The Weather Wire

 

October 2004                                                                                                                 Volume 11 Number 10

 

Contents

 

·   Mt St. Helens

 

·   Drought Monitor

 

·   September

    Summary

 

·   September Stats

 

·   October Preview

 

·   Sunrise/Sunset

 

·   Rainfall Totals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

September 2004

 

Avg High 77.6

Avg Low 44.7

Snow - 0.0"

Season Snow - 0.0"

Precipitation - 1.99"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

October

Avg High 66.0

Avg Low 35.9

Avg Snow - 4.1"

Avg Precip - 0.99"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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 2004

Skyview Weather

Mt St. Helens and Weather... 

With Mt. St. Helens becoming active again after almost 20 years a little volcano weather would be rather topical.  Mt. St. Helens is located in the Cascade Mountain range and is one of many volcano’s that ring the west coast of the Untied States.  Right now she is one of the few active volcanoes in the continental U.S..  Mt. St. Helens has its origins going back millions of years and was formed due to continental drift.  The pacific plate is diving under the U.S. continental plate.  Where these two plates collide they generate tremendous amount of heat, hot enough to melt solid rock.  This is where we see numerous volcanoes along this line of colliding and heating plates.

Now I’m sure just about everyone has see films or pictures of Hawaii’s volcanoes.  Where hot molten rock flows out of the volcano and down its slopes in large lava flows.  Mt. St. Helens is a different type of volcano and has a totally different type of eruption. The lava in St. Helens has a vast amount of gas and steam in it.  As the lava breaks the surface this gas expands explosively and cools.  This process cools the lava quickly back to a solid and then shatters the cooled lava into thousand of small rocks and millions of particles of volcanic ash.  With this type of volcano we never see a lava flow, but explosive eruptions that throw tons of material into the atmosphere. Those are the basics of the volcano.  Believe me it is much more complicated than that, but we are not volcanologists, we are weather forecasters.  So how does this erupting volcano play a part in our weather??

All volcanoes emit large amounts of water and CO2 into the atmosphere.  CO2 is a green house gas and has been a hot topic with the global warming set.  Long before people walked on this planet, volcanoes put large amounts of CO2 into the air.  It is one theory that during the age of the dinosaurs when the climate was quite tropical for much of the globe that a very active volcanic period preceding the dinosaurs and changed the climate to one of warm and tropical very much suitable to the dinosaurs. So in some ways global warming is not a new phenomenon.  This is just one way volcanoes can affect the weather.

Getting back to the type of Volcano we have in Mt. St. Helens.  The eruptions of the past few days have been minor with more steam being vented than ash.  When St. Helens blew its top in 1980, literally thousands of tons of volcanic material was thrown into the atmosphere.  Some of that volcanic dust even made it way to Denver and the Front Range.  Giving us more than a few hazy days and also providing us with some spectacular sunsets.  More importantly tons of that dust made its way 50-80 thousand feet into the atmosphere and circled the globe in the stratosphere.  The dust particles literally spread out over the entire world.  Once in the upper parts of the atmosphere the dust particles acted like millions of tiny mirrors reflecting light from the sun back into outer space.  Since sunlight is our source of heat from the sun, having some of it reflected back away from us had a cooling influence over the weather for the next couple of years.  The weather records here in the United States actually do show a slight cooling in the two years after the eruption.

In the grand scale of Mother Nature what we saw with Mt. St. Helens in 1980 was a small time eruption.  In our geologic past were many much larger volcanic eruptions having a much larger effect on the weather for planet earth and some of those effects lasted centuries not just a couple of years. 

Fortunately we no longer see major volcanic outbreaks like in our distant past that made major changes to the earths weather, but even the ones we have, like Mt. St. Helens can have an impact on our weather, however, in absence of an extreme eruption occurred in 1980, it is very unlikely that Mt. St Helens will impact the weather patterns of Colorado, or the United States.

