Thornton, Colorado, USA
UpdatedFri, 02-Dec-2016 5:20pm MST 


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Dry, warm & breezy for Thornton’s Monday, balance of week to be cooler

Monday, October 3rd, 2016 5:15am MST

Thornton starts out the week with a mild day and one that brings high fire danger. That changes tomorrow as a series of troughs will move through during the rest of the week bringing cooler temperatures and the possibility of our first freeze and snow.

For today mostly to partly sunny skies will be above. Temperatures will be climbing to highs right near the 80 degree mark, maybe a couple of degrees higher than that.

Winds will be increasing in speed with gusts in the 25 to 30 mph range being possible this afternoon and evening. The wind coupled with low humidity and dry fuels on the ground have caused a Red Flag Warning to be issued and in effect from noon to 7:00pm. Please be careful!

Looking ahead, the first trough moves in tonight with a second one to follow Thursday. These will lead to temperatures a bit below normal Tuesday and Wednesday. Then the second, coupled with a cold front, will bring much colder temperatures Thursday. We will stand a chance to see our first freeze and perhaps our first snow Thursday morning.

Get more details in our extended forecast.

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October 2 to October 8: This Week in Denver Weather History

Sunday, October 2nd, 2016 6:02am MST
This Week In Denver Weather History

October 2 to October 8: This Week in Denver Weather History

October is usually a relatively calm weather month in Denver but can see some interesting events. In our look back at this week in Denver weather history we see tornadoes, damaging wind and of course snow.

From the National Weather Service:


In 1903…southwest winds were sustained to 42 mph with gusts as high as 60 mph. The strong Chinook winds warmed the temperature to a high of 78 degrees.

In 1910…an apparent dry microburst produced sustained northeast winds to 43 mph.

In 1934…a trace of rain was the only precipitation of the month. This was the driest October on record.


In 1875…very dense haze hid the mountains from view as observed from the city.

In 1933…rainfall of just 0.01 inch was the only precipitation of the month. This was the second driest October on record.

In 1954…the low temperature cooled to only 60 degrees…the all-time record high minimum for the month October.


In 1969…the first snowfall of the season totaled 16.0 inches at Stapleton International Airport. There was a thunder snow shower on the evening of the 3rd…but otherwise little wind with the storm. The greatest snow depth on the ground was 8 inches due to melting. Heavy wet snow accumulated on trees…which were still in full leaf…and caused widespread damage from broken limbs and downed utility lines.


In 1984…the remnants of pacific hurricane Polo produced heavy rain over northeastern Colorado. Most locations received between 1.00 to 2.50 inches of rain…but 3.45 inches fell in Littleton. Rainfall totaled 1.73 inches at Stapleton International Airport…where north winds gusted to 24 mph.


In 1912…sustained south winds to 55 mph with gusts to 60 mph raised the temperature to a high of 83 degrees… The warmest temperature of the month that year.

In 1924…west winds were sustained to 46 mph with gusts to 50 mph in the city. The apparent Bora winds cooled the temperature to a high of 57 degrees from a high of 70 degrees on the 3rd.

In 2004…several small tornadoes touched down near Brighton… Barr lake…and Hudson in Adams and southern Weld counties. Most of these caused no damage. However…a small tornado 5 miles southeast of Brighton caused extensive damage to a recreational vehicle and severely damaged a barn. The barn was torn from its foundation…and the roof was thrown 100 feet. Four llamas in the barn were injured when it collapsed.


In 1997…unusually warm weather resulted in two temperature records. High temperature of 87 degrees on the 4th exceeded the old record set in 1922 by one degree. High temperature of 86 degrees on the 5th equaled the record set in 1990 and previous years.


In 1962…unusually severe thunderstorms for this late in the season affected areas from Boulder northward. Hail up to golf ball size and strong gusty winds did much damage to roofs…windows…and signs in Boulder. Heavy rainfall caused local flooding.

In 1994…lightning caused a power outage to over 2400 homes for a few hours in and around Nederland in the foothills southwest of Boulder. Very strong winds accompanied the thunderstorm. Thunderstorm winds gusted to 60 mph and hail to 1/2 inch diameter fell in Lafayette. Strong microburst winds gusting to 69 mph near Strasburg caused an oil rig to topple onto two vehicles…injuring one person. The strong winds in the area also downed a few power poles… But caused power outages to only a few homes.

In 1995…strong winds spread from the foothills onto the plains. Wind gusts to 77 mph were reported atop Squaw Mountain west of Denver. On the plains…winds gusted to 60 mph at Kennesburg and to 62 mph near Strasburg. North winds gusted to 41 mph at Denver International Airport.

