Climatological Report (Monthly)
Issued by NWS Portland, ME

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CLIMATE REPORT
NATIONAL WEATHER SERVICE GRAY ME
304 PM EST TUE JAN 3 2017

...................................

...THE PORTLAND ME CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2016...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1941 TO 2016 /FOR TEMPERATURES/
CLIMATE RECORD PERIOD 1871 TO 2016 /FOR PRECIPITATION/
CLIMATE RECORD PERIOD 1882 TO 2016 /FOR SNOWFALL/

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              71   12/06/2001
                        12/07/1998
 LOW              -21   12/31/1963
HIGHEST            53   12/27        56      -3       62  12/25
LOWEST             -3   12/16         2      -5       17  12/29
AVG. MAXIMUM     36.6              37.3    -0.7     45.8
AVG. MINIMUM     19.6              20.4    -0.8     30.0
MEAN             28.1              28.8    -0.7     37.9
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      8               8.7    -0.7        2
DAYS MIN <= 32     27              27.2    -0.2       19
DAYS MIN <= 0       1               0.8     0.2        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         9.69   1969
 MINIMUM         0.93   1874
TOTALS           5.31              4.02    1.29     5.34
DAILY AVG.       0.17              0.13    0.04     0.17
DAYS >= .01        14              11.5     2.5       15
DAYS >= .10        10               7.2     2.8       12
DAYS >= .50         4               2.6     1.4        4
DAYS >= 1.00        2               1.2     0.8        1
GREATEST
 24 HR. TOTAL    1.84   12/29 TO 12/30

SNOWFALL (INCHES)
RECORDS
 TOTAL           54.8   1970
TOTALS           18.9              13.2     5.7      7.3
SINCE 7/1        19.4              15.1     4.3      7.3
SNOWDEPTH AVG.      2
DAYS >= TRACE      13               6.1     6.9
DAYS >= 1.0         5               3.4     1.6
GREATEST
 SNOW DEPTH         7   12/18
 24 HR TOTAL      7.7   12/29 TO 12/30

DEGREE_DAYS
HEATING TOTAL    1135              1121      14      831
 SINCE 7/1       2387              2612    -225     2077
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        553               359     194      492
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              7.5
HIGHEST WIND SPEED/DIRECTION    32/290    DATE  12/16
HIGHEST GUST SPEED/DIRECTION    43/290    DATE  12/15

SKY COVER
AVERAGE SKY COVER           0.50

AVERAGE RH (PERCENT)     68

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              1     HEAVY RAIN                 2
RAIN                      3     LIGHT RAIN                 8
FREEZING RAIN             1     LT FREEZING RAIN           3
HEAVY SNOW                2     SNOW                       6
LIGHT SNOW               12     FOG                       16
FOG W/VIS <= 1/4 MILE     5     HAZE                       1

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

&&

DECEMBER STARTED ON A WARM NOTE AS THE FIRST TWO DAYS OF THE MONTH
SAW THE TEMPERATURE WARM ABOVE 50 DEGREES, BUT THEN THERE WAS A
SHIFT TOWARD COLDER WEATHER. A FAIRLY ACTIVE WEATHER PATTERN BROUGHT
A NEW STORM SYSTEM TOWARD THE AREA EVERY FEW DAYS OFTEN RESULTING IN
SNOWFALL. A QUICK 2 INCHES FELL ON THE 5TH AND THEN ANOTHER 4 INCHES
FELL ON THE 12TH. NOT LONG AFTERWARDS AN ARCTIC AIR MASS BROUGHT
SOME VERY COLD EARLY WINTER TEMPERATURES. ON THE 16TH THE HIGH
TEMPERATURE ONLY REACHED 9 DEGREES, THE COLDEST DECEMBER HIGH
TEMPERATURE IN MORE THAN 30 YEARS AND THE SECOND EARLIEST SINGLE
DIGIT HIGH TEMPERATURE ON RECORD AT PORTLAND. THE LOW TEMPERATURE ON
THE 16TH WAS 3 BELOW ZERO, THE EARLIEST SUBZERO TEMPERATURE SINCE
1989. ANOTHER SNOWSTORM BROUGHT MORE THAN 4 INCHES OF SNOW ON THE
17TH FOLLOWED BY A BRIEF WARM UP BEFORE THE COLDER AIR MOVED BACK IN
AGAIN. BY THE 21ST THE BRUTAL COLD HAD EASED UP AND TEMPERATURES
CLIMBED BACK TO NEAR OR ABOVE NORMAL FOR THE REST OF THE MONTH, BUT
NOT WARM ENOUGH TO PREVENT A WHITE CHRISTMAS FOR THE FIRST TIME IN 3
YEARS. JUST AS THE SNOW PACK BEGAN TO DWINDLE DOWN TO JUST A TRACE,
AN INTENSE LOW PRESSURE SYSTEM BROUGHT VERY HEAVY SNOW ON THE NIGHT
OF THE 29TH INTO THE EARLY MORNING HOURS OF THE 30TH. THIS STORM
BEGAN AS SNOW BEFORE CHANGING TO RAIN FOR SEVERAL HOURS. AS THE RAIN
CHANGED BACK TO SNOW IT WAS ACCOMPANIED BY THUNDER AND LIGHTNING AND
SNOWFALL RATES IN EXCESS OF 2 INCHES PER HOUR. A TOTAL OF 7.7 INCHES
FELL, MOST OF THAT IN JUST A FEW HOURS THAT NIGHT.

