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Thornton, Colorado, USA
UpdatedThu, 20-Sep-2018 5:30am MDT 
 

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Cooler temperatures, slight chance for storms in Thornton on Thursday

Thursday, July 12th, 2018 5:08am MDT

A little bit of a change in the weather pattern we have been seeing in recent days. Temperatures will cool a bit and with moisture increasing, we see a bit of a chance for a thunderstorm.

We start out under sunny to mostly sunny skies in the morning. As moisture aloft increases in the afternoon, so too will the cloud cover.  Highs today will top out close to the average for the date of 90 degrees.

Isolated thunderstorms will initially develop in the high country then we may see some activity here at lower elevations in the afternoon. Best opportunity will be from about 3:00pm to 6:00pm. Gusty winds will be the most notable threat, perhaps some brief, heavy rain under spots that the storm cells pass over.

Tonight, skies will be partly clear with lows in the low to mid-60s.

Keep an eye out for the storms with our interactive radar here.

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Another hot one in Thornton Wednesday, some relief on the way tomorrow

Wednesday, July 11th, 2018 4:58am MDT

We are set to “enjoy” another day of temperatures well above normal today. Tomorrow however, we should finally start seeing some of that much-anticipated monsoonal flow and with it, cooler temperatures and perhaps some precipitation.

For today, we start out under sunny skies and there will be plenty of blue above this morning. The afternoon will bring a few clouds here and there.

Overall conditions will be calm and dry. Temperatures will begin a climb this morning toward a high of around 97 degrees.

Tonight, skies will be partly clear with lows in the low 60s.

Looking ahead, the first batch of monsoonal moisture from the southwest should arrive tomorrow with more coming early next week. This will cool things down and give us some chances for thunderstorms. Get more details in the extended weather forecast here.

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July 8 to July 14: This week in Denver weather history

Wednesday, July 11th, 2018 3:40am MDT
This week in Denver weather history

July 8 to July 14: This week in Denver weather history

In looking back at this week in Denver weather history, one cannot be struck by the hail storms listed, if not for sheer number then by the damage they caused. The biggest of these storms occurred in 1990 and stands in the books as the most damaging hailstorm in United States history.

From the National Weather Service:

29-15

In 2000…the 29th marked the beginning of a near record hot streak for metro Denver. The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.

29-15

In 2000…the 29th marked the beginning of a near record hot streak for metro Denver. The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.

1-18

In 1874…a streak of 18 consecutive days of 90 degrees tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.

4-8

In 1989…one of the most intense heat waves on record roasted metro Denver. The temperature reached 100 degrees or more on 5 consecutive days. The city had previously never recorded more than 2 straight 100-degree days since records began in 1872. Water and electricity usage reached all time highs. The heat wave created extremely dry weather conditions…which contributed to a major forest fire in Boulder canyon on July 9th. The temperature reached 103 degrees on the 8th…and the mercury climbed to 101 degrees on both the 4th and 5th…and to 102 degrees on both the 6th and 7th. The low temperature of 68 degrees on the 8th equaled the record high minimum for the date.

6-23

In 1901…a streak of 18 consecutive days of 90 degrees tied for second with another streak set in the summer of 1874. The record of 24 consecutive days was established in the summer of 2008.
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.

8

In 1905…a thunderstorm produced 0.82 inch of rainfall and northeast winds sustained to 48 mph.

In 1977…strong winds turned over 2 light aircraft at Arapahoe County Airport…now centennial airport.

In 1987…a weak tornado was observed near Bennett.

In 1988…three separate tornadoes were sighted near Bennett. No damage was reported. One inch diameter hail was also reported.

In 1991…lightning started three house fires in Castle Rock. Damage totaled 13 thousand dollars. No injuries were reported.

In 1993…a dry thunderstorm microburst wind gust to 55 mph briefly reduced the surface visibility to 3 miles at Stapleton International Airport.

In 1997…one construction worker was killed and two others injured when a strong thunderstorm wind gust caused the scaffolding they were standing on to collapse near Parker. A dry microburst produced a wind gust to 54 mph at Denver International Airport.

In 1998…heavy thunderstorm rain forced the closure of Hampden Avenue between I-25 and Havana Street in southeast Denver. The high water made 2 or 3 lanes of the street impassable.

