Issued by NWS Denver/Boulder, CO
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41 42
43
44
45
46
47
48
49
50
000
NOUS45 KBOU 241510
PNSBOU
PUBLIC INFORMATION STATEMENT...RETRANSMISSION
NATIONAL WEATHER SERVICE DENVER CO
115 PM MDT WED MAR 25 2009
...A PREVIEW OF DENVER`S APRIL WEATHER...
...APRIL CAN PRODUCE A VARIETY OF WEATHER...
APRIL IS A TRANSITIONAL MONTH FOR MOST OF THE COUNTRY AND THIS IS ESPECIALLY
TRUE FOR DENVER. ALMOST ANY TYPE OF WEATHER CAN OCCUR AND USUALLY DOES.
TORNADOES... THUNDERSTORMS...HAIL...SNOW AND DUST STORMS ARE POSSIBLE DURING
THE MONTH. IN ADDITION...THERE ARE PLENTY OF PLEASANT SUNNY DAYS WITH
TEMPERATURES RANGING FROM THE 60S TO THE LOW 80S. NORMAL HIGH TEMPERATURES
RANGE FROM THE UPPER 50S TO THE MID 60S WHILE OVERNIGHT NORMAL LOW
TEMPERATURES RANGE FROM THE LOW 30S TO THE UPPER 30S. ON APRIL 30TH IN
1992...THE MERCURY CLIMBED TO THE HIGHEST APRIL TEMPERATURE EVER...90 DEGREES.
THE TEMPERATURE RANGE FOR APRIL IS FROM 90 DEGREES DOWN TO 2 BELOW ZERO.
IN APRIL...DENVER IS ASSAULTED FROM ALL SIDES BY VARYING TYPES OF AIR MASSES
WHICH ACCOUNTS FOR THE WIDE SWINGS IN THE TYPES OF WEATHER. ARCTIC AIR STILL
OCCASIONALLY INVADES THE AREA AND OFTEN TEAMS UP WITH AN EASTWARD MOVING
PACIFIC STORM PRODUCING SNOW IN DENVER. AT OTHER TIMES...WARM MOIST AIR FROM
THE GULF OF MEXICO MOVES INTO THE AREA AND THUNDERSTORMS OCCUR...SOMETIMES
OCCURRING JUST BEFORE THE SNOW. IN ADDITION...WARM DRY AIR FROM THE DESERT
SOUTHWEST CAN BRING WARM TEMPERATURES AND LOW HUMIDITIES TO THE DENVER METRO
AREA.
APRIL IS THE THIRD SNOWIEST MONTH OF THE YEAR WITH AN AVERAGE OF 9.1 INCHES
AND IS THE WINDIEST MONTH OF THE YEAR WITH AN AVERAGE SPEED OF 10.0 MILES PER
HOUR. THE PREDOMINANT WIND DIRECTION IS FROM THE SOUTH. ON AN AVERAGE, YOU
CAN EXPECT 2 THUNDERSTORMS TO OCCUR DURING APRIL. AND THERE IS ALWAYS THE
POSSIBILITY OF SEVERE THUNDERSTORMS WHICH INCLUDES HAIL, HIGH WINDS, AND/OR
TORNADOES.
APRIL 2001 WAS HIGHLIGHTED BY A STRONG WINTER STORM THAT PRODUCED BLIZZARD
LIKE CONDITIONS THAT MOVED ACROSS THE METRO AREA ON THE 10TH AND 11TH. THE
STORM DUMPED 10.0 INCHES OF SNOW ON THE FORMER STAPLETON INTERNATIONAL
AIRPORT. THE STORM PRODUCED COPIOUS AMOUNTS OF VERY HEAVY WET SNOW ACROSS THE
DENVER METRO AREA. OTHER AREAS AROUND THE METRO AREA THAT REPORTED HEAVY
SNOWFALL WERE: SOUTHEAST AURORA PICKED UP 18 INCHES OF SNOW AND REPORTED 5
FOOT DRIFTS. PARKER REPORTED 16 INCHES WITH 3 FOOT DRIFTS...LAFAYETTE 10
INCHES...WESTMINSTER 9 INCHES AND LITTLETON 8 INCHES. EVEN THOUGH A GREAT DEAL
OF SNOW WAS REPORTED... BY THE 12TH... NEARLY ALL OF THE WHITE STUFF HAD
MELTED AWAY.
