As temperatures start to drop, September reminds us that summer is at an end and fall is now here. Sunshine is predominant though as the month actually has the highest percentage of sun out of any month. Sunny days and clear, cool nights are the standard weather pattern for the month.
Normal highs on the first of the month are 82 degrees with a low of 53. By the end of the month we see those high temperatures drop to an average of 73 and the lows get to a chilly 42. Overall the month averages 63.4 degrees.
Denver has broken or tied seven different warm weather temperature records this month.
With the arrival of August we typically see a decrease in daytime high temperatures making the month one of the more pleasant in Denver. This year however that has not been the case as we have seen records fall and we appear on our way into the record books with one of the hottest Augusts on record.
With three days remaining in the month, Denver has tied or broken seven warm weather temperature marks so far. These include:
August 18 – Denver ties the record high temperature for the date of 98°. The mark was last set in 1986.
August 23 – The high temperature at DIA hits 98°. This ties the record high for the date last set in 2009.
August 24 – Denver hits 98°. Breaks old record of 97° set in 1936
August 25 – Denver reaches 99°. Breaks old record of 96° set in 1913. Also marks the latest date in the year that Denver’s temperature reached 99 degrees. Previously the date was August 16.
August 28 – Denver tops out at 96°. Breaks old record of 94° set in 1969 and previous years
August 28 – The mercury only drops to 67° over the 24 hour period. This sets a new record high minimum for the date. The previous record was 66° set in 2010 and previous years.
One important aspect to these records is that most of those marks would never have been reached were it not for the measurements being taken at DIA. Other station’s closer to the historical Denver weather sites near Stapleton and downtown never approached as warm of temperatures.
One high temperature record was tied and another broken over the past two days.
If you thought with the kids heading back to school summer was coming to an end Mother Nature has other plans. The hot weather continues and in the past two days it has reached record setting heights.
Yesterday, August 23rd, Denver hit a high temperature of 98 degrees as measured at Denver International Airport. This tied the previous record high for the date last set in 2009 and previous years. Thornton fared a bit cooler as we ‘only’ reached 96 degrees.
Despite forecasts calling for cooler temperatures today, the mercury just kept on climbing and topped out at 98 degrees at 3:17pm. This broke the old record high temperature of the date of 97 degrees set 75 years ago in 1936. Mercifully, Thornton again was cooler with a high of 95 degrees.
As with all Denver records since 1995 when the National Weather Service moved the city’s official monitoring station to DIA, the records come with an asterisk. That move of 12 miles has resulted in consistently higher temperatures than what is seen at the historical site at Stapleton or closer to downtown.
Another official station, located at Denver City Park, provides evidence of this over the last two days. The station is much closer to where historical records were taken and thus can be more accurately used to compare to the past.
That station recorded a high of 97 degrees yesterday and 95 degrees today. Neither of these would be records had Denver’s station not made the move to a different microclimate at DIA.
This video screen capture shows the stage at the Indianapolis State Fair as it collapsed. Watch the video below. (YouTube / JSilas7)
Winds alone are not normally associated with the loss of life but a sad reminder of the dangers was seen at the Indianapolis State Fair on Saturday. Powerful thunderstorm winds downed a stage killing five people and injuring dozens while officials appeared to ignore warnings of the impending danger.
The Natural Disasters Examiner wrote in a story on Monday that the warning signs for severe weather in central Indiana were readily apparent as early as two days before the storm.
The National Weather Service discussed the thunderstorm and high wind dangers in its Hazardous Weather Outlook multiple times. A Severe Thunderstorm Watch was issued hours before and a Warning 10 minutes before.
Despite this, officials at the fair failed to make a timely decision to cancel the Sugarland concert. When the winds, estimated at 50 to 70mph struck, it only took a matter of seconds for the stage’s rigging to collapse. Five people died and more than 40 were injured due to their failure.
The tragedy should serve as a reminder to everyone to pay attention to changing weather. Do not ignore weather watches and warnings, no matter what others are doing. The life you save may be your own.
The video below captures the event with shocking clarity. It may be disturbing for some so viewer discretion is advised.
Our hearts and prayers go out to all those affected by the tragedy.
July 2011 was much wetter and slightly warmer than normal. (ThorntonWeather.com)
Historically July is a pretty busy month in terms of weather as thunderstorms are very common. July 2011 lived up to the month’s reputation as the middle of the month saw a seemingly endless stream of heavy, wet thunderstorms. This was followed by a string of 90 degree and warmer days that approached record setting territory.
