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Thornton, Colorado, USA
UpdatedWed, 25-Apr-2018 5:50pm MDT 
 

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Severe Weather 101 – Floods and Flash Floods

Wednesday, April 18th, 2018 5:05am MDT
The Big Thompson Flood in 1976 claimed the lives of 144 Coloradoans and serves to remind us of the dangers of floods.

The Big Thompson Flood in 1976 claimed the lives of 144 Coloradoans and serves to remind us of the dangers of floods.

For much of Colorado, floods and flash floods present a grave danger to life and property. These usually are the result of one of two things – spring snow melt occurring rapidly or a severe thunderstorm. Colorado is very susceptible to flash flooding and these occur somewhere every year in the state.

The waters from flash floods can move with extraordinary speed and strike with little or not warning.  Their force can be extremely destructive and when coupled with trees, dirt, rocks and other debris they carry downstream, they are deadly.

Flooding is the number one weather killer in the United States.

» Click here to read the rest of Severe Weather 101 – Floods and Flash Floods

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Thornton’s Wednesday to bring calm, cool weather conditions

Wednesday, April 18th, 2018 5:00am MDT

Well, after yesterday’s windy drama, today brings a much-needed break. Conditions will be a bit cooler than normal but also a whole lot calmer.

We start out with sunny skies and will see more of the same throughout the day. The evening may bring a few clouds but nothing intrusive. Winds will be shifting around a bit today but generally calm. Temperatures start out on the chilly side then will see a gradual increase toward a mid-afternoon high in the upper 50s.

Tonight, skies remain clear with lows around freezing.

ICYMI, you can see some of the pics of the damage from yesterday’s wind in our April photo slideshow. Share your images and we will add them.

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Severe Weather 101 – Tornadoes and tornado safety

Tuesday, April 17th, 2018 5:50am MDT
Last year's Windsor Tornado highlights the very real danger twisters present in Colorado. Do you know when to do when one strikes?

The 2008 Windsor Tornado highlights the very real danger twisters present in Colorado. Do you know when to do when one strikes?

One fact that may surprise those new to Colorado is that we are actually on the western edge of the infamous Tornado Alley. This large swath of land comprises much of the nation’s midsection and is a unique place as the United States sees more tornadoes than any other place on earth. In fact, tornadoes have been recorded in all 50 states including Alaska and Hawaii.

Closer to home, Colorado sees our share of these storms. In fact, one metro area county – Weld County – holds the distinction of being the “tornado capital of the world.” With 252 tornados from 1950-2011, no single county in the nation has had more tornadoes! Adams County is number two in the state and isn’t far behind with 156 over that same period.  Granted these numbers are skewed a bit simply due to the sheer size of those counties, but it does serve to highlight the real danger that tornadoes present.

Even here in the metro area tornadoes are a real danger. The Thornton area was struck in 1981, one of the worst tornadoes to strike the Denver area in history. At 2:30 p.m. this tornado touched down and by 2:45 p.m., the tornado had hit Thornton City Hall. The tornado’s destruction sent 53 injured people to hospitals, 25 homes were destroyed and 239 structures were damaged.

One common myth is that tornadoes don't strike metropolitan areas. This has been disproved many times including here in Colorado in 1982 when an F2 tornado struck Thornton. Image courtesy the City of Thornton archives.

One common myth is that tornadoes don’t strike metropolitan areas. This has been disproved many times including here in Colorado in 1981 when an F2 tornado struck Thornton. Image courtesy the City of Thornton archives.

The most well known tornado outbreak in the metro area occurred on June 15, 1988. Five tornadoes resulted in seven injuries and damage in excess of $15 million.

We all of course also remember in 2008 when the town of Windsor, not far from Denver, was struck with an EF-3 tornado that claimed one life and destroyed and damaged hundreds of buildings.

The greatest threat for tornadoes occurs during late spring and early summer when you have a combination of heat and moisture in the lower atmosphere. Here in Colorado, tornadoes are frequent from May through August with June being the most active month.