BETWEEN APRIL 23 AND 24...2007...2.10 INCHES OF RAINFALL WAS RECORDED AT THE
DENVER INTERNATIONAL AIRPORT (DIA). THIS WAS A 24 HOUR PRECIPITATION RECORD
SURPASSING THE OLD RECORD OF 1.29 INCHES SET WAY BACK IN 1891. THE MONTH
FINISHED WITH A TOTAL OF 2.65 INCHES WHICH WAS 0.72 INCH ABOVE NORMAL. HAD IT
NOT BEEN FOR THE DOWNPOUR ON THE 23RD AND 24TH...DENVER WOULD HAVE ONCE AGAIN
TALLIED ANOTHER BELOW NORMAL PRECIPITATION MONTH. THREE OUT OF THE PREVIOUS 5
MONTHS HAD REGISTERED ABOVE NORMAL IN THE MOISTURE CATEGORY.
...LOOKING BACK AT APRIL 2008...
...APRIL 2008 IS DENVER`S 5TH DRIEST APRIL ON RECORD...
APRIL 2008 BECAME DENVER`S 5TH DRIEST APRIL SINCE DENVER PRECIPITATION RECORD
KEEPING BEGAN IN 1872 FINISHING ONLY 0.01 INCH ABOVE THE 6TH PLACE DRIEST.
THE APRIL LIQUID MOISTURE TOTAL WAS ONLY 0.32 INCH WHICH IS 1.61 INCHES BELOW
THE NORM. THE DRIEST APRIL ON RECORD OCCURRED IN 1963 WITH A MERE 0.03 INCH
TOTAL. THERE WERE ONLY 4 DAYS WITH MEASURABLE PRECIPITATION AND 1 DAY THAT
EXCEEDED 0.10 INCH. MOST OF THE PRECIPITATION WAS WATER EQUIVALENT FROM
SNOWFALL. APRIL SNOWFALL WAS ALSO ON THE DISMAL SIDE WITH ONLY 2.9 INCHES
RECORDED WHICH IS 6.2 INCHES BELOW NORMAL. APRIL WAS OUR LAST SHOT TO GET THE
SEASONAL SNOWFALL UP TO NORMAL. BUT THE ONE STORM THAT WE NEEDED WAS NOT TO
BE. SEASONAL SNOWFALL THROUGH APRIL 30TH STANDS AT 42.9 INCHES WHICH IS 18.8
INCHES BELOW THE NORMAL OF 61.7 INCHES. THE BEST 24 HOUR SNOWFALL TALLIED WAS
A ONLY 1.8 INCHES. KEEP IN MIND THAT APRIL IS DENVER`S 3RD SNOWIEST MONTH
FOLLOWING NOVEMBER AND MARCH. THERE WERE NO PRECIPITATION RECORDS SET OR TIED
DURING APRIL.
APRIL 2008 FINISHED WITH AN AVERAGE TEMPERATURE OF 46.1 DEGREES WHICH IS 1.5
DEGREES BELOW THE NORMAL 47.6 DEGREES. TEMPERATURES RANGED FROM A
COMFORTABLE 82 DEGREES DOWN TO CHILLY 13 DEGREES. THERE WERE 21 MORNINGS
WHERE THE LOW TEMPERATURE DIPPED TO FREEZING OR BELOW WHICH IS 10 ABOVE
NORMAL. THERE WERE NO HIGH TEMPERATURES BELOW FREEZING AS WELL AS NO LOW
TEMPERATURES BELOW ZERO. THE AVERAGE APRIL 2008 TEMPERATURE OF 46.1 DEGREES
WAS 3.1 DEGREES TOO WARM TO GET INTO THE TOP TEN COLDEST DENVER APRILS.
