Tag Archives: August Weather

August 12 to August 18: This week in Denver weather history

August 15, 2018 Thornton Weather Leave a comment

Denver’s weather calms considerably in August as compared to many other months but the history books show plenty of notable events in our past. Lightning, flooding rain and even a tornado highlight this week in Denver weather history.

8-13

In 1875…clouds of grasshoppers were seen flying through the air on the prevailing winds during each day.

In 1876…the temperature climbed to a high of 100 degrees in downtown Denver.

In 1941…excessive thunderstorm rainfall flooded streets and delayed traffic for a few hours in some sections of the city. The basements of a considerable number of homes and commercial buildings were flooded. The total value of the damage was unknown. Only 0.94 inch of thunderstorm rainfall was recorded downtown.

In 1969…a man and a 9-year old boy were injured…when lightning struck a tree near where they were standing. Both were revived after treatment…but the boy later died of respiratory failure due to electrical shock.

In 1984…heavy thunderstorm rains drenched southern metro Denver. Rural roads in Douglas County received minor washouts. Hail…as large as 3/4 inch in diameter…was reported in southeast Aurora with one inch diameter hail reported near Parker. Rainfall totaled 1.00 inch at Stapleton International Airport.
12-13 in 1975…heavy rains caused flash flooding along the foothills from Denver north. Thunderstorm rainfall totaled 1.56 inches at Stapleton International Airport.

In 2004…a brief cool spell resulted in two daily temperature records. The low temperature of 49 degrees was a record minimum for the 12th…as was the low temperature of 48 degrees on the 13th.

In 1959…thunderstorm winds gusted to 53 mph at Stapleton Airport.

In 1983…thunderstorms dumped torrential rain in Northglenn… Thornton…and Broomfield. Northglenn was drenched with 1.72 inches in 30 minutes. Street flooding was widespread. Hail…as large as 3/4 inch in diameter…was reported 7 miles northeast of Boulder along with heavy rain which caused some street flooding.

In 2000…lightning sparked 3 small grass fires near Golden. The fires were quickly contained. Hail as large as 3/4 inch in diameter fell in Castle Rock.

In 1960…a bolt of lightning struck a man in Henderson… Causing serious burns.

In 1962…the temperature climbed to a high of 100 degrees at Stapleton Airport.

In 1968…a young man on a golf course in Denver was injured when lightning struck a tree under which he was standing. Lightning caused minor damage to a house in Denver. Heavy thunderstorm rain caused local street flooding. One inch diameter hail fell at Jefferson County Airport near Broomfield.

In 1973…winds as high as 85 mph damaged 20 aircraft at the Arapahoe County airport…now centennial airport.

In 1977…three tornadoes were sighted in Bennett. A man suffered a broken leg when hit by a flying board. He was outside his camper home…which was destroyed. All windows were broken in a near-by farmhouse where some shingles were ripped off and a 2 car garage was knocked down. Several vehicles were damaged and a cat…some rabbits…and chickens were killed. A broken oar from a boat was driven into the side of a house. A mobile home was overturned. One old barn was destroyed. Half a dozen homes and several agricultural buildings were damaged just west of State Highway 79.

In 1978…high winds produced much blowing dust…causing many traffic accidents in the Denver-Boulder area. Winds gusts of 70 to 101 mph were recorded. Northwest winds gusted to 44 mph at Stapleton International Airport.

In 1980…lightning hit two power poles in Littleton…causing 400 dollars in damage. Rainfall of 1.23 inches in a short time caused minor flooding…which included damage to a ground floor apartment and partially submerging a few vehicles in water. Thunderstorm rainfall totaled 0.98 inch at Stapleton International Airport.

In 1983…2.10 inches of rain drenched Golden in an hour with similar amounts in Lakewood and Boulder. Over ten thousand dollars worth of plants were washed away at a nursery in Lakewood.

In 1997…twelve motorists were injured in a multi-car accident when strong microburst winds estimated to 50 mph blew blinding dust across I-70 near Bennett.