However, there is no hard and fast rule for when tornadoes strike, as Colorado witnessed on March 29, 2007 when Holly, Colorado was struck by an EF-3 tornado with winds of 165 mph. Two women lost their lives as a result of that event and 160 homes were damaged.

Colorado ranks 10th in terms of the number of tornadoes with 1,911 events from 1950-2011. One good thing is that our high altitude and drier air do make it harder for the monster supercells that spawn the biggest tornadoes to form. Most of our tornadoes are small and short lived. Further, thanks to the wide open spaces of the eastern half of our state, many strike sparsely populated areas. This is reflected in the fact that we rank 38th for tornado related deaths.

» Click here to read the rest of Severe Weather 101 – Tornadoes and tornado safety

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Batten down the hatches: Strong winds to be main weather feature on Tuesday

Tuesday, April 17th, 2018 5:00am MDT

Make sure you keep those small dogs on a leash today and secure your lawn furniture. A significant pressure gradient caused by a passing system is going to bring us some significant wind today.

We start out relatively mild under sunny skies. Cloud cover will see some increase through the morning into the first half of the afternoon before easing again in the evening. Temperatures will be aided by the warm, downslope flow with a high in the mid to upper 60s expected. That high will however come somewhat early then we will cool down through the afternoon.

The most significant things to watch for today will be the strong winds. They will be increasing in speed through the day before peaking in the late afternoon / early evening. At their height, gusts to 50mph or so will be the possible.

A High Wind Warning has been issued as the blowing will have the potential to cause damage and create hazardous driving conditions. Additionally, those winds coupled with dry conditions and fuels means a Red Flag Warning will also be in effect.

Tonight, it will remain breezy under mostly clear skies with low temperatures dipping to around the freezing mark.

Keep an eye on those wind speeds with our live weather gauges here.

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Severe Weather 101 – Watches, Warnings and More

Monday, April 16th, 2018 6:15am MDT
Last year's Windsor tornado highlighted just how dangerous weather in Colorado can be. Are you and your family prepared? Do you know what the watches and warnings all mean?

The 2008 Windsor tornado highlighted just how dangerous weather in Colorado can be. Are you and your family prepared? Do you know what the watches and warnings all mean?

We’ve all seen TV or Internet news of a weather related watch or warning being issued. But, how many really know what they mean? There is a pretty big difference between the two and it is important to be aware just what it means to you so you can take the appropriate precautions.

Dozens of weather related fatalities occur every year in Colorado, many simply out of ignorance. Taking the time to be aware of the conditions around you and taking appropriate action will keep you from becoming a statistic.

Naturally you can get information on current advisories from television as local stations usually do a good job of “crawling” them on the screen when they are issued. This works well if you have a TV available but if not, the radio would be a secondary source. The Internet and the National Weather Service’s website are a great one when at a computer.

The problem with relying on news media or the Internet is that their ability to warn you of a developing weather situation is dependent on your monitoring them.  Severe weather can strike without little warning.  How will you know if severe weather is about to strike if you don’t have the TV or radio on?

Your first line of defense – NOAA All Hazards Radio

NOAA Weather RadioFor just about anywhere, a special radio that picks up the NOAA’s All Hazard Radio broadcasts is the way to go and provides information from the source. Oftentimes simply called a weather radio, we highly recommend every household have one of these.

These radios are relatively inexpensive and allow you to be immediately notified of official National Weather Service warnings, watches, and forecasts as well as other hazard information like earthquakes, avalanches, chemical spills, and even AMBER alerts.  In fact, with these radios, you will be notified at the exact same time the news media is made aware giving you a head start on preparing for a developing situation.

To learn more about these devices and what you should look for when buying one, click here.

A high-tech alternative – Cell phone weather apps

Many people now have smartphones that allow for downloadable apps and weather-related ones are among the most popular.

All of these applications have a number of weather related features in common.  All provide current conditions for either the location the user is in now or for saved locations and all provide some sort of radar.

Most can be configured to sound an alert when the National Weather Service issues a watch or warning.  While they are no substitue for a weather radio, these apps provide you with immediate notification no matter where you are at.

