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UpdatedTue, 29-Jul-2014 6:40am MDT 


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July 2014 top shots: Monthly photo slideshow

Monday, July 28th, 2014 5:38am MDT
July 3, 2014 - A gorgeous July sunset. (LE Worley)

July 3, 2014 – A gorgeous July sunset. (LE Worley)

The month of July typically brings a pretty tried and true daily weather pattern with hot days and afternoon thunderstorms.  Like any month of the year in Colorado, a wide variety of subjects will be presented for photo opportunities.

Flowers are now in full bloom, wildlife is abundant with many creatures showing their young for the first time, and then of course there is the weather.  Scorching heat, damaging thunderstorms, heavy rains and more are all possible during the month.

  • Slideshow updated July 28, 2014
  • To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather-related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

Click the play button below and sit back and enjoy the images.

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

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July 27 to August 2: This Week in Denver Weather History

Monday, July 28th, 2014 5:36am MDT
This Week In Denver Weather History

July 27 to August 2: This Week in Denver Weather History

The end of July and beginning of August has historically been a rather active one. Looking back at the history books, deadly and damaging lightning, heavy monsoon rains and extreme heat are the dominate extremes we have seen.

From the National Weather Service:


In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.


In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.
26-27 in 1885…heavy cloudbursts on the palmer divide south of Denver caused flooding on Cherry Creek in the city overnight. The high water washed away street and railroad bridges and a few houses. The flood waters completely inundated the rail yards in lower downtown. This was the worst flood on Cherry Creek since May 19-20…1864…but the damage was mitigated by stream improvements and fewer structures near the channel. There was also no simultaneous flood on the South Platte River to slow the flow of water through the city. Rainfall in the city was only 0.08 inch on the 26th.


In 1897…an apparent dry microburst produced sustained west winds to 48 mph with gusts to 60 mph and a trace of rain.

In 1901…a thunderstorm produced north winds to 38 mph with gusts to 41 mph and rainfall of only 0.01 inch in downtown Denver. This was the only measurable rainfall of the month… Making this the driest July on record.

In 1953…an unconfirmed tornado in south Lakewood touched down briefly and abruptly dissipated. No damage was reported from the twister.

In 1955…the public sighted a funnel cloud estimated at 500 feet above the ground near the western edge of Lowry Field. Wind estimates up to 60 mph were reported in the vicinity.

In 1956…a severe thunderstorm produced 3/4 inch diameter hail and wind gusts to 48 mph at Stapleton Airport where rain fall totaled 1.08 inches.

In 1965…a tornado was sighted 21 miles south of Denver in Douglas County. No damage was reported.

In 1977…a thunderstorm wind gust to 51 mph was recorded at Stapleton International Airport. A funnel cloud was sighted by an aircraft east of Parker.

In 1982…heavy rain doused Boulder with 1 1/2 to 3 inches of rain over a short period of time…causing extensive street flooding.

In 1984…strong thunderstorms drenched several areas. Rainfall of 1.04 inches occurred in just 20 minutes at Boulder. Downpours also hit Aurora and northeast Denver… Delaying flights at Stapleton International Airport for an hour. Up to 3/4 inch of rain fell in central Aurora in 15 minutes.

In 1989…lightning hit a home in Littleton…setting a bed on fire. Damage was confined to the bedroom.

In 1994…lightning struck a furniture store in Boulder… Igniting a fire which caused major damage to the building and contents.

In 1997…lightning sparked a fire…causing extensive damage to a home in Watkins. Heavy rain caused Lena Gulch to surge 2 feet over its banks in Golden. The fire department had to rescue a man when his van stalled in high waters. High waters from swollen creeks and streams washed out bridges and several sections of road in southeast Aurora. A 200-to-300 foot section of road was washed away where Picadilly Street dips across Coal Creek. Three youths had to be rescued when they became stranded by rapidly rising water in another normally dry creek bed.

