The Weather Wire

 

April 2004                                                                                                 Volume 11 Number 4

 

Contents

 

·   Drought

 

·   Drought Monitor

 

·   March

    Summary

 

·   March Stats

 

·   April Preview

 

·   Sunrise/Sunset

 

·   Snowfall Totals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

March 2004

 

Avg High 62.0

Avg Low 30.7

Snow - 1.8"

Season Snow - 22.7"

Precipitation - 0.14"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

April

Avg High 60.9

Avg Low 34.2

Avg Snow - 9.1"

Avg Precip - 1.93"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Skyview Weather 

2350 N Rocky View Rd

Castle Rock, CO 80104

 

Phone: (303) 688-9175

Fax: (303) 660-0548

 

E-mail:    

tim@skyview-wx.com

 

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Copyright 2004

Skyview Weather

Does the Drought Continue????

 

March 2004 now becomes the 9th month in a row with below normal precipitation.  So now the question becomes does the drought for Colorado continue???  A quick look back at 2003.  We finished the year with a total of 13.92 inches of moisture. This was 1.89 inches below the normal of 15.81 inches.  This comes to a little bit more than 10% below normal.  Not exactly a big difference. So far for 2004 we have 0.58" of moisture compared to a normal of 2.28".  This is a more significant 75% below normal, but remember that amount can be made up in a matter of a few days with one good storm. So yes we have been dry so far this year, but it is still early.

Lets review some things, especially for those new to our area within the last few years and to no lesser extend to the local media along the Front Range who many times are more interested in making the news rather than reporting it!  Living along the Front Range in the lee of the Rocky Mountains the climate classification for all of eastern Colorado is semi-arid.  The average annual rainfall for Denver is only 15.81 inches.  Anything below 10 inches annually is considered a desert climate. So that with a reduction of only 37% in our annual rainfall we would fall into the desert climate category.  In other words our climate for eastern Colorado is normally dry!  In addition with the small amounts of moisture that we normally get it only takes small shortages to give us real dry conditions.  The reason for our dry climate lies to the west, called the Rocky Mountains. The mountains act as a barrier to moisture that comes in from the west.  The moisture falls in the high country and then the dried out air blows across eastern Colorado.

Another factor that should not be ignored is the huge increase in the population along the Front Range in the past 30 years.  Hundreds of thousands more people live in eastern Colorado drawing on the same limited supply of water.  Many of these people have move to Colorado from areas that are quite wet by our standards.  Along the east coast annual rainfalls of 40 to 50 inches are common!  Along the Gulf coast 40 to 60 inches are common and in the Pacific Northwest 60-80 inches is not out of the question!  Compare that to the 15 to 16 inches common here.   Many people move here and expect to have a nice big yard with grass that soaks up a large percentage of our limited water supplies. Fine for those wet areas they came from where 'mother nature' does most of the watering, but here in eastern Colorado to maintain a green yard you have to irrigate it!  Now this wasn't as much of a problem when the population was smaller, but with the large growth in eastern Colorado this problem is not going to go away anytime soon.  Until the mountains to the west disappear the rainfall for eastern Colorado will continue to be semi-arid! 

So the question of "does the drought continue"  is a bit more complicated than just rainfall amounts. As the population in Colorado continues to grow, perhaps it is more accurate to say the water shortages will continue rather than to question whether or not the drought continues. Because the climate of Colorado hasn't changed, but the population sure has!

How prudently we use our limited water supplies is the bigger question and a question that will be with us for a long time!

 

DENVER PRECIPITATION AFTER THE DRIEST MARCHES ON RECORD
(based on the top 15 driest Marches in Denver weather history)


     This interesting review was compiled by the National Weather Service in Boulder, CO. They have rank ordered the top 15 driest Marches and then took a look at what the 3 months immediately following each of these dry Marches totaled for their precipitation.  It is interesting to note that several significant records occurred in one or more of the months that followed these dry Marches.  From the below listed statistics, the best shot at above normal precipitation would be May. (Thanks to Paul Gard and Kyle Fredin for their statistical input)

MONTH MARCH APRIL MAY JUNE
NORMAL 1.28 1.93 2.32 1.56


 