» Click here to read the rest of October 2 to October 8: This Week in Denver Weather History

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Thornton’s weekend to bring slightly cooler temps, slight chances for storms

Friday, September 30th, 2016 5:13am MST

Just a little bit of a change in the weather pattern of recent days. Moisture moving in from the south is going to bring increased cloud cover leading to slightly cooler temperatures and offer just a slight chance for storms during the first part of the three-day period.

For Friday the moisture will give us mostly cloudy skies for most of the day. That will help to hold temperatures down to the mid to upper 80s; still above normal but cooler than the past few. This afternoon some isolated showers and thunderstorms will develop along the Front Range bringing us just a slight chance for precipitation.

Tomorrow the moisture begins to work its way out and that will lead to mostly sunny skies. Mercury readings will be similar to today and the afternoon brings just a slight chance for storm activity.

We close out the weekend on Sunday with a very mild, calm day. Temperatures will again be topping out close to the 80 degree mark.

Have a great weekend!

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Thornton’s Thursday forecast another repeat, just with a few more clouds

Thursday, September 29th, 2016 5:05am MST

Modifying our forecast graphic the last few days has been quite simple as the weather has remained quite constant. That trend more or less continues today with the only really change being the addition of more clouds.

We start out the day with mostly clear skies then will see a gradual increase in clouds as the morning and early afternoon progresses. This will be due to upper level moisture streaming in from the south. That moisture will not infiltrate lower levels keeping us dry. Temperatures today will again be topping out right around 82 degrees.

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Wednesday to again offer lots of sun, above normal temps

Wednesday, September 28th, 2016 5:14am MST

We are set to enjoy a day of weather today almost identical to yesterday. Similar above average mercury readings will be seen along with a nearly cloudless sky above.

The day starts with completely clear skies that will be with us most of the day. The afternoon and evening may bring a few clouds but not many. Temperatures will again be climbing to the low to mid-80s, about 10 degrees above normal.

What lies beyond today? Get the extended forecast here.

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Elon Musk unveils plans for colonizing Mars

Wednesday, September 28th, 2016 4:16am MST

LOS ANGELES — SpaceX Chief Executive Elon Musk on Tuesday unveiled his plans for colonizing Mars, which could eventually involve a fleet of up to 1,000 spaceships to transport as many as 1 million people to the Red Planet. Musk envisions continuous launches from Earth, with massive rockets returning for reuse and spacecraft refueling in a… » Click here to read the rest of Elon Musk unveils plans for colonizing Mars

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Sunny skies, calm conditions and mild temps for Tuesday

Tuesday, September 27th, 2016 5:34am MST

A very simple weather forecast for Thornton today with a total lack of drama. High pressure has settled in with no moisture to be seen and that will lead to a calm, dry and unseasonably warm day.

We will start out with clear skies and that won’t change through the day. No moisture in the air means no clouds. Temperatures today will be climbing to the low 80s, well above the average for the date of 74 degrees.

Live gauges.

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Thornton’s workweek starts with seasonal temps, lots of sun

Monday, September 26th, 2016 5:03am MST

We start out the morning with a bit of a nip in the air as it got quite chilly. That however will wear off quickly and we will enjoy a gorgeous fall day.

Sunny skies will be the rule for Monday lasting throughout the daytime hours. Conditions will be calm, winds light. Temperatures will be warming up to right at or just above the average for the date of 74 degrees.

The balance of the week is going to be nice but also warmer with highs in the general area of the 80-degree mark. The latter part of the week brings slight chances for storms.

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September 25 to October 1: This week in Denver weather history

Sunday, September 25th, 2016 7:14pm MST
This Week In Denver Weather History

September 25 to October 1: This week in Denver weather history

Colorado’s famously inconsistent weather can be seen in our look back at this week in Denver weather history. Not only do we see damaging thunderstorms and winds but even major snowstorms that deposited more than a foot of the white stuff on the city.

From the National Weather Service:


In 1873…a fire was sighted in the woods near Platte Canyon… Probably caused by high winds blowing sparks among the timber.

In 1896…an apparent cold front produced northeast sustained winds to 40 mph with gusts to 48 mph.

In 1910…a thunderstorm produced sustained north winds to 51 mph. This was the highest recorded wind speed in the city in September at the time.