In 2001…severe thunderstorms produced large hail…damaging winds…and heavy rain across south metro Denver. Two people received minor injuries when a severe thunderstorm wind gust to 58 mph blew over several tents at the Cherry Creek Arts Festival. The same storm caused the roof of a hardware store in Tamarac Square to collapse. One employee received minor injuries when she was struck in the head by falling debris. The combination of intense rain and wind downed trees and power lines. Electrical power outages affected 35 thousand homes and businesses. At least 50 trees in city parks across south Denver were damaged. Up to 4.50 inches of thunderstorm rain fell across portions of southeast metro Denver. The underpass at I-25 and Parker road was inundated with 5 feet of water. Several other streets and underpasses in Aurora were also closed due to high water. Heavy rain caused extensive damage to several exhibits at the Cherry Creek Arts Festival. Flash flooding occurred when heavy thunderstorm rainfall caused toll gate creek to jump its banks. Several underpasses across south Denver had to be closed due to high water. A man received minor injuries when lightning struck a nearby tree at the Wellshire Golf Course. Hail as large as 1 1/4 inches in diameter fell in Englewood with 1 inch hail in the city of Denver…and 3/4 inch hail in Littleton. Thunderstorm winds gusted to 63 mph at Denver International Airport and to 62 mph in Englewood.

In 2005…a tornado touched down briefly near Brighton…but caused no damage.

In 2011…severe thunderstorms produced hail…up to 1 inch in diameter…and wind gusts to 60 mph across parts of Adams…Broomfield and Denver counties. At Denver International Airport…a peak wind gust to 59 mph from the west.

In 2017…a strong thunderstorm produced hail up to 7/8 inch in diameter in southwest Denver.

9

In 1872…a very brisk wind between 2:00 pm and 3:00 pm spread a cloud of dust and sand into the city.

In 1874…northeast winds at sustained speeds up to 36 mph blew immense clouds of dust from the prairie through the streets of the city around mid-morning. The houses across the street from the weather station were not visible at the peak of the storm.

In 1875…heavy thunderstorm rains caused stream flooding… Which damaged nearly all railroads into the city. Rainfall in the city was only 0.14 inch.

In 1953…heavy thunderstorm rains caused an estimated 2 million dollars damage from flooded stores and basements across metro Denver. The flood waters reached a depth of 3 feet on streets in some sections of the city…damaging streets and automobiles. The heavy rainfall at Lowry Air Force Base totaled 3.90 inches. At Stapleton Airport where the heavy rain briefly reduced the surface visibility to 1/2 mile…only 1.05 inches of rain were measured. North winds gusting to 52 mph caused some damage in east Denver.

In 1982…two small tornadoes were spotted east of Rocky Flats… And a tornado touched down briefly 5 miles east of Brighton. No damage was reported.

In 1984…heavy rain fell over southern sections of metro Denver. Rainfall totaled 1.50 inches in just 15 minutes between Littleton and Sedalia.

In 1987…a thunderstorm microburst produced a wind gust of 58 mph at Erie north of Denver.

In 1988…hail to 3/4 inch in diameter piled up 2 to 4 inches deep in Idaho Springs. Some basements were flooded and several thousand gallons of fuel were contaminated when water flooded a gasoline storage tank. A tornado sighted near Manilla 5 miles west of Bennett remained on the ground for 9 minutes. No damage was reported.

In 1990…a severe thunderstorm produced a tornado and heavy rain over northeast metro Denver. As much as 4 inches of rain fell in just 20 minutes in Commerce City…causing the South Platte River to rise quickly and flood lowland areas. The raging flood waters caused extensive damage to a 30-foot stretch of railroad track embankment…destroyed a railroad trestle and a nearby garage…and washed away a vintage 1960’s show car near east 58th avenue and York Street. The car was found a couple of miles downstream in a pool of deep mud and murky water. Rainfall totaled 1.34 inches at Stapleton International Airport where 1/2 inch diameter hail fell. The same thunderstorm produced a brief tornado in a vacant field near 64th avenue and tower road just east of the rocky mountain arsenal. No damage was reported from the twister. Lightning from the storm caused power outages to as many as 7 thousand homes and businesses.