In 1999…lightning was suspected of igniting a fire which caused substantial damage to a farm in Hudson. The blaze destroyed a 10-foot by 60-foot metal pole barn…a pick-up truck…a SUV…a boat and trailer…3 four wheeler vehicles… And other farm equipment.

In 2007…a man was struck and killed by lightning while jogging at Matthews Winters Park in Morrison.


In 1956…96 percent of the total precipitation for the month of July occurred over the last five days of the month. Heavy thunderstorms produced 4.00 inches of rainfall at Stapleton Airport. This amount of precipitation in 5 days or less had been exceeded only 3 times in previous record. The last time had been in December of 1913 as snow. Considerable property damage occurred across metro Denver from flooding.


In 1882…intense thunderstorm lightning struck a number of places in the city…but no significant damage was reported.

In 1910…heavy thunderstorm rainfall totaled 2.21 inches in downtown Denver. Rainfall was 1.11 inches in an hour during the early afternoon.

In 1922…heavy rainfall to the south of Denver caused Cherry Creek to rise to the top of the retaining walls in the city. The creek did not flood; however…the large volume of water discharged into the South Platte River did inundate a few blocks of Globeville. Flooding also occurred along bayou creek near Franktown to the south of the city.

In 1923…thunderstorm winds were sustained to 38 mph with gusts to 52 mph.

In 1957…iridescent cirrocumulus clouds of unusual formation and brilliant color…oriented from southwest to northeast over metro Denver…were sighted by U.S. Weather Bureau observers at Stapleton Airport shortly after noon.

In 1966…heavy rains from a severe thunderstorm caused flash flooding on Deer Creek…southwest of Littleton. A child was injured when washed from a car caught in the flood waters. The flooding damaged property along the creek. Strong winds damaged several houses in suburban Littleton.

In 1970…a microburst wind gust to 52 mph was recorded at Stapleton International Airport.

In 1974…a tornado was sighted just east of Buckley Field in Aurora. No damage was reported.

In 1982…up to 2.50 inches of rain drenched an area just southwest of Denver in 30 minutes. This was the second day of heavy rain across portions of metro Denver.

In 1984…1.25 inches of rain fell in 45 minutes in Arvada. Minor flooding occurred on Bear Creek after a small dam broke.

In 1989…lightning killed two men in Arvada. They were taking wash from a clothesline when a bolt hit the older man…39… Killing him instantly. The bolt then traveled along the line…which was stretched between 2 tall trees…and hit his 26-year-old brother who died the next day.

In 1996…several weak tornadoes developed along a thunderstorm outflow boundary that moved into southern weld…northern Jefferson…and Adams counties. The tornadoes sighted near Bennett…Barr Lake…and in Arvada caused little damage. Strong thunderstorm winds downed several trees in the city of Denver and toppled several trees 7 miles west of Arvada where shingles were blown off several houses. Thunderstorm wind gusts reached 58 mph in Broomfield.

In 1997…a weak tornado touched down briefly in Parker… Damaging a greenhouse. Twenty pieces of the fiberglass roof were ripped away. Heavy rainfall in the foothills washed out some culverts in the pine and Conifer areas. Heavy rainfall spread over the plains with 4 to 7 inches reportedly falling near Hudson. Several County roads were washed out between Fort Lupton and Hudson. Several basements in the area were flooded up to the ceiling. Standing water…up to 3 feet deep…was reported in some backyards. Later in the evening…a flash flood killed 5 people and injured 40 others in two mobile home parks in Fort Collins. The torrential rainfall also caused extensive damage on the Colorado state university campus. Thunderstorm rainfall totaled 0.80 inch at Denver International Airport and 1.09 inches at the site of the former Stapleton International Airport.

In 1999…heavy rainfall…up to 3 inches an hour…triggered a massive rock and mudslide along I-70 near Bakerville. The slide area was about 200 feet wide and 20 feet deep. Several other smaller slides were also reported along the highway. As a result…I-70 was closed for nearly 25 hours in both directions until the debris could be cleared from the roadway. The blockage of I-70 was one of the longest in the history of the highway in Colorado. A severe thunderstorm produced a wind gust to 64 mph at Denver International Airport. The storm also produced 1.56 inches of rain and briefly reduced the visibility to 1/4 mile.

