Thornton, Colorado, USA
UpdatedSun, 23-Oct-2016 1:45am MDT 


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Wednesday offers hot temps, chance for storms late

Wednesday, August 3rd, 2016 5:22am MDT

One more hot day then we expect to see some relief. Today will bring some of the hottest temperatures of the week with some storm activity expected but later than normal.

We start out with mostly sunny skies to be followed by a slow increase in cloud cover as the day progresses. Temperatures will be climbing toward a high in the mid-90s, well above the average for the date of 89 degrees. Some scattered thunderstorms may be seen this evening.

Looking ahead, we continue to track a cold front expected to arrive tomorrow and bring a change in the overall pattern. Temperatures Thursday and Friday should drop into the upper 70s and then warm back up close to normal for the weekend.

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Above normal temperatures, slight chance for storms Tuesday

Tuesday, August 2nd, 2016 5:14am MDT

The same weather pattern we have been seeing lately continues today and tomorrow. However, we do continue to expect a change toward cooler conditions for the latter part of the workweek.

For today we start out with mostly sunny skies that will last for the morning and the early afternoon. There will be a little bit of moisture to work with so from mid to late afternoon into this evening we see just a slight chance for thunderstorms. Temperatures today will be climbing into the low to mid-90s.

Looking ahead, tomorrow offers conditions similar to today, perhaps even a bit warmer. After that, we expect a cold front to arrive bringing much cooler mercury readings Thursday and Friday along with better chances for precipitation. More details in the extended forecast.

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Thornton’s workweek starts off mild and dry

Monday, August 1st, 2016 6:11am MDT

With drier air now in place, we see our small chances of storms disappear on Monday – not that they have been bringing any precipitation to us anyway.

Sunny skies start things off then we will see a few clouds as the day progresses but overall a healthy dose of sun will be with us. Temperatures will be climb to a high in the low 90s and we aren’t expecting any storm activity.

Looking ahead, Tuesday and Wednesday are expected to continue the heat with minimal chances for storms. However, a trough looks to dig in later in the week and that should provide not only cooler temperatures but better chances for precipitation.

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Thornton’s weekend to start cooler, then warm right back up

Friday, July 29th, 2016 5:50am MDT

We do get a bit of a break from the above normal temperatures today but with a healthy dose of humidity and chance for storms. The rest of the three-day period is going to see the mercury return to levels at or above normal.

For today we see a good deal of low level moisture which is going to cause some cloud cover and possibly storms later. Temperatures will be cooler with highs in the mid-80s but it will feel sticky with humidity levels around 50%. We do see another chance for storms this afternoon and particularly this evening, some of which could turn severe so keep close watch.

Saturday looks to be quite nice with a healthy dose of sun but also which temperatures back in the low 90s.

We close out the weekend on Sunday with more clouds but also with increased temperatures. The afternoon brings a slight chance for storms.

Have a great weekend!

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NOAA to develop new global weather model

Thursday, July 28th, 2016 7:17pm MDT

The EarthThe primary model created by the United States for weather forecasting has been long overdue for some significant upgrades.  NOAA has recently been making great strides in improving the system and has announced more details on the latest.

From NOAA:

July 27, 2016 NOAA took a significant step toward building the world’s best global weather model today, a priority for the agency and the nation. NOAA announced the selection of a new dynamic core, the engine of a numerical weather prediction model, and will begin developing a state-of-the-art global weather forecasting model to replace the U.S. Global Forecast System (GFS).

The new global model will continue to be called the GFS. As with the current GFS, the new GFS will run in the background of NOAA’s suite of weather and climate models improving skill across all NOAA’s forecast mission areas.

“Using our powerful supercomputers, our new dynamic core which drives the model, and the newest modeling techniques, we are poised to develop and run a more accurate and reliable global model that is used as a basis for all weather forecasts in the U.S.,” said Louis W. Uccellini, director, NOAA’s National Weather Service.

The new dynamic core, Finite-Volume on a Cubed-Sphere (FV3), was developed by NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey. The FV3 core brings a new level of accuracy and numeric efficiency to the model’s representation of atmospheric processes such as air motions. This makes possible simulations of clouds and storms, at resolutions not yet used in an operational global model.