THE AVERAGE TEMPERATURE FOR THE MONTH WAS 28.1 DEGREES WHICH WAS 0.7
DEGREES BELOW NORMAL AND THE FIRST BELOW NORMAL MONTH AT PORTLAND
SINCE APRIL. ALTHOUGH THIS DECEMBER WAS ONLY SLIGHTLY BELOW NORMAL
IT WAS NEARLY 10 DEGREES COLDER THAN LAST DECEMBER. DECEMBER 2015
WAS THE WARMEST ON RECORD WITH AN AVERAGE TEMPERATURE OF 37.9
DEGREES. THE COLDEST DECEMBER WAS IN 1989 WHEN THE AVERAGE
TEMPERATURE WAS ONLY 14.0 DEGREES.

THE HIGH TEMPERATURE ON DECEMBER 16 WAS ONLY 9 DEGREES. THIS WAS THE
SECOND EARLIEST SINGLE DIGIT HIGH TEMPERATURE ON RECORD AT PORTLAND
AND THE COLDEST DECEMBER HIGH TEMPERATURE SINCE CHRISTMAS DAY 1983.
THE FOLLOWING TABLE LISTS THE EARLIEST DAYS IN THE SEASON WHICH DID
NOT SEE THE TEMPERATURE RISE OUT OF THE SINGLE DIGITS.

EARLIEST SINGLE DIGIT HIGH TEMPERATURES (1940 TO PRESENT)...
RANK  HIGH  DATE
1       9   DEC 12, 1977
2       9   DEC 16, 2016 <===
3       7   DEC 19, 1942
4       7   DEC 22, 1970
5       9   DEC 24, 1975
6       8   DEC 25, 1968
        7   DEC 25, 1983
8       7   DEC 31, 1956

A TOTAL OF 5.31 INCHES OF PRECIPITATION FELL WHICH WAS 1.29 INCHES
ABOVE NORMAL. THE HEAVIEST PRECIPITATION FELL ON THE 29TH AND 30TH
WHEN 1.84 INCHES OF RAIN AND MELTED SNOWFALL WAS RECORDED. THE WET
WEATHER HELPED TO ALLEVIATE DROUGHT CONDITIONS WHICH HAD DEVELOPED
DURING THE SUMMER AND EARLY FALL. THE WETTEST DECEMBER ON RECORD WAS
IN 1969 WHEN 9.69 INCHES WAS MEASURED. THE DRIEST WAS IN 1874 WHEN
ONLY 0.93 INCHES WAS RECORDED.

THERE WAS 18.9 INCHES OF SNOWFALL WHICH WAS 5.7 INCHES ABOVE NORMAL.
THERE WERE THREE SNOWSTORMS WHICH DROPPED 4 INCHES OR MORE OF
SNOWFALL ON THE 12TH, 17TH, AND 29TH TO 30TH. THE HEAVIEST SNOWSTORM
WAS ON THE NIGHT OF THE 29TH INTO THE EARLY MORNING OF THE 30TH WHEN
7.7 INCHES WAS MEASURED. SNOW WAS OBSERVED ON THE GROUND ON EVERY
DAY EXCEPT THE FIRST 5 DAYS OF THE MONTH. THE SNOWIEST DECEMBER WAS
IN 1970 WHEN 54.8 INCHES WAS MEASURED. THE LEAST SNOWY DECEMBER WAS
IN 1999 WHEN ONLY A TRACE OF SNOW WAS RECORDED.


THE FOLLOWING DAILY RECORDS WERE SET OR TIED IN DECEMBER 2016...
DATE RECORD                                  PREVIOUS
16   9  - COLDEST HIGH TEMPERATURE           10 IN 1951

$$

KIMBLE


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