The Weather Wire

 

May 2008                                                                                                            Volume 16 Number 05

 

Contents

 

 

 
·   Lightning Season
 

·   Drought Monitor

 

·   March

    Summary

 

·   April Stats

 

·   May Preview

 

·   Sunrise/Sunset

 

·   Snow Totals

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April 

Avg High 61.6

Avg Low 30.6

Snow - 2.9"

Season Snow - 42.9"

Precipitation - 0.32"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

May

Avg High 70.5

Avg Low 43.8

Avg Snow -  1.3"

Avg Precip - 2.32"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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 2008

Skyview Weather

Lightning Season Again!!!

Yes it is that time of year again! Usually March brings the first claps of thunder and the first bolts of lightning. If not in March, definitely in April and May.  On average some 20 million bolts of lightning strike the U.S. during a single year.  Of these over half strike the ground at more than one point.  So we have at a minimum 30 million spots struck by lightning each year!  That is a lot of lightning!  The lightning capital of the nation is Florida, but Colorado is not far behind.  This is due to our closeness to the mountains to our west.  The mountains help to trigger thunderstorms for our area spring through fall. A typical thunderstorm day for Colorado starts out with a sunny morning.  Clouds begin to develop on the mountains and foothills to the west.  As the clouds grow taller and develop into thunderstorms upper level steering winds push the storms out onto the plains.

Lightning is caused as rising air currents in the storms carry water droplets to areas of the clouds below freezing, where some of these droplets freeze.  It is in the mixture of water and ice that a charge develops.  When this charge is sufficiently large a bolt of lightning reaches from the cloud to the ground releasing large amounts of electricity.  In the tropics where the atmosphere is warmer to a higher altitude many storms can and do produce torrential rains but produce no lightning so having a low altitude freezing level such as we have here in Colorado increases the number of lighting strikes we see along the Front Range.  This low freezing level is also conducive to producing hail, which we see quite a bit of in eastern Colorado.

Cloud to ground lightning can kill or injure people by direct or indirect means.  The lightning current can branch off to a person from a tree, fence, pole or other tall object.  In addition, lighting strikes may conduct their current through the ground to a person after the lightning strikes a nearby tree, antenna or other tall object.  The current also may travel through power or telephone lines, or plumbing pipes to a person who is in contact with an electric appliance, telephone or plumbing fixture.  Now lets think about the golfer who is carrying a metal rod and wearing spikes shoes, not the best combination when there is lightning around!

During the past 30 years, lightning killed an average of 73 people per year in the United States based on documented cases. This is more than the average of 68 deaths per year caused by tornadoes and the average of 16 deaths per year caused by hurricanes. However, because lightning usually claims only one or two victims at a time, and because lightning does not cause the mass destruction left in the wake of tornadoes or hurricanes, lightning generally receives much less attention than the more destructive weather-related killers. While documented lightning injuries in the United States average about 300 per year, undocumented injuries caused by lightning are likely much higher.

One of the factors here in Colorado that causes a false sense of security and causes many people to stay out too long is our naturally dry air.  Many times thunderstorms develop, the rain falls from the clouds, but evaporates before it gets to the ground.  Lighting is still produced in these ‘dry’ thunderstorms, but with no rain to chase people indoors the tendency to stay outside until it is too late.  In addition lighting has been know to strike as far as 10 miles from the approaching stormSo just because it is not raining yet, does not mean you are safe from lightning!! You should always stay alert to changing weather conditions while you are outside and have a good idea where you will go if lighting becomes a threat. 

The most important statement for everyone to understand, memorize and act on is:  NO PLACE OUTSIDE IS SAFE FROM LIGHTING NEAR THUNDERSTORMS!!

Drought Update

Little in the way of meaningful drought across Colorado as of early May though some dry areas do persist across Eastern Colorado.

The map below shows forecasted temperature deviances for May 2008. As can be seen, much of northern and central Colorado is expected to have below normal temperatures for May 2008.