In 1936…a vigorous cold front produced a deadly dust storm in the city. North winds sustained to 36 mph with gusts to 38 mph produced much blowing dense dust…greatly restricting the visibility. The temperature plunged from a high of 84 degrees to a low of 38 degrees by midnight. The weather observer described the event with the following. “at 6:00 pm the temperature was 82 degrees and the wind velocity was only 4 mph; but with the wind shifting to the north and the barometer rising quite rapidly…the temperature fell sharply. By 6:30 pm…the wind velocity increased rapidly and by 7:00 pm had reached a maximum sustained velocity of 36 mph…bringing with it clouds of dust which had been picked up by gale force winds in southern Wyoming and northern Colorado…covering the city. The visibility was generally reduced to about 1/4 mile; however…the whirling of the dust down the streets and alleys…the visibility was at times somewhat less. Airplanes were grounded…traffic was halted at times…and homes filled with dust. The strong winds damaged electric power and telephone lines…leaving homes in darkness for a few hours in the city and for 18 hours in suburban towns and putting 2500 telephones out of service because of broken lines. An electric lineman was killed while repairing damage by the high winds. The dust storm was followed by rain that began falling at 10:55 pm…which turned to snow during the early morning hours of the 26th. A major snow storm followed on the 27th through the 29th.”

In 1999…high winds developed in the foothills of Boulder County. Winds gusted to 90 mph at Wondervu.


In 1908…apparent post-frontal rain changed to snow overnight and totaled 6.5 inches in downtown Denver. This was the first snow of the season. Precipitation totaled 0.76 inch. North winds were sustained to 39 mph on the 25th.


In 1996…an early season snowstorm brought heavy snow to the Front Range eastern foothills. Snowfall totals included: 8 to 12 inches around conifer…7 inches on Floyd Hill…and 6 inches at both Bailey and Chief Hosa. Snowfall totaled only 4.7 inches at the site of the former Stapleton International Airport. This was the first measurable snow of the season. After the passage of a strong cold front…north winds gusted to 38 mph at Denver International Airport on the 25th.


In 1907…a late afternoon thunderstorm produced hail…0.23 inch of precipitation…and north winds sustained to 24 mph.

In 1927…snowfall of 1.7 inches…mixed at times with sleet… Was the first measurable snowfall of the season.

In 2012…a man was seriously injured when he was struck by lightning outside the Hebrew Educational Alliance as he and his family were getting in their car. The victim stopped breathing but was saved when his wife performed cardiopulmonary resuscitation on him immediately.


In 1936…the heaviest snowfall ever recorded in September and the heaviest snowfall ever recorded so early in the season dumped a total of 16.5 inches of snow on downtown Denver and 21.3 inches at Denver Municipal Airport. The 15.0 inches of snow measured from 6:00 pm on the 27th to 6:00 pm on the 28th is the greatest 24 hour snowfall ever recorded in September. This was the first snow of the season. The snow was intermittent through the 26th…but continuous from early afternoon on the 27th to around midnight on the 28th…except for a period of rain during the afternoon of the 28th which contributed to a loss of depth on the ground. The greatest snow depth on the ground downtown was 13 inches with 8 inches at Denver Municipal Airport. There were no high winds with the storm and traffic was interrupted for only a short period. The storm produced property damage estimated at 7 million dollars. With trees and shrubs in full foliage…the leaves caught and held the heavy water-laden snow…until the branches snapped from the weight. More than 3000 workmen were called to remove the debris and snow from the city. The city firemen who were off duty…as well as all the reserves… were asked to report to their stations. All schools in the city remained open…but attendance was only 50 percent of normal. Grade school students were sent home at noon on the 28th. The early storm caught stockmen with many cattle still in higher ranges. Warm weather followed the snow…which had all melted by the end of the month…except for a few inches in sheltered places.


In 1877…smoke from heavy forest fires in the mountains spread over the city on upper wind currents.

In 1935…the first snow of the season was 2.8 inches in downtown Denver. The low temperature dipped to 31 degrees for the first freeze of the season.

» Click here to read the rest of September 25 to October 1: This week in Denver weather history

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Top of Trail Ridge Road closed due to snow

Saturday, September 24th, 2016 6:25pm MST

Ah yes, the changing of the seasons is here and that means our weather conditions go from one extreme to the next.  Following a dry, warm week, Mother Nature brought snow to Colorado’s high country Friday night into Saturday leading to the closure of the highest, continues road in North America.

Rocky Mountain National Park reported dangerous conditions near the top of the Trail Ridge Road resulting in its temporary closure at Rainbow Curve on the east side and Milner Pass on the west side.  Also closed was Old Fall River Road.  Video from Trail Ridge showed a wintry scene looking like the Arctic tundra.

The agency said this was not the seasonal closure – yet.

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