The Weather Wire

 

August 2010                                                                                                            Volume 17 Number 08

 

Contents

 

 

 
·   When will Thunderstorm season come to an end?
 

·   Drought Monitor

 

·   July

    Summary

 

·   July Stats

 

·   August Preview

 

·   Sunrise/Sunset

 

·   Precipitation Totals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

July

Avg High - 89.3

Avg Low - 59.5

Snow - 0.0"

Season Snow - 0.0"

Precipitation - 3.70"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

August

Avg High - 88.0

Avg Low - 58.7

Avg Snow -  0.0"

Avg Precip - 2.16"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Skyview Weather 

2350 N Rocky View Rd

Castle Rock, CO 80108

 

Phone: (303) 688-9175

Fax: (303) 380-3338

 

E-mail:    

tim@skyview-wx.com

 

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

 

Copyright 2010

Skyview Weather

When will Thunderstorm Season Come to an End?

Actually, the summer thunderstorm season is already beginning to wind down now that we are past the first week of August but it will be another month plus a week or two before the Front Range experiences a major drop off in thunderstorm activity.  There are 2 major reasons why the thunderstorm season shuts down by mid September:  1. Loss of daytime heating  2. Monsoonal moisture pushed southward. 

The loss of daytime heating due to shorter and shorter days is a major reason why thunderstorms become less likely and weaker.  The atmosphere above the surface still retains the heat of summer but the air near the ground is beginning to cool which results in a more stable air mass.  This is due to the fact that warm air rises and if the air at the surface does not warm sufficiently it will not be able to rise thus no storm clouds are created.  Even if the air does warm enough to rise it will not rise with as much force as earlier in the summer when temperatures aloft were cooler and there was a greater temperatures difference between the air aloft and at the surface.  This results in the storms that do develop being weaker and less likely to produce severe weather.  Moderate and heavy rainfall becomes the greatest threat from late season thunderstorms.

The monsoon moisture that typically arrives in the first week of July from the Desert Southwest has a much more difficult time remaining in place over Colorado as Pacific storm systems become stronger and more numerous pushing the monsoon moisture further and further south.  The northern storm track becomes energized as temperatures at the North Pole begin to cool while the lower latitudes remain warm creating a larger temperature gradient from north to south.  This temperature gradient fuels the jet stream allowing for more potent storm systems to move onto the west coast which eventually move into Colorado and literally sweep the monsoon moisture away from the state.  Ahead of these disturbances moisture can be lifted northward resulting in a day or two of active weather but behind these disturbances a north to northwest flow pushes the moisture back to the south.  This keeps the potential for prolonged wet weather at bay with more dry days than days with precipitation.

 Drought Update

With the widespread precipitation of the last several months few areas of drought remain over Colorado, though some dry areas have developed in western Colorado.

The map below shows forecasted temperature deviances for July 2010. As can be seen, normal temperatures are expected the eastern 2/3s of Colorado with above average temperatures the western 1/3 of the state. 

The map below shows forecasted precipitation deviances for July 2010.  Normal precipitation is expected for the eastern 2/3s of Colorado with below normal precipitation the western 1/3 of the state.

Little in the way of drought remains in Colorado.

July Summary

July of 2010 was very wet for most areas of the Front Range as DIA reported 3.70” of precipitation for the month and 13 days with measurable rainfall.  Normal precipitation for DIA is 2.16” and with a surplus of 1.54” for July we are now 0.25” above normal for the year.  This July missed out on being in the top ten wettest July’s ever recorded by only 0.01” out of 10th place.  What a difference a month can make!  July of 2010 was also a little warmer than average with a mean temperature of 74.4 degrees compared to 73.4 on average.  There were 18 days with high temperatures of 90 degrees or more with 15 days during an average July.

July Stats

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

89.3

NORMAL

88.0

DEPARTURE

1.3

AVERAGE MIN

59.5

NORMAL

58.7

DEPARTURE

0.8

MONTHLY MEAN

74.4

NORMAL

73.4

DEPARTURE

1.0

HIGHEST

102 on the 17th

LOWEST

53 on the 4th, 5th and 9th

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

18

NORMAL

15

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

 

New record high of 102 recorded on the 17th.

