The Weather Wire

 

September 2007                                                                                                            Volume 15 Number 09

 

Contents

 

·   Snow Season

 
·   Safety Classes
 

·   Drought Monitor

 

·   August

    Summary

 

·   August Stats

 

·   September Preview

 

·   Sunrise/Sunset

 

·   Rain Totals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

August 2007

Avg High 89.8

Avg Low 61.0

Snow - 0.0"

Season Snow - 0.0"

Precipitation - 2.76"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

September

Avg High 77.4

Avg Low 47.3

Avg Snow -  2.1"

Avg Precip - 1.14"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Skyview Weather 

2350 N Rocky View Rd

Castle Rock, CO 80108

 

Phone: (303) 688-9175

Fax: (303) 660-0548

 

E-mail:    

tim@skyview-wx.com

 

We’re on the Web!

http://www.skyview-wx.com/

 

Copyright 2007

Skyview Weather

Another Heavy Snow Season on Tap??? 

September is a month of transition from the heat of summer into the cool, crisp feel fall.  The month is typically relatively dry as it marks the end of the monsoon season, which occurs in the first week or two of the month.   There is more sunshine observed in September than any other month on the calendar with 74% of possible sunshine.  We usually have our first frost sometime in the third or fourth week of the month and the season’s first snowfall usually occurs with just over 2” on average for the month.  High and low temperatures drop around 10 degrees as the start of September highs average 82 and lows average 53.  By the end of the month average temperatures are 73 for highs and 42 for lows.  The first day of fall also occurs on the 23rd of September as it is the autumnal equinox.  The leaves begin to change colors and the animals prepare for winter.  This change in season gets most people thinking about what to expect for the upcoming snow season and as always Skyview Weather will take a look ahead and tell you what we think of the 2007/2008 winter season.

After a rather active winter of 2006 with many areas experiencing well above normal snowfall this winter will have to be very impressive to top last year.  The spring and summer have been quite active with near normal precipitation in most areas.  It is our opinion here at Skyview that the average to above average precipitation pattern will continue through the winter with most areas expected to receive at or slightly above normal snowfall for the 2007/2008 snow season.

As was the case last year it continues to be a La Niña year which generally means at or slightly below average temperatures here on the Front Range, and at or slightly above normal snowfall for northern areas of Colorado and slightly below normal snowfall in southwestern Colorado.  In general being so far from the ocean El Niño and La Niña really does not make much of a difference here in this state, unlike the media and television commercials would like to make you think!  Also, the high pressure that dominated the weather pattern a couple years back forcing the weather systems to our north and south has migrated eastward allowing these Pacific storms and northern cold fronts to penetrate the state.  This is a long term cycle and appears that it will continue through the winter this year.             

Expecting a more typical to above average year here in the Front Range it can be expected that some of our heaviest snows will come early and late in the season, unlike last year as the heaviest snow fell on the shortest day of the year and did not melt until late February.  I do not anticipate such a heavy snowfall in December or January this year, but a good snow or two of around a foot or more in October or November certainly seems likely.  Heavy snowfall in the spring is always anticipated and there is no reason to think it will be any different this snow season with a 2-3 heavy, wet, branch breaking snows towards the end of winter into spring. 

Typically Denver averages around 60” of snow in a season with foothill locations getting much more of the white stuff, while Colorado Springs averages a little less with 30-50” pending location within the city.  This year expect Denver to be in the 60-80” range with 100” or more in the foothills and 40-75” in the city of Colorado Springs.  This will make the skiers very happy with these predictions and for the people who have to plow get ready for a busy year once again.

In summary a winter like last year is not expected, but an average to slightly above average winter is anticipated with temperatures running at or slightly below normal.  Heavy snows early and late in the season are likely with relatively frequent light, powdery snows in the months of December and January.  There will also be a period of Indian summer which is typical sometime in December or January with relatively warm and dry weather pattern for that time of year which will normally last 2-3 weeks.  It will be interesting to see how this winter comes together and Skyview will be continue to be on top of the ever changing conditions here in our wonderful state of Colorado.              

Skyview Offers Safety Classes

As in many endeavors, awareness equals safety.  One component of awareness is education, and Skyview Weather has a number of educational classes intended to promote weather awareness and increased safety.  At this time, the following classes are available. We highly recommend these safety classes for your facility, please contact us for more information!

Basic Weather Safety - This 1 hour safety oriented class reviews basic weather safety, including flash flood safety, lightning safety, and tornado safety as well as reviewing NWS products, with specific emphasis on watches and warnings.

Basic Weather Safety and Severe Weather Spotting - This 3 hour class begins with basic weather safety, including flash flood safety, lightning safety, and tornado safety as well as reviewing NWS products, with specific emphasis on watches and warnings. Basic weather concepts  and basic weather spotting is included, with emphasis on thunderstorm features.

Basic Weather Safety for Coaches - This 60-90 minute safety oriented class is similar to Basic Weather Safety, but designed for coaches and other administrators that must determine whether to suspend or cancel outdoor sports events.  Heavy emphasis on lightning safety, as well as severe thunderstorm safety is presented. A review of NWS publicly disseminated products, including watches and warnings, is included. Basic weather safety, including flash flood safety, lightning safety, and tornado safety is discussed.

