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000
NOUS45 KBOU 241522
PNSBOU
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
810 AM MDT FRI APR 24 2008
...A PREVIEW OF DENVER`S MAY WEATHER...
...MAY WEATHER CAN GO FROM ONE EXTREME TO ANOTHER...
THE WEATHER IN DENVER IS QUITE CHANGEABLE THROUGHOUT THE YEAR. HOWEVER...THE
MONTH OF MAY SEEMS TO FEATURE THE MOST CHANGES FROM YEAR TO YEAR...DAY TO
DAY...OR EVEN HOUR TO HOUR. DENVER`S MAY WEATHER CAN INCLUDE ALMOST ANY TYPE
OF WEATHER...EVEN WEATHER THAT IS NORMALLY EXPERIENCED PRIMARILY DURING OTHER
MONTHS.
LATE SEASON FROSTS CAN NIP PLANT GROWTH BECAUSE THE AVERAGE DATE OF THE LAST
FREEZE IS MAY 5TH BUT THE LATEST DATE OF A DENVER FREEZE IS JUNE 8TH. ON THE
OTHER HAND...AFTERNOON TEMPERATURES IN THE 80S ARE COMMON AND THE MERCURY
OCCASIONALLY CLIMBS INTO THE 90S.
MAY NORMALLY MARKS THE BEGINNING OF THE SEVERE WEATHER SEASON. VIOLENT
THUNDERSTORMS WITH LARGE HAIL AND TORNADOES ARE POSSIBLE. THESE SEVERE STORMS
OCCUR WHEN MOISTURE FROM THE GULF OF MEXICO MOVES INTO COLORADO AND COLLIDES
WITH COLD FRONTS STILL MOVING IN FROM EITHER CANADA OR FROM THE PACIFIC
NORTHWEST.
MAY IS ALSO THE WETTEST MONTH OF THE YEAR AND ON THE AVERAGE...PRECIPITATION
NORMALLY OCCURS ONCE EVERY THREE DAYS. MAY IS TIED WITH NOVEMBER AS HAVING
THE LOWEST PERCENTAGE OF POSSIBLE SUNSHINE.
SNOWFALL IN DENVER DURING MAY HAS BEEN NEARLY NON-EXISTENT DURING THE PAST 12
YEARS. THERE WAS NO SNOWFALL IN 2007...2000...1999..1998...1996...1995
...1994...1993 AND 1992. ONLY A 0.1 INCH WAS RECORDED DURING MAY 1997 AND
1990 AND ONLY A TRACE WAS RECORDED IN 2005 AND 1991. DENVER`S HIGH ELEVATION
INTENSIFIES LATE SEASON COLD AIR MASSES AND ON THE AVERAGE MAY SNOW OCCURS IN
ABOUT TWO OUT OF EVERY FIVE YEARS. THE AVERAGE MAY SNOWFALL IS 1.3 INCHES.
BUT JUST LAST YEAR...2008...MAY REGISTERED 3.1 INCHES OF SNOW ON MAY 1ST AND
THEN ANOTHER 0.3 INCH ON THE 14TH FOR A TOTAL OF 3.4 INCHES. THAT IS THE MOST
SNOW RECORDED IN MAY SINCE MAY 2003 WHEN 7.0 INCHES WAS RECORDED.
...TAKING A LOOK BACK TO MAY 2008...
...DENVER`S MAY 2008 WAS COOLER AND DRIER THAN NORMAL...
DENVER`S MAY 2008 FINISHED SLIGHTLY COOLER AND SOMEWHAT DRIER THAN
NORMAL. IN THE PRECIPITATION CATEGORY...THE MONTH FINISHED WITH A
TOTAL OF 1.56 INCHES OF LIQUID IN THE RAIN BUCKET WHICH WAS 0.76
INCH BELOW THE 2.32 INCH NORM. THIS WOULD MARK THE 7TH MONTH IN A ROW
WITH BELOW NORMAL PRECIPITATION. A GOOD COMBINATION OR RAIN AND
SNOW ON THE 1ST AND 2ND PRODUCED A 24 HOUR MOISTURE TOTAL OF 0.49
INCH. 0.29 INCH WAS RECORDED BETWEEN THE 13TH AND 14TH. THUNDERSTORM
ACTIVITY...NONE OF WHICH WERE SEVERE...RETURNED TO A MORE NORMAL LEVEL
WITH 8 STORMS OBSERVED AT THE DENVER INTERNATIONAL AIRPORT...DIA...
NORMAL IS 6. THERE WERE 11 DAYS WITH MEASURABLE MOISTURE WHICH WAS RIGHT ON
NORMAL. OUT OF THE 11 DAYS...7 RECORDED PRECIPITATION AMOUNTS OF 0.10 INCH OR
GREATER. SINCE JAN 2008...THE TOTAL MOISTURE HAS ONLY 2.31 INCHES WHICH WAS A
WHOPPING 4.22 INCHES BELOW NORMAL.
