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Thornton, Colorado, USA
UpdatedSun, 18-Nov-2018 6:10am MST 
 

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Thornton’s workweek starts off cooler than normal, warmer weather lies ahead

Monday, July 30th, 2018 5:00am MST

We will enjoy one more day with temps a good ways below normal for this time of year. The rest of the week will feature warming temperatures with most days seeing highs right near average.

For today, we start out with a good bit of cloud cover. That will be easing by mid-morning and by the evening we will have mostly clear skies. Temperatures today will top out in the mid-70s, about 15 degrees below normal. At this time, we don’t expect to see any showers or thunderstorms in our area.

Tonight, skies will continue to clear with lows in the mid-50s.

Looking ahead, high pressure returns and that will help drive temperatures higher. Tomorrow will see highs in the mid-80s then the rest of the week will feature temps within a few degrees of normal for this time of year (90 degrees). Get more details in the extended weather forecast here.

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July 29 to August 4: This week in Denver weather history

Sunday, July 29th, 2018 5:21pm MST
This week in Denver weather history

July 29 to August 4: This week in Denver weather history

The effects of our annual monsoon season are portrayed in detail in our look back at this week in Denver weather history. Numerous cases of flooding resulting from heavy rainfall are seen as are other severe weather events including hail and even tornadoes.

From the National Weather Service:

13-5

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.

18-2

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.
27-31 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.

28-30

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.

29

In 1878…a total eclipse of the sun was observed at 2:20 pm. From before to during the eclipse…the temperature in the sun fell from 114 degrees to 82 degrees…while the shade temperature fell from 89 degrees to 83 degrees.

In 1880…heavy thunderstorm rain and hail flooded streets and ditches.

In 25 minutes…0.76 inch of rain fell on the city along with large hail to 3/4 inch in diameter. There were no strong winds with the storm.

In 1890…a thunderstorm produced sustained west winds to 48 mph with gusts to 60 mph…but only 0.01 inch of rain.

In 1956…heavy rain and hail fell over west and north Denver.

In 1964…hail to 3/4 inch in diameter fell at Lowry Airfield.

In 1978…a small tornado was sighted just east of Parker. No damage was reported.

In 1989…heavy rain drenched all areas of the Front Range… Both in the foothills and adjacent plains. Amounts of 1 to 3 inches were general over the area. Damage was confined to a few minor road washouts and some street…basement…and crop flooding. Thunderstorm rainfall totaled 1.44 inches at Stapleton International Airport where north winds gusted to 43 mph. Lightning struck a 250 thousand dollar home near Nederland and started a fire which destroyed all of it except two garages. Lightning started a fire in a home in Evergreen. It reached the house by hitting a tree…then traveling through a metal clothesline strung between the tree and the building.

In 1995…thunderstorm winds gusted to 59 mph in Brighton. Thunderstorm winds from the south-southeast gusted to 41 mph at Denver International Airport. High temperature of 99 degrees was a new record maximum for the date in Denver.

In 1997…heavy rain caused flooding in an apartment building in Westminster. Several residents had to be evacuated from their apartments. A woman in aspen park received minor injuries…when lightning passed through an office window and struck her. She suffered temporary blindness for about 15 minutes.

In 2003…hail as large as 1 inch in diameter pelted Conifer… Highlands Ranch…and Franktown.

29-30

In 1997…heavy rain caused flooding and flash flooding in central portions of Adams and Arapahoe counties. Two homes were extensively damaged when water flooded the basements and adjacent pasture area in Strasburg. Water 4 to 5 feet deep had pooled in the lower lying areas of the town. A portion of Quincy Road was closed in Arapahoe County when 4 feet of water covered the roadway. Rainfall totaled 3.06 inches at Denver International Airport…establishing a new record for 24-hour rainfall in July. The previous record was 2.42 inches set in 1965 on the 24th and 25th.

30

In 1879…lightning struck a brick kiln in north Denver. Three men were knocked senseless…but all recovered. Rainfall in the city was only 0.09 inch.