For a look at some of these weather apps and their features, click here.

» Click here to read the rest of Severe Weather 101 – Watches, Warnings and More

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Thornton’s workweek starts out with unseasonably warm temps, calm conditions

Monday, April 16th, 2018 5:00am MDT

A pretty good way to start things off. High pressure will dominate today leading to one of the warmest days of the year so far.

The day starts with mostly sunny skies and similar conditions will be above for most of the day. The evening will bring a brief increase in cloud cover. Temperatures start out on the chilly side but will warm up nicely with a high today around 77 degrees. The average high for today’s date is 61 degrees.

Tonight, cloud cover decreases and lows will dip to the mid-40s.

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April 15 to April 21: This week in Denver weather history

Sunday, April 15th, 2018 4:13pm MDT
This week in Denver weather history

April 15 to April 21: This week in Denver weather history

As we enter the latter half of April the weather history calendar starts to reflect shift in the type of weather events we see. There are still plenty of significant snowfall events. However spring severe weather starts to appear with greater frequency including heavy rain, hail and even tornadoes.

From the National Weather Service:

12-15

In 1927…snowfall totaled 8.5 inches in downtown Denver. Most of the snow fell on the 14th. Northwest winds were sustained to 27 mph during the storm.

13-15

In 1945…heavy snowfall totaled 9.8 inches in downtown Denver. Most of the snow…4.8 inches…fell on the 14th. Snow fell for a total of 53 consecutive hours. This was the second big snow in less than 2 weeks. The air mass was very cold for April. High temperatures of 21 degrees on the 14th and 32 degrees on the 15th were record low maximums for the those dates.

13-17

In 2001…a huge dust storm over southern and inner Mongolia during April 3rd through the 6th lifted desert dust into the jet stream. This dust cloud moved over metro Denver on the 13th and persisted through the 17th. The cloud created widespread haze…giving the sky a milkish cast due to the scattering of incoming solar radiation.

14-15

In 1873…north winds blew a gale during the afternoon on both days. Winds were brisk throughout each day.

In 1902…snowfall totaled 6.0 inches in downtown Denver. Most of the snow melted as it fell. Northeast winds were sustained to 20 mph.

In 1910…strong winds occurred on both days. Northeast winds were sustained to 52 mph on the 14th. North winds were sustained to 44 mph on the 15th.

In 1921…heavy snowfall and strong winds produced near- blizzard conditions in the city. Snowfall totaled 10.0 inches. Strong north winds sustained to 48 mph with gusts to 54 mph on the 15th produced drifts to several feet in depth. The heavy wet snow caused extensive damage to trees…utility poles…and buildings. Precipitation from the storm was 1.73 inches. Very heavy snow also fell in the foothills. At Silver Lake…in the mountains west of Boulder…95 inches of snow fell in 32.5 hours on the 14th and 15th.

In 1935…dense dust…apparently behind a dry cold front… Enveloped the city at 1:00 pm on the 14th and persisted through the night. The dust blew into the city on northeast winds sustained to 30 mph with gusts to 32 mph. By mid-morning on the 15th…the dust had become light and continued as such into the evening. North winds were sustained to only 13 mph on the 15th.

In 1999…a spring storm dumped heavy snow over portions of metro Denver. Nearly 2 feet of snow fell in the foothills with half a foot to a foot over western and southern suburbs. The heavy snow alleviated drought conditions and associated high fire danger that prevailed during much of the winter season. Snowfall totals included: 22 inches in Coal Creek Canyon…20 inches at Wondervu…19 inches at Genesee…17 inches near Evergreen and Nederland and at Idaho Springs and Tiny Town…14 inches at Georgetown…13 inches at Morrison…10 inches near Sedalia…9 inches in south Boulder… 8 inches at Highlands Ranch and Wheat Ridge…and 7 inches at Littleton and Parker. Only 3.4 inches of snow fell at the site of the former Stapleton International Airport. North- northwest winds gusted to 41 mph on the 15th at Denver International Airport.