The big story for the month was the precipitation as there was a lot of it. DIA saw sixteen thunderstorms during July, five more than normal. The official Denver monitoring at the airport recorded 3.41 inches of rain which was well above the normal of 2.16 inches. The measurement fell just shy of making the list of top 10 wettest July’s on record.
The station at DIA however lived up to its reputation as under-reporting rainfall as compared to locations closer to downtown. In fact, a station the old Stapleton site recorded 6.54 inches. Here in Thornton 5.51 inches fell into our rain bucket.
One precipitation record was set during the month when 1.03 inches of rain fell on the 13th. This easily bested the previous 24 hour record for the date of 0.45 inch set in 1993.
Temperatures for the month were considerably above normal but fell short of ‘top 10’ status. The average temperature for the month, as recorded at DIA, was 75.9 degrees. This was 2.5 degrees above the normal of 73.4.
The warmest temperature of the month occurred on the Fourth of July when the mercury climbed to 99 degrees. On the opposite end, 56 degrees on the 1st of the month was the coldest reading.
In all, 20 days saw temperatures at or above 90 degrees during July 2011; five more than normal. July 15th started a string of 18 consecutive days of 90 degree or warmer high temperatures. That streak will go into the books as tying for the second longest in history.
Thornton, like most other places in the metro area, was not near as warm. Our average temperature was 73.8 degrees, right near normal. Our warmest temperature occurred on the 4th as well and matched Denver’s mark of 99 degrees. The mercury dipped to 53.6 degrees on the 1st and was our coldest temperature.
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JULY 2011...
CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2011
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 105 07/20/2005
LOW 42 07/04/1903
07/31/1873
HIGHEST 99 07/31 105 -6 102 07/17
07/04
LOWEST 56 07/01 42 14 53 07/09
07/05
07/04
AVG. MAXIMUM 91.1 88.0 3.1 89.3
AVG. MINIMUM 60.7 58.7 2.0 59.5
MEAN 75.9 73.4 2.5 74.4
DAYS MAX >= 90 20 15.0 5.0 18
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 6.41 1965
MINIMUM 0.01 1901
TOTALS 3.41 2.16 1.25 3.70
DAILY AVG. 0.11 0.07 0.04 0.12
DAYS >= .01 11 9.3 1.7 13
DAYS >= .10 7 MM MM 5
DAYS >= .50 2 MM MM 2
DAYS >= 1.00 2 MM MM 2
GREATEST
24 HR. TOTAL 1.08 07/12 TO 07/13 1.84 07/04/10 TO 07/04/10
SNOWFALL (INCHES)
RECORDS
TOTAL 0.0 NONE EVER RECORDED IN JULY
TOTALS 0.0 0.0
DEGREE_DAYS
HEATING TOTAL 0 1 -1 3
SINCE 7/1 0 1 -1 3
COOLING TOTAL 346 261 85 303
SINCE 1/1 481 422 59 482
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
......................................................
WIND (MPH)
AVERAGE WIND SPEED 9.5 9.1
RESULTANT WIND SPEED/DIRECTION 3/181 MM
HIGHEST WIND SPEED/DIRECTION 51/210 DATE 07/13 41 07/30/10
HIGHEST GUST SPEED/DIRECTION 68/300 DATE 07/14 48 07/30/10
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.50
NUMBER OF DAYS FAIR 6
NUMBER OF DAYS PC 22
NUMBER OF DAYS CLOUDY 3
AVERAGE RH (PERCENT) 50
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 0 MIXED PRECIP 0
HEAVY RAIN 4 RAIN 6
LIGHT RAIN 17 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 4
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 5 FOG W/VIS <= 1/4 MILE 0
HAZE 4
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
Hot or cold: Denver's problematic weather records. (Denver Weather Examiner)
Does a move of 12 miles make a difference in what type of weather is seen in Colorado? Longtime residents know that our weather can vary greatly over short distances and this has many questioning the placement of Denver’s official weather monitoring station.
From 1871 to 1949 Denver’s weather was recorded at the National Weather Service’s office in downtown Denver. In January 1950 a move was made to Stapleton International Airport.
As that facility aged Denver opened Denver International Airport on the plains northeast of Denver in 1995. The weather service followed suit and moved the Mile High City’s official weather station the 12 miles to DIA.
Since that time, many weather watchers have noticed problems – DIA is consistently warmer and drier than the old site at Stapleton. Further, its remote location gives conditions far from where most people in Denver live and thus doesn’t accurately represent what they are experiencing.
Even bigger issues arise when comparing weather data taken today with measurements previously recorded at Stapleton or downtown. The different microclimates of the sites are so different that it becomes much like comparing apples and oranges.