The FV3 core enables the model to provide localized forecasts for several weather events simultaneously all while generating a global forecast every six hours. Looking 10 years ahead, the GFS model with the FV3 core will run in higher resolution and be able to zoom in on smaller and smaller storm systems to provide forecasters better pictures of how storms will evolve.

Goals for the new model are:

  • a unified system to improve forecast accuracy beyond 8 to 10 days
  • better model forecasts of hurricane track and intensity, and
  • the extension of weather forecasting through 14 days and for extreme events, 3 to 4 weeks in advance.

Engaging the meteorology community during model development and improvement is a priority for NOAA. The agency plans to develop a program to involve researchers in testing and improving algorithms, data assimilation methods and physics. The goal is to incorporate successful enhancements into operations.

“We are collaborating with the best model developers in the U.S. and around the world to ensure the GFS has the most recent advances in weather prediction modeling, and so we can accelerate improvements to the model as they are developed,” Uccellini added.

Building the Next Generation Global Prediction System will take a tremendous amount of testing, analysis and verification. Model components, including the physics package, data assimilation and post processing—all parts of the existing architecture—will be rebuilt and improved to work with the new software.

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NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses

Thursday, July 28th, 2016 6:23pm MDT
A new NASA study says that Antarctica is overall accumulating ice. Still, areas of the continent, like the Antarctic Peninsula photographed above, have increased their mass loss in the last decades. (NASA's Operation IceBridge)

A new NASA study says that Antarctica is overall accumulating ice. Still, areas of the continent, like the Antarctic Peninsula photographed above, have increased their mass loss in the last decades. (NASA’s Operation IceBridge)

Interesting. NASA study conflicts directly with much of the climate change narrative about ice in Antarctica.

From NASA:

A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.

The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report, which says that Antarctica is overall losing land ice.

According to the new analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. That net gain slowed   to 82 billion tons of ice per year between 2003 and 2008.

“We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” said Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, which was published on Oct. 30 in the Journal of Glaciology. “Our main disagreement is for East Antarctica and the interior of West Antarctica – there, we see an ice gain that exceeds the losses in the other areas.”  Zwally added that his team “measured small height changes over large areas, as well as the large changes observed over smaller areas.”

Scientists calculate how much the ice sheet is growing or shrinking from the changes in surface height that are measured by the satellite altimeters. In locations where the amount of new snowfall accumulating on an ice sheet is not equal to the ice flow downward and outward to the ocean, the surface height changes and the ice-sheet mass grows or shrinks.

But it might only take a few decades for Antarctica’s growth to reverse, according to Zwally. “If the losses of the Antarctic Peninsula and parts of West Antarctica continue to increase at the same rate they’ve been increasing for the last two decades, the losses will catch up with the long-term gain in East Antarctica in 20 or 30 years — I don’t think there will be enough snowfall increase to offset these losses.”

The study analyzed changes in the surface height of the Antarctic ice sheet measured by radar altimeters on two European Space Agency European Remote Sensing (ERS) satellites, spanning from 1992 to 2001, and by the laser altimeter on NASA’s Ice, Cloud, and land Elevation Satellite (ICESat) from 2003 to 2008.

Zwally said that while other scientists have assumed that the gains in elevation seen in East Antarctica are due to recent increases in snow accumulation, his team used meteorological data beginning in 1979 to show that the snowfall in East Antarctica actually decreased by 11 billion tons per year during both the ERS and ICESat periods. They also used information on snow accumulation for tens of thousands of years, derived by other scientists from ice cores, to conclude that East Antarctica has been thickening for a very long time.

“At the end of the last Ice Age, the air became warmer and carried more moisture across the continent, doubling the amount of snow dropped on the ice sheet,” Zwally said.

The extra snowfall that began 10,000 years ago has been slowly accumulating on the ice sheet and compacting into solid ice over millennia, thickening the ice in East Antarctica and the interior of West Antarctica by an average of 0.7 inches (1.7 centimeters) per year. This small thickening, sustained over thousands of years and spread over the vast expanse of these sectors of Antarctica, corresponds to a very large gain of ice – enough to outweigh the losses from fast-flowing glaciers in other parts of the continent and reduce global sea level rise.