In 1998…lightning struck a hydro-electric plant in Nederland… Causing a power outage. Residents in the foothills west of Boulder…including Nederland…Ward…Eldora…Jamestown… And Gold Hill…were without power for about an hour.

In 2006…heavy thunderstorm rainfall near Deckers washed away some the banks along State Highway 67 between Deckers and Westcreek. Several driveways on both sides of the highway were also damaged.

In 1899…a thunderstorm produced southwest sustained winds to 43 mph with gusts to 46 mph.

In 1972…a pilot reported a funnel cloud briefly touching the ground in open fields…17 miles east-northeast of Stapleton International Airport.

In 1980…thunderstorm winds gusted to 55 mph in Boulder.

In 1982…brief heavy rain and winds estimated as high as 70 mph occurred in the conifer-Evergreen area. No damage was reported.

In 1990…lightning triggered a small attic fire in a house near Sedalia…20 miles south of Denver. A furious lightning storm caused widespread power outages across southern sections of metro Denver. One lightning bolt knocked out an electrical substation…causing a 90-minute blackout in southeast Denver affecting nearly 10 thousand homes and businesses.

In 2007…severe thunderstorms produced large hail…up to 2 inches in diameter…near larkspur. Extensive damage to vehicles in the area was reported.

In Parker…lightning struck a residence. The ensuing fire damaged the attic and top floor; causing $100000 in property damage.

In 2008…at least three homes were hit by lightning during the early morning hours in Arapahoe County. Lightning also struck two homes in Castle Rock…damaging the roofs.

In 2013…a dry microburst uprooted 30 to 40 large trees across a 12-block area of the Park Hill neighborhood in east central Denver. Several trees were snapped near the base along with numerous branches…8 to 10 inches in diameter. Power poles and lines were also downed with resulted in outages which affected seven hundred residents. One of the downed trees crushed a car`s hood… narrowly missing the driver. At Denver International Airport…a peak wind gust of 22 mph was observed from the southwest.

Continue reading August 12 to August 18: This week in Denver weather history →

Climatology, Thornton Weather

Thornton’s August 2018 preview: Temperatures moderate, severe weather decreases

August 6, 2018 Thornton Weather Leave a comment

As summer vacations wind down and families prepare to send their kids back to school in August, Colorado weather also starts to settle down. The chances for severe weather decrease markedly during August and by the end of the month daytime temperatures are dropping quite a bit as well.

Find out more about what lies ahead with Thornton’s August weather here.

Weather History

August 5 to August 11: This week in Denver weather history

August 5, 2018 Thornton Weather Leave a comment

As we enter August the weather typical is a bit calmer as the atmosphere settles down. However our look back at this week in Denver weather history shows that Mother Nature can still visit plenty of excitement on us.

From the National Weather Service:

In 1881…the low temperature cooled to only 76 degrees…the record high minimum temperature for the month.

In 1889…southwest winds were sustained to 42 mph.

In 1918…hail pelted the city…but was light and caused no damage. Precipitation totaled 0.25 inch. Northwest winds were sustained to 31 mph.

In 1964…lightning struck two boys in Denver while playing ball. One was treated and released from the hospital…but the other boy suffered second degree electrical shock and cardiac arrest and was hospitalized in critical condition for several days.

In 1969…two tornadoes touched down briefly in an open field southeast of Buckley Field in Aurora. No damage was reported.

In 1970…heavy rain in the Indian Hills area in the foothills west of Denver caused flash flooding…which washed out roads and damaged other property. Hail accumulated to a 3 inch depth with stones up to golf ball size; however…most of the damage was from flooding.

In 1982…2.38 inches of rain fell in an hour in Arvada… Causing minor flooding on Ralston Creek. In Westminster… 1 1/2 inches of rain fell…causing damage to streets and culverts. In addition…lightning caused some minor power outages across metro Denver.

In 1983…very heavy thunderstorms hit the southern portion of metro Denver. Heavy rainfall…as much as 2.89 inches in 38 minutes…caused widespread street flooding in southeast Denver. Two feet of water covered a section of I-25. Hail up to golf ball size accompanied the storm in Littleton and Englewood…along with 60 mph winds.