In 1881…a thunderstorm dumped heavy rain and hail on the city…causing street flooding and much damage. A heavy torrent of rain fell with 1.10 inches measured in just 20 minutes. Storm total rainfall was 1.60 inches. The rain turned streets into running streams. Wood street crossings were torn up and washed away. The storm caused great damage by flooding many cellars where goods were stored. The brick yards suffered severe damage when the heavy rainfall destroyed many unfired bricks.

In 1913…northeast winds were sustained to 41 mph with gusts to 48 mph.

In 1939…a thunderstorm produced 0.08 inch of rainfall. This was the only measurable precipitation of the month…making the month the second driest July on record.

In 1961…heavy rain and lightning disrupted power lines and caused flooding in Denver. Thunderstorm rains totaled 1.60 inches at 11th and Lincoln in central Denver.

In 1972…the temperature climbed to a high of 100 degrees at Stapleton International Airport.

In 1983…hail 3/4 to 1 inch in diameter fell in central and southeast Denver and in Littleton. Rainfall of 1.50 inches occurred in just 30 minutes in Littleton. There was some street flooding in both cities with wind gusts up to 55 mph.

In 1984…central Aurora was hit by a downpour that produced 1.80 inches of rain and sent water 2 to 3 feet deep into some streets. Before the rain stopped later in the evening… The storm had dropped as much as 2.80 inches of moisture on the city. Thunderstorm rainfall totaled only 0.82 inch at Stapleton International Airport.

In 1985…a tornado was spotted in open country 10 miles southwest of Bennett. No damage was reported. One inch hail was reported in south Lakewood.

In 1997…one man was killed and his girlfriend critically injured when they were struck by lightning on the Kennedy Golf Course in southeast Denver. Both were struck in the head when they took refuge under a tree during a downpour. Lightning struck a home in unincorporated Arapahoe County east of Buckley Field. The fire started in the electrical panel boxes…causing extensive damage to the home. Heavy rain and hail triggered a flash flood in Boulder…which sent water through a window of the financial aid office on the University of Colorado campus. In addition…ceiling tiles…carpets…and dressing rooms were damaged at the Coors Events Center when a pipe draining rainwater broke during the downpour. In all…10 buildings on the campus received water damage estimated at 100 thousand dollars. Hail as large as 1.25 inches in diameter accompanied the heavy rain in Boulder. Thunderstorm rainfall totaled 2.71 inches at Denver International Airport where west winds gusted to 41 mph. This was the greatest calendar day official precipitation ever recorded in July.

In 1998…heavy rain…up to 3 inches in an hour…caused flash flooding problems from Castle Rock to Parker. I-25 north of Castle Rock was closed as high waters covered sections of the highway. Some cars were left floating in the flood waters.

In 2001…a severe thunderstorm produced a wind gust to 70 mph at a wind sensor on the northeast corner of Denver International Airport.

In 2004…a severe thunderstorm produced wind gusts to 71 mph in Evergreen.

In 2005…the temperature climbed to a high of 101 degrees at Denver International Airport. This was a new record maximum temperature for the date.

In addition…this was the 7th day of the month with a high temperature of 100 degrees or more…which set a new Denver record for the most 100 degree days in a month…for a season…and in a year.

31

In 1873…the all-time lowest recorded temperature in July… 42 degrees…occurred. The same temperature also occurred on July 4…1903.

In 1874…during the late afternoon rain and hail fell for 5 minutes followed by brief heavy rain. Pieces of solid ice of irregular shape fell upon the roof of the station. The hail stones measured 1 1/2 inches in diameter. Precipitation (rain and melted hail) was only 0.16 inch.

In 1889…the high temperature climbed to 100 degrees in downtown Denver.

In 1919…heavy thunderstorm rainfall totaled 2.59 inches in downtown Denver during the evening. Rainfall was 1.90 inches in an hour…a new record at that time.

In 1961…over an inch of rain in a short period of time caused flooding of streets and basements in Denver. Rainfall totaled 1.30 inches at 11th and Lincoln in central Denver.

In 1964…the temperature reached 91 degrees in Denver…making this the 27th day of the month that the temperature reached 90 degrees or more. This is the all time record for 90 degree days in a month in Denver.