Extended Weather Safety and Spotting - As with the above classes, this all day class begins with basic weather safety, including flash flood safety, lightning safety, and tornado safety as well as reviewing NWS products, with specific emphasis on watches and warnings.  Basic weather concepts and definitions are discussed, with extensive time on the role of spotters, and key spotting features of developing severe storms. Video presentations are included as well.

Radar 101 - Everyone utilizes radar on the internet, but just what exactly are you looking at?  This 2 hour class answers that question, providing an introduction to radar,  a review of publicly available radar products on the internet, and how to interpret and utilize those products to your advantage.  This class is critical for those organizations attempting to use publicly available internet weather for client and employee safety.

Getting the most from Skyview Weather ... Client-Skyview interaction - This 2 hour class focuses on how existing clients of Skyview Weather can get the most from Skyview Weathers extensive services.  A review of what Skyview offers, product delivery, and Skyview Weather terms is presented.

All classes are presented using PowerPoint, and include handouts.  Questions are always welcome, and encourage..  Selected classes include video as well.  Please contact Skyview Weather for scheduling and pricing information.  As always, you can reach us at 303-688-9175 or via email at tim@skyview-wx.com .

Drought Update

The west slope of Colorado continued to see dry conditions, with little improvement in drought conditions.  The remainder of the state generally saw normal to above normal precipitation during August.

The map below shows forecasted temperature deviances for September 2007. As can be seen,  above average temperatures are expected for Southwestern Colorado for September 2007, with the remainder of the state seeing normal temperatures.

The map below shows forecasted precipitation deviances for September 2007.  Normal precipitation is expected for  Eastern Colorado for September 2007, though western areas of the state look to receive below normal precipitation..

As can be seen in the below map, little overall change is anticipated for much of Colorado through October, with the exception of Northwest Colorado where drought conditions persist or intensify.

August Summary

...August 2007 Became Denver's 2nd Warmest August since 1872...

Eighteen days with temperatures between 91 and 99 degrees helped in August 2007 becoming the 2nd warmest august in Denver weather history since 1872.  The daily maximum average temperature was a very warm 89.8 degrees while the daily minimum average finished at an even 61 degrees.  The monthly average mercury reading finalized with a warm 75.4 degrees...3.7 degrees above the normal of 71.7 degrees.  This was only 0.1 degree above the former second place holder 1995...but still 1.4 degrees below the warmest August which was August 1937 with a 76.8 degree average.  Only 2 records were establish during the month:  on the 13th...a record high of 99 degrees was established breaking the old record of 96 degrees last set in 1996.  And on the 21st...the record high of 97 degrees was tied along with 1960. Since 1969...August 2007 recorded the highest number of cooling degree days with a total of 329.

Precipitation was a welcome amount finishing the month with a well above normal total of 2.76 inches.  This was a whopping 0.94 inch above the normal of 1.82 inches.  There were 13 days with measurable moisture.  One day measured 0.58 inch but the 24 hour total for this day was 0.91 inch measured between august 23 and 24.  2.76 inches was not near enough to get into the top 10 wettest Denver Augusts.  Holding down 10th place was August 1908 with 3.19 inches and the wettest Denver August occurred in 1979 with a very wet 5.85 inches.  On the other hand...the driest august was 0.02 inch recorded in 1924.

During August 2007...the Denver International Airport recorded 17 thunderstorms...none of which were severe.  There were 2 days with hail observed.  On the 24th...pea size hail was observed and then on the final day of the month...marble size hail accompanied the 0.43 inch of rainfall.  There were 8 days with fog but the fog never restricted the visibility to 1/4 mile or less.  Peak wind gust during the month was a 45 mph gust on august 1st from a northeast direction (030).

August Stats

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

89.8

NORMAL

86.0

DEPARTURE

3.8

AVERAGE MIN

61.0

NORMAL

57.4

DEPARTURE

3.6

MONTHLY MEAN

75.4

NORMAL

71.7

DEPARTURE

3.7

HIGHEST

99 on the 13th

LOWEST

52 on the 25th

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

18

NORMAL

9

DAYS WITH MAX 32 OR BELOW

0

NORMAL

0

DAYS WITH MIN 32 OR BELOW

0

NORMAL

0

DAYS WITH MIN ZERO OR BELOW

0

NORMAL

0

 

 

 

 

 

 

TEMPERATURE RECORDS

 

Record high of 99 on the 13th

Record high of 97 tied previous record

 

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

0

NORMAL

9

DEPARTURE

-9

SEASONAL TOTAL

0

NORMAL

10

DEPARTURE

-10

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

329

NORMAL

217

DEPARTURE

112

YEARLY TOTAL

875

NORMAL

639

DEPARTURE

236

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

2.76"

NORMAL

1.82"

DEPARTURE

0.94"

YEARLY TOTAL

9.63"

NORMAL

12.07"

DEPARTURE

-2.44"