In 1984…a heavy thunderstorm drenched Littleton with up to 2.35 inches of rain in an hour…along with small hail that piled up to 2 inches deep. Flood waters were up to 4 feet deep in parts of town with many basements flooded. There were some power outages caused by lightning.

In 1990…a thunderstorm dumped 1.25 inches of rain in 12 minutes near tower and smoky hill roads in southeast Aurora. Minor street flooding was reported in the area.

In 1992…a pilot reported two funnel clouds near Cheery Creek Reservoir. Both dissipated quickly. Dime size hail fell near Franktown.

In 1994…one inch diameter hail fell near Strasburg. No damage was reported.

In 1999…a dog kennel east of Denver International Airport… Was flooded when a small dam…upstream in Elbert County… Was breached. The floodwaters…up to 4 feet deep…washed away some 6-foot fences and other small buildings. Ten of the 70 dogs boarded at the kennel drowned.

In 2002…a mail carrier was struck by lightning as he inserted a key into a multi-unit mailbox in Bailey. The shock knocked the man back against the mail truck. He suffered minor injuries. Lightning struck a residence in Commerce City. The resulting fire destroyed the roof of a detached garage and damaged much of its contents. Hail as large as 1 3/4 inches in diameter pelted pine. One inch diameter hail fell in Arvada and southwest Denver. Heavy rain triggered a mudslide along U.S. Highway 285 near Bailey. Both lanes of traffic had to be closed until debris could be removed from the highway. Several residences in the Bailey and Glenisle areas were also flooded.

In 2004…heavy thunderstorm rainfall caused localized flash flooding in Virginia canyon near Idaho Springs. Sections of the Virginia Canyon Road had to be closed due to the floodwaters.

In 2008…a severe thunderstorm produced large hail…up to 1 1/4 inches in diameter…northeast of Parker. Several automobiles were damaged.

In 1877…a severe rain…hail…and wind storm struck Denver. The storm produced a one minute sustained wind speed of 75 mph. Rainfall totaled 1.00 inch in 25 minutes. The hail storm damaged vegetable gardens in the city.

In 1954…an unconfirmed tornado was reported in Westminster. A funnel cloud was sighted in the area…but it was not certain if it had touched down. No damage was reported.

In 1980…the temperature reached 100 degrees…setting a new record high for the date.

In 1982…3/4 inch diameter hail was reported in north Denver. Heavy rain caused street flooding in central Denver where 4 to 5 feet of water inundated I-25…closing the freeway for a while. Rainfall across metro Denver ranged up to 2.35 inches in just over an hour. An estimated 2000 basements were flooded. Only 0.01 inch of rain fell at Stapleton International Airport.

In 1991…heavy rain caused flooding at the junction of I-25 and I-70. Dime size hail was reported northeast of Boulder near Niwot.

In 1995…microburst winds gusting as high as 58 mph caused minor damage to an apartment complex in Broomfield. Some homes under construction were also damaged when the winds knocked over 2 by 4 wood beams along with some insulation and roofing materials…which broke a few windows. Microburst winds also overturned a camper near Barr Lake.

In 1996…hail ranging in size from 1 to 1 1/2 inches fell near Bennett.

In 2001…3/4 inch hail fell in the foothills near conifer.

In 2008…a record daily rainfall record was set at Denver International Airport. The record of 1.29 inches in 24 hours broke the previous record of 1.10 inches set in 1929.

In 1948…a brief west moving tornado was sighted 3 miles north-northeast of Stapleton Airport. The white funnel silhouetted against a gray cloud background was very narrow…nearly vertical…and estimated at nearly 5 thousand feet high. A dust cloud formed on the ground around the funnel. No damage was reported.

In 1952…a thunderstorm wind gust to 52 mph was recorded at Stapleton Airport.

In 2014…severe thunderstorms produced large hail across western and southern parts of metro Denver. Near Centennial and Golden…hail up to quarter size was reported. Near Bennett…a peak thunderstorm wind gust to 65 mph was also reported. At Denver International Airport…a peak wind gust to 46 mph was recorded.