In 1996…a tornado (f0) was reported 5 miles south of Hudson. No damage was reported. Twin weak tornadoes (f0) formed for a short time near the northeast runways at Denver International Airport. Less than 15 minutes later…a weak tornado (f0) touched down in the employee parking lot at dia. Several car windows were blown out…and a few vehicles sustained minor body damage from flying debris. Several signs were also blown down. Later…twin weak tornadoes (f0) touched down again in open country between DIA and Watkins.

In 2004…severe thunderstorms produced hail to 3/4 inch in diameter near tiny town and wind gusts to 66 mph in Bennett. A thunderstorm wind gust to 56 mph was measured at Denver International Airport.

In 2005…a thunderstorm produced a wind gust to 54 mph at Denver International Airport.

9-10

In 1980…a series of severe thunderstorms hit metro Denver… Dumping heavy rain and producing a spectacular lightning display lasting for several hours. A number of homes were damaged by lightning. Winds gusted to 60 mph at Stapleton International Airport where about half an inch of rain fell in just 10 minutes along with 1/4 inch diameter hail. The evening thunderstorms continued into the early morning hours with total rainfall of 1.35 inches at Stapleton International Airport.

In 1998…thunderstorm rainfall totaled 2.04 inches at the site of the former Stapleton International Airport.

10

In 1878…a lunar rainbow was observed during a light mist and fog.

In 1895…the temperature warmed to a high of only 53 degrees… The all-time record lowest maximum temperature for the month of July.

In 1967…golf ball size hail damaged aircraft at Jefferson County Airport near Broomfield.

In 1983…two people were injured when struck by lightning just southwest of Morrison. A man was injured when he was swept downstream by a flash flood on a tributary of Clear Creek in the canyon 8 miles west of Golden. Heavy thunderstorm rains caused mudslides which closed several roads. Rainfall amounts included: 1.75 inches in 20 minutes in southeast Denver…1.26 inches in 35 minutes in Boulder…2.14 inches in 2 hours in Lakewood…1.70 inches in 45 minutes in Aurora…and 1.25 inches in 30 minutes atop Floyd Hill in the foothills west of Denver.

In 1992…storm spotters reported 3/4 inch diameter hail near the construction site of the new Denver airport just northeast of the city.

In 1995…microburst winds toppled a pine tree 60 feet high and 2 feet in diameter in Denver. The tree fell and injured a man nearby. Microburst winds to 59 mph broke the glass on a door at the national weather service forecast office at the site of the former Stapleton International Airport.

In 1998…thunderstorm rainfall totaled 2.35 inches at Denver International Airport.

In 2000…three children were injured…one critically…when lightning hit a nearby tree at panorama point atop flagstaff mountain just west of Boulder. Lightning hit the tree…entered the ground…then struck the children. Lightning sparked a grassfire that burned about 50 acres at the Rocky Flats Environmental Test Facility. Also… Lightning sparked at least 6 fires in the Hudson and Keenesburg areas as thunderstorms…accompanied with heavy rain…large hail…and tornadoes…moved through southern Weld County. Over 2 inches of very heavy rain caused flooding along an I-76 exit ramp near Keenesburg. The fire department rescued 15 stranded motorists as high water inundated sections of the exit ramp and adjacent highway. Basements were also flooded in Keenesburg. One home reportedly had 7 feet of standing water in the basement before the rain subsided. A weak tornado (f0) touched down briefly near Brighton…but caused no damage.

In 2001…a severe thunderstorm dumped 7/8 inch diameter hail in Wheat Ridge.

In 2002…severe thunderstorms pelted the southern suburbs of metro Denver with large hail. Hail as large as 3 inches in diameter fell 6 miles southeast of Parker. Other large hail reports included 2 inch diameter hail around centennial airport and 3/4 inch hail near Sedalia and Deckers. Hail as large as 3/4 inch was also reported in Broomfield. Runoff from heavy thunderstorm rainfall in the Hayman fire burn area flooded lost creek ranch with up to 18 inches of water just off State Highway 126. Floodwaters damaged a very expensive rug in the lodge. A driveway to a residence was washed away.

In Douglas County…runoff damaged forest access roads in the turkey creek drainage.

In 2011…a severe thunderstorm produced intense microburst winds in southeast Boulder County. A peak wind gust to 75 mph was recorded in superior with gust to 58 mph…2 miles south of Lafayette. At Denver International Airport…a peak wind gust of 31 mph was recorded.