In 2004…a severe thunderstorm produced hail as large as 1 inch in diameter in Thornton.

In 2010…a wet microburst produced very heavy rain and torrential hail in Boulder County…in the vicinities of Caribou…Nederland and Eldora. Flash flooding washed out sections of County roads 126 and 128 near Caribou. Several large boulders had fallen across the roadways. Considerable flooding was reported in Nederland. Water was also observed running across County Road 130…between Eldora and Nederland. The hail had accumulated up to 8 inches deep near Eldora. Several vehicles were stuck in the ice…forcing the temporary closure of cr130 and the Lake Eldora ski road until snowplows could clear away the hail. Lightning strikes caused minor damage to two local businesses in Nederland. At Denver International Airport…a thunderstorm produced 0.30 inches of rain along with a peak wind gust to 38 mph.

In 2012…a tornado touched down briefly at the southeast corner of Mt. Evans near Lincoln Lake. The estimated elevation where this tornado touched down was near 12500 feet. This would make this tornado one of the highest ever observed in the U.S.


In 1889…dense smoke from forest fires in the mountains obscured the sun over the city for three days.

In 1971…a vigorous cold front late on the 28th produced northeast wind gusts to 39 mph and record breaking cold temperatures on the 29th and 30th. The temperature dipped to 47 degrees on the 29th and 43 degrees on the 30th… Setting record minimums for the dates. Upslope cloudiness along with rain and fog early on the 29th helped set a record low maximum temperature of 58 degrees for the date.

» Click here to read the rest of July 27 to August 2: This Week in Denver Weather History

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Cooler, unsettled weather starts off a workweek that will offer more of the same

Monday, July 28th, 2014 5:06am MDT

The last week of July is going to see a departure from the hot weather we have been seeing.  Cooler than average temperatures and decent chances for showers and thunderstorms will be the rule through this coming weekend.

For Monday we expect a day similar to what we saw yesterday.  There will be a good bit of cloud cover above and we will be heading for a high temperature in the mid-80s.

Scattered thunderstorms are again expected to develop this afternoon and evening.  Unfortunately most of the activity is again expected to be to our south and southwest.  However a stray storm in our area would not be surprising.

For the balance of the week, look for temperatures to be even cooler with daily highs in the upper 70s / low 80s.  Right now it looks like there will be better chances for widespread showers, especially Tuesday and Wednesday.

See the image for today’s outlook and check out the extended Thornton weather forecast here.

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Thornton’s Friday and weekend to feature two hot days, then cooler temps arrive

Friday, July 25th, 2014 6:36am MDT

Are you tired of the recent heat?  If so then hang on for a couple more days – a trend toward cooler mercury readings is set to arrive.

For Friday we are going to close out the workweek with temperatures right near the average for the date of 90 degrees.  Partly sunny skies will be above.  Thunderstorms and showers are again expected to develop this afternoon, possibly with greater coverage than what we saw yesterday.  Gusty winds and brief heavy rain will be possible.

Saturday will see more sun above and temperatures a degree or two warmer than today.  PM thunderstorms will again be possible but are expected to be more isolated than what we see today.

A cold front will be moving in later Saturday and that is going to bring the break from the heat.  In fact, over the longer term, those colder temperatures are expected to linger well into next week.

Sunday’s high temperatures are expected to be in the mid-80s and we will have a slight chance for thunderstorms.  For much of the next workweek, highs will remain cooler than normal, many days only around 80 degrees.

See the image for your weekend weather outlook and monitor http://www.thorntonweather.com throughout the period for the latest.

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July 20 to July 26: This Week in Denver Weather History

Friday, July 25th, 2014 5:50am MDT
This Week In Denver Weather History

July 20 to July 26: This Week in Denver Weather History

Heavy rain events become more commonplace as we get further into Colorado’s monsoon season. Our look back at this week in Denver weather history contains many examples of the damage these fast-moving events can cause.