Zwally’s team calculated that the mass gain from the thickening of East Antarctica remained steady from 1992 to 2008 at 200 billion tons per year, while the ice losses from the coastal regions of West Antarctica and the Antarctic Peninsula increased by 65 billion tons per year.

“The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away,” Zwally said. “But this is also bad news. If the 0.27 millimeters per year of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for.”

“The new study highlights the difficulties of measuring the small changes in ice height happening in East Antarctica,” said Ben Smith, a glaciologist with the University of Washington in Seattle who was not involved in Zwally’s study.

“Doing altimetry accurately for very large areas is extraordinarily difficult, and there are measurements of snow accumulation that need to be done independently to understand what’s happening in these places,” Smith said.

To help accurately measure changes in Antarctica, NASA is developing the successor to the ICESat mission, ICESat-2, which is scheduled to launch in 2018. “ICESat-2 will measure changes in the ice sheet within the thickness of a No. 2 pencil,” said Tom Neumann, a glaciologist at Goddard and deputy project scientist for ICESat-2. “It will contribute to solving the problem of Antarctica’s mass balance by providing a long-term record of elevation changes.”

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July 2016 top shots: Monthly photo slideshow

Thursday, July 28th, 2016 5:15pm MDT
The McNeil twins take in the fireworks on the 4th of July. (Jennifer McNeil)

The McNeil twins take in the fireworks on the 4th of July. (Jennifer McNeil)

Colorado offers outdoor opportunities unlike any other state and while the summer heat settles in, photos of the amazing scenes across our state provide a view into why we love it here so much.

The weather this time of year has a pretty standard pattern of quickly warming temperatures followed by afternoon thunderstorms that can cool things down.  These storms sometimes provide a good bit of ‘excitement’ and are a prime photo subject.

  • Slideshow updated July 25, 2016

Recreationalists head outdoors and take advantage of urban, suburban and rural opportunities.  As they do, our abundant wildlife that is found just about anywhere comes into focus.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather and nature related imagery.   Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted.

To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

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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Thornton’s Thursday continues the heat, brings better chance of storms

Thursday, July 28th, 2016 5:24am MDT

Temperatures a bit above normal will continue the recent trend today. We do however see a chance for thunderstorms, our best chance for them in recent days.

We start out the day under mostly sunny skies and those will be with us for most of the day. The afternoon will bring an increase in coverage. In terms of temperatures, look for a high today in the low to mid-90s again.

As for the thunderstorm chances, things a bit unsettled in the forecast on that front. We do see a good bit of instability but the winds and moisture are the wildcards. The SPC does put us within an area of ‘marginal’ risk for severe storms and we do see the potential as being there.

Strong winds, brief, heavy rain and hail will be a possibility. The question is though whether it will come to us or remain further east. As for timing, from mid-afternoon forward the potential for storms is there with the best opportunity looking to come starting at around 6:00pm.

Our Severe Weather Briefing Page has all the latest.

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July 24 to July 30: This week in Denver weather history

Wednesday, July 27th, 2016 4:09pm MDT
This Week In Denver Weather History

July 24 to July 30: This week in Denver weather history

As we near the end of July the weather in Denver tends to be a bit more stable. That doesn’t mean the severe weather threat disappears as can be seen at our look back at this week in Denver weather history. Particularly notable are lightning injuries and deaths, flash flood events and even tornadoes.

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 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.


In 1896…heavy cloudbursts in the foothills west of Denver caused flash flooding on Bear Creek…Clear Creek…Golden Gate Gulch…and Mount Vernon Creek…resulting in a total of 27 deaths. The downpour dislodged large Boulders…one of which crushed a house. The heavy rain also caused a dam on cub creek to wash out…adding even more water to the flood. A wall of water as high as 10 feet flooded Evergreen and passed down bear creek…washing away many structures along the way. The flood crest produced 3 feet of water in downtown Morrison during the early evening. Flash flooding on Mount Vernon Creek added to the flooding in Morrison. In Golden…the flooding washed out bridges on clear creek and on Cresman and Tucker gulches and forced the closure of the power plant. In Denver…a thunderstorm produced hail of unknown size during the afternoon and rainfall of 1.23 inches overnight.

In 1958…a thunderstorm wind gust to 52 mph was recorded at Stapleton Airport.