Drought Update

In many portions of Colorado, September 2004  continued to see above normal precipitation, particularly across Eastern Colorado.  With the moisture, the drought situation improved across much of Colorado.

The map below shows forecasted temperature deviances for the October 2004 time period. As can be seen, above  normal temperatures are expected for  all of Colorado for October.

The map below shows forecasted precipitation deviances for October 2004.  Normal or near normal precipitation is expected for October 2004 all of Colorado.

As can be seen in the below map, drought conditions are expected to continue to improvement across much of Colorado through December2004.

September Summary

4th month in a row with above normal Precipitation

Denver has notched its 4th month in a row with above normal precipitation.  In fact, Denver is currently above normal through September for the year so far with 13.32 inches, which is 0.11 inch above the normal of 13.21 inches.  The last time Denver recorded 4 months in a row of above normal in the rainfall category was in 1995 covering the period of April, may, June and July.  The 24 hour maximum precipitation during September was 0.91 inch which occurred on September 4th, but was not a 24 hour record.  There were 8 days with measurable moisture, which is 2 days above normal.  The 1.99 inches of rainfall was not near enough to get into the top 10 wettest Septembers, 2.27 inches holds down the number 10 spot recorded both in 1970 and 1940.  The wettest September was 4.67 inches in 1967.

Temperatures for the month of September 2004 were pretty much normal.  The month finished 0.3 degrees above the normal of 62.4 degrees.  There were only two 90 degree days which were exactly 90 degrees and both were the warmest days during September.  The normal number of 90 degree days for September is 2.  Temperatures ranged from the two 90 degree readings down to 37 degrees.  There were no temperature records set or tied during the month. 

No severe weather was observed at DIA during September.  Eight thunderstorms were recorded and all except one were accompanied by rainfall.  No hail was observed at DIA for the month.

So with the exception of above normal rainfall September 2004 was pretty much the norm.

September Stats

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

77.6

NORMAL

77.4

DEPARTURE

0.2

AVERAGE MIN

44.7

NORMAL

47.3

DEPARTURE

0.4

MONTHLY MEAN

62.7

NORMAL

62.4

DEPARTURE

0.3

HIGHEST

90 the 2nd and 18th

LOWEST

37 on the 234d

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

2

NORMAL

2

DAYS WITH MAX 32 OR BELOW

0

NORMAL

0

DAYS WITH MIN 32 OR BELOW

0

NORMAL

3

DAYS WITH MIN ZERO OR BELOW

0

NORMAL

0

 

 

 

 

 

 

TEMPERATURE RECORDS

 

None  

 

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

131

NORMAL

136

DEPARTURE

-5

SEASONAL TOTAL

179

NORMAL

146

DEPARTURE

33

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

67

NORMAL

57

DEPARTURE

10

YEARLY TOTAL

495

NORMAL

696

DEPARTURE

-201

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

1.99

NORMAL

1.14

DEPARTURE

0.85

YEARLY TOTAL

13.32

NORMAL

13.21

DEPARTURE

0.11

GREATEST IN 24 HOURS

0.91 on the 4th

DAYS WITH MEASURABLE PRECIPITATION

8

 

 

 

 

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

 

GREATEST DEPTH

 

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED

10.2

       

PEAK WIND GUST

36mph from S on the 3rd

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

9

NORMAL

4

NUMBER OF DAYS WITH HEAVY FOG

4

NORMAL

1

NUMBER OF DAYS WITH HAIL

0

 

 

PERCENT OF SUNSHINE

80

NORMAL

71

 

 

 

October Preview

October is normally one of the quietest weather months in Denver with an abundance of mild sunny days and clear cool nights.  It has the second highest amount of sunshine with 72 percent. The month with the highest percentage is September with 74 percent and coincidently the month after October, November is one of the lowest sunshine months with only 64 percent.  In most years October brings the first taste of winter with the average date of the first freeze on the 7th and the average first snow on the 15th.

