Category Archives: Climatology

Climatology, Thornton Weather

Denver gets new National Weather Service weather station near downtown

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Denver now as an official weather monitoring station closer to downtown but some say this doesnt solve the problem of the citys climate records being altered. (Examiner.com)
Denver now as an official weather monitoring station closer to downtown but some say this doesn't solve the problem of the city's climate records being altered. (Examiner.com)

It only took 14 years but Denver finally has an official monitoring station near downtown again. The new station amongst the greens of City Park Golf Course finally gives residents of Denver a place to see what the weather is doing closer to home.

With the opening of Denver International Airport in 1995, the National Weather Service moved its station to the new airport. That distance of 12 miles from the old Stapleton facility to DIA confounded citizens, television meteorologists and weather enthusiasts as they all noted that no one lives out at the airport and the conditions reported there do not reflect what is happening closer to town.

Recognizing the problem, a public-private partnership came together to do what they could to rectify the problem. The City and County of Denver, the Denver Museum of Nature and Science, the National Weather Service and NOAA, 7News Chief Meteorologist Mike Nelson and Colorado State Climatologist Nolan Doesken identified a site for the new station.

Eclar Fence and Mercury Electric donated the infrastructure for the new site. Weather equipment manufacturer Vaisala donated the weather monitoring hardware and services, estimated at up to $60,000.

Certainly there is little doubt the new station will provide area residents the ability to view conditions closer to where they actually live. The new station will not however address the very real problem of Denver’s climate records having been altered since the move to DIA. The National Weather Service has said the official records for Denver will still come out of DIA and as such many believe those records come with an asterisk.

There's more to this story on the Denver Weather Examiner's site!Why is there still a problem with Denver’s climate records?  What does the new station look like?  Check out the complete story including photos of the station, an interactive map and more on Examiner.com.

Climatology

October 2009 ends as second coldest and fifth snowiest on record

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October 2009 in Denver was the second coldest and fifth snowiest October on record.
October 2009 in Denver was the second coldest and fifth snowiest October on record.

Most of the month of October was cooler than normal in the Mile High City and now that the month is over we see just how cold it was. Denver finished October 2009 with an average temperature more than 8 degrees below normal and had 9 inches more snow than what is normal for the month.

October 2009’s 42.9 degree average makes it the second coldest since record keeping began in 1873 – 136 years ago! re in Thornton we were actually slightly cooler with an average temperature of 42.0 degrees.  Only October 1969 was colder as that year Denver had an average temperature of a chilly 39 degrees.  He

Across the board temperatures for the month were well below normal. The average daily high temperature of 54.7 degrees was 11.3 degrees below the normal of 66.0 degrees. Low temperatures were similarly well below normal with an average of 31.1 degrees – 4.8 degrees below the normal of 35.9. 

Thornton was warmer for daytime highs than the Denver official temperatures as we averaged 55.6 degrees.  In terms of low temperatures, we were cooler having averaged 30.7 degrees. 

There's more to this story on the Denver Weather Examiner's site!What about the snowfall?  Denver finished with the fifth snowiest October on record.  Click here to get all the details on Examiner.com.

Why do we link to Examiner.com?  Click here to find out.

Climatology, Thornton Weather

Thornton’s November weather preview – Our second snowiest month

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November is Denvers second snowiest month. What else can we expect?
November is Denver's second snowiest month. What else can we expect?

Typically November is a quiet weather month with plenty of nice, fall days but it can also turn wet with plenty of snow and moisture.  Just like Forest Gump’s proverbial box of chocolates, you never quite know what you are going to get.

Looking into the weather history books, we see that November is actually Denver’s second snowiest month, second only to March (April is third).  Historically we average 10.7 inches of snow during the month.

In 1994, November was the snowiest month of that year with 16.9 inches – over 12 inches of which fell within a 12 hour period on the 13th and 14th.  In 1991 we saw 29.6 inches of snow (the 2nd snowiest November) and the following year in 1992 we had 20.1 inches of snow (the 8th snowiest November).  Those examples though pale in comparison to the snowiest November on record which was in 1946 when a whopping 42.6 inches of snow fell! 