In 1874…swarms of grasshoppers invaded the city. Millions of them were seen cruising through the air. The insects were apparently picked up by a thunderstorm gust front and carried into the city. The grasshoppers had ravaged crops in surrounding counties for the last month.

In 1878…the highest temperature ever recorded in Denver…105 degrees…occurred at 3:20 pm. This temperature was equaled on July 20th in 2005.

In 1969…the temperature reached 100 degrees at Stapleton International Airport.

In 1976…in Thornton…a 13 year old boy riding a bicycle was struck and killed by lightning.

In 2000…lightning struck three homes in central Arapahoe County east of Denver. Damage was estimated at 47 thousand dollars.

In 2003…hail to 1 inch in diameter pelted Denver. Hail to 7/8 inch was measured in Boulder.

In 2008…heavy rain also caused flash flooding over south Denver and its nearby suburbs. Heavy rain…from 2.5 to 4 inches…fell in less than 90 minutes. Firefighters rescued 20 people as the water quickly rose along creeks…flooded roadways…and stranded motorists. Three people had to be rescued along Cherry Creek when the bike path flooded.

In Evergreen…a man suffered minor injuries when he was struck by lightning. It entered his finger…traveled down his body… And exited his foot.

In 2013…heavy rain caused localized flash flooding in Aurora. An undergound parking garage at an apartment complex was inundated with 3 to 4 feet of water. Flash flooding forced a road closure at East Mississippi Ave. and Alton St. Also… several people had to be rescued when three vehicles stalled in floodwaters at Alameda Ave. and Havana St. The stationary thunderstorms dumped 2.75 inches of rain in less than 45 minutes. In addition…large hail…up to one inch in diameter…was reported north of Roxbourough State Park. At Denver International Airport…just a trace of rainfall was observed.

Continue reading August 5 to August 11: This week in Denver weather history →

Weather History

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

July 29, 2018 Thornton Weather Leave a comment

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.

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.

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.

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.

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

Climatology, Thornton Weather

August 2017 weather recap: Cooler than normal with near average precipitation

September 5, 2017 Thornton Weather Leave a comment

The last full summer month of the year has come to a close in a rather un-dramatic fashion. Thornton saw a largely pleasant month with temperatures a good bit cooler than we usually expect to see. Precipitation was right near normal however, all of it fell during the first half of the month.

High pressure ruled for the first two days of the month but then the ridge broke down bringing about cooler temperatures on the 3rd of the month. The cool down didn’t last long and while the heat returned for a couple of days, we did finally receive some moisture on the 4th and 5th.

Cooler than normal temperatures returned on the 6th and lasted through the next 10 days. The first half of the month also saw 10 days with measurable precipitation, our only precipitation for the month as the last half of the month saw none at all.

Dry and warm conditions were the rule of thumb for the last two weeks of the month. Both Thornton and Denver saw six of the last nine days of the month bring high temperatures at or above 90 degrees.

Our average temperature for the month came in at 68.9 degrees. This was a good bit below the long term Denver average for August of 72.5 degrees. Out at DIA where the Mile High City’s official measurements are taken, the month was warmer than us but still cooler than normal with an average of 71.5 degrees.

Temperatures in Thornton ranged from a high mark reading of 94.9 degrees on the 29th of the month down to a low of 51.2 degrees on the 11th. Denver saw a maximum reading of 95 degrees on the 19th of the month and a low of 51 degrees on the 4th.

In terms of precipitation, Denver averages 1.69 inches of precipitation during August. Thornton wasn’t too far short of that with 1.43 inches. However, all of that came during the first 15 days of the month. After that, we saw nothing. Denver best us, and the average, with 1.86 inches in their rain bucket.

Click here to view Thornton’s August 2017 climate report.