This was recently made evident with the string of 90 degree or warmer days we put together. If you went by the station at DIA, the streak lasted 18 days putting in a three way tie for the second longest streak in Denver history. However, no monitoring station closer to the city was as warm.
Further, while July was certainly a wet month, DIA’s precipitation measurements fell far short of most other locations.
Amid concerns about a warming climate, can we trust the measurements at DIA? How is it possible to compare the weather today with historical weather when there is such a large discrepancy?
We recently tackled this topic on the Denver Weather Examiner and the conclusion is obvious – It simply is impossible to correlate current weather records with Denver’s historical ones. Further, the National Weather Service seems intent on ignoring the issue.
Denver easily broke the 24 hour precipitation record for July 13th.
It is readily apparent that July has thus far been a wet month given that we have seen eight straight days of thunderstorms. Yesterday the storms set a record for precipitation and Denver is on pace to make the month one of the wettest Julys on record.
Out at Denver International Airport yesterday, 1.03” of precipitation was recorded. This set the record for the date easily besting the old record of 0.45” set in 1993.
Here in Thornton we recorded 0.45” yesterday so a good bit less than out at the airport but still a decent shot of precipitation.
This brings Denver’s official total to 3.19” for the month so far. Average for the entire month of July is 2.16” so we are far ahead of that.
Number 10 on the ‘top 10 wettest Julys’ occurred in 1985 with 3.71”. Given the fact that the forecast continues to contain daily thunderstorms for the foreseeable future, there is a good chance we will exceed that before the month is over.
Thornton is ahead of the game in comparison to DIA as we have recorded 4.52” so far this month.
Lightning strikes east of 120th Avenue and Fairfax during Tuesday night's storms. View more images in the slideshow below. (ThorntonWeather.com)
For eight days in a row monsoonal flow fed thunderstorms have struck Thornton and Tuesday night brought arguably the best show yet. Heavy rain, hail, gusty winds and an extraordinary amount of lightning roused residents soon after nightfall.
Storms initially formed in the afternoon and were focused south of Denver in Elbert County. Near Kiowa, Elizabeth and Agate hail up to 1 3/4” in diameter was recorded. The slow-moving storms deposited as much as five inches of rain near Agate. Three twisters were reported in Elbert County but no damage was realized.
It appeared for a time that Thornton was going to escape the intense weather but once the sun went down the picture changed dramatically. Seemingly out of nowhere a storm cell popped up at around 9:20pm and moved across the north Denver metro area.
Heavy rain fell across a large part of the area from downtown northward to Thornton. 1.76 inches of rain was recorded north of downtown Denver at DenverWX.com as the storm passed through.
Street flooding was reported across the surrounding areas causing difficulty for motorists.
Here in Thornton we were pounded with heavy rain and a great deal of pea-sized hail. ThorntonWeather.com recorded its first inch of rain in only 14 minutes and the storm total for the overnight storm was 1.90 inches.
Strong winds also brought down trees and power lines knocking out power to nearly 10,000 Denver area residents including some in Thornton. Xcel Energy reports power has been restored to most areas this morning.
Denver International Airport recorded a thunderstorm wind gust of 66mph shortly before 10:00pm. A ground stop was issued and all flights were temporarily delayed while the storm moved through.
Forecasters had predicted a late and shorter than normal monsoon season due to La Niña’s lasting effect – that however has not proven to be true.
A common scene this past week - thunderstorms develop over the Denver area. Watch video of the recent street flooding in Thornton below. (Twitpic / CodyCrouch)
La Niña is winding down and normally we would expect a drier than normal monsoon. Mother Nature however has other plans as she not only brought the season to Thornton early, it came with a vengeance this week.
In a presentation that just came out at the first of the month, the National Weather Service discussed the coming monsoon. At that time forecasters predicted a drier and shorter than normal monsoon for the Colorado Front Range. Thus far it has been anything but.
This past week copious amounts of moisture have streamed into Colorado. Coupled with daytime heating leading to a good deal of atmospheric instability, thunderstorms have been a daily occurrence. Strong winds and heavy rain have occurred virtually daily.
Over the past five days Denver has recorded 1.78 inches of rain at the city’s official monitoring station at Denver International Airport. Closer to where population actually lives even greater amounts have been seen.
On Friday evening, a slow-moving thunderstorm dumped heavy rain on the southern parts of Thornton. Video footage from storm chaser Tony Laubach (below) shows the end result as streets in the area of I-25 and 84th Avenue were flooded.