It isn’t always that snowy though. November 2002 was at the time the 16th month in a row with below normal precipitation and the calendar year of 2002 marked the driest in Denver weather history. This pattern of below normal precipitation continued for 19 months through February 2003. Since 1882, one year (1949) recorded no snow, six more recorded only a trace of snow and four had less than one inch of snow.

For the rest of the November weather preview including complete historical statistics, averages and much more, click here.

Climatology, Thornton Weather

Preview of Thornton’s October Weather – Fall is Here

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What does October weather hold for Denver?
What does October weather hold for Denver?

With the first full month of fall here, October usually brings one of the quietest weather months in the Denver area with plenty of mild, sunny days and clear, cool nights. The month actually has our second highest amount of sunshine with 72 percent with September having the most with 74 percent. Interestingly enough, the month following, November, is one of the lowest sunshine months with only 64 percent. Typically October brings our first real taste of winter with the first freeze on average coming on the 7th of the month and the first snow on the 15th of the month.

Average temperatures in October steadily drop throughout the month. On the first we average 72 degree highs but by the 31st that drops to 59 degrees. October also sees our average low temperatures start to reach below freezing as well. At the start of the month we will average 42 degrees as the low temperature but by the end of the month the mercury dips to 30 degrees. This truly begins the sign that winter is approaching.

Get all the details on Denver’s October weather in our complete preview here.

Climatology, National Weather

NOAA: Summer 2009 was 34th coolest on record; thousands of low temp records set

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Highlighting the cooler summer, thousands of record low temperatures were experienced in July 2009. (NCDC)
Highlighting the cooler summer, thousands of record low temperatures were experienced in July 2009. (NCDC)

The National Oceanic and Atmospheric Administration (NOAA) announced this week that the summer of 2009 was the 34th coolest since 1895. Covering the months from June to August for the contiguous United States, the average temperature was 0.4 degrees below the 20th century average.

Emphasizing the lower temperatures experienced in the United States over the summer, a closer look at the statistics provides some telling information.

Over the three month period, stations reporting to the National Climatic Data Center (NCDC) showed 2,254 daily record low temperatures and 1,296 low temperature records were tied according to preliminary data. Similarly, 4,051 daily record low maximums were recorded and 1,501 records were tied across the nation during the summer.

July in particular was notably cooler than normal and the single month by itself counted for roughly half of the records set across the three month summer. For the month, 2,212 record low maximum temperatures were recorded and 737 were tied. 1,225 new record low temperatures were recorded and 657 records were tied.

There's more to this story on the Denver Weather Examiner's site!For all the details on the United States’ summer weather including NOAA’s summary and a look back at the country’s August weather, go to Examiner.com.

Climatology, Thornton Weather

August 2009 climate and weather preview posted

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Thorntons August weather preview.
Thornton's August weather preview.

As summer vacations wind down and families prepare to send their kids back to school in August, Colorado weather also starts to settle down. The chances for severe weather decrease markedly during August and by the end of the month daytime temperatures are dropping quite a bit as well.

At the start of the month Denver usually averages around 88 degrees for a high temperature. By the end of August that drops to 82 degrees. Similarly, nighttime lows drop from 60 to 53 from the start to the end of the month. Generally clear skies can be expected between midnight and noon but the afternoon often brings showers and thunderstorms. These storms typically develop over the foothills then bring precipitation to the Denver metro area.

Despite that moisture, the chance for severe weather decreases considerably compared to the first two months of summer. Cooler air near the surface helps to create a stable atmosphere thus keeping thunderstorms from usually becoming too intense. After the middle of August, tornadoes and damaging hail are pretty rare. The slow movement of storms this time of year are more likely to produce potentially heavy rain.

Click here to read the complete preview including a look back at what was a record setting month last year.