From the National Weather Service:


In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.


In 2008…a streak of 24 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874. Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.


In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.


In 2005…the high temperature climbed above 100 degrees on each of the 5 days with readings of 101 on the 19th…105 on the 20th…104 on the 21st…and 102 on both the 22nd and 23rd. A new record maximum temperature for the month of July of 105 degrees was set on the 20th…which also equaled the all-time record maximum for Denver of 105 degrees first set on August 8th in 1878. Daily maximum temperature records were set on each day…and the 5 day period equaled the record for the most consecutive days of 100 degrees or more first set from July 4th through 8th in 1989. The intense heat resulted in a high use of electricity for cooling purposes. The demand for electric power exceeded the supply and rolling black-outs… Each lasting about an hour…were scheduled across metro Denver during the afternoons and early evenings.


In 1898…an apparent thunderstorm produced sustained northwest winds to 45 mph with gusts to 51 mph.

In 1939…the high temperature reached 102 degrees in downtown Denver. This was the highest temperature recorded since August 8…1878…a period of 61 years…and the third highest temperature of record at the time. Six miles to the east… At Denver municipal airport…the maximum temperature reached 104 degrees. A dry period during mid-July…combined with low relative humidities…resulted in an unusually large number of forest fires in the mountains west of Denver.

In 1941…an afternoon thunderstorm caused two lightning deaths. The men were struck by lightning near the Denver airport.

In 1951…a thunderstorm wind gust to 54 mph was recorded at Stapleton Airport.

In 1965…heavy rain west of Denver damaged roads and bridges. Two bridges in Golden were washed out. Lightning in Denver caused some power failures and fires…mostly in the northeast section of the city. Heavy rain caused street flooding in the city of Denver. Hail as large as 1/2 inch in diameter and 0.40 inch of rain in 5 minutes were measured at Stapleton International Airport where precipitation totaled 1.09 inches. Lightning damaged a house in Littleton…and caused a power outage in Idaho Springs.

In 1973…lightning damage was reported west of Arvada.

In 1975…heavy rains caused flash flooding across metro Denver…resulting in the closing of several streets and damage to numerous homes and businesses. Hail 1/2 to 3/4 inch in diameter was reported.

In 1976…heavy thunderstorms caused flooding of streets in southeast Denver and western Arapahoe counties. A total of 3.35 inches of rain was measured at Kassler southwest of Littleton.

In 1978…a girl was injured by lightning at a country club southwest of Denver.

In 1984…heavy rain was reported just east of Buckley Field in Aurora where 1.15 inches fell in just 45 minutes.

In 1986…thunderstorms dumped heavy rain across metro Denver causing extensive street flooding…power outages…and basement flooding. The greatest recorded rainfall was 4.39 inches in Lakewood. In extreme northwest Denver…2.29 inches of rain fell in just 20 minutes. Arvada was drenched with 2.60 inches of rain…and over an inch fell in southeast Denver and adjacent sections of Aurora.

In 1990…heavy thunderstorm rains caused flash flooding in sections of Littleton where 1.20 inches of rain fell in less than 30 minutes. The deluge caused dry creek to jump its banks…causing damage to residential streets…curbs…and sidewalks. Nearly 100 vehicles were stranded for a time in fender-deep water when sewers and drainage ditches became choked with debris. The heavy runoff submerged many Littleton streets and intersections.

In 1992…strong thunderstorms moved slowly through east metro Denver…producing rainfall up to 2.50 inches in a short time. Weather spotters reported 0.75 to 1.00 inch of rain in less than 30 minutes. Many areas of southeast Denver were flooded…including I-25 where up to 6 feet of water filled some underpasses. Hail to 3/4 inch in diameter fell in Aurora.

In 1995…a tornado touched down briefly in an open field near Strasburg. Thunderstorm winds gusted to 58 mph at Centennial Airport.

In 1996…strong thunderstorm winds damaged the building of a telephone installation company in the city of Denver.

In 1998…the high temperature reached 100 degrees at Denver International Airport.