Is there an end in sight? Not in the immediate future. For at least the next few days atmospheric moisture will continue to be in abundance and we will continue to see the same general pattern. By mid-week we may see some drying but we can’t entirely eliminate the threat of afternoon thunderstorms.
Thornton’s June 2011 weather was a relatively typical one with average temperatures but also with above normal precipitation. The month also signifies the official end of the 2010 to 2011 snow season which was absolutely dismal.
In terms of temperatures Denver saw an average temperature for the month of 68.2 degrees. This was just a bit above the normal of 67.6 degrees. Temperatures ranged from a high of 96 degrees on the 28th and 29th down to a low of 45 degrees on the 10th. DIA recorded seven days with 90 degrees or higher temperatures which is one above normal. No temperature records were set for the month.
Here in Thornton we came quite close to mirroring Denver’s official temperatures. Our average temperature was 68.1 degrees with the highest mercury reading of 96.4 degrees coming on the 29th. The lowest temperature in Thornton came on the 3rd at 45.4 degrees.
Precipitation for the month was above normal as DIA’s rain bucket recorded 2.43 inches. This was 0.87 inch above the normal of 1.56 inch and the second month in a row with above normal precipitation. In all, eight days had measurable precipitation and DIA reported thunderstorms on 10 days which is average.
One precipitation record was set during the month when 1.05 inches of rain was recorded on the 20th. This beat the old record for the date of 0.50 inch set in 1939.
We were quite a bit drier in Thornton as our precipitation for the month fell below the Denver normals. We recorded 1.14 inches for the month with the majority of that, 0.87 inch, falling on the 20th.
Denver’s snow season runs from July 1 to June 30 and with the end of the 2010 to 2011 season the numbers show just how poorly we faired in terms of snowfall. The Mile High City recorded a mere 22.8 inches of the white stuff at DIA. This is a whopping 38.9 inches below the normal of 61.5 inches. The season will go into the record books as the second least snowiest snow season since Denver began keeping records in 1882.
Here in Thornton we did not fare any better than Denver on the snowfall front. Our season wrapped up with a dismal 21.2 inches.
Denver, Colorado June 2011 Climate Summary
CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2011
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 104 06/26/1994
LOW 30 06/02/1951
HIGHEST 96 06/29 104 -8 99 06/25
06/28
LOWEST 45 06/10 30 15 47 06/23
06/18
06/14
06/12
AVG. MAXIMUM 83.3 82.1 1.2 84.1
AVG. MINIMUM 53.0 53.0 0.0 53.6
MEAN 68.2 67.6 0.6 68.9
DAYS MAX >= 90 7 6.3 0.7 10
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 4.96 1882
MINIMUM T 1890
TOTALS 2.43 1.56 0.87 1.60
DAILY AVG. 0.08 0.05 0.03 0.05
DAYS >= .01 8 8.7 -0.7 5
DAYS >= .10 4 MM MM 3
DAYS >= .50 2 MM MM 2
DAYS >= 1.00 1 MM MM 0
GREATEST
24 HR. TOTAL 1.55 06/19 TO 06/20 1.25 06/11 TO 06/12
SNOWFALL (INCHES)
RECORDS
TOTAL 0.4 1919
TOTALS 0.0 T
DEGREE_DAYS
HEATING TOTAL 26 60 -34 38
SINCE 7/1 5707 6128 -421 6441
COOLING TOTAL 126 136 -10 163
SINCE 1/1 135 161 -26 179
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
.................................................
WIND (MPH)
AVERAGE WIND SPEED 10.4
RESULTANT WIND SPEED/DIRECTION 3/148
HIGHEST WIND SPEED/DIRECTION 48/190 DATE 06/29
HIGHEST GUST SPEED/DIRECTION 72/200 DATE 06/29
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.50
NUMBER OF DAYS FAIR 7
NUMBER OF DAYS PC 21
NUMBER OF DAYS CLOUDY 2
AVERAGE RH (PERCENT) 45
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 0 MIXED PRECIP 0
HEAVY RAIN 3 RAIN 2
LIGHT RAIN 10 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 1
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 4 FOG W/VIS <= 1/4 MILE 0
HAZE 6
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
Weather, natural disasters & climate news and information.
As temperatures start to drop, September reminds us that summer is at an end and fall is now here. Sunshine is predominant though as the month actually has the highest percentage of sun out of any month. Sunny days and clear, cool nights are the standard weather pattern for the month.
Thornton’s June 2011 weather was a relatively typical one with average temperatures but also with above normal precipitation. The month also signifies the official end of the 2010 to 2011 snow season which was absolutely dismal.