In 1972…one inch diameter hail fell in Hudson northeast of Denver.

In 1976…during the evening hours extremely heavy thunderstorm rains produced flash flooding in Big Thompson Canyon which killed 144 people between Estes Park and Loveland. No significant weather occurred in metro Denver at the time.

In 1987…1 inch diameter hail fell in Lakewood and 3/4 inch hail fell near Louisville. Southeast Boulder County was drenched with 1.25 inches of rain in just 20 minutes.

In 1993…thunderstorm winds damaged a chimney of a home near Parker.

In 1996…a weak tornado (f0) was sighted 12 miles east of Denver International Airport. No damage was reported.

In 1998…heavy monsoonal thunderstorm rain triggered a mud slide in Blackhawk. The mudslide blocked Main St. and caused an estimated half million dollars in damage to a casino. Heavy thunderstorm rain…up to 3 inches in an hour…caused a flash flood along Buffalo Creek. Portions of County road 126 just south of the town of Buffalo Creek were washed out. The flood waters nearly washed away the bridge as mud and debris slammed into the structure. Hail to 1 3/4 inches in diameter fell near Idaho Springs.

In 2004…severe thunderstorm winds toppled a 65-foot blue spruce tree in Parker. The tree landed on a home damaging the roof and gutters. The downed tree poked dozens of holes into the shingles.

In 2013…severe thunderstorm winds…with gusts estimated to 80 mph…downed power poles which caused scattered outages in and around Byers…Bennett and Strasburg. Some property damage was also observed. Near Byers…aluminum siding and roofing was peeled off sheds. Large hail…up to one inch in diameter…was reported north of Bennett. At Denver International Airport… a peak wind gust to 40 mph was observed from the northeast.

» Click here to read the rest of July 29 to August 4: This week in Denver weather history

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Thornton’s weekend continues the unsettled weather of recent days

Friday, July 27th, 2018 5:08am MST

We’ve managed to enjoy some cooler temperatures and nice precipitation this week so far. Heading into the weekend, temperatures will be largely below normal and we have chances for storms each day.

For Friday, mostly sunny skies will be above with the usual increase in cloud cover in the afternoon. Highs today will top out in the upper 80s. We have a bit less moisture to work with today but may still see some scattered thunderstorm activity from mid-afternoon into the evening. Tonight, partly cloudy skies will be above with lows near the 60 degree mark.

Saturday will again bring mostly sunny skies for the morning, then partly clear conditions in the afternoon. Highs will be a bit cooler and in the mid-80s. The afternoon brings better chances for thunderstorms. Saturday night into Sunday morning, partly cloudy skies will be above with lows again near 60 degrees.

A cold front will arrive Sunday morning leading to cooler temperatures. Highs will be around 80 degrees. There will be more cloud coverage during the day and the afternoon and evening offer up chances for showers and thunderstorms.

Have a great weekend!

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Thornton’s Thursday to feature comfortable temps, another chance for storms

Thursday, July 26th, 2018 5:01am MST

Yesterday brought us another nice shot of rain in somewhat dramatic fashion. Today will see temperatures cooler than normal and again offer a chance for PM storms.

A few showers moved through this morning in the pre-dawn hours but will have moved out by sunrise leaving us mostly sunny skies for much of the day. The afternoon will see an increase in cloud cover as storms move through.

The best chance for storms will come between about 4:00pm and 8:00pm. Right now, models aren’t giving us many hints as to where these will set up. It does appear they will have the potential for brief, heavy rain, gusty winds and perhaps some hail.

High temperatures today will top out near the 80 degree mark.

Tonight, there may be a few lingering showers initially and then skies should clear a good bit. Overnight lows will be near 60 degrees.

Keep an eye on the sky with our interactive weather radar here.

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Seasonal temperatures, increased chance for thunderstorms Wednesday

Wednesday, July 25th, 2018 5:05am MST

A relatively typical day for Thornton for this time of year. We’ll enjoy some sun and temps near normal and the late afternoon and evening give us a decent chance for thunderstorms.