Thornton, Colorado's August 2017 Temperature Summary. (ThorntonWeather.com) — Thornton, Colorado’s August 2017 Temperature Summary. (ThorntonWeather.com)

Thornton, Colorado's August 2017 Precipitation Summary. (ThorntonWeather.com) — Thornton, Colorado’s August 2017 Precipitation Summary. (ThorntonWeather.com)

CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
639 PM MDT FRI SEP 1 2017

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

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF AUGUST 2017...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2017

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH             105   08/08/1878
 LOW               40   08/26/1910
                        08/25/1910
                        08/24/1910
HIGHEST            95   08/19        96      -1       97  08/09
LOWEST             51   08/04        50       1       47  08/25
                                                          08/20
AVG. MAXIMUM     85.7              87.2    -1.5     86.3
AVG. MINIMUM     57.3              57.9    -0.6     56.2
MEAN             71.5              72.5    -1.0     71.2
DAYS MAX >= 90     10              11.5    -1.5       15
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         5.85   1979
 MINIMUM         0.02   1924
TOTALS           1.86              1.69    0.17     0.22
DAILY AVG.       0.06              0.05    0.01     0.01
DAYS >= .01         6               8.6    -2.6        4
DAYS >= .10         4               4.3    -0.3        1
DAYS >= .50         2               1.2     0.8        0
DAYS >= 1.00        0               0.3    -0.3        0
GREATEST
 24 HR. TOTAL    0.90   08/07 TO 08/07           08/24 TO 08/24

SNOWFALL (INCHES)
RECORDS TOTAL     0.0
TOTALS            0.0 2017          0.0


DEGREE_DAYS
HEATING TOTAL       8                10      -2       15
 SINCE 7/1          8                16      -8       15
COOLING TOTAL     216               244     -28      218
 SINCE 1/1        749               688      61      762

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

WIND (MPH)
AVERAGE WIND SPEED              9.2
RESULTANT WIND SPEED/DIRECTION   2/189
HIGHEST WIND SPEED/DIRECTION    49/320    DATE  08/04
HIGHEST GUST SPEED/DIRECTION    62/320    DATE  08/04

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            7
NUMBER OF DAYS PC             21
NUMBER OF DAYS CLOUDY          3

AVERAGE RH (PERCENT)     50

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM             13     MIXED PRECIP               0
HEAVY RAIN                3     RAIN                       4
LIGHT RAIN               12     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                0     SLEET                      0
FOG                      10     FOG W/VIS <= 1/4 MILE      2
HAZE                      2

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

Weather History

August 27 to September 2: This week in Denver weather history

August 28, 2017 Thornton Weather Leave a comment

This time of year we usually see calm conditions as we begin the transition to fall. However, that is not always the case as is seen in our look back at this week in history. Everything from thunderstorms with hail to tornadoes can and have been experienced.

From the National Weather Service:

19-30

In 1875…grasshoppers appeared in great numbers at 10:00 am on the 19th. Thousands landed on the ground. The streets were literally covered with them. Swarms of grasshoppers were seen on each day. All gardens in the city were devastated…and in the countryside the grasshoppers were very destructive to ripened grain. On the 30th the grasshoppers were so numerous as to almost darken the sun.

26-27

In 1980…two heavy thunderstorms hit Arvada and Westminster… Dumping up to 1.50 inches of rain in less than an hour. At least two streets were washed out and a number of homes and cars were damaged when a creek flooded. Three homes in Arvada sustained minor lightning damage.

In 1910…a thunderstorm produced south winds sustained to 40 mph.

In 1961…strong thunderstorm winds and heavy rain occurred at 79th and Federal Blvd. in Westminster. The strong winds blew the roofs off lumber sheds onto parked cars.

In 1967…a young woman was killed by lightning while horseback riding in the suburbs just west of Denver. Her horse died several hours after the incident. A young man and another young woman were also knocked from their horses by the impact of the lightning and required hospitalization.

In 1991…heavy thunderstorm rainfall totaled 0.91 inch at Stapleton International Airport…where 1/4 inch diameter hail was measured.

In 1996…localized street flooding occurred in the Fort Lupton area when 2 to 3 inches of rain fell in 45 minutes. The roof of a community college began leaking…which caused damage to ceiling tiles. The roof was under repair from hail damage which had occurred earlier in the summer. A weak tornado (F0) was sighted near Fort Lupton. No damage was reported.

In 1999…a slow moving thunderstorm dumped 5 inches of rain in 2 hours near Dacono. A severe thunderstorm produced 3/4 inch diameter hail in Castle Rock.