Climatology, Thornton Weather

A Preview of Thornton’s July Weather – A Stormy Month

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Change is of course the one constant in Denver’s weather but come July, things actually get pretty consistent. The standard formula for a day in July is a sunning morning, clouds developing in the late morning and early afternoon. Come mid-afternoon, thunderstorms are rolling off of the foothills and into the metro area and the eastern plains. These storms do occasionally reach severe status containing hail, gusty winds and heavy downpours of rain.

In fact, the worst hail storm on record in Denver history hit western sections of the city on July 11th, 1990. Baseball and softball sized hail from this ferocious storm caused millions of dollars worth of property damage.

July is the most stormy month of the year in fact with thunderstorms occurring on average 11 days per month – or once every three days. These slow moving storms are one of the reasons July is Denver’s second rainiest month with an average of 2.16 inches of rain (second only to May). However, these storms are also often very localized and cause widely varying precipitation amounts across the metro area. It is not unusual for one area of down to be deluged while others remain entirely dry. With these severe storms, flash flooding remains a possibility.

View the complete July 2009 preview along with a look back at July 2008 here.

Climatology, Thornton Weather

June 2009 is now the 2nd wettest Denver June

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From the National Weather Service: June 2009 has moved into the second wettest June since Denver weather records began in 1872.  So far for June 2009, through June 26th, the Denver International Airport (DIA) has measured 4.86 inches of liquid (and there are still 4 more days left in June).  The 4.86 inches of water is 3.52 inches above normal through the 26th.  Last year, June 2008 had only measured 0.73 inch again through the same June time frame.

The wettest June on record for Denver was in June 1882 when 4.96 inches of moisture was collected in the rain bucket.

For the 2009 year so far, 10.38 inches of water has been measured at DIA which is a very impressive 2.51 inches above the normal through June 26th.   Last year in June, only 3.04 inches had been recorded through the same time frame.

Note:  The average Denver annual precipitation is 15.81 inches.

As always, we have to ask, do Denver weather and climate records have an asterisk attached?  Read our Examiner.com investigation to see why maybe they should.

Climatology, Thornton Weather

A Preview of Thornton’s June Weather – The Severe Weather Month

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Denver is historically Thornton's true severe weather month.
Denver is historically Thornton's true severe weather month.

June is historically Denver’s severe weather month and severe thunderstorms, tornadoes and hail are notorious visitors to Denver and across eastern Colorado during the month.  In fact, over 40 percent of the tornadoes that occur in Colorado are observed in June and these are typically the most destructive of the year.  Severe thunderstorms have also caused major property damage across the Front Range during the month.

In just the last 25 years or so, there have been some particularly notable storms in June.  Tornadoes have struck the metro area including one that longtime Thornton residents will recall on June 3, 1981.  53 residents were injured, 25 homes were destroyed and 239 other structures were damaged.  Others tornadoes in the metro area include southeast Denver and Aurora on June 8, 1986 and east Denver on June 13, 1984.  Severe thunderstorms occurring on June 13, 1984 dumped large hail making it one of the worst and the second costliest storm in Denver history.  More recently, on June 20, 2001, a major hail storm moved across Denver International Airport dropping hailstones as big as two inches in diameter. Damage was extensive on and near the airport.

For complete details on what we can expect in June, click here to view our June weather preview.

Climatology, Thornton Weather

Denver officially breaks high temperature record for this date

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Denver set a temperature record for today, May 19.
Denver set a temperature record for today, May 19.

It’s official.  At 1:24pm today the temperature at Denver International Airport reached 90 degrees setting a new record high temperature for May 19.  This breaks the previous record high for this date of 89 degrees set in 2006. 

Wtih some cloud cover moving in and a chance for thunderstorms in the forecast, it appears that is as high as the mercury will climb today. 

But is it truly a record?

One does have to wonder though, is it truly fair to call this a record?  When the National Weather Service moved Denver’s official monitoring station from Stapleton to Denver International Airport, some say the city’s climate records were forever altered.  For more information and analysis of the controversy, check out this story:  Do Denver weather and climate records have an asterisk attached?