIONED TO WARM AND DRY CONDITIONS FOR THE SECOND AND
THIRD WEEKS. THE LAST WEEK OF THE MONTH TURNED COOL WITH RAIN AND
SNOW SHOWERS.

THE AVERAGE HIGH TEMPERATURE AT THE FAIRBANKS AIRPORT WAS 57.2
DEGREES WHICH WAS 2.6 DEGREES ABOVE THE NORMAL HIGH TEMPERATURE OF
54.4 DEGREES. THE AVERAGE LOW TEMPERATURE WAS 35.5 DEGREES WHICH
WAS 0.4 DEGREES ABOVE THE NORMAL LOW TEMPERATURE OF 35.1 DEGREES.
THE AVERAGE TEMPERATURE FOR SEPTEMBER 2014 WAS 46.4 DEGREES WHICH
WAS 1.5 DEGREES ABOVE THE NORMAL AVERAGE TEMPERATURE FOR SEPTEMBER
OF 44.9 DEGREES. THE AVERAGE TEMPERATURE FOR SEPTEMBER 2014 RANKED
AS THE 35TH WARMEST OF 109 YEARS OF RECORD.

THE WARMEST TEMPERATURE RECORDED AT THE FAIRBANKS AIRPORT IN
SEPTEMBER 2014 WAS 76 DEGREES ON THE 14TH OF SEPTEMBER. NOT ONLY
WAS THIS A DAILY RECORD HIGH TEMPERATURE BUT THERE HAS ONLY BEEN
ONE OTHER DAY IN THE CLIMATE RECORD IN FAIRBANKS THAT THE
TEMPERATURE HAS BEEN WARMER THAN 76 DEGREES ON A DATE LATER THAN
THE 14TH OF SEPTEMBER. IN 1995 THE TEMPERATURE REACHED 78 DEGREES
ON THE 21ST DURING A RECORD BREAKING CHINOOK EVENT.

THE COLDEST TEMPERATURE RECORDED AT THE FAIRBANKS AIRPORT IN
SEPTEMBER 2014 WAS 24 DEGREES WHICH OCCURRED ON THE 28TH. THE
FIRST SNOW OF THE SEASON FELL ON THE 23RD WHICH IS A COUPLE DAYS
LATER THAN THE AVERAGE FIRST SNOW FALL IN FAIRBANKS.

2.89 INCHES OF PRECIP FELL DURING THE MONTH OF SEPTEMBER AND WAS
1.79 INCHES ABOVE THE NORMAL PRECIP OF 1.10 INCHES. SEPTEMBER WAS
THE 4TH CONSECUTIVE MONTH WITH ABOVE NORMAL PRECIPITATION AND
RANKED AS THE 4TH WETTEST SEPTEMBER OF 101 YEARS OF RECORD.
1.43 INCHES OF RAIN FELL ON THE 1ST WHICH WAS A NEW DAILY RAIN
FALL RECORD FOR THAT DAY. 0.3 INCHES OF SNOW FELL AT THE AIRPORT
DURING THE MONTH OF SEPTEMBER WHICH WAS 1.5 INCHES BELOW THE
NORMAL SNOWFALL OF 1.8 INCHES. THIS RANKS AS THE 37TH SNOWIEST OF
101 YEARS OF RECORD.

LOOKING FORWARD TO OCTOBER...THE PERMANENT SNOW PACK IS ALMOST
ALWAYS ESTABLISHED SOMETIME DURING THE MONTH OF OCTOBER. AS A
RESULT OF THE ESTABLISHED SNOW PACK AND RAPIDLY DIMINISHING
POSSIBLE SUNSHINE THE AVERAGE DAILY TEMPERATURE FALLS 20 DEGREES
DURING THE MONTH. THE AVERAGE HIGH TEMPERATURE FALLS FROM ON 37
DEGREES ON THE 1ST TO 17 DEGREES ON THE 31ST. OVER THE LAST 109
YEARS TEMPERATURES HAVE RANGED FROM 72 IN 2003 TO 28 BELOW IN
1935. TOTAL PRECIPITATIONS AVERAGES 0.83 INCHES. MUCH OF THIS
TYPICALLY FALLS AS SNOW...AND SIGNIFICANT RAINFALL IS RARE AFTER
MID-MONTH. NORMAL SNOWFALL IS ABOUT 11 INCHES. THE LAST TIME
FAIRBANKS DID NOT HAVE A WHITE HALLOWEEN WAS 1962...HOWEVER IN
2013...SNOW DEPTH AT THE AIRPORT REMAINED ZERO UNTIL 0.6 INCHES OF
SNOW FELL ON THE EVENING OF THE 31ST. POSSIBLE SUNSHINE CONTINUES
TO DECREASE BY OVER 6 MINUTES PER DAY...FALLING FROM 11 HOURS AND
17 MINUTES ON THE 1ST TO 7 HOURS AND 56 MINUTES ON THE 31ST.

THE FORECAST FOR OCTOBER FROM THE CLIMATE PREDICTION CENTER CALLS
FOR EQUAL CHANCES FOR ABOVE NORMAL...NEAR NORMAL OR ABOVE NORMAL
TEMPERATURES AND EQUAL CHANCES FOR ABOVE NORMAL...NEAR NORMAL OR
ABOVE NORMAL PRECIPITATION.

OBSERVED LAST MONTH...09/2014

                         OBSERVED   RANK
AVG MAX TEMP (F)             57.2   31ST WARMEST OF 109 YEARS
AVG MIN TEMP (F)             35.5   45TH WARMEST OF 109 YEARS
AVG TEMP (F)                 46.4   35TH WARMEST OF 109 YEARS
TOTAL PRECIP (IN)            2.89   4TH WETTEST OF 101 YEARS
TOTAL SNOW (IN)              0.30   37TH SNOWIEST OF 101 YEARS

CCC

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