The day starts out under mostly sunny skies with cloud cover gradually increasing. By mid to late afternoon it will be partly sunny. As a cold front backs in, winds will be a bit breezy from mid-morning into the afternoon. Temperatures will top out in the upper 80s then cool as storms start popping up in the afternoon.

As for those storms, by mid-afternoon we should start seeing some activity along the Front Range with the best opportunity coming in the evening. Depending on how things play out, these storms could become numerous and some may turn severe with strong winds and sizeable hail. You will definitely want to keep an eye on the sky.

Some storms may continue to rumble and rain overnight with lows around 60 degrees.

Use our interactive radar to keep watch.

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July 22 to July 28: This week in Denver weather history

Tuesday, July 24th, 2018 8:14am MST
This week in Denver weather history

July 22 to July 28: 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:

7-25

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.

13-5

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.

18-2

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.

19-23

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.

20-23

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.

20-25

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.

22

In 1874…a severe thunderstorm during the late afternoon produced 1.36 inches of rainfall in an hour…most of which fell in 20 minutes. There was much damage from flooding of streets and considerable damage to private property. The lightning was brilliant and continuous during the storm. Seven buildings were struck by lightning in the city…in addition to many places where it struck only the ground. A magnificent example of ball lightning was observed. When about 200 feet above the house tops…the ball exploded and broke into 7 or 8 different balls…each about 6 inches in diameter. Upon reaching about 20 feet above the ground…these balls broke into small fragments about 3 inches long and 1/2 inch wide. A shed situated in an alley about one block away was literally covered with these sparks. After the storm was over…the shed and adjacent area showed no trace of the event. Not the slightest mark could be detected on structures or on the ground.

In 1879…a terrific electrical storm passed over the city during the afternoon. The lightning display was unusually vivid and the crash of thunder seemed at the very house tops. A few homes and buildings were struck by lightning. A home on Capitol Hill sustained much damage to furniture… But the residents in another wing of the house were not injured. Lightning struck a fence at the corner of Curtis and Broadway. A lightning bolt stunned a workman and knocked a mason’s trough from his hand. A school was struck but was not damaged. Lightning struck the ground near tenth and Colfax. Rain fell in torrents for a time…but the heaviest was on the outskirts of the city. Rainfall in the city was only 0.30 inch.

In 1882…lightning struck and killed a man in the northern part of the city.

In 1895…heavy rainfall of 1.53 inches was measured in downtown Denver.

In 1931…the high temperature reached 100 degrees in downtown Denver.

In 1965…lightning struck and killed a boy standing by an automobile near Stapleton International Airport. Scattered heavy showers accompanied by hail and wind occurred across metro Denver. Heavy rain caused some street damage in Commerce City.

In 1973…minor thunderstorm wind damage was reported in Aurora.

In 1983…heavy thunderstorms dumped torrential rain and large hail across metro Denver. The most serious problems were caused by heavy rainfall in the foothills…which produced flooding on bear creek. Runoff from 3 inches of rain in 45 minutes at Kittredge caused bear creek to rise 5 feet in 10 minutes at Morrison…washing out two bridges. One bridge collapsed…plunging a fire truck into the water…but the occupants were not injured. The town was evacuated for 2 hours. Evergreen was drenched with 2.61 inches of rain in 30 minutes…which caused street flooding along with power outages. Hail to golf ball size damaged cars. A deck on a house east of Evergreen was washed away. At Idaho Springs… 2 inches of rain fell in 45 minutes. Golden received 3 inches of rain in an hour with 0.80 inch of rain in seven minutes at Littleton. Heavy rain and large hail also fell in the city of Denver and its northern and eastern suburbs… Causing street flooding. Water was 6 feet deep on one Aurora street.

In 1991…heavy rains caused extensive flooding across north metro Denver. Ralston creek in Arvada flowed out of its banks. At the intersection of I-25 and I-70…up to 8 feet of water covered the highway. A foot of water covered a stretch of I-70 in northwest Denver. Thunderstorm rainfall totaled only 0.82 inch at Stapleton International Airport.