In 1965…heavy rain caused flooding on clear creek and tucker gulch in Golden and west Denver. Damage in Golden was estimated at 80 thousand dollars. Heavy rain south of Denver washed out temporary earthen bridges constructed following the June floods in Castle Rock…Littleton… Englewood…and Denver. Bear creek in south Denver reached flood stage. A cloudburst on cub creek in Evergreen washed out bridges and roads. Heavy rain fell over all the Denver and Aurora areas…causing some flooding of roads…streets… And bridges. A man drowned in a flooded irrigation canal near Hudson. Heavy rain caused flooding of streets and roads in Blackhawk and central city. Hail caused minor damage in Idaho Springs.

In 1967…seven bridges were washed out along a normally dry creek bed south of State Highway 7 west of Brighton. One car was washed into the creek when a bridge gave way.

In 1970…hail stones to 1 1/4 inches in diameter fell in the foothills of Jefferson County southwest of Denver.

In 1971…golf ball size hail was reported in foothill areas of Jefferson County west of Denver. A funnel cloud was sighted in Aurora. Wind gusts estimated at 60 mph…hail… And heavy rain up to an inch in 15 minutes caused local flooding and some other damage in several areas of metro Denver. Hailstones to 3/4 inch in diameter fell 7 miles southeast of Denver.

In 1973…a thunderstorm wind gust to 52 mph was recorded at Stapleton International Airport where one inch diameter hail was measured.

In 1981…strong winds downed a power line in northeast Denver. Wind gusts to 50 mph were recorded at Chatfield Reservoir.

In 1987…3/4 inch diameter hail fell 5 miles northeast of Commerce City.

In 1996…hail…up to 1 3/4 inches in diameter…fell at Chatfield Reservoir. Hail to 3/4 inch in diameter was measured near Bennett.

In 2000…lightning struck near two golfers at ute creek golf course near Longmont…knocking them to the ground. The men received only minor injuries.

In 2001…lightning from a thunderstorm knocked out electrical power to about 1500 residents in the city of Denver.

In 2004…a chilly day with fog and thunderstorms resulted in two temperature records. The low temperature of 49 degrees was a record minimum for the date. The high temperature of only 58 degrees was a record low maximum for the date.


In 2003…maximum temperature of 100 degrees on the 24th was a record high for the date. Low temperature of 73 degrees on the 25th was a record high minimum for the date.


In 1875…brief heavy rain and hail lasted only 5 minutes… But the 1/4 inch diameter hail covered the ground to a depth of 1/2 inch and made the streets look like there had been snowfall. There was much crop damage…especially to corn…and some sheep were killed. Precipitation totaled 0.51 inch in the city.

In 1896…a heavy thunderstorm produced sustained northwest winds to 45 mph with gusts to 50 mph and 1.02 inches of rain.

In 1965…a cloudburst dumped 1.99 inches of rain in 30 minutes at Stapleton International Airport. The storm was accompanied by strong winds gusting to 70 mph. The heavy rain flooded numerous streets in east Denver and Aurora. One inch diameter hail accompanied a cloudburst…9 miles southwest of Denver. A funnel cloud was sighted 25 miles northwest of Denver. In Aurora…there were unofficial reports of 2.30 inches of rain in 40 minutes and 3.30 inches of rain in 30 to 40 minutes. Rainfall totaled 2.05 inches at Stapleton International Airport. Rainfall of 2.42 inches for 24 hours on the 24th and 25th was the second greatest on record for July.

In 1977…a tornado touched down briefly in Aurora southeast of Cheery Creek Reservoir. No damage was reported. A funnel cloud was sighted for 4 minutes by national weather service personnel 10 miles north of Stapleton International Airport near Henderson.

In 1991…heavy rain…up to half an inch in 10 minutes…caused flooding in Westminster…Northglenn…and north Denver where a section of railroad track was washed away. At Stapleton International Airport…heavy thunderstorm rain totaled 1.85 inches and briefly reduced the visibility to 1/4 mile. Hail to 1/8 inch in diameter was also measured. A tornado touched down briefly near Fort Lupton. No damage was reported.

