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CXUS55 KBOU 051333
CLMDEN

DENCLMDEN 000
TTAA00 KBOU 010810


CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
126 PM MDT THU MAY 2 2013

..........APRIL 2013 COLDER AND WETTER THAN NORMAL..........

A SERIES OF STORM SYSTEMS MOVED ACROSS COLORADO DURING APRIL 2013
BRINGING BELOW NORMAL TEMPERATURES AND MUCH NEEDED PRECIPITATION TO
NORTH CENTRAL AND NORTHEASTERN COLORADO. THIS IS THE 3RD CONSECUTIVE
MONTH WITH COLDER AND WETTER WEATHER AT DENVER. THE LAST THREE MONTH
PERIOD WITH BELOW NORMAL TEMPERATURES AND ABOVE NORMAL PRECIPITATION
OCCURRED BACK IN JUNE THROUGH AUGUST OF 2009.

APRIL 2013 STARTED OUT WITH SLIGHTLY BELOW NORMAL TEMPERATURES AND LIGHT
PRECIPITATION. UPPER LEVEL HIGH PRESSURE BROUGHT ABOVE NORMAL
TEMPERATURES TO THE REGION FROM THE 4TH THROUGH THE EIGHTH...WITH
TEMPERATURES IN THE 60`S AND LOWER 70`S. THE WARM AND DRY WEATHER
WOULD NOT LAST AS A SERIES OF STRONG STORM SYSTEMS WERE POISED TO
MOVE ACROSS COLORADO. FROM THE 9TH THROUGH THE 25TH...THREE
SIGNIFICANT SNOW EVENTS WERE RECORDED AT DENVER INTERNATIONAL
AIRPORT....WITH SEVENTEEN OF EIGHTEEN DAYS DURING THIS PERIOD BEING
BELOW NORMAL.

THE FIRST STORM SYSTEM AND ASSOCIATED ARCTIC COLD FRONT MOVED
INTO THE ROCKY MOUNTAIN REGION ON THE EVENING OF THE 8TH. THIS
SYSTEM BROUGHT MUCH COLDER TEMPERATURES AND SNOW TO MUCH OF
NORTH CENTRAL AND NORTHEASTERN COLORADO. 6.6 INCHES OF SNOW FELL
AT DENVER INTERNATIONAL AIRPORT FROM THE EVENING OF THE 8TH THOUGH
THE MORNING OF THE 10TH. MAXIMUM TEMPERATURES ON THE 9TH AND 10TH
WERE ONLY IN THE LOWER 20`S...WITH LOW TEMPERATURES IN THE SINGLE
DIGITS.

ON THE 14TH...THE SECOND MAJOR STORM SYSTEM BEGAN TAKING SHAPE OVER
THE NORTHERN ROCKIES. BY THE 15TH...A LARGE UPPER TROUGH OF LOW
PRESSURE COVERED THE WESTERN TWO THIRDS OF THE UNITED STATES...WITH
A STRONG JET STREAM OVER COLORADO. UPSLOPE FLOW INCREASED ALONG AND
EAST OF THE MOUNTAINS AFTER THE PASSAGE OF A COLD FRONT. HEAVY SNOW
BANDS DEVELOPED ALONG AND NORTH OF INTERSTATE 70 DURING THE AFTERNOON
OF THE 15TH AND CONTINUED THROUGH THE NIGHT. 7.0 INCHES OF SNOW WAS
RECORDED AT DENVER INTERNATIONAL AIRPORT...WITH HEAVIER AMOUNTS WEST
AND NORTH OF DENVER. ANOTHER WEAKER STORM SYSTEM BROUGHT AN ADDITIONAL
2.0 INCHES OF SNOW TO DENVER ON THE 17TH.

THE THIRD SIGNIFICANT STORM SYSTEM BROUGHT 4.7 INCHES OF SNOW TO DENVER
INTERNATIONAL AIRPORT ON THE 22ND AND 23RD...WITH HEAVIER AMOUNTS
WEST OF DENVER.

DRIER AND MUCH WARMER WEATHER RETURNED TO NORTH CENTRAL AND NORTHEASTERN
COLORADO TOWARDS THE END OF THE MONTH...WITH TEMPERATURES IN THE 70`S TO
LOWER 80`S FROM THE 27TH THROUGH THE 29TH.

TEMPERATURES:

THE AVERAGE TEMPERATURE FOR THE MONTH OF APRIL WAS 41.7 DEGREES F
WHICH WAS 5.7 DEGREES BELOW NORMAL. THIS MAKES APRIL 2013 THE 5TH
COOLEST APRIL ON RECORD. APRIL OF 1946 AND 1981 ARE THE WARMEST
APRILS ON RECORD WITH AN AVERAGE TEMPERATURE OF 56.4 DEGREES F BOTH
OF THOSE YEARS. THE COLDEST APRIL ON RECORD WAS 38.8 BACK IN 1920.