There is a great temperature extreme difference for October.  The record high October Temperature is 90 degrees set October 1st 1892, while the coldest October temperature is 2 degrees below zero set on October 29th 1917.  On October 2nd 1969 the Denver temperature was 85 degrees.  On October 3rd and 4th 15 inches of snow fell across the metro area.  In 1991 a record high or 89 degrees was set on the 16th followed by lows of 7 degrees on the 30th and 10 degrees on the 31st.

One of Denver’s most famous snowstorms was the “Bronco Blizzard” which occurred on October 15th 1984.  This storm was witnessed by a nationwide television audience on Monday night football.  By the time the game ended the entire field was covered by 3-4 inches of snow.  By the time the storm ended over a foot of snow had fallen over most of the metro area.  October 1997 turned out to be a snow record setter.  The blizzard of October 24th-25th produced 19.1 inches of snow in a 24 hour period setting a new October record.  Before the storm ended 21.9 inches of snow had fallen at old Stapleton Airport during the 2 day period.  The month finished with 22.1 inches making it the 3rd snowiest October in Denver history.

DENVER'S OCTOBER CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

66.0

AVERAGE LOW

35.9

MONTHLY MEAN

52.0

DAYS WITH HIGH 90 OR ABOVE

0

DAYS WITH HIGH 32 OR BELOW

0

DAYS WITH LOW 32 OR BELOW

9

DAYS WITH LOWS ZERO OR BELOW

0

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

0.99"

DAYS WITH MEASURABLE PRECIPITATION

5

AVERAGE SNOWFALL IN INCHES

4.1"

DAYS WITH 1.0 INCH OF SNOW OR MORE

1

 

 

MISCELLANEOUS OCTOBER AVERAGES

 

 

 

HEATING DEGREE DAYS

436

COOLING DEGREE DAYS

0

WIND SPEED (MPH)

7.8

WIND DIRECTION

SOUTH

DAYS WITH THUNDERSTORMS

2

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

72

 

 

OCTOBER EXTREMES

 

 

 

RECORD HIGH

90 DEGREES ON 10/01/1892

RECORD LOW

-2 DEGREES ON 10/29/1917

WARMEST

59.9 DEGREES IN 1950

COLDEST

39.0 DEGREES IN 1969

WETTEST

4.17 INCHES IN 1969

DRIEST

TR IN 1934

SNOWIEST

31.2 IN 1969

LEAST SNOWIEST

0.0 IN 14 YEARS

Sunrise/Sunset (Denver area)

     Date

Sunrise

Sunset

     October 1  

06:56

18:43

     October 5

07:00

18:36

     October 10

07:05

18:29

     October 15

07:10

18:21

     October 20

07:16

18:14

     October 25

07:21

18:07

     October30

07:27

17:59

 Rainfall

City

May 

June

July

Aug Sept

May - September Totals

Arvada

1.06

3.07

0.79

2.36 1.42

8.70

Aurora (Central)

0.83

1.93

1.18 2.88 0.75

7.57

Castle Rock 4 NE

0.41

3.63

 1.93

4.34 1.05

11.36

Colorado Springs

0.61

6.01

4.13

4.84 0.50

16.09

Denver DIA 1.30 2.33 2.52 2.84 1.99

10.98

Denver Downtown

1.06

2.17

0.67

4.65 1.34

9.89

Golden

1.10

4.77

0.95

2.56 0.67

10.05

Highlands Ranch

0.95

2.88

1.06

2.17 1.38

8.44

Lakewood

1.10

3.63

1.19

2.60 1.62

10.14

Littleton

0.87

2.09

1.26

2.68 1.06

7.96

Louisville

1.38

3.78

2.05

2.72 1.73

11.66

Parker

1.02

2.13

2.52

4.02 0.59

10.28

Sedalia

1.18

4.06

0.75

3.11 0.79

9.89

Thornton

0.67

1.81

0.67

1.73 0.83

5.71

Westminster

0.79

1.06

3.27

2.44 1.58

9.14

Wheatridge

1.22

1.42

0.71

3.23 1.65

8.23