» Click here to read the rest of July 8 to July 14: This week in Denver weather history

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Thornton’s Tuesday may offer our third 100 degree reading of the year

Tuesday, July 10th, 2018 5:06am MDT

“Toasty Tuesday” seems an appropriate way to describe our weather today. Temperatures are going to climb, potentially hitting three digits for the third time this year.

The day starts out with sunny skies and more of the same will be with us throughout the day. Winds are going to be generally calm and out of the southeast. As for those mercury readings, high pressure continues to be the dominant factor and will keep moisture at bay and temperatures up.

Tonight, skies will be mostly clear with lows to the low to mid-60s.

How hot is it right now? Find out here.

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Sunny, dry and hot are the key weather words for Thornton’s Monday

Monday, July 9th, 2018 4:57am MDT

A rather simple forecast for us today. High pressure is going to dominate all of northeastern Colorado leading to dry conditions and hot temperatures.

Sunny skies above will be the rule throughout the day and we don’t expect any sort of thunderstorm activity. The temperatures will be the main story with highs topping out around 97 degrees.

Tonight, skies remain mostly clear with lows to the mid-60s.

Keep an eye on the thermometer here.

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Unseasonably warm temps, calm and dry conditions for Thornton’s weekend

Friday, July 6th, 2018 5:03am MDT

Following last night’s nice little rain, we now dry out and warm up. Friday and the weekend will see temps above normal and dry conditions.

For Friday, mostly sunny skies will be above for most of the day with just a few more clouds in the late afternoon. Highs today will top out in the low 90s. Tonight, skies will be partly clear with lows in the low to mid-60s.

Saturday will offer up more sun than today and similarly dry, calm conditions. Highs will be in the mid-90s. Saturday night into Sunday morning lows will be down to the mid-60s under partly clear skies.

We close out the weekend on Sunday with a few more clouds but again with hot temps. Highs will be in the mid-90s under mostly sunny skies.

Have a great weekend!

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Cooler temperatures, good chances for storms for Thursday

Thursday, July 5th, 2018 5:03am MDT

Moisture is on the increase and that will lead to more clouds today. Most notably though, it also gives us a decent chance to see some precipitation.

We start out under partly clear skies followed by the usual increase in cloud cover in the afternoon. Temperatures will be heading toward a high in the mid-80s offering a break from the 90s of the last few days.

This afternoon and brings a good chance for thunderstorms and showers. Some of these showers could become a bit heavy at times.

Tonight, any lingering showers should be done by midnight or so. Overnight lows will be down to around 60 degrees.

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June 2018 weather recap: Another warm, dry month

Wednesday, July 4th, 2018 7:20am MDT

The running theme so far for 2018 seems to be warmer than normal temperatures and drier that average conditions.  That trend continued in June for Thornton.

Like May, June was somewhat a tale of two halves.  The first half of the month was marked by very dry conditions with no precipitation until the 16th of the month. Similarly, overall temperatures trended well above normal during the first half of June.

While the warm and dry conditions were notable, the most memorable weather event came on the evening of the 18th when large hail pounded the northern half of Thornton.  Extensive damage to homes and vehicles was seen as hailstones pushing 2 inches in diameter struck.

The month also featured Thornton’s hottest mercury reading in six years. We saw a high of 102.4 degrees on the 28th.  You have to go back to June 25, 2012 to find a warmer reading (102.9). Additionally, the reading ties for the second warmest high temperature ThorntonWeather.com has recorded since coming online in 2007.

Thornton saw an overall average temperature for the month of 71.3 degrees. This was well above the 30 year average June temperature for Denver of 67.4 degrees. Out at DIA where Denver’s official measurements are taken, it was even warmer with an average for the month of 72.4 degrees.

Temperatures ranged from a high of 102.4 degrees on the 28th down to a low of 46.8 degrees on the morning of the 25th.  The Mile High City saw it warmest reading of 105 on the 28th as well and its coldest reading of 44 degrees on the 2nd.

The National Weather Service reports that June 2018 will go into the books as the seventh warmest June on record for Denver.  Additionally, three days saw record tying or setting highs. The 5th brought a record high of 95 degrees, the 6th saw a record-tying high of 95 degrees and the 105 degree reading on the 28th was a record for that date.

Denver averages 1.98 inches of precipitation during the month of June. Both Thornton and Denver fell short of that mark.  Thornton saw 1.28 inches fall in its rain bucket while at the airport, it was even drier with only 0.43 inches.