SNOWFALL WAS ABOVE NORMAL FOR THE FIRST TIME SINCE MAY 2003. 3.4 INCHES WAS
RECORDED THANKS TO A LATE SPRING SNOWSTORM ON THE FIRST WHICH COLLECTED 3.1
INCHES OF THE WHITE STUFF. IN SPITE OF THE SNOW SEASON ENDING JUNE 30TH...THE
SEASONAL SNOWFALL FOR DENVER FOR THE 2007-2008 SNOW YEAR WAS 46.3 INCHES WHICH
WAS 15.4 INCHES BELOW THE SEASONAL NORMAL OF 61.7 INCHES. THERE WERE NO
PRECIPITATION OR SNOWFALL RECORDS SET OR TIED DURING MAY 2008. AS A
REMINDER...SEASONAL SNOWFALL IS MEASURED FROM JULY 1ST THROUGH JUNE 30TH.
THE MONTHLY AVERAGE TEMPERATURE AT DIA WAS 55.9 DEGREES WHICH IS 1.3 DEGREES
BELOW THE 57.2 DEGREE AVERAGE. MERCURY READINGS RANGED FROM A HIGH OF 89
DEGREES ON THE 21ST DOWN TO A LOW OF 21 DEGREES ON THE 3RD. NEITHER THE HIGH
OR THE LOW TEMPERATURE EXTREMES WERE RECORDS. IN FACT...THERE WERE NO
TEMPERATURE RECORDS SET OR TIED DURING THE MONTH. THE 90 DEGREE MARK WAS NOT
REACHED AND THERE WERE 6 DAYS WHEN THE MERCURY FELL TO FREEZING OR BELOW...4
ABOVE NORMAL.
THERE WERE 2 DAYS AT DIA THAT RECORDED SNOW PELLETS...NOT HAIL...3 DAYS WITH
DENSE FOG...VISIBILITY 1/4 MILE OR LESS...9 DAYS WITH LIGHT FOG AND 2 DAYS
WITH HAZE. THE PEAK WIND GUST DURING THE MONTH WAS A RECORD SETTING 61 MPH
FROM THE SOUTH...180 DEGREES. THE PREVIOUS RECORD WAS 60 MPH SET IN 1991.
THE NATIONAL WEATHER SERVICE 30-DAY OUTLOOK MODEL FOR MAY 2009 INDICATES THAT
DENVER WILL HAVE AT OR SLIGHTLY ABOVE NORMAL TEMPERATURES BUT THE MODELS DO
NOT FAVOR ANY PARTICULAR PATTERN FOR PRECIPITATION. SO PRECIPITATION NORMALS
ARE SUGGESTED FOR GUIDANCE.
DENVER`S CLIMATOLOGICAL MAY NORMALS ARE LISTED BELOW:
...MAY AVERAGE STATISTICS...
(NORMALS PERIOD 1971-2000)
...TEMPERATURE...
AVERAGE HIGH........................... 70.5
AVERAGE LOW............................ 43.8
MONTHLY MEAN........................... 57.2
DAYS WITH HIGH 90 OR ABOVE............. 0* *LESS THAN ONE
DAYS WITH HIGH 32 OR BELOW............. 0
DAYS WITH LOW 32 OR BELOW.............. 2
DAYS WITH LOW ZERO OR BELOW............ 0
...PRECIPITATION...
MONTHLY MEAN............................ 2.32 INCHES
(MAY IS DENVER`S WETTEST MONTH)
AVERAGE SNOWFALL........................ 1.3 INCHES
DAYS WITH MEASURABLE PRECIPITATION...... 11
DAYS WITH 1.0 INCH OR MORE SNOWFALL..... 0 *LESS THAN ONE
**NOTE** SNOWFALL AND SUNSHINE DATA ARE MEASURED BY COOP OBSERVERS
NEAR THE FORMER STAPLETON INTERNATIONAL AIRPORT.
...MISCELLANEOUS...
HEATING DEGREE DAYS..................... 267
COOLING DEGREES DAYS.................... 23
AVERAGE WIND SPEED...................... 9.3 MPH
AVERAGE WIND DIRECTION.................. SOUTH
DAYS WITH THUNDERSTORMS................. 6 (4TH MOST MONTH WITH T-STORMS)
DAYS WITH DENSE FOG..................... 1
PERCENT OF SUNSHINE POSSIBLE............ 64
(LEAST SUNSHINE MONTH TIED WITH NOVEMBER)
...MAY EXTREMES...
RECORD HIGH.................... 95 ON 5/26/1942
RECORD LOW..................... 19 ON 5/3/1907
WARMEST........................ 64.6 IN 1934
COLDEST........................ 48.7 IN 1917
WETTEST........................ 8.57 INCHES IN 1876...
(WETTEST MONTH IN DENVER HISTORY)
24 HOUR RECORD RAINFALL........ 6.53 INCHES IN 1876 (MOST IN DENVER HISTORY)
DRIEST......................... 0.06 INCH IN 1974
SNOWIEST....................... 15.5 INCHES IN 1898
24 HOUR RECORD SNOWFALL........ 12.0 INCHES IN 1917 (UPDATED)
LEAST SNOWIEST................. 0.0 INCH...40 YEARS WITH ZERO SNOWFALL
MOST HEATING DEGREE DAYS....... 506 IN 1917
LEAST HEATING DEGREE DAYS...... 102 IN 1934
MOST COOLING DEGREE DAYS....... 60 IN 1994
LEAST COOLING DEGREE DAYS...... 0 IN 1995, 1971
$$
BENTON
