Climatological Report (Monthly)
Issued by NWS Portland, ME

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CLIMATE REPORT
NATIONAL WEATHER SERVICE GRAY ME
1229 PM EST WED JAN 3 2018

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

...THE PORTLAND ME CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2017...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1941 TO 2017 /FOR TEMPERATURES/
CLIMATE RECORD PERIOD 1871 TO 2017 /FOR PRECIPITATION/
CLIMATE RECORD PERIOD 1882 TO 2017 /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            54   12/06        56      -2       53  12/27
LOWEST            -13   12/30         2     -15       -3  12/16
                        12/29
AVG. MAXIMUM     31.1              37.3    -6.2     36.6
AVG. MINIMUM     15.5              20.4    -4.9     19.6
MEAN             23.3              28.8    -5.5     28.1
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32     15               8.7     6.3        8
DAYS MIN <= 32     31              27.2     3.8       27
DAYS MIN <= 0       5               0.8     4.2        1

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         9.69   1969
 MINIMUM         0.93   1874
TOTALS           3.46              4.02   -0.56     5.31
DAILY AVG.       0.11              0.13   -0.02     0.17
DAYS >= .01        13              11.5     1.5       14
DAYS >= .10         8               7.2     0.8       10
DAYS >= .50         2               2.6    -0.6        4
DAYS >= 1.00        0               1.2    -1.2        2
GREATEST
 24 HR. TOTAL    0.81   12/12

SNOWFALL (INCHES)
RECORDS
 TOTAL           54.8   1970
TOTALS           21.4              13.2     8.2     18.9
SINCE 7/1        21.5              15.1     6.4     19.4
SNOWDEPTH AVG.      4
DAYS >= TRACE      12               6.1     5.9
DAYS >= 1.0         5               3.4     1.6
GREATEST
 SNOW DEPTH         9   12/31
                        12/30
                        12/29
 24 HR TOTAL      6.4   12/09 TO 12/10

DEGREE_DAYS
HEATING TOTAL    1283              1121     162     1135
 SINCE 7/1       2448              2612    -164     2387
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        433               359      74      553
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              7.4
HIGHEST WIND SPEED/DIRECTION    35/180    DATE  12/06
HIGHEST GUST SPEED/DIRECTION    45/170    DATE  12/05

SKY COVER
AVERAGE SKY COVER           0.50

AVERAGE RH (PERCENT)     73

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     HEAVY RAIN                 0
RAIN                      2     LIGHT RAIN                 5
FREEZING RAIN             0     LT FREEZING RAIN           3
HEAVY SNOW                1     SNOW                       3
LIGHT SNOW               12     FOG                       16
FOG W/VIS <= 1/4 MILE     1     HAZE                       6

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

&&

THE COLD WEATHER THAT HAD LASTED MUCH OF NOVEMBER BEGAN TO EASE UP
IN EARLY DECEMBER. FOR THE FIRST WEEK OF THE MONTH, PORTLAND SAW THE
TEMPERATURE WARM INTO THE 40S AND EVEN THE 50S. THAT WAS SOON TO
CHANGE. THE FIRST SIGNIFICANT SNOWSTORM OF THE SEASON ARRIVED ON
DECEMBER 9 WHEN PORTLAND RECEIVED MORE THAN 6 INCHES OF SNOW.
ANOTHER STORM BROUGHT SNOW CHANGING TO FREEZING RAIN A FEW DAYS
LATER ON THE 12TH, FOLLOWED BY MUCH COLDER WEATHER. THE NEXT TWO
STORMS BROUGHT SIMILAR CONDITIONS WITH SNOW CHANGING TO FREEZING
RAIN ON THE 18TH AND AGAIN ON THE 22ND AND 23RD. BY CHRISTMAS
MORNING ANOTHER SNOW STORM HAD ARRIVED, THIS ONE BRINGING ONLY SNOW
WITH SEVERAL INCHES ACCUMULATING IN JUST A FEW HOURS. BRUTALLY COLD
ARCTIC AIR POURED IN BEHIND THIS STORM. THE TEMPERATURE DID NOT RISE
ABOVE FREEZING FOR THE REST OF THE MONTH, WITH THE LAST 5 DAYS OF
THE MONTH FAILING TO RISE ABOVE 15 DEGREES AND FALLING TO ZERO OR
COLDER AT NIGHT.

THE AVERAGE TEMPERATURE FOR THE MONTH WAS 23.3 DEGREES WHICH WAS 5.5
DEGREES BELOW NORMAL AND THE COLDEST DECEMBER SINCE 1989. THE
COLDEST DECEMBER ON RECORD WAS IN 1989 WHEN THE AVERAGE TEMPERATURE
WAS 14.0 DEGREES. THE WARMEST WAS IN 2015 WHEN THE AVERAGE
TEMPERATURE WAS 37.9 DEGREES.

A TOTAL OF 3.46 INCHES OF PRECIPITATION FELL WHICH WAS 0.56 INCHES
BELOW NORMAL AND THE DRIEST DECEMBER SINCE 2006. THE HEAVIEST
PRECIPITATION WAS ON THE 12TH WHEN 0.81 INCHES OF MELTED SNOW AND
FREEZING RAIN WAS RECORDED. THE DRIEST DECEMBER WAS IN 1874 WHEN
ONLY 0.93 INCHES FELL. THE WETTEST WAS IN 1969 WHEN 9.69 INCHES WAS
RECORDED.

A TOTAL OF 21.4 INCHES OF SNOW FELL WHICH WAS 8.2 INCHES ABOVE
NORMAL AND THE SNOWIEST DECEMBER SINCE 2013. THE HEAVIEST SNOWFALL
WAS ON DECEMBER 9 AND 10 WHEN 6.4 INCHES WAS RECORDED. THE SNOWIEST
DECEMBER ON RECORD WAS IN 1970 WHEN 54.8 INCHES FELL. THE LEAST
SNOWY WAS IN 1999 WHEN ONLY A TRACE OF SNOW WAS RECORDED.


THE FOLLOWING DAILY RECORDS WERE SET OR TIED IN DECEMBER 2017...
DATE  RECORD                                PREVIOUS
28    8   - COLDEST HIGH TEMPERATURE        11 IN 1946
28    1   - COLDEST AVERAGE TEMPERATURE     2 IN 1951
29    6   - COLDEST HIGH TEMPERATURE        13 IN 1993
29    -13 - COLDEST LOW TEMPERATURE         -9 IN 1963
29    -3  - COLDEST AVERAGE TEMPERATURE     5 IN 1989
30    12  - COLDEST HIGH TEMPERATURE        13 IN 1963

$$

KIMBLE



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