The map below shows forecasted precipitation deviances for May 2008.  Normal precipitation is anticipated across  most of Colorado, with extreme northeastern Colorado forecast to have slightly above average precipitation.

Little change in conditions is anticipated over the next 3 months, with most of the state not expected to see drought conditions.  Extreme southeastern Colorado  is anticipated to experience drought conditions persisting and possibly intensifying.

April Summary

April of 2008 was one of the driest in Denver history with only 0.32" of precipitation becoming the 5th driest April on record.  For the year Denver is now nearly 3.5" of precipitation below normal and this will be very difficult to make up.  For snowfall only a meager 2.9" was reported at the Stapleton site which is 6.2" below the normal value of 9.1".  Looks like the Stapleton site will end up around 18" below normal in snowfall while many other areas west and south of town are at or slightly above normal.  Despite the lack of precipitation the skies were unusually cloudy with only 55% of possible sunshine which is well below the average of 67%.  Temperatures were slightly above average for highs with 61.6 degrees as compared to 60.9 degrees on a normal year.  Lows on the other hand were below normal with 30.6 degrees compared to 34.2 on average.  The monthly mean was below average by 1.5 degrees which is keeping the streak going for at or below normal temperatures going all the way back to December.  The dry month and periods of strong winds resulted in an unusually high amount of fire weather watches and warnings.  Three firefighters have already lost their lives this year and is the most in the state since the Storm King Fire in western Colorado all the way back in 1994 when 14 firefighters were lost.

April Stats

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

61.6

NORMAL

60.9

DEPARTURE

0.7

AVERAGE MIN

30.6

NORMAL

34.2

DEPARTURE

-3.6

MONTHLY MEAN

46.1

NORMAL

47.6

DEPARTURE

-1.5

HIGHEST

82 on the 15th and 30th

LOWEST

13 on the 1st

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

0

NORMAL

0.2

DAYS WITH MAX 32 OR BELOW

0

NORMAL

0.2

DAYS WITH MIN 32 OR BELOW

21

NORMAL

11.4

DAYS WITH MIN ZERO OR BELOW

0

NORMAL

0.1

 

 

 

 

 

 

TEMPERATURE RECORDS

 

None

 

 

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

558

NORMAL

524

DEPARTURE

34

SEASONAL TOTAL

5689

NORMAL

5801

DEPARTURE

-112

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

0

NORMAL

2

DEPARTURE

-2

YEARLY TOTAL

0

NORMAL

2

DEPARTURE

-2

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

0.32

NORMAL

1.93

DEPARTURE

-1.61

YEARLY TOTAL

0.75

NORMAL

4.24

DEPARTURE

-3.49

GREATEST IN 24 HOURS

0.18"

DAYS WITH MEASURABLE PRECIPITATION

4

 

 

 

 

 

SNOWFALL (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

2.9"

NORMAL

9.1"

DEPARTURE

-6.2"

SEASONAL TOTAL

42.9"

NORMAL

60.4"

DEPARTURE

-17.5"

GREATEST IN 24 HOURS

1.8" 4/10 to 4/11

GREATEST DEPTH

N/A

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED 12.0mph

PEAK WIND GUST

52mph from the west

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

1

NORMAL

2

NUMBER OF DAYS WITH HEAVY FOG

1

NORMAL

1

NUMBER OF DAYS WITH HAIL

0

 

 

PERCENT OF SUNSHINE

55%

NORMAL

67%

 

 

 

May Preview

May can be an unpredictable month along the Front Range of Colorado which can feature late season snowfall and hard freezes as well as warm and sunny days or rain showers and afternoon thunderstorms.  The last freeze is "normally" around May 5th but can be as late as June 8th.  Believe it or not, May is also the wettest month here in Denver with 2.32" of precipitation on average and we will need all of it and then some to begin to catch up in our deficit so far this year.  It can happen as May is the wettest month in Denver history with 8.57" back in 1876, however with the current weather pattern the chances are next to zero.  Thunderstorms become more numerous in May with 6 thunderstorm days on average.  Last May of 2007 was very active with 17 thunderstorm days.  Typically 11 days of the month will feature measurable precipitation which about one out of every three days.  So far 0.7" of snow has been recorded on the 1st of this month and average is only about 1.5".  High and low temperatures climb significantly in May with temperatures in the 70s during the day and low to mid 40s overnight.       