Click here to view Thornton’s June 2018 climate report.

June 2018 temperature summary chart for Thornton, Colorado. (ThorntonWeather.com)

June 2018 temperature summary chart for Thornton, Colorado. (ThorntonWeather.com)

June 2018 precipitation summary chart for Thornton, Colorado. (ThorntonWeather.com)

June 2018 precipitation summary chart for Thornton, Colorado. (ThorntonWeather.com)

CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
320 PM MDT SUN JUL 1 2018

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JUNE 2018...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2018

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH             105   06/28/2018
                        06/26/2012
                        06/25/2012
 LOW               30   06/02/1951
HIGHEST           105R  06/28       104       1       99  06/20
LOWEST             44   06/02        30      14       42  06/13
AVG. MAXIMUM     88.8              82.4     6.4     85.5
AVG. MINIMUM     56.0              52.3     3.7     53.6
MEAN             72.4              67.4     5.0     69.5
DAYS MAX >= 90     16               7.9     8.1        9
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      0               0.0     0.0        0
DAYS MIN <= 0       0               0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         4.96   1882
 MINIMUM            T   1890
TOTALS           0.43              1.98   -1.55     0.33
DAILY AVG.       0.01              0.07   -0.06     0.01
DAYS >= .01         5               8.4    -3.4        5
DAYS >= .10         2               4.6    -2.6        2
DAYS >= .50         0               1.4    -1.4        0
DAYS >= 1.00        0               0.3    -0.3        0
GREATEST
 24 HR. TOTAL    0.25   06/17 TO 06/17

SNOWFALL (INCHES)
TOTAL             0.0               0.0
RECORD            0.4   1919

DEGREE_DAYS
HEATING TOTAL       9                62     -53       25
 SINCE 7/1       5410              6058    -648     5109
COOLING TOTAL     241               133     108      167
 SINCE 1/1        289               155     134      173

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              10.5
RESULTANT WIND SPEED/DIRECTION   1/129
HIGHEST WIND SPEED/DIRECTION    40/240    DATE  06/05
HIGHEST GUST SPEED/DIRECTION    57/160    DATE  06/27

SKY COVER
AVERAGE SKY COVER               0.40
NUMBER OF DAYS FAIR               11
NUMBER OF DAYS PC                 16
NUMBER OF DAYS CLOUDY              3

AVERAGE RH (PERCENT)              42

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORMS            12   MIXED PRECIP           0
HEAVY RAIN                2   RAIN                   5
LIGHT RAIN                5   FREEZING RAIN          0
LT FREEZING RAIN          0   HAIL                   0
HEAVY SNOW                0   SNOW                   0
LIGHT SNOW                0   FOG W/VIS <=1/4 MILE   1
FOG                       5   HAZE                   2

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.
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Thornton’s Independence Day to bring very warm temps, decent chance for storms

Wednesday, July 4th, 2018 5:46am MDT

Not too bad of looking weather for a birthday celebration today. However, afternoon and evening thunderstorms are going to need close watch.

We start out under mostly sunny skies to be followed by a bit of an increase in cloud cover in the afternoon. Winds will be out of the northeast. High temperatures today will be a couple of degrees warmer than normal topping out at around the 90 degree mark.

The afternoon brings a chance for some isolated thunderstorm activity. Best opportunity comes between about 4:00pm and 8:00pm. Things then will begin to settle down and be wrapped up by midnight. Those thunderstorms this afternoon and evening could impact outdoor celebrations with gusty winds, some hail, brief, heavy rain. Be sure to keep an eye on the sky.

Overnight lows will be around 60 degrees.

Watch out for the storms with our interactive radar here.

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Toasty temps, just a slight chance for thunderstorms for Thornton’s Tuesday

Tuesday, July 3rd, 2018 5:01am MDT

Another unseasonably warm day ahead for us. While there is a bit of a chance for storms, it is more likely we will be skipped over.

The day starts under sunny skies then this afternoon we will see an increase in cloud cover. By late afternoon, partly clear skies will be above. Some periods of haze from smoke will be seen.

After about 4:00pm and into the evening we see a slight chance for thunderstorms with gusty winds being the biggest threat from any that do develop. High temperatures today will top out in the mid-90s.

Tonight, skies will be partly clear with an overnight low in the low 60s.

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