Weather History

October 30 to November 5 – This Week in Denver Weather History

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October 30 to November 5 - This Week in Denver Weather History
October 30 to November 5 - This Week in Denver Weather History

The further we go into the cold season, the more we see significant winter-like events in our look back at Denver weather history. Many significant snowstorms have occurred this week in the past including one in 1946 that dumped more than 30 inches of snow on Denver.

From the National Weather Service:

28-30

In 1971…a vigorous cold front plunged temperatures from a high of 70 degrees on the 27th to record low levels on the 29th and 30th. Snowfall totaled 3.1 inches at Stapleton International Airport where north winds gusted to 23 mph. Some freezing drizzle also fell on the 28th. Record daily low maximum temperatures of 32 degrees on the 28th and 25 degrees on the 29th were established along with a daily record minimum of 13 degrees on the 30th.

28-31

In 1929…rain changed to snow on the afternoon of the 28th and continued until midday on the 30th followed by intermittent light snow which continued through the 31st. Snowfall over the four days totaled 16.2 inches in the city. Most of the snow…8.5 inches…fell on the 29th with 6.1 inches on the 30th. Temperatures hovered in 20’s during most of the storm.

29-30

In 1905…heavy snowfall developed on the evening of the 29th and continued through the evening of the 30th. Snowfall totaled 11.0 inches in downtown Denver. Precipitation was 1.02 inches. Temperatures were generally in the 20’s.

In 1959…rain during most of the day on the 28th changed to snow early on the 29th and continued through most of the 30th. Heavy snowfall totaled 7.4 inches at Stapleton Airport. North-northeast winds gusted to 24 mph on the 30th. Some freezing drizzle also occurred on the 30th.

In 1981…4 to 8 inches of new snow were recorded in the foothills west of Denver. Snowfall totaled only 0.4 inch at Stapleton International Airport where north winds gusted to 25 mph.

29-31

In 1889…the first snowfall of the season totaled 14.0 inches over the three days in downtown Denver. Snowfall was 8.0 inches on the 29th and 5.0 inches on the 31st. North to northeast winds gusted to 30 mph on the 29th.

In 1950…a warm spell resulted in five daily temperature records. Record highs of 84…80…and 79 degrees occurred on the 29th…30th…and 31st…respectively. Low temperature of 49 degrees on the 30th was the record high minimum for the date.

In 1991…the second surge of cold arctic air in a matter of days plunged metro Denver into the deep freeze. While low temperatures remained above zero…high temperatures were only in the 20’s. Three temperature records were set: record lows of 7 degrees on the 30th and 10 degrees on the 31st and a record low maximum of only 21 degrees on the 30th. Snowfall was light with only 1.9 inches recorded at Stapleton International Airport where east winds gusted to 23 mph.

In 2002…snowfall totaled 4.3 inches at the site of the former Stapleton International Airport. North winds gusted to 32 mph on the 29th behind a cold front…which plunged temperatures well below seasonal normals. High temperatures of 18 degrees on the 30th and 19 degrees on the 31st were record low maximums for each date. Low temperatures dipped to 12 degrees on the 30th and 15 degrees on the 31st.

29-1

In 1972…heavy snowfall totaled 15.5 inches at Stapleton International Airport. However…the heaviest snow occurred on Halloween night when 7 inches fell on trick-or-treaters during a short 3-hour period. I-25 was closed south of Denver. North winds gusting to 29 mph caused some blowing snow on the 1st. The snow started late on the 29th and ended during the mid afternoon on the 1st. The greatest snow depth on the ground at Stapleton International Airport was 13 inches on the 1st.

30

In 1974…a rare thunderstorm for so late in October produced hail to 3/8 inch in diameter and 0.10 inch of rain at Stapleton International Airport.

In 1991…the high temperature warmed to only 21 degrees…the all-time record low maximum for the month of October. The same temperature also occurred on October 25…1997.

31

In 1997…high winds buffeted the foothills and adjacent areas of metro Denver. West winds gusted to 70 mph in Broomfield and to 40 mph at Denver International Airport. The strongest winds occurred in the mountains west of Denver and in the foothills north of Denver.

In 2001…high winds developed in the foothills. Peak wind gusts were measured to 74 mph at the National Center for Atmospheric Research on the mesa in Boulder and to 72 mph near Rollinsville. West winds gusting as high as 53 mph warmed the temperature to a high of 71 degrees at Denver International Airport.

31-1

In 1951…6.4 inches of snowfall were measured at Stapleton Airport.

In 1989…a Halloween storm dropped 3 to 6 inches of snow on metro Denver with the adjacent foothills receiving 5 to 10 inches. Snowfall totaled 4.5 inches at Stapleton International Airport…where north winds gusted to 31 mph on the 31st. Most of the snow fell on the evening of the 31st…but the storm left icy streets throughout metro Denver on the morning of the 1st…making it a “spooky” commute for many motorists.

In 2004…heavy snow fell in and near the foothills of Jefferson and Douglas counties. Storm total snowfall included: 14.5 inches in aspen park…10 inches at Boxborough state park and and near Sedalia…8 inches near bergen park…and 7 inches in Highlands Ranch. Snowfall totaled only 3.2 inches in the Denver Stapleton area. Post-frontal northeast winds gusted to 41 mph at Denver International Airport.

Continue reading October 30 to November 5 – This Week in Denver Weather History →

Thornton Weather

City of Thornton offers residents winter weather preparedness tips

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The City of Thornton wants residents to be prepared for the coming cold weather.
The City of Thornton wants residents to be prepared for the coming cold weather.

As we have been covering all week, by the governor’s declaration this is Winter Weather Preparedness Week in Colorado.  The City of Thornton has gotten on board with information to help the city’s residents prepare themselves for the coming season.

Thornton has become much more ‘weather aware’ in recent years and we applaud them for that.  Weather has a direct impact on everyone’s lives, too often with deadly effects, and it is important that people are aware of the dangers it presents.

The new page on the city’s website provides some great resources for residents.  On the page you will find information from