The Weather Wire
May 2005 Volume 13 Number 05
Avg High 59.0
Avg Low 33.8
Snow - 11.4"
Season Snow - 37.9"
Precipitation - 2.45"
Avg High 70.5
Avg Low 43.8
Avg Snow - 1.3"
Avg Precip - 2.32"
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!!
Online Forecasts Available Again
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!
Drought conditions continue to improve across most of Colorado, with normal to slightly above average precipitation during April 2005. Improvement continued through much of Colorado, with few areas of drought remaining..
The map below shows forecasted temperature deviances for the May 2005 time period. As can be seen, normal to above temperatures are expected for much of Colorado for May 2005.
The map below shows forecasted precipitation deviances for May2005. Normal or near normal precipitation is expected for much of Colorado for May 2005.
As can be seen in the below map, most of the state has come out of the widespread drought conditions of a year ago, improvement will continue in Northwest and Northwest Colorado through July2005.
April 2005 finally recorded above normal precipitation ending the 2004-2005 below normal streak at 6. Eleven days had either rain or snow and accounted for all the measurable precipitation. Between April 9th and 10th 1.27 inches of liquid was recorded. We did set a 24 hour record for precipitation on the 10th with 1.09 inches. This surpassed the old record of 0.76 set back in 1908. There were 6 days with 0.10 inch or higher, 1 day with 0.50 inch or higher and the record day that had over 1.00 inch of moisture. Even though Denver was above normal for liquid, the 2.45 inches was not near enough to get into the top 10 wettest. The wettest Denver April occurred in 1900 with a total of 8.24 inches.
There were 2 decent snow storms that accounted for the 11.4 inches of snowfall measured near the former Stapleton Airport. Of the total 11.4, 9.9 inches was the total from the 1st snow storm on the 10th and 11th. The monthly total finished 2.3 inches above normal.
Temperatures were pretty close to normal for the month with an average temperature of 46.4 degrees which was only 1.2 degrees below normal. Temperatures ranged from a high of 78 degrees down to a low of 24 degrees. There were no Temperatures records set or tied during April 2005.
There were no occurrences of severe weather, but there was one day, the 20th when small hail was observed at DIA. The first thunderstorm of the season was recorded on the 9th, with a total of 4 thunderstorm days for the month.
The weather in Denver is quite changeable throughout the year. However, the month of May seems to feature the most changes from year to year, day to day or even hour to hour. Denver’s May weather can include almost any type of weather.
Late season frosts can nip plant growth because the average date of the last freeze is May 5th, but the latest date of a Denver freeze is June 2. On the other hand, afternoon temperatures in the 80s are common and the mercury occasionally climbs into the 90s.
May normally marks the beginning of the severe weather season. Violent thunderstorms with large hail and tornadoes are possible. These severe storms occur when moisture from the Gulf of Mexico moves into Colorado and collides with cold fronts still moving in from Canada or from the Pacific Northwest.
May is also the wettest month of the year and on average, precipitation normally occurs once every three days. May is tied with November as having the lowest percentage of possible sunshine.
Snowfall in Denver during May has been nearly non-existent during the past 12 years, so the snow recorded on May first of this year breaks that streak. Denver’s high elevation intensifies late season cold air masses and on the average snow occurs in about two out of every five years.
Sunrise/Sunset (Denver area)