In 2006…heavy rainfall in the overland wildfire burn area caused minor flash flooding in Jamestown. The roads behind the Jamestown fire hall were washed out…when a culvert was blocked by debris. A rockslide was also reported in town.

In 2009…a severe thunderstorm produced damaging winds…large hail and very heavy rain across the western and southern suburbs of Denver. Widespread damage was observed in the cities of Arvada…Lakewood and Wheat Ridge. The intense straightline winds were the result of a wet microburst which downed hundreds of trees and snapped power poles. Wind gusts to 80 mph were reported along with hail up to 1 3/4 inches in diameter. The combination of wind and hail caused widespread damage to homes and vehicles. The damage claim estimates totaled 350 million dollars; about 32900 claims were filed for homes…while another 19500 claims were filed for vehicles. As many as 90000 homes and businesses were left without power. In some areas it took up to 3 days to completely restore electrical service. Minor injuries were reported from broken glass during the storm…but no one was hospitalized. The storm crippled the computers at the Colorado crime information center in Lakewood for nearly 3 hours. One weak tornado touched down near Parker but did no damage. In southern Weld County… Severe thunderstorms produced widespread damage over 150 square miles of farmland. In all…400 farms were directly impacted by severe weather. Damage to crops alone was estimated to 3 million dollars. At Denver International Airport…a peak wind gust to 48 mph was observed from the northeast. In addition…1.01 inches was measured at the airport.


In 1961…unusually cool weather for July resulted in several temperature records. Record minimum temperatures were set or equaled on each day with readings of 51…51…49… And 49 degrees. High temperature of only 64 degrees on the 21st was a record low maximum for the date.


In 1965…heavy showers and thunderstorms doused metro Denver with significant rain each day. Rainfall for the six days totaled 5.16 inches at Stapleton International Airport. Massive rainfall occurred on the 20th…21st…and 25th… Flooding streets and basements and causing streams to overflow. The heaviest rainfall…2.05 inches…at Stapleton International Airport occurred on the 25th.

» Click here to read the rest of July 20 to July 26: This Week in Denver Weather History

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Above normal temps remain Thursday, better chance for PM thunderstorms

Thursday, July 24th, 2014 6:02am MDT

Yesterday cooled slightly as Thornton saw a high of 90 degrees, right at the average for the date.  Today should be a couple of degrees warmer and we have a chance to see some thunderstorms in the afternoon and early evening.

Mostly sunny skies start things off but we will be seeing an increase in cloud cover and partly sunny skies for most of the day.  High temperatures will be topping out in the low to mid-90s.

Thunderstorms will be possible beginning this afternoon with the best chances occurring from 2:00pm to 6:00pm.

See the image for today’s planning weather outlook and keep an eye on our radar for those storms here.

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Wednesday temps remain in the 90s, slight chance for thunderstorms

Wednesday, July 23rd, 2014 5:59am MDT

Today’s weather in Thornton looks to be much like that which we have seen the last couple of days but with a slight chance for PM thunderstorms.  It continues to look like it will be Sunday before we see any relief from the heat.

For today mostly sunny skies start things out to be followed by an increase in cloud cover beginning around the noon hour.  The mercury will be climbing once again to a high in the mid-90s.

From about 2:00pm to 8:00pm there is a slight chance for some thunderstorms.  Storms that do develop are only expected to bring some brief rain and gusty winds.

See the image for today’s outlook and check out the extended forecast here: http://www.thorntonweather.com/forecast.php

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Tuesday’s temperatures remain hot, little change expected this week

Tuesday, July 22nd, 2014 5:19am MDT

Thornton’s weather forecast for Tuesday looks much like the conditions we saw Monday.  The notable exceptions are less cloud cover and temperatures a degree or two hotter.

We start out the day with sunny skies and then will see some gradual increase in clouds.  Coverage however is not expected to be as extensive or thick as yesterday and that will help to drive the mercury up.

We’ll be heading for a high temperature in the mid-90s this afternoon.  Thunderstorm activity should stay south of our area.

See the image for today’s outlook and head over to our main page for the latest.

