Climatological Report (Monthly)
Issued by NWS Denver/Boulder, CO

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CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
144 AM MST WED JAN 1 2014

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

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2013...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2013

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              79   12/05/1939
 LOW              -25   12/22/1990
                        12/24/1876
HIGHEST            68   12/18        79     -11       69  12/05
LOWEST            -15   12/05       -25      10       -2  12/26
AVG. MAXIMUM     42.9              42.8     0.1     44.2
AVG. MINIMUM     14.0              17.1    -3.1     18.3
MEAN             28.4              30.0    -1.6     31.2
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      8               5.8     2.2        8
DAYS MIN <= 32     29              29.4    -0.4       28
DAYS MIN <= 0       6               2.0     4.0        2

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         5.21   1913
 MINIMUM         0.00   1881
TOTALS           0.25              0.35   -0.10     0.27
DAILY AVG.       0.01              0.01    0.00     0.01
DAYS >= .01         7               4.1     2.9        5
DAYS >= .10         1               1.1    -0.1        1
DAYS >= .50         0               0.1    -0.1        0
DAYS >= 1.00        0               0.0     0.0        0
GREATEST
 24 HR. TOTAL    0.12   12/03 TO 12/04           12/24 TO 12/25
                                                          12/25 TO 12/25
                                                          12/25 TO 12/25
 STORM TOTAL       MM                                 MM
 (MM/DD(HH))            MM                    12/25(00) TO 12/25(00)
                                                 12/25(00) TO 12/25(00)5
                                                 12/25(00) TO 12/25(00)5

SNOWFALL (INCHES)
RECORDS
 TOTAL             MM   MM
TOTALS            4.7               8.5

DEGREE_DAYS
HEATING TOTAL    1128              1086      42     1038
 SINCE 7/1       2451              2468     -17     2233
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        999               769     230     1236

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
......................................................

WIND (MPH)
AVERAGE WIND SPEED              9.3
RESULTANT WIND SPEED/DIRECTION   3/229
HIGHEST WIND SPEED/DIRECTION    33/010    DATE  12/28
HIGHEST GUST SPEED/DIRECTION    42/290    DATE  12/15

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            9
NUMBER OF DAYS PC             17
NUMBER OF DAYS CLOUDY          5

AVERAGE RH (PERCENT)     54

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       0
LIGHT RAIN                0     FREEZING RAIN              0
LT FREEZING RAIN          2     HAIL                       0
HEAVY SNOW                1     SNOW                       3
LIGHT SNOW               14     SLEET                      0
FOG                      13     FOG W/VIS <= 1/4 MILE      2
HAZE                      8

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.
______________________________________________________________________________
...DECEMBER 2013 A MONTH OF TEMPERATURE EXTREMES...

DECEMBER 2013 STARTED OUT MILD AND DRY AS A WESTERLY TO NORTHWESTERLY
FLOW ALOFT PRODUCED DOWNSLOPE FLOW ALONG THE LEE OF THE ROCKIES. THE
HIGH TEMPERATURE DURING THE FIRST THREE DAYS OF THE MONTH AVERAGED
13.0 DEGREES ABOVE NORMAL. THE MILD AND DRY WEATHER CAME TO AN
ABRUPT END AS A DEEP UPPER LEVEL TROUGH OF LOW PRESSURE ORIGINATING
IN ALASKA DROPPED INTO THE WESTERN U.S. AN ARCTIC AIRMASS ASSOCIATED
WITH THIS TROUGH SWEPT ACROSS NORTHEASTERN COLORADO AROUND MIDDAY ON
THE 3RD BRINGING SNOW ON MUCH COLDER TEMPERATURES TO THE FRONT RANGE
OF COLORADO. THIS ARCTIC BLAST WOULD LEAVE NORTHEASTERN COLORADO IN
THE DEEP FREEZE FOR SEVERAL DAYS. FROM THE 4TH THROUGH THE 8TH HIGH
TEMPERATURES DID NOT RISE ABOVE THE TEENS...WITH MAX TEMPERATURES
FROM THE 5TH THROUGH THE 7TH ONLY IN THE SINGLE DIGITS. DURING THE
COLD SNAP...DENVER EXPERIENCED A SIX CONSECUTIVE DAY STRETCH
(DECEMBER 4TH-9TH) WITH LOW TEMPERATURES BELOW ZERO. DECEMBER OF
1972 STILL HOLDS THE RECORD OF 11 CONSECUTIVE DAYS OF MINIMUM
TEMPERATURES BELOW ZERO. MOST NOTABLE CONSECUTIVE BELOW ZERO
STRETCHES IN DECEMBER ARE LISTED BELOW:

11 DAYS DECEMBER 13TH-18TH 1972

6 DAYS DECEMBER 13TH-18TH 1878
6 DAYS DECEMBER 25TH-30TH 1878
6 DAYS DECEMBER 20TH-25TH 1983
6 DAYS DECEMBER 19TH-24TH 1998

