The Weather Wire
April 2006 Volume 14 Number 4
Avg High 52.3
Avg Low 24.5
Snow - 8.6"
Season Snow - 29.9"
Precipitation - 0.56"
Avg High 60.9
Avg Low 34.2
Avg Snow - 9.1"
Avg Precip - 1.93"
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 storm. So 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!!
Skyview Offers Safety Classes
As we discussed in last months newsletter, risk management is a critical component of each organization. One component is education, and Skyview Weather is proud to announce educational classes intended to promote weather awareness and increased safety. At this time, the following classes are available.
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 what the radar. 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 firstname.lastname@example.org .
Online Forecasts Available
Skyview Weather is happy to announce that online forecasts and snow reports are again available on our sister www.anythingweather.com website. Forecasts and snow reports are password protected, but an email to Tim@Skyview-WX.com requesting your forecast and/or snow reports be available online will result in an account being setup for you. As always, forecasts and snow reports are for client use only, but with the online access, forecasts and snow reports are just a click away from any computer with an internet connection!
More increases in drought conditions across Colorado was noted during March 2006, primarily over eastern and southern portions of the state.
The map below shows forecasted temperature deviances for April 2006. As can be seen, normal temperatures are expected for the Western 2/3s of Colorado with above normal temperatures anticipated for Southeastern Colorado for April 2006.
The map below shows forecasted precipitation deviances for April2006. Normal or near normal precipitation is expected for the western 2/3s of Colorado with below normal precipitation anticipated for Southeastern Colorado for April 2006.
As can be seen in the below map, much of the state remains out of widespread drought conditions, though the southern and southeastern portions of the state are seeing increased areas of drought.
Another Denver month goes into the weather history books with below normal precipitation registering it as the 5th month in a row. Four days recorded measurable liquid with 3 days recording only trace amounts. The maximum 24 hour moisture was 0.20 inch measured on the 8th. We did see however, 0.33 inch over a 2 day period between the 19th and 20th. The month finished with 0.56 inch which was 0.72 inch below normal. Snowfall for March, Denver’s snowiest month, only finished with a total of 8.6 inches which is 3.1 inches below normal. For the season, the total is a mere 29.9 inches, a full 21.4 inches below normal. The 24 hour Maximum fell between the 20th and 21st with a total of 5.0 inches. The greatest snow depth during the month was 3.0 inches on the 21st.
The temperature average was near normal with an average temperature of 38.4 degrees which is 1.2 degrees below the normal of 39.6. There were no temperature records broken or tied for the month and March did not see any below zero temperatures. There were also no thunderstorms recorded for the month, guess we will have to wait for April for the first rumble.
April is a transitional month for most of the country and this is especially true for Denver. Almost any type of weather can occur and usually does. Tornadoes, thunderstorms, hail, snow and dust storms are all 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 the 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 with an average of 8.9 inches. April is also the windiest month of the year with an average speed of 10.0 miles per hour. On average you can expect 2 thunderstorm days to occur during April.
Sunrise/Sunset (Denver area)
October 2005 to April 2006