In 1998…heavy monsoonal thunderstorm rains caused flooding and flash flooding in eastern and southern sections of metro Denver…including Englewood and Aurora…when about 2 to 3 inches of rain inundated the area. Both I-25 and I-70 were closed for 2 to 3 hours as several low lying areas became impassable due to the high waters. The water was estimated to be 15 feet deep in one flooded underpass along I-25. As a result…the freeway was closed from south of 6th Avenue to University Blvd. Standing water forced the closure of I-70 at gun club road east of Denver. In Englewood…U.S. Highway 285 was closed…when high water made it impassable. Several cars were reportedly floating down the roadway near Sheridan Blvd. In Aurora…the intersection at Yale Ave. And chambers rd. Was flooded by high water up to 4 feet deep when a spillway on the high line canal was breached. Lightning also knocked out 11 transformers across metro Denver…causing several small fires and scattered power outages. Flood and flash flooding also occurred north of Strasburg when as much as 2.51 inches of rain fell in an hour. The deluge resulted in considerable flooding of local streets and County roads. Torrential rainfall of 2 to 3 inches in less than an hour triggered a flash flood in Virginia Canyon. County road 279 between Idaho Springs and Central City was closed for two days to clear debris from mudslides. Several cars in Idaho Springs were washed off the road…and numerous basements were flooded in town. Thunderstorm rainfall totaled 2.69 inches at Denver International Airport.

In 2001…lightning struck two homes in Lafayette…damaging the roof and attic of one and shorting out the electrical system in another. Hail to 1 3/4 inch in diameter was measured 7 miles north of Castle Rock with 3/4 inch hail 7 miles north of Sedalia.

In 2005…heavy thunderstorm rain in the vicinity of the overland wildfire burn scar triggered a mudslide in Jamestown. Rocks the size of bowling balls…along with silt and mud slid down the mountain into the town. No one was injured. One parked car was buried by the debris.

In 2006…heavy thunderstorm rainfall caused flash flooding 1 mile north of the town of Westcreek in southwestern Douglas County. Several maintenance roads were washed out by the floodwaters.


In 1891…a thunderstorm produced sustained northeast winds to 44 mph with gusts to 60 mph and 0.16 inch of rain.

In 1894…a thunderstorm produced sustained southwest winds to 36 mph with gusts to 58 mph…but only 0.04 inch of rain.

In 1910…the high temperature reached 100 degrees in downtown Denver.

In 1959…a Denver man was stunned while standing by a car that was struck by lightning. He was treated for burns and shock at a local hospital. Thunderstorm winds gusted to 55 mph at Stapleton Airport.

In 1983…two heavy thunderstorms hit the northern and western suburbs. The first drenched Northglenn with an inch of rain in 30 minutes. The second storm dumped an inch or more of rain in Idaho Springs and Evergreen. The heaviest rainfall… 2.90 inches in an hour…caused minor street flooding in Golden.

In 1984…heavy early morning thunderstorms drenched the foothills southwest of Denver. Rainfall to 1 1/2 inches in just 30 minutes occurred between Evergreen and Conifer. In nearby Turkey Creek Canyon…1.80 inches of rain was recorded in 35 minutes.

In 1985…a long rope-like white tornado touched down 5 miles east of Erie and stayed on the ground…mainly over an open field…for 18 minutes. However…the twister damaged a few cars on I-25 and injured 3 people from broken glass. The storm flipped over a van…blew out car windows…and ripped a highway sign. It also blew an outbuilding off its foundation. A tornado also touched down briefly 8 miles north of Bennett. No damage was reported from this storm.

In 1988…a 9-year-old girl was slightly injured by lightning in Parker.

In 2003…a severe thunderstorm in and south of Franktown produced hail as large as 1.75 inches in diameter.

» Click here to read the rest of July 24 to July 30: This week in Denver weather history

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More above normal temps for Wednesday, little chance for precipitation

Wednesday, July 27th, 2016 5:24am MDT

These forecasts lately are sounding like a broken record. The same basic pattern of above average temperatures and slight chances for storms keeps repeating, just as it will today.

We start out the day with mostly sunny skies and will see clouds slowly increasing as the day progresses but never becoming overly thick. Temperatures will be climbing to a high in the low to mid-90s.

As for storms, activity today unfortunately looks to be focused to our east. We have just a slight chance and that will come a bit later than usual, closer to 6:00pm.

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