In 2002…severe thunderstorms spread large hail over metro Denver. Hail as large as 2 inches in diameter fell in Jefferson County 5 to 11 miles northwest of Golden. Other large hail reports included: 1 1/2 inches near Golden and in Lakewood; 1 1/4 inches in Nederland; 1 inch hail near Elizabeth…Louviers…Rollinsville…and Blackhawk; 7/8 inch hail near Acequia in Douglas County. A thunderstorm produced a trace of rain and a microburst wind gust to 52 mph at Denver International Airport.

In 2003…lightning struck a house and sparked a fire in Arvada. Damage to the roof and ceiling was extensive.

In 2005…lightning struck an unoccupied home in Parker. The resulting fire damaged the roof…attic…and second floor bedroom. Damage was estimated at 15 thousand dollars.

27-28

In 2004…a brief chilly spell resulted in three temperature records. The high temperature of 55 degrees on the 27th was a record low maximum for the date. The low temperature of 48 degrees on the 27th equaled the record minimum for the date. The low temperature of 42 degrees on the 28th was a record minimum for the date.

In 1887…a dry thunderstorm produced north winds to 48 mph but only a trace of rainfall.

In 1968…one man was seriously injured by lightning while riding on a roller coaster at a Denver amusement park. An airline employee was injured when lightning struck a jetliner he was servicing at Stapleton International Airport. A lightning-caused fire did extensive damage to one house and minor damage to several others in the city of Denver.

In 1970…a microburst wind gust to 53 mph was recorded at Stapleton International Airport.

In 2002…a severe thunderstorm produced 3/4 inch diameter hail near Parker.

In 2005…lightning sparked a small fire near Jamestown. The blaze was quickly contained and consumed less than an acre.

In 1876…after the passage of a gentle rain shower to the east during the late evening hours…the moon shone brightly and a remarkably bright lunar rainbow appeared.

In 1910…an apparent cold front produced sustained northeast winds to 40 mph.

In 1946…the high temperature warmed to only 55 degrees…the record low maximum for the month.

In 1989…a spectacular lightning display knocked out power to 300 blocks in southeast Denver. One bolt started a fire in a lumber yard in the northeast part of the city…and the attic of a home in the same area was set ablaze by a lightning bolt.

In 1996…3/4 inch diameter hail was measured in Parker.

In 2000…lightning struck two homes in Thornton. The extent of damage was unknown.

In 2002…two small tornadoes caused damage in southeast metro Denver. The first tornado…associated with a multi-vortex storm…touched down briefly near E-470 and South Jordan Road. Some fences were damaged…and a few trees were blown down. A few of the homes also sustained minor roof damage. Damage from this storm totaled 100 thousand dollars. The second tornado associated with the storm touched down in a subdivision that was under construction at Gartrell and Arapahoe roads. Four large condominiums under construction were destroyed. The most heavily damaged portions of the structures were still in the framing stages. Adjacent sections where enclosed walls were in place were not destroyed. A man suffered 4 broken ribs and several cuts and bruises when the trailer he sought shelter in was flipped three times and torn apart by the twister. Damage from this storm totaled 6 million dollars. A severe thunderstorm produced 1 inch diameter hail near Evergreen.

In 2006…severe thunderstorms produced large hail in the foothills west of Denver. Hail to 1 inch in diameter fell near Blackhawk. Hail as large as 7/8 inch was measured near Idaho Springs…along with 3/4 inch hail near Nederland and conifer.

In 1981…60 mph winds were reported in Boulder.

In 2004…a severe thunderstorm produced hail as large as 1 inch in diameter in south Aurora near Cherry Creek.

In 1951…hail as large as 1 3/4 inches in diameter caused an estimated 300 thousand dollars damage in metro Denver. Hail as large as 1 1/2 inches in diameter was measured at Stapleton Airport.

In 1978…strong thunderstorm winds tore the roof off an apartment building in Aurora…downed trees…and damaged windows in Denver. A microburst wind gust to 58 mph was recorded at Stapleton International Airport.