  MARCH APRIL MAY JUNE
1908 0.11   0.39 2 2.82 1.68
2004 0.14 ?.?? ?.?? ?.??
1982 0.18   0.34 4 3.48 2.26
1999 0.19    5.86 5 2.37 2.52
1882 0.20 1.47 2.98   4.96 8
1880 0.21    0.31 1 1.11 1.22
1883 0.21 3.10 4.30 0.85
1945 0.22 2.58 2.06 1.75
1887 0.23 2.16 1.13 0.53
1893 0.23 0.87 3.09   0.13 9
1935 0.23    4.07 3 4.95 0.60
1997 0.26 1.30 1.57 2.57
1898 0.28 1.20   4.88 6 0.94
1911 0.28 1.41   0.52 7 0.56
1995 0.28 2.44 4.67 3.07
1946 0.30 1.33 1.67 0.87

 
avg pcpn 1.92 2.77 1.63
  departure % -0.41% +19.5% +4.7%
  occurrences
greater than
normal %
6
 
40.0%
9
 
60.0%
7
 
46.7%
          1  April 1880 4th driest April           May 1898 6th wettest May  
          2  April 1908 7th driest April             7  May 1911 8th driest  May
          3  April 1935 7th wettest April           8  June 1882 wettest June 
          4  April 1982 6th driest April             9  June 1893 5th driest June
          5  April 1999 2nd wettest April  

 

Drought Update

In many portions of Colorado, March 2004 was well below normal for precipitation.  As a result, drought conditions worsened across much of Colorado.

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

The map below shows forecasted precipitation deviances for April 2004.  Normal or near normal precipitation is expected for April 2004 across Colorado.

As can be seen in the below map, conditions are expected to continue to worsen  through June across much of Colorado. Snow pack is generally below normal in most basins, with the South Platte drainage well below normal at this time.

March Summary

March 2004 became Denver's second driest March since records began in 1872.  Ironically, March 2003 registered as the 5th wettest and the snowiest month in Denver weather history.  March 2004 was the driest march all the way until 0.05 inch of rain was recorded at DIA on the 27th, increasing the total from 0.09 up to the month's total of 0.14 inches, which is 1.14 inches below normal.  The driest march on record was recorded in 1908 when 0.11 inch was all that fell that month.  March 2004 also became the 9th month in a row with below normal precipitation.  Only 4 days recorded measurable moisture with the greatest in a 24 hour period a mere total of only 0.08 inch.

With so little moisture, snowfall was accordingly well below normal.  March is Denver's snowiest month, but not this year.  Only 1.8 inches of snow was measured, 9.9 inches below the normal of 11.7 inches.  For the season so far only 22.7 inches has been recorded at the old Stapleton Airport location.  Through March, this ranks as the 4th lowest seasonal Denver snowfall in over 120 years.  There was only 1 day with measurable snowfall and it occurred on the 5th with the month's total of 1.8 inches.

The month finished tied as the 6th warmest March with an average temperature of 46.4 degrees, 6.8 degrees above normal.  The warmest March, 50.4 degrees was recorded in 1910.  Temperatures during the month ranged from a record setting high of 79 degrees down to a low of 18 degrees.  The only record set was a 79 degree reading on the 22nd, breaking the old record of 78 degrees set in 1910. 

March Stats

 

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

62.0

NORMAL

53.7

DEPARTURE

8.3

AVERAGE MIN

30.7

NORMAL

25.4

DEPARTURE

5.3

MONTHLY MEAN

46.4

NORMAL

39.6

DEPARTURE

6.8

HIGHEST

79 on the 22nd & 26th

LOWEST

18 on the 2nd

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

0

NORMAL

0

DAYS WITH MAX 32 OR BELOW

0

NORMAL

3

DAYS WITH MIN 32 OR BELOW

19

NORMAL

24

DAYS WITH MIN ZERO OR BELOW

0

NORMAL

1

 

 

 

 

 

 

TEMPERATURE RECORDS

 

22nd - New record high 79, old record 78 set in 1910

 

 

 

 

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

569

NORMAL

788

DEPARTURE

-219

SEASONAL TOTAL

4938

NORMAL

5277

DEPARTURE

-339

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

0

NORMAL

0

DEPARTURE

0

YEARLY TOTAL

0

NORMAL

0

DEPARTURE

0

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

0.14

NORMAL

1.28

DEPARTURE

-1.14

YEARLY TOTAL

0.58

NORMAL

2.28

DEPARTURE

-1.70

GREATEST IN 24 HOURS

0.08 on the 4th-5th

DAYS WITH MEASURABLE PRECIPITATION

4

NORMAL

9

 

 

SNOWFALL (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

1.8

NORMAL

11.7

DEPARTURE

-9.9

SEASONAL TOTAL

22.7

NORMAL

51.3

DEPARTURE

-28.6

GREATEST IN 24 HOURS

 