DENVER'S NOVEMBER CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

70.5

AVERAGE LOW

43.8

MONTHLY MEAN

57.2

DAYS WITH HIGH 90 OR ABOVE

Less than 1

DAYS WITH HIGH 32 OR BELOW

0

DAYS WITH LOW 32 OR BELOW

2

DAYS WITH LOWS ZERO OR BELOW

0

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

2.32"

DAYS WITH MEASURABLE PRECIPITATION

11

AVERAGE SNOWFALL IN INCHES

1.3"

DAYS WITH 1.0 INCH OF SNOW OR MORE

Less than 1

 

 

MISCELLANEOUS AVERAGES

 

 

 

HEATING DEGREE DAYS

267

COOLING DEGREE DAYS

23

WIND SPEED (MPH)

9.3mph

WIND DIRECTION

South

DAYS WITH THUNDERSTORMS

6

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

64%

 

 

EXTREMES

 

 

 

RECORD HIGH

95 on the May 26, 1942

RECORD LOW

19 on May 3, 1907

WARMEST

64.6 in 1934

COLDEST

48.7 in 1917

WETTEST

8.57" in 1876

DRIEST

0.06" in 1974

SNOWIEST

15.5" in 1898

LEAST SNOWIEST

0.0" 40 years with zero snowfall
 

Sunrise/Sunset (Jan - June Denver area)

       JAN             FEB                 MAR           APR              MAY               JUN
       sr - ss           sr - ss            sr - ss           sr - ss           sr - ss             sr - ss
01  0720-0445 | 0708-0517 | 0632-0551 | 0643-0723 | 0600-0753 | 0533-0821  01
02  0721-0446 | 0707-0519 | 0630-0552 | 0641-0724 | 0558-0754 | 0533-0822  02
03  0721-0447 | 0706-0520 | 0629-0553 | 0640-0725 | 0557-0755 | 0533-0823  03
04  0721-0448 | 0705-0521 | 0627-0554 | 0638-0726 | 0556-0756 | 0532-0823  04

05  0721-0449 | 0704-0522 | 0626-0555 | 0637-0727 | 0555-0757 | 0532-0824  05
06  0721-0450 | 0703-0523 | 0624-0556 | 0635-0728 | 0554-0758 | 0532-0825  06
07  0721-0451 | 0702-0525 | 0623-0557 | 0633-0729 | 0553-0759 | 0532-0825  07
08  0721-0452 | 0701-0526 | 0621-0558 | 0632-0730 | 0551-0800 | 0531-0826  08

09  0720-0453 | 0700-0527 | 0720-0700 | 0630-0731 | 0550-0801 | 0531-0826  09
10  0720-0454 | 0658-0528 | 0718-0701 | 0629-0732 | 0549-0802 | 0531-0827  10
11  0720-0455 | 0657-0529 | 0716-0702 | 0627-0733 | 0548-0803 | 0531-0827  11
12  0720-0456 | 0656-0530 | 0715-0703 | 0626-0734 | 0547-0804 | 0531-0828  12

13  0720-0457 | 0655-0532 | 0713-0704 | 0624-0735 | 0546-0805 | 0531-0828  13
14  0719-0458 | 0654-0533 | 0712-0705 | 0623-0736 | 0545-0806 | 0531-0829  14
15  0719-0459 | 0652-0534 | 0710-0706 | 0621-0737 | 0545-0807 | 0531-0829  15
16  0718-0500 | 0651-0535 | 0708-0707 | 0620-0738 | 0544-0808 | 0531-0829  16