In 1985…a thunderstorm wind gust to 60 mph was clocked at Buckley Field in Aurora.

In 1997…hail to 1 1/4 inches in diameter was measured in Aurora.

In 2006…a female postal worker was struck and injured by lightning while delivering mail in Westminster.

In 2008…lightning struck a home in Brighton…damaging the roof and a bedroom. The damaged totaled 20 thousand dollars.

Continue reading August 27 to September 2: This week in Denver weather history →

Weather History

August 20 to August 26: This week in Denver weather history

August 20, 2017 Thornton Weather Leave a comment

Denver’s weather is not often boring. Lightning, hail, tornadoes and even swarms of grasshoppers have made appearances this week in Denver weather history.

From the National Weather Service:

19-30

In 1980…winds to 55 to 60 mph were recorded in south Boulder.

In 1982…strong thunderstorm winds blasted the Jefferson County Airport near Broomfield…causing an estimated 3 million dollars in damage. At least 5 hangars and 15 airplanes were damaged…many seriously; one hangar was completely destroyed. Torrential rains accompanied the winds. Heavy rains also dumped on Boulder where 1.65 inches fell in just 15 minutes…causing street flooding. Wind gusts to 72 mph were recorded in Boulder. Over half an inch of rain fell in just 5 minutes in Littleton where two homes were struck by lightning. Lightning also struck a house in Arvada where over an inch of rain sent Ralston Creek over its banks. Strong winds accompanied the storms.

In 1984…slow moving thunderstorms dumped 1.25 inches of rain in Evergreen…causing street flooding. A half inch of rain fell in just 18 minutes in southeast Denver. Littleton and Boulder were also drenched with about an inch of rain. Rainfall totaled 0.92 inch at Stapleton International Airport.

In 2001…severe thunderstorms produced damaging winds and large hail across metro Denver. Hail as large 1 inch in diameter fell in Aurora near Cherry Creek. Strong thunderstorm winds gusting as high as 58 mph blew the roof from a building between Thornton and Denver and toppled several trees in Denver. One tree landed on a mail truck. Other thunderstorm winds were clocked to 60 mph near Parker… 62 mph in Broomfield…and 61 mph at Denver International Airport.

In 2006…a tornado (f0) touched down near Bennett…but caused no reported damage.

In 2013…severe thunderstorms pounded the southern Denver suburbs and other parts of the Front Range. In Jefferson County…water rescues were reported for some people in stranded cars. In the Ken Caryl area…large hail from one inch to 1 3/4 inches in diameter was reported. On West Chatfield Avenue in Jefferson County…hail runoff gathered six inches deep in spots and “hail plows” were sent out to clear some streets. Hail up to one inch in diameter was also reported near Castle Rock.

In 1876…heavy thunderstorm rain and hail struck the city. Hail stones as large as partridge eggs accumulated to a depth of 1 1/2 feet over eastern portions of the city. The heavy rainfall flooded streets and gutters. However… No significant damage was reported. Rainfall totaled 0.85 inch in central Denver.

In 1903…a thunderstorm produced west winds sustained to 42 mph with gusts to 48 mph.

In 1957…heavy thunderstorm rainfall and hail over the bear creek basin flooded portions of State Highway 8 in and near Morrison. There was also minor property damage in Morrison.

In 1995…a 68-year-old woman was struck by lightning while standing near a tree in Brighton.

In 2006…a severe thunderstorm produced 7/8 inch diameter hail in Franktown.

Continue reading August 20 to August 26: This week in Denver weather history →

Weather History

August 13 to August 19: This week in Denver weather history

August 14, 2017 Thornton Weather Leave a comment

Severe weather is a fact of life in Colorado during the summer months and while August is historically relatively calm, that isn’t always the case. In our look back at this week in Denver weather history we see the dangers of lightning, incidents of large hail and flooding rains and even a tornado.

From the National Weather Service:

8-13

In 1875…clouds of grasshoppers were seen flying through the air on the prevailing winds during each day.

12-13

In 1975…heavy rains caused flash flooding along the foothills from Denver north. Thunderstorm rainfall totaled 1.56 inches at Stapleton International Airport.