THE FIRST THUNDERSTORM OF THE SEASON AND THE ONLY THUNDERSTORM IN APRIL
OCCURRED ON APRIL 9TH. THE STORM WAS RESPONSIBLE FOR 0.18 INCH OF
PRECIPITATION IN THE FORM OF RAIN AND SNOW. THE NORMAL AMOUNT OF APRIL
THUNDERSTORMS AT THE DENVER INTERNATIONAL AIRPORT IS 2. APRIL ONLY HAD ONE
DAY WITH DENSE FOG WHICH IS VISIBILITY OF 1/4 MILE OR LESS. THERE WERE 7 DAYS
THAT HAD LIGHT FOG OBSERVED. THE PEAK WIND GUST DURING THE MONTH WAS 52 MPH
FROM A WESTERLY DIRECTION (260 DEGREES).
THE NATIONAL WEATHER SERVICE 30-DAY OUTLOOK MODEL PREDICTS THAT APRIL 2009
WILL HAVE SLIGHTLY ABOVE NORMAL TEMPERATURES AND SLIGHTLY BELOW NORMAL
PRECIPITATION. DENVER`S CLIMATOLOGICAL NORMALS FOR APRIL ARE LISTED BELOW.
...DENVER`S APRIL AVERAGE STATISTICS...
(NORMALS PERIOD 1971-2000)
...TEMPERATURE...
AVERAGE HIGH.............................. 60.9
AVERAGE LOW............................... 34.2
MONTHLY MEAN.............................. 47.6
DAYS WITH HIGH 90 OR ABOVE................ 0 * LESS THAN ONE
DAYS WITH HIGH 32 OR BELOW................ 0 * LESS THAN ONE
DAYS WITH LOW 32 OR BELOW................ 11
DAYS WITH LOWS ZERO OR BELOW.............. 0 * LESS THAN ONE
...PRECIPITATION...
MONTHLY MEAN.............................. 1.93 INCHES
AVERAGE SNOWFALL.......................... 9.1 INCHES
DAYS WITH MEASURABLE PRECIPITATION........ 9
DAYS WITH 1.0 INCH OR MORE SNOWFALL....... 3
...MISCELLANEOUS...
HEATING DEGREE DAYS....................... 524
COOLING DEGREES DAYS...................... 2
AVERAGE WIND SPEED........................ 10.0 MPH (HIGHEST MONTHLY
AVERAGE)
AVERAGE WIND DIRECTION.................... SOUTH
DAYS WITH THUNDERSTORMS................... 2
DAYS WITH DENSE FOG....................... 1
PERCENT OF SUNSHINE POSSIBLE.............. 67
...EXTREMES...
RECORD HIGH................ 90 ON APRIL 30, 1992
RECORD LOW................. -2 ON APRIL 2, 1975
WARMEST.................... 56.4 DEGREES IN 1946 AND 1981
COLDEST.................... 38.8 DEGREES IN 1920
MOST HEATING DEGREE DAYS... 784 DAYS 1920
LEAST HEATING DEGREE DAYS.. 260 DAYS 1981
MOST COOLING DEGREE DAYS... 19 DAYS 1989 (SINCE 1969)
LEAST COOLING DEGREE DAYS.. 0 (27 TIMES SINCE 1969)
WETTEST.................... 8.24 INCHES IN 1900
MAXIMUM 24 HOUR RAINFALL... 3.25 INCHES ON THE 13TH IN 1967
DRIEST..................... 0.03 INCH IN 1963
SNOWIEST................... 33.8 INCHES IN 1933
MAXIMUM 24 HOUR SNOWFALL... 23.0 INCHES ON 22-23 IN 1885
LEAST SNOWIEST............. 0.0 INCHES IN 1888, 1930, 1943, 1992
............. T THERE WERE 8 YEARS WITH TRACE AMOUNTS
BENTON...NCH...3/25/09