17  0718-0500 | 0650-0536 | 0707-0708 | 0618-0739 | 0543-0809 | 0531-0830  17
18  0718-0501 | 0649-0537 | 0705-0709 | 0617-0740 | 0542-0810 | 0531-0830  18
19  0717-0502 | 0647-0539 | 0704-0710 | 0615-0741 | 0541-0811 | 0531-0830  19
20  0717-0503 | 0646-0540 | 0702-0711 | 0614-0742 | 0540-0812 | 0532-0831  20

21  0716-0505 | 0645-0541 | 0700-0712 | 0613-0743 | 0540-0812 | 0532-0831  21
22  0715-0506 | 0643-0542 | 0659-0713 | 0611-0744 | 0539-0813 | 0532-0831  22
23  0715-0507 | 0642-0543 | 0657-0714 | 0610-0745 | 0538-0814 | 0532-0831  23
24  0714-0508 | 0640-0544 | 0656-0715 | 0609-0746 | 0538-0815 | 0533-0831  24

25  0713-0509 | 0639-0545 | 0654-0716 | 0607-0747 | 0537-0816 | 0533-0831  25
26  0713-0510 | 0638-0547 | 0652-0717 | 0606-0748 | 0536-0817 | 0533-0831  26
27  0712-0511 | 0636-0548 | 0651-0718 | 0605-0749 | 0536-0817 | 0534-0832  27
28  0711-0513 | 0635-0549 | 0649-0719 | 0603-0750 | 0535-0818 | 0534-0832  28

29  0710-0514 | 0633-0550 | 0648-0720 | 0602-0751 | 0535-0819 | 0535-0832  29
30  0709-0515 |                      | 0646-0721 | 0601-0752 | 0534-0820 | 0535-0831  30
31  0709-0516

 Snowfall

October 2007 to April 2008

City

Oct

Nov

Dec

Jan Feb Mar Apr

Seasonal Totals

Aurora (Central)

4.5" 1.8" 23.8" 4.6" 7.8" 7.1" 7.0" 56.6"
Brighton 2.2" 2.8" 19.5" 1.2" 5.0" 6.0" 2.8" 39.5"
Broomfield 2.5" 2.7" 23.1" 5.1" 5.3" 11.3" 3.7" 53.7"

Castle Rock 4 NE

7.0" 2.5" 24.7" 11.2" 7.8" 5.9" 7.9" 67.0"

Colorado Sprgs Airport

0.0" 1.2" 7.2" 8.0" 2.7" 11.4" 2.2" 32.7"
Denver Stapleton 3.0" 2.5" 20.9" 3.1" 5.1" 5.4" 2.9" 42.9"

Denver Downtown

2.2" 2.6" 22.9" 6.9" 7.9" 7.9 3.5" 53.9"

Golden

1.8" 3.6" 27.7" 6.4" 11.9" 7.9" 6.7" 76.6"

Highlands Ranch

6.0" 2.7" 28.5" 10.9" 7.9 15.3" 10.8" 82.4"

Lakewood

2.5" 2.0" 22.0" 5.8" 4.5" 8.9" 2.0" 47.7"

Littleton

4.0" 3.0" 26.0" 5.8" 8.5" 13.7" 5.9" 66.9"

Parker

4.5" 2.3" 23.3" 6.6" 7.6" 7.5" 9.2" 61.0"

Sedalia - Hwy 67

4.0" 4.0" 23.7" 14.0" 10.0" 8.9" 7.3" 71.9"

Thornton

2.5" 2.0" 19.5" 3.4" 5.7" 8.8" 3.1" 45.0"

Westminster

1.8" 2.5" 22.1" 8.7" 6.9" 14.0" 6.1" 62.1"

Wheatridge

2.9" 2.9" 25.2" 8.6" 8.8" 10.4" 4.9" 63.7"