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NCAR launches study of Colorado Front Range ozone pollution

Monday, July 21st, 2014 10:51am MDT
The NSF/NCAR C-130 aircraft, one of the aircraft involved in FRAPPÉ, is based at NCAR’s Research Aviation Facility (RAF) at Rocky Mountain Metropolitan Airport in Broomfield, Colorado. RAF develops and operates instrumented research aircraft for the atmospheric science community. (©UCAR, photo by Carlye Calvin, used with permission)

The NSF/NCAR C-130 aircraft, one of the aircraft involved in FRAPPÉ, is based at NCAR’s Research Aviation Facility (RAF) at Rocky Mountain Metropolitan Airport in Broomfield, Colorado. RAF develops and operates instrumented research aircraft for the atmospheric science community. (©UCAR, photo by Carlye Calvin, used with permission)

Over the past week you may have noticed a relatively persistent ‘drone’ of aircraft over the Denver area and seen a relatively large aircraft flying overhead.  The plane is a specially outfitted C-130 taking part in a major field study of the Front Range’s ozone.

Scientists at the National Center for Atmospheric Research (NCAR) will be using the aircraft, radar, balloons and other sensors and systems in the coming weeks.  The project has many goals including mapping possible sources of ozone pollution and using the data to better interpret satellite data.

From NCAR:


BOULDER – Scientists at the National Center for Atmospheric Research (NCAR) and partner organizations are launching a major field project across the northern Front Range of Colorado this month to track the origins of summertime ozone, an invisible but harmful pollutant.

The researchers will use specially equipped aircraft, mobile radars, balloon-mounted sensors, and sophisticated computer simulations to measure local and far-flung pollution sources. Results from the month-long study will provide needed information to officials seeking to ensure that air in the region is healthy to breathe.

It marks one of the largest research projects to look at summertime air pollution on the northern Front Range, including Denver, which often exceeds federal standards for safe levels of ground-level ozone pollution despite efforts to reduce emissions. Ozone can lead to increased asthma attacks and other respiratory ailments. It also damages vegetation, including crops.

“Our goal is to produce an accurate and detailed view of all the diverse sources of ozone pollution along the Front Range,” said NCAR scientist Gabriele Pfister, a principal investigator on the project. “We want to fingerprint where the pollution comes from and analyze what happens when it mixes in the atmosphere.”

Known as the Front Range Air Pollution and Photochemistry Experiment (FRAPPÉ), the study will track emissions from both human-related activities and natural sources. It will focus on the urban corridor from south of Denver, north to Fort Collins, as well as the adjacent plains and mountains. Scientists also want to determine how much pollution comes from upwind areas, including other states and countries.

Funded through a federal-state partnership, FRAPPÉ is supported by the Colorado Department of Public Health and Environment and by the National Science Foundation, which is NCAR’s sponsor.


To provide additional detail across the region, scientists will closely coordinate FRAPPÉ with a second air quality mission taking place on the Front Range at the same time. DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) is a major study led by NASA that seeks to improve the ability of satellites to usefully assess our air quality.

“What we learn from these flights will help us to better interpret satellite remote sensing of air quality from geostationary orbit in the future,” said NASA scientist Jim Crawford, a principal investigator on DISCOVER-AQ. “It also will help us to define the best combination of instruments on the ground to connect air quality monitoring networks with satellite information.”

The DISCOVER-AQ flights and ground observations will focus on the northern Front Range, while FRAPPÉ will gather measurements from the surrounding region.

In all, approximately 200 scientists, technicians, pilots, and students from around the country will converge on the Front Range for the combined projects.

The researchers will quantify emissions from industrial facilities, power plants, motor vehicles, agricultural operations, oil and gas drilling, fires, and other sources. They also will measure naturally occurring emissions from trees and other plants that then combine with emissions generated by human activity to form ozone and other pollutants.


Colorado, like other states, relies on a limited number of ground-based stations to monitor air quality and help guide statewide policies and permitting. But a full, three-dimensional picture of the processes that affect air quality, including conditions far upwind and high up in the atmosphere, requires a three-pronged approach with measurements from aircraft, satellites, and the ground.