THERE WERE NO DAYS IN WHICH THE MAXIMUM TEMPERATURE EXCEEDED 90
DEGREES. THERE WERE 4 DAYS IN WHICH THE DAYTIME HIGH TEMPERATURE DID
NOT EXCEED 32 DEGREES F AND NO DAYS WITH LOW TEMPERATURES AT OR
BELOW ZERO DEGREES F. THE HIGHEST TEMPERATURE OF THE MONTH WAS 80
DEGREES WHICH OCCURRED ON THE 29TH. THE COLDEST TEMPERATURE OF THE
MONTH WAS 6 DEGREES ON THE MORNING OF THE 10TH.

BELOW IS A LIST OF TEMPERATURE RECORDS FOR APRIL 2013:

DAILY RECORDS:

DATE        TEMPERATURE     TYPE OF RECORD     OLD RECORD  YEAR LAST SET
APRIL 9TH    22 DEGREES     RECORD LOW MAX     27 DEGREES      1973
APRIL 9TH     9 DEGREES      RECORD LOW        12 DEGREES      1959
APRIL 10TH    6 DEGREES      RECORD LOW         7 DEGREES      1959
APRIL 16TH   22 DEGREES     TIED RECORD LOW    22 DEGREES      1999
APRIL 22ND   21 DEGREES      RECORD LOW        22 DEGREES      1874

PRECIPITATION:

PRECIPITATION FOR THE MONTH OF APRIL WAS 1.87 INCHES...WHICH IS 0.16
INCHES ABOVE THE NORMAL 0F 1.71 INCHES. THE WETTEST APRIL ON RECORD
OCCURRED WAY BACK IN 1900 WHEN 8.24 INCHES OF PRECIPITATION WAS
RECORDED. THE DRIEST APRIL ON RECORD OCCURRED BACK IN 1963...WHEN
ONLY 0.03 INCHES OF PRECIPITATION WAS RECORDED.

20.4 INCHES OF SNOW WAS RECORDED DURING THE MONTH...WHICH IS 13.6
INCHES ABOVE THE NORMAL OF 6.8 INCHES. APRIL 2013 JUST FELL SHORT
OF MAKING IT INTO THE TOP TEN SNOWIEST APRIL LIST.

10 SNOWIEST APRIL`S    10 LEAST SNOWIEST APRIL`S

    33.8  1933             0.0 1888, 1930, 1943, 1992
    32.0  1885           TRACE 1887, 1889, 1910, 1915, 1925, 1946
    28.3  1920
    28.2  1945
    25.5  1957
    25.4  1909
    25.0  1907
    24.8  1973
    23.3  1935
    21.0  1922

ONE THUNDERSTORMS WAS OBSERVED AT DENVER INTERNATIONAL
AIRPORT DURING THE MONTH. THERE WERE 5 DAYS WITH DENSE FOG WITH
A VISIBILITY AT OR BELOW 1/4 MILE DURING THE MONTH. A PEAK WIND
OF 55 MPH FROM A NORTHERLY DIRECTION WAS RECORDED ON THE 8TH.
...........................................................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF APRIL 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              90   04/30/1992
 LOW               -2   04/02/1975
HIGHEST            80   04/29        83      -3       88  04/24
LOWEST              6   04/10        -2       8       24  04/07
AVG. MAXIMUM     54.7              61.5    -6.8     68.6
AVG. MINIMUM     28.7              33.3    -4.6     37.9
MEAN             41.7              47.4    -5.7     53.3
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      4               0.3     3.7        0
DAYS MIN <= 32     17              13.0     4.0        4
DAYS MIN <= 0       0               0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         8.24   1900
 MINIMUM         0.03   1963
TOTALS           1.87              1.71    0.16     1.39
DAILY AVG.       0.06              0.06    0.00     0.05
DAYS >= .01        13               9.1     3.9        8
DAYS >= .10         7               4.5     2.5        4
DAYS >= .50         0               0.9    -0.9        0
DAYS >= 1.00        0               0.5    -0.5        0
GREATEST
 24 HR. TOTAL    0.50   04/22 TO 04/23           04/26 TO 04/27

SNOWFALL (INCHES)
RECORDS
 TOTAL           33.8  1933
TOTALS           20.4               6.8

DEGREE_DAYS
HEATING TOTAL     690               529     161      352
 SINCE 7/1       5802              5731      71     5215
COOLING TOTAL       0                 1      -1        6
 SINCE 1/1          0                 1      -1        6

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

WIND (MPH)
AVERAGE WIND SPEED              11.0
RESULTANT WIND SPEED/DIRECTION   1/016
HIGHEST WIND SPEED/DIRECTION    49/290    DATE  04/14
HIGHEST GUST SPEED/DIRECTION    55/350    DATE  04/08

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.70
NUMBER OF DAYS FAIR            2
NUMBER OF DAYS PC             20
NUMBER OF DAYS CLOUDY          8

AVERAGE RH (PERCENT)     53

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              1     MIXED PRECIP               0
HEAVY RAIN                1     RAIN                       3
LIGHT RAIN               10     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                3     SNOW                       6
LIGHT SNOW                8     SLEET                      0
FOG                      12     FOG W/VIS <= 1/4 MILE      5
HAZE                     11

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

$$