ON THE 9TH...THE COLD AIR BEGAN TO LOSE ITS GRIP ON COLORADO AS THE
LARGE UPPER LOW MOVED INTO THE CENTRAL UNITED STATES. ON THE
10TH...THE HIGH TEMPERATURE IN DENVER FINALLY MADE IT ABOVE
FREEZING. ABOVE NORMAL TEMPERATURES RETURNED TO DENVER FROM THE 12TH
THROUGH THE 14TH. MUCH ABOVE NORMAL TEMPERATURES OCCURRED FROM THE
15TH THROUGH THE 18TH AS UPPER LEVEL HIGH PRESSURE DOMINATED THE
WESTERN U.S AND DRY NORTHWEST FLOW ALOFT PRODUCED A WARM DOWNSLOPE
FLOW ALONG THE LEE OF THE ROCKIES. AVERAGE TEMPERATURES DURING THIS
FOUR DAY PERIOD AVERAGED NEARLY EIGHTEEN DEGREES ABOVE NORMAL. THE
68 DEGREES ON THE 18TH...SET A NEW RECORD FOR THE DATE AND WAS THE
WARMEST DAY OF THE MONTH. ANOTHER UPPER LEVEL STORM SYSTEM AND
ASSOCIATED COLD FRONT BROUGHT LIGHT SNOW AND COLDER TEMPERATURES TO
DENVER FROM THE 19TH THROUGH THE 23RD. TEMPERATURES REBOUNDED TO
ABOVE NORMAL VALUES ON THE 24TH...HOWEVER A COLD FRONT MOVED INTO
DENVER AROUND MIDDAY BRINGING COLDER TEMPERATURES AND A FEW
FLURRIES. DENVER EXPERIENCED DRY WEATHER AND NEAR NORMAL
TEMPERATURES ON CHRISTMAS DAY. A WARMING TREND BEGAN ON THE 26TH AND
CONTINUED THROUGH THE 28TH AS UPPER LEVEL HIGH PRESSURE REBUILT OVER
THE ROCKY MOUNTAIN REGION. ANOTHER SURGE OF COLD AIR BROUGHT COLDER
TEMPERATURES AND LIGHT SNOW TO DENVER LATE ON THE 28TH THROUGH THE
29TH. THE MONTH ENDED ON A MILD AND DRY NOTE.

TEMPERATURES:

THE AVERAGE TEMPERATURE FOR THE MONTH OF DECEMBER WAS XX.X DEGREES F
WHICH WAS X.X DEGREES BELOW NORMAL. DECEMBER OF 1933 WAS THE WARMEST
DECEMBER ON RECORD WITH AN AVERAGE TEMPERATURE OF 43.8 DEGREES F.
THE COLDEST DECEMBER ON RECORD WAS 17.5 DEGREES F BACK IN 1983.

THERE WERE EIGHT DAYS IN WHICH THE DAYTIME HIGH TEMPERATURE DID NOT
EXCEED 32 DEGREES F...AND SIX DAYS IN WHICH THE LOW TEMPERATURE
DROPPED BELOW ZERO. THE HIGHEST TEMPERATURE OF THE MONTH WAS 68
DEGREES WHICH OCCURRED ON THE 18TH...AND THE COLDEST TEMPERATURE OF
THE MONTH WAS -15 DEGREES ON THE MORNING OF THE 5TH.

BELOW IS A LIST OF RECORDS FOR DECEMBER 2013:

DAILY TEMPERATURE RECORDS:

  DATE        TEMPERATURE   TYPE OF RECORD    OLD RECORD   YEAR LAST SET

DECEMBER 4TH  -13 DEGREES    NEW RECORD LOW    -5 DEGREES      2008^
DECEMBER 5TH  -15 DEGREES   TIED RECORD LOW   -15 DEGREES      1972
DECEMBER 18TH  66 DEGREES   NEW RECORD HIGH    66 DEGREES      1979^
DECEMBER 18TH  40 DEGREES  TIED REC HIGH MIN   40 DEGREES      1917

^ DENOTES AND PREVIOUS YEARS

PRECIPITATION:

PRECIPITATION FOR THE MONTH OF DECEMBER WAS 0.25 INCHES...WHICH IS
0.10 INCHES BELOW THE NORMAL 0F 0.35 INCHES. 0.11 INCHES OF
PRECIPITATION FELL ON THE 4TH WHICH IS THE GREATEST DAILY AMOUNT FOR
THE MONTH.

TOP FIVE WETTEST DECEMBERS:

PRECIPITATION   YEAR

5.21 INCHES     1913
2.84 INCHES     1973
2.34 INCHES     1982
2.32 INCHES     1883
1.70 INCHES     1876

TOP FIVE DRIEST DECEMBERS:

0.00  1881*     *DRIEST MONTH IN DENVER WEATHER HISTORY
TRACE 1905
0.01 INCHES 1895
0.01 INCHES 1906
0.03 INCHES 1931, 1977

SNOW:

4.7 INCHES OF SNOW WAS RECORDED DURING THE MONTH...WHICH IS 5.4
INCHES BELOW THE NORMAL OF 8.5 INCHES. THE GREATEST 24 DAILY
SNOWFALL TOTAL OCCURRED ON THE 4TH WHEN 2.8 INCHES FELL.


TOP FIVE SNOWIEST DECEMBERS:

57.4 INCHES 1913*   *SNOWIEST MONTH IN DENVER WEATHER HISTORY
30.8 INCHES 1973
29.4 INCHES 2006
27.1 INCHES 1982
21.5 INCHES 1987

THERE WERE NO DAYS IN WHICH THUNDER WAS OBSERVED AT DENVER INTERNATIONAL
AIRPORT...AND TWO DAYS WITH DENSE FOG WITH A VISIBILITY AT
OR BELOW 1/4 MILE DURING THE MONTH. A PEAK WIND OF
$$



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