15

In 1874…light snow developed around daybreak and became moderate to heavy by mid-morning and continued into the early evening. While most of the snow melted as it fell… Total precipitation from the melted snow was 0.95 inch. This would make the estimated snowfall nearly 10 inches.

In 1963…high winds were widespread across metro Denver. West winds gusted to 63 mph in Denver at Stapleton Airport with sustained winds of 35 mph and gusts to 70 mph in downtown Boulder. The winds caused extensive damage to buildings and other property. Visibility was briefly reduced to 1/2 mile in blowing dust at Stapleton Airport.

In 1998…another spring storm brought heavy snow to the foothills. Thirty to 40 vehicles were involved in accidents along I-70 near Georgetown. The combination of poor visibilities…slick roads…and careless drivers led to the multi-car pileups. Only minor injuries were reported. The accidents forced the closure of all of I-70’s eastbound lanes. Snowfall totals included 12 inches at Genesee and 10 inches at Aspen Springs…Chief Hosa…Georgetown…near Morrison…and on North Turkey Creek. Only 0.1 inch of snow fell at the site of the former Stapleton International Airport. East winds gusted to 30 mph at Denver International Airport.

In 2002…unseasonable warm weather resulted in two records being broken. The high temperature of 84 degrees was a record maximum for the date. The low temperature of 57 degrees was a record high minimum for the date.

15-16

In 1900…heavy rainfall totaled 2.33 inches. A trace of snow was mixed with the rain at times.

In 1950…thunderstorms and heavy rain behind a cold front produced 2.13 inches of rain in 24 hours at Stapleton Airport.

In 2003…a fast moving pacific storm system moved across Colorado allowing strong winds to develop over the eastern foothills and metro Denver. Northwest winds gusted to 59 mph at Denver International Airport late in the evening of the 15th.

15-17

In 1922…heavy snowfall totaled 9.0 inches in downtown Denver. Most of the snow…6.0 inches…fell on the 16th. This was the third major snow storm in a week. Northwest winds were sustained to 43 mph with gusts to 47 mph on the 15th.

16

In 1960…a wind storm struck all of metro Denver. Estimated wind gusts up to 80 mph were registered in Boulder. At Stapleton Airport sustained west-northwest winds over 50 mph with gusts as high as 70 mph produced some blowing dust. The high winds damaged buildings…power and telephone lines…and signs. Five people were injured in metro Denver as a result of the wind storm. Blowing dust reduced visibility at times. The winds were strong and gusty for most of the day.

16-17

In 1944…heavy snowfall totaled 7.5 inches in downtown Denver. Northwest winds were sustained to 18 mph on the 16th.

16-18

In 2009…a potent spring storm brought heavy snow to locations in and near the Front Range foothills. A deep easterly upslope produced nearly 5 feet of snow in parts of the foothills. The heavy snow resulted in the closure of Interstate 70…from Golden west to Vail…for approximately 16 hours. The heavy snow snapped power lines in Evergreen and Nederland. The ensuing outages affected 14200 residents. In the Front Range foothills…storm totals included: 56 inches…3 miles south of Rollinsville; 54 inches…3 miles southeast of Pinecliffe…43 inches at Aspen Springs…42 inches at Evergreen…38 inches near conifer; 37 inches at St. Mary’s glacier…and 34 inches near Nederland. Along the urban corridor and Palmer Divide…the heaviest snow occurred above 5500 feet on the 17th. Storm totals included: 22 inches…8.5 miles southwest of Franktown; 18 inches…10 miles south-southeast of Buckley Air Force Base; 17 inches near Cherry Creek and 7 miles south of Sedalia… 16 inches…6.5 miles southwest of Castle Rock; 15 inches near Beverly Hills; 12 inches near Highlands Ranch and Lafayette…with 11 inches in Broomfield. Elsewhere storm totals ranged from 4 to 10 inches. Officially…only 2.6 inches of snow was observed at Denver International Airport. The 24-hr precipitation for the day however was 1.16 inches… Which established a new record for April 17th.