GREATEST IN 24 HOURS

0.91" 8/23 to 8/24

DAYS WITH MEASURABLE PRECIPITATION

13

 

 

 

 

 

SNOWFALL (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

0.0"

NORMAL

0.0"

DEPARTURE

0.0"

SEASONAL TOTAL

0.0"

NORMAL

0.0"

DEPARTURE

0.0"

GREATEST IN 24 HOURS

0.0"

GREATEST DEPTH

0"

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED 8.6 from the south

PEAK WIND GUST

45mph from NE

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

17

NORMAL

8

NUMBER OF DAYS WITH HEAVY FOG

0

NORMAL

0

NUMBER OF DAYS WITH HAIL

0

 

 

PERCENT OF SUNSHINE

76%

NORMAL

71%

 

 

 

September Preview

September is normally a sunny, pleasant month in Denver with the highest monthly percentage of sunshine for the year.  The general weather pattern features fall-like weather consisting of bright sunny days and clear cool nights.

Summer can linger as late as the end of the month.  On September 30th 1980 a record was set when the temperatures reached a high of 90 degrees.  In fact, the first 20 days of September all have record highs in the 90s.  97 degrees stands as the hottest temperature ever recorded during September and that occurred 4 different times, with the last 2 occurrences recorded on September 1st and 4th in 1995.  Thunderstorms are still around in September, however, they are less frequent and severe storms are rare.

Winter can also sneak in during September.  The earliest measurable snowfall on record occurred on September 3rd in 1961 when 4 inches of snow fell at the old Stapleton Airport and the temperature dropped to 33 degrees.  The earliest freeze in Denver was September 8th in 1962 with a record low of 31 degrees.  A real taste of early winter came in 1985 when on the 29th, 9 inches of snow fell on the city and the mercury dropped to a low of 17 degrees after only reaching a high for the day of 29 degrees.  Both of those temperatures were records for the date.  Although we can see snow during the month of September there have been 80 Septembers’ since 1882 that have reported no snow.

DENVER'S SEPTEMBER CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

77.4

AVERAGE LOW

47.3

MONTHLY MEAN

62.4

DAYS WITH HIGH 90 OR ABOVE

2

DAYS WITH HIGH 32 OR BELOW

0

DAYS WITH LOW 32 OR BELOW

1

DAYS WITH LOWS ZERO OR BELOW

0

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

1.14"

DAYS WITH MEASURABLE PRECIPITATION

6

AVERAGE SNOWFALL IN INCHES

2.1"

DAYS WITH 1.0 INCH OF SNOW OR MORE

LT 1

 

 

MISCELLANEOUS AVERAGES

 

 

 

HEATING DEGREE DAYS

136

COOLING DEGREE DAYS

57

WIND SPEED (MPH)

7.9

WIND DIRECTION

SOUTH

DAYS WITH THUNDERSTORMS

4

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

74

 

 

EXTREMES

 

 

 

RECORD HIGH

97 DEGREES ON 9/4/1995

RECORD LOW

17 DEGREES ON 9/29/1985

WARMEST

68.3 DEGREES IN 1948

COLDEST

54.8 DEGREES IN 1912

WETTEST

4.67 INCHES IN 1961

DRIEST

TR IN 1944

SNOWIEST

17.2" INCHES in 1936

LEAST SNOWIEST

0.0 IN MANY YEARS

Sunrise/Sunset (Denver area)

     Date

Sunrise

Sunset

     Sept 1  

06:26

19:32

     Sept 5

06:30

19:26

     Sept 10

06:35

19:18

     Sept 15

06:39

19:10

     Sept 20

06:44

19:02

     Sept 25

06:49

18:53

     Sept 30

06:54

18:45

 Rainfall

May 2007 to Sept 2007

City

May

June

July

August Sept

Seasonal Totals

Aurora (Central)

2.40" 0.75" 1.46" 1.89"   6.50"
Brighton 1.14" 0.28" 1.65" 2.15"   5.22"
Broomfield 2.17" 0.24" 0.91" 2.55"   5.87"

Castle Rock 4 NE

2.14" 1.43" 2.61" 1.43"   7.61"

Colorado Sprgs Airport

 2.35" 0.94" 1.74" 2.69"   7.72"
Denver DIA  1.79" 0.52" 0.43" 2.76"   5.50"

Denver Downtown

3.11" 0.63" 1.26" 2.93"   7.93"

Golden

3.11" 0.67" 0.55" 2.95"   7.28"

Highlands Ranch

2.64" 0.39" 1.38" 1.38"   5.79"

Lakewood

 1.93" 0.83" 1.30" 2.73"    6.82"

Littleton

 3.43" 1.02" 1.57" 2.75"    8.77"

Parker

1.69" 0.55" 1.26" 1.26"   4.76"

Sedalia - Hwy 67

 3.74" 0.98" 0.43" 1.89"   7.04"

Thornton

 1.61" 0.31" 0.51" 2.91"    5.34"

Westminster

 2.56" 0.47" 1.22" 2.78"    7.03"

Wheatridge

 2.95" 0.52" 1.34" 2.08"    6.89"