“By bringing together aircraft, satellites, and ground-based instruments, we can analyze the amounts and types of pollutants that are emitted in the Front Range as well as transported from other places, how they evolve, and how air circulation patterns near the mountains move them around,” said NCAR scientist Frank Flocke, a principal investigator on FRAPPÉ.

During the projects, which run from July 16 to mid-August, Front Range residents may notice occasional low-flying research aircraft that are taking measurements of the atmosphere. The aircraft will spiral down at times, taking samples of air as they spiral directly above ground instruments that will be measuring air at the surface and observing the atmosphere above.

Ozone, a principal component of smog, forms from the reaction of hydrocarbons and carbon monoxide in the presence of nitrogen oxides (NOx) and sunlight. It peaks during summer months when sunlight is strongest and air conditions are more likely to be stagnant.

Although the scientists will focus on ozone, they will also measure the size and chemical composition of airborne particles to better quantify particle pollution and track its sources. Microscopic airborne particles can have a major impact on people’s respiratory health.

The data gathered by the projects will go through a quality assurance process and then become publicly available in about six months. Scientists will use the data to begin publishing research results in about a year.


FRAPPÉ and DISCOVER-AQ will use similar payloads for their aircraft. The teams will conduct wingtip-to-wingtip intercomparison flights several times during the project, sampling air in the same place to make sure the instrument readings are comparable.

A network of instruments on towers, rooftops, and other sites will continuously monitor ozone and the gases that react to form it. Other ground-based activities, such as measurements from tethered balloons and from lidars (laser-based radars), will be closely coordinated with the flights. The researchers will draw on forecasts and nowcasts of both weather and air quality from a large number of computer models to assess daily conditions and make final decisions on when to fly and where to gather atmospheric samples.

“This is a unique opportunity for the state to work with others on a study that combines ground-based measurements with aircraft-borne sensing,” said Will Allison, director of the Colorado Department of Public Health and Environment’s Air Pollution Control Division. “It will help us more fully understand complex questions such as the factors contributing to ozone formation in the region. And that will help us continue to implement effective measures to reduce air pollution.”

“FRAPPÉ is a major collaborative study that will produce the most complete picture ever of summertime air pollution on the Front Range,” said Thomas Bogdan, president of the University Corporation for Atmospheric Research, which manages NCAR. “This effort will dramatically advance our understanding of air quality and its potential impacts. The results have the potential to help not only people living on Colorado’s Front Range, but residents of other metropolitan areas with similar conditions, too.”

In addition to NCAR and the Colorado Department of Public Health and Environment, the FRAPPÉ team includes scientists from the National Oceanic and Atmospheric Administration; Cooperative Institute for Research in Environmental Sciences; National Park Service; Regional Air Quality Council; Global Ozone Project; Western Regional Air Partnership; Environmental Protection Agency; University of Colorado Boulder; Colorado State University; University of California, Berkeley; University of Wisconsin; University of Cincinnati; Georgia Institute of Technology; University of California, Riverside; Aerodyne Inc.; U.S. Naval Academy; University of Rhode Island; University of California, Irvine; and Princeton University.

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Fast climbing mercury to top out in mid to upper 90s Monday

Monday, July 21st, 2014 5:49am MDT

A hot Monday and week ahead are going to make last week’s wet and cool weather nothing but a memory very quickly.  Above normal temperatures are expected to remain with us until at least this weekend.

For today we are starting out the morning quite mild and will see the temperature climb quickly.  By noon we will have already eclipsed the 90 degree mark and be well on our way to a high pushing 99 degrees.  Afternoon cloud cover may inhibit that high temperature a bit much like it did yesterday.

Thunderstorm activity today is expected to remain to the south along the foothills and Palmer Divide but there is just a slight chance something pops up near Thornton.

See the image for today’s outlook and keep an eye on the thermometer here: http://www.thorntonweather.com/live-weather-2.php

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