GREATEST DEPTH

1.8 on the 4th-5th

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED

10.5

NORMAL

9.7

DEPARTURE

-0.8

PEAK WIND GUST

43MPH  from the northwest on the 16th

 

 

 

 

 

 

SEA LEVEL PRESSURE (IN INCHES OF MERCURY

 

 

 

 

 

 

HIGHEST

30.53 Inches on the 20th

LOWEST

29.47 Inches on the 4th

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

1

NORMAL

0

NUMBER OF DAYS WITH HEAVY FOG

0

NORMAL

1

NUMBER OF DAYS WITH HAIL

0

 

 

PERCENT OF SUNSHINE

81

NORMAL

69

TOTAL MINUTES OF SUNSHINE

 

18032

TOTAL MINUTES OF SUNSHINE POSSIBLE

 

22266

 

 

 

April Preview

April is a transitional month for most of the country and this is especially true in 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.  On April 30th 1992, the mercury climbed to the highest April temperature ever, 90 degrees.

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 snow.  In addition, warm dry air from the desert southwest can bring warm temperatures and low humidity's to eastern Colorado.

The temperature range for April is from 90 degrees down to 2 below zero.  April is the third snowiest month of the year with an average of 8.9 inches and is the windiest month of the year with an average speed of 10 miles per hour.  On average, you can expect 2 thunderstorms to occur during the month.

The National Weather Service 30-day outlook model does not favor any particular weather pattern for temperature or precipitation for April 2004.  So normal temperatures and normal precipitation are anticipated for this April.

DENVER'S APRIL CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

60.9

AVERAGE LOW

34.2

MONTHLY MEAN

47.6

DAYS WITH HIGH 90 OR ABOVE

0

DAYS WITH HIGH 32 OR BELOW

0

DAYS WITH LOW 32 OR BELOW

11

DAYS WITH LOWS ZERO OR BELOW

0

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

1.93 inches

DAYS WITH MEASURABLE PRECIPITATION

9

AVERAGE SNOWFALL IN INCHES

9.1 inches

DAYS WITH 1.0 INCH OF SNOW OR MORE

3

 

 

MISCELLANEOUS APRIL AVERAGES

 

 

 

HEATING DEGREE DAYS

523

COOLING DEGREE DAYS

2

WIND SPEED (MPH)

10.0 mph

WIND DIRECTION

SOUTH

DAYS WITH THUNDERSTORMS

2

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

67

 

 

APRIL EXTREMES

 

 

 

RECORD HIGH

90 DEGREES 04/30/1992

RECORD LOW

-2 DEGREES 04/02/1975

WARMEST

56.4 DEGREES IN 1946

COLDEST

38.8 DEGREES IN 1920

WETTEST

8.24 INCHES IN 1900

DRIEST

0.03 in 1963

SNOWIEST

33.8 INCHES in 1933

LEAST SNOWIEST

0.0 in 1930, 1943, 1992

Sunrise/Sunset (Denver area)

     Date

Sunrise

Sunset

     April 1  

05:43

18:23

     April 5

06:37

19:27

     April 10

06:29

19:32

     April 15

06:21

19:37

     April 20

06:14

19:42

     April 25

06:07

19:47

     April 30

06:01

19:52

 Snowfall

City

Mar 1

Mar 4

to

Mar 5

Mar 27

Mar 28

Seasonal Totals

Arvada

0.0

4.0

0.0

TR

33.0

Aurora (Central)

TR

1.5

0.0

TR

22.8

Castle Rock  4NE

0.5

1.2

0.3

0.1

38.3

Colorado Springs Airport

0.3

1.7

TR

TR

16.5

Douglas Cnty  SE

0.5

4.2

0.0

TR

34.5

Downtown Denver

TR

2.5

0.0

TR

25.8

Golden

0.0

6.0

0.0

TR

52.5

Highlands Ranch

0.0

3.0

0.0

TR

32.7

Lakewood Cntrl

0.3

4.0

0.0

TR

37.7

Littleton

0.8

4.5

0.0

TR

38.5

Louisville

0.0

7.5

0.0

0.5

37.8

Parker

TR

2.0

0.0

1.0

30.5

Roxborough Park

0.5

7.4

0.0

TR

47.6

Sedalia

0.6

6.0

0.0

0.5

53.0

Thornton

0.0

3.5

0.0

TR

26.2

Westminster

0.0

4.0

0.0

TR

30.3

Wheatridge

0.2

5.1

0.0

TR

39.1