» Click here to read the rest of April 15 to April 21: This week in Denver weather history

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Severe Weather Awareness Week in Colorado gets started

Sunday, April 15th, 2018 6:00am MDT

In 1981 a tornado ripped through Thornton and caused major damage. Last year, funnel clouds were spotted across much of the area. Image courtesy City of Thornton archives.

As is customary, Colorado Governor John Hickenlooper has declared this coming week Severe Weather Awareness Week.  This is an opportunity for the public to get reacquainted with the dangers severe weather presents in Colorado.

Tornadoes, lightning, hail, severe wind and flooding are very real hazards that Coloradans face every year during severe weather season.  It is important that you know what to do to protect you and your family.

Just nine years ago in what was Denver’s weather story of the year, we suffered through a period of unusually severe weather including a tornado that ripped through the Southlands Mall.

Ten years ago on May 22nd an EF3 tornado raced north through Weld and Larimer counties resulting in one fatality near Windsor and causing several injuries and destroyed or heavily damaged hundreds of homes.

And of course in 1981 Thornton was the site of the worst tornado to ever strike the Denver metro area.

Tornadoes may get all the press but other severe weather can be damaging and deadly.

Just four years ago, late summer flooding caused millions of dollars of damage across northeastern Colorado.  It was 40 years ago that thunderstorms brought a raging torrent of water down the Big Thompson and caused one of Colorado’s worst natural disasters.  Six years ago hail struck the Thornton area causing damage to homes and vehicles.

In conjunction with the National Weather Service’s statements on Severe Weather Awareness Week, ThorntonWeather.com will be publishing our Severe Weather 101 series.  Each day this week a weather hazard will be discussed in depth and we will outline protective measures you can take to keep yourself and your family safe.  Please be sure to check back every day to read these important message.

» Click here to read the rest of Severe Weather Awareness Week in Colorado gets started

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Cold and blustery conditions start Thornton’s weekend to be followed by warmer, drier conditions

Friday, April 13th, 2018 5:31am MDT

We have a little bit of everything Colorado spring offers in our three-day period. We start out with cold conditions, a bit of snow and a good dose of wind. By the end, we will be clear, calm and mild.

Friday will be the most notable weather day as we a strong low pressure system works its way through. We’ll see cloudy skies throughout the day with a few flakes of snow here and there. Little, if any, accumulation is expected. Most notable will be the wind which is going to increase in speeds this morning and then be quite strong in the afternoon and evening.

Tonight, some snow will be seen with maybe just a touch of accumulation. Winds will continue to be strong with low temperatures dipping to the upper 20s.

Saturday offers some improvement with clearing skies and temperatures rebounding to the mid-50s. However, winds are going to continue to be quite breezy throughout the day, settling down in the evening finally.

Saturday night into Sunday morning, partly cloudy skies will be above with lows near freezing.

Sunday is going to be the nicest day of the period, closing out the weekend in fine fashion. Mostly sunny skies will be above, those winds will be gone, and high temperatures will be in the mid-60s.

Have a great weekend!

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Another warm and windy day for Thornton’s Thursday, snow possible tonight and tomorrow

Thursday, April 12th, 2018 5:15am MDT

A little bit of ‘fire and ice’ in the weather forecast over the next 48 hours or so. We start out with unseasonably warm temperatures and high fire danger today but then will see much colder temperatures and a chance for snow tomorrow.

For today, we start out with partly sunny skies then will see some clearing in the afternoon leading to mostly sunny skies. Winds today will be similar to yesterday with speeds increasing by mid to late morning. They will continue to be quite breezy through tonight. Temperatures today will top out in the upper 70s, coming close to Denver’s record high for the date of 79 degrees.

The wind coupled with low humidity and dry fuels means another Red Flag Warning will be in effect until 9:00pm so please be careful.

Tonight, we may see a sprinkle of rain, perhaps some snow after midnight but little or no accumulation is expected. Lows will dip to the mid-30s.

Friday is going to see a return of blustery, wintry conditions with highs only around 40 degrees, chilly winds and some light snow.

What lies ahead for the weekend? Check out the extended forecast here.

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