In 1998…lightning sparked a fire which caused extensive damage to a home in Englewood. Most of the second floor was destroyed.

In 2004…severe thunderstorms produced hail to 1.25 inches in diameter in Commerce City and near Brighton.

22-23

In 1991…heavy rains over the palmer divide and along the Front Range caused the South Platte River to flood from near Henderson to Fort Lupton. The river was out of its banks at several locations with water covering the roads through the night. Only minor damage was reported.

» Click here to read the rest of July 22 to July 28: This week in Denver weather history

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Monday’s rain brings big bump in monthly and annual precipitation numbers

Tuesday, July 24th, 2018 5:22am MST

With 1.80 inches having fallen in the bucket yesterday afternoon and evening, Thornton saw a big boost in our rainfall totals for July and the entire year.

In fact, the 1.80 inches from that one storm was more precipitation than we had seen in any single month yet this year.

It did push the month’s rainfall total to above the 11 year average for July however, for 2018 we are still lagging almost 2 inches below what we would normally see by the end of July.

There are still seven days left in the month and monsoonal flow does look to be present in the coming days so we certainly could see things improve further.

You can check out this chart and other monthly summary reports for other weather data here.

Thornton, Colorado monthly rainfall summary for 2018 as of July 24. (ThorntonWeather.com)

Thornton, Colorado monthly rainfall summary for 2018 as of July 24. (ThorntonWeather.com)

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Thornton’s Tuesday to offer pleasant weather with seasonal temperatures

Tuesday, July 24th, 2018 5:07am MST

Following yesterday’s drenching (1.80” of rain), we dry out and warm up today.

The day starts with partly clear skies and perhaps a few spots with fog. Clouds and fog will dissipate not long after sunrise leading to mostly sunny skies for most of the day. The afternoon will see a few more clouds.

Temperatures will be topping out close to the average high for the date of 90 degrees.

This evening may bring some isolated, weak thunderstorms but right now it looks like most activity will be to our south.

Overnight tonight, lows will dip to the mid-60s under partly cloudy skies.

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Thornton’s workweek starts off cooler, potentially wetter

Monday, July 23rd, 2018 5:14am MST

A nice change in the weather for us today as moisture and instability increase giving us a decent chance for precipitation while cooling things down.

The day starts off under cloudy skies and while there may be a slight break or two in the coverage at a few points, for the most part the sky will be covered. Temperatures will be much cooler today with highs topping out in the mid to upper 70s.

For precipitation, a few light showers maybe possible this morning but most of the activity looks to begin around noon with scattered activity then increase in coverage in the afternoon and evening. Some brief, heavy rain with perhaps a bit of hail may be seen along with gusty winds.

Tonight, storm activity should be done by midnight and we will see overnight lows around the 60 degree mark.

Looking ahead, tomorrow we should bounce back with temps near normal and dry conditions. The balance of the week though looks to be a bit cooler than normal with some chances for storms each day. Get more details in the extended weather forecast here.

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Thornton’s weekend to start hot, then cool a bit and bring better chances for storms

Friday, July 20th, 2018 5:29am MST

Hang in there. We see a couple more days with unseasonably warm temperatures then things should cool down and temps near normal can be expected over the longer term.

For Friday, mostly sunny skies will be above with the usual afternoon and evening increase in cloud cover. Temperatures will climb and top out in the mid-90s. We have just a slight chance for thunderstorms in the late afternoon and evening. Tonight, skies remain partly clear with lows in the mid-60s.

Saturday will see a few more clouds throughout the day as moisture increases. Temperatures will still be quite warm with highs in the mid-90s. We do see a better chance for showers in the afternoon and evening tomorrow. Saturday night into Sunday morning, mostly cloudy skies will be above with lows in the mid-60s.

The weekend closes out on Sunday with mostly cloudy skies above and temperatures coming close to normal for the date (90 degrees). We stand a decent chance to see some shower activity.

Previewing next week, Monday should be a good bit cooler as a cold front will have moved through. Then we do rebound but temperatures should stay close to normal.

Have a great weekend!

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