 

 

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

3

NORMAL

1

DEPARTURE

2

SEASONAL TOTAL

3

NORMAL

1

DEPARTURE

2

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

303

NORMAL

261

DEPARTURE

42

YEARLY TOTAL

482

NORMAL

422

DEPARTURE

60

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

3.70

NORMAL

2.16

DEPARTURE

1.54

YEARLY TOTAL

9.50

NORMAL

9.25

DEPARTURE

0.25

GREATEST IN 24 HOURS

1.84" on the 4th

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

0.0

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED

9.1 mph

PEAK WIND GUST

48 mph from the NNW

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

14

NORMAL

11

NUMBER OF DAYS WITH HEAVY FOG

2

NORMAL

<1

NUMBER OF DAYS WITH HAIL

1

 

 

PERCENT OF SUNSHINE

NA

NORMAL

71%

August Preview

August is typically the last month of true “summer” along the Front Range as temperatures towards the end of the month begin to fall off and thunderstorms become less likely.  Upper level winds are typically quite light this month reducing the necessary wind shear for severe storms with slow moving moderate and heavy rainfall producing thunderstorms being most likely which are fed by monsoonal moisture being drawn northward from the Desert Southwest.  The average high for August is 86.0 and the average low is 57.4 producing a monthly mean temperature of 71.7 which is cooler than July.  Average precipitation for the month is 1.82” with 9 days of measurable precipitation.  The record high for the month is 105 degrees which is tied for the hottest in Denver history and the record low is 40.  August of 2010 will likely be around normal in both precipitation and temperature.       

DENVER'S NOVEMBER CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

86.0

AVERAGE LOW

57.4

MONTHLY MEAN

71.7

DAYS WITH HIGH 90 OR ABOVE

9

DAYS WITH HIGH 32 OR BELOW

0

DAYS WITH LOW 32 OR BELOW

0

DAYS WITH LOWS ZERO OR BELOW

0

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

1.82"

DAYS WITH MEASURABLE PRECIPITATION

9

AVERAGE SNOWFALL IN INCHES

0

DAYS WITH 1.0 INCH OF SNOW OR MORE

0

 

 

MISCELLANEOUS AVERAGES

 

 

 

HEATING DEGREE DAYS

9

COOLING DEGREE DAYS

217

WIND SPEED (MPH)

8.0 mph

WIND DIRECTION

South

DAYS WITH THUNDERSTORMS

8

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

71%

 

 

EXTREMES

 

 

 

RECORD HIGH

105 on 7/20/2005

RECORD LOW

40 on 8/25/1910

WARMEST

76.8 in 1937

COLDEST

66.5 in 1915

WETTEST

5.85" in 1979

DRIEST

0.02" 1924

SNOWIEST

No snow ever recorded

LEAST SNOWIEST

No snow ever recorded
 

Sunrise/Sunset (July - Dec Denver area)

                 JUL            AUG           SEP              OCT            NOV          DEC
______________________________________________________________________________
           sr - ss           sr - ss          sr - ss           sr - ss           sr - ss           sr - ss
 01  0535-0831 | 0558-0813 | 0627-0732 | 0656-0643 | 0728-0558 | 0701-0436  01
 02  0536-0831 | 0559-0812 | 0628-0731 | 0657-0642 | 0729-0556 | 0702-0435  02
 03  0536-0831 | 0600-0811 | 0629-0729 | 0658-0640 | 0731-0555 | 0703-0435  03
 04  0537-0831 | 0601-0810 | 0630-0727 | 0659-0639 | 0732-0554 | 0704-0435  04

 05  0537-0831 | 0602-0809 | 0631-0726 | 0700-0637 | 0733-0553 | 0705-0435  05
 06  0538-0831 | 0603-0808 | 0632-0724 | 0701-0635 | 0734-0552 | 0706-0435  06
 07  0539-0830 | 0604-0807 | 0633-0723 | 0702-0634 | 0635-0451 | 0707-0435  07
 08  0539-0830 | 0605-0806 | 0634-0721 | 0703-0632 | 0636-0450 | 0708-0435  08

 09  0540-0830 | 0606-0804 | 0635-0719 | 0704-0631 | 0637-0449 | 0709-0435  09
 10  0541-0829 | 0607-0803 | 0636-0718 | 0705-0629 | 0639-0448 | 0710-0435  10
 11  0541-0829 | 0608-0802 | 0637-0716 | 0706-0628 | 0640-0447 | 0710-0435  11
 12  0542-0828 | 0609-0801 | 0638-0715 | 0707-0626 | 0641-0446 | 0711-0435  12

 13  0543-0828 | 0610-0759 | 0639-0713 | 0708-0625 | 0642-0445 | 0712-0436  13
 14  0543-0827 | 0611-0758 | 0640-0711 | 0709-0623 | 0643-0445 | 0713-0436  14
 15  0544-0827 | 0612-0757 | 0641-0710 | 0710-0622 | 0644-0444 | 0713-0436  15
 16  0545-0826 | 0612-0755 | 0641-0708 | 0711-0620 | 0645-0443 | 0714-0436  16

 17  0546-0826 | 0613-0754 | 0642-0706 | 0712-0619 | 0646-0442 | 0715-0437  17
 18  0546-0825 | 0614-0753 | 0643-0705 | 0713-0617 | 0648-0442 | 0715-0437  18
 19  0547-0825 | 0615-0751 | 0644-0703 | 0714-0616 | 0649-0441 | 0716-0437  19
 20  0548-0824 | 0616-0750 | 0645-0701 | 0715-0614 | 0650-0440 | 0716-0438  20

 21  0549-0823 | 0617-0749 | 0646-0700 | 0716-0613 | 0651-0440 | 0717-0438  21
 22  0550-0822 | 0618-0747 | 0647-0658 | 0717-0612 | 0652-0439 | 0717-0439  22
 23  0551-0822 | 0619-0746 | 0648-0656 | 0718-0610 | 0653-0439 | 0718-0439  23
 24  0551-0821 | 0620-0744 | 0649-0655 | 0719-0609 | 0654-0438 | 0718-0440  24

 25  0552-0820 | 0621-0743 | 0650-0653 | 0720-0608 | 0655-0438 | 0719-0441  25
 26  0553-0819 | 0622-0741 | 0651-0652 | 0722-0606 | 0656-0437 | 0719-0441  26
 27  0554-0818 | 0623-0740 | 0652-0650 | 0723-0605 | 0657-0437 | 0719-0442  27
 28  0555-0817 | 0624-0738 | 0653-0648 | 0724-0604 | 0658-0437 | 0720-0443  28

 29  0556-0816 | 0625-0737 | 0654-0647 | 0725-0602 | 0659-0436 | 0720-0443  29
 30  0557-0815 | 0626-0735 | 0655-0645 | 0726-0600 | 0700-0436 | 0720-0444  30
 31  0558-0814 | 0627-0734 |                   | 0727-0559 |                    | 0720-0445  31



Precipitation

May 2010 to Sept 2010

City

May

June

July

Aug

Sept

Seasonal Totals

Aurora (Central)

1.02 2.32 2.44     5.78
Brighton 2.83 4.06 0.71     7.60
Broomfield 1.50 1.54 0.83     3.87

Castle Rock 4 NE

0.63 1.30 4.67     6.60

Colorado Sprgs Airport

0.82 0.34 2.67     3.83
Denver DIA 1.52 1.60 3.70     6.82

Denver Downtown

2.09 1.81 1.54     5.44

Golden

1.61 3.29 1.81     6.71

Fort Collins

1.97 1.74 1.30     5.01

Highlands Ranch

1.10 2.24 2.13     5.47

Lakewood

1.42 1.46 1.30     4.18

Littleton

1.22 1.89 0.87     3.98

Parker

0.79 1.54 2.36     4.69

Sedalia - Hwy 67

0.98 2.28 3.03     6.29

Thornton

1.91 2.48 1.40     5.79

Westminster

1.26 2.17 2.48     5.91

Wheatridge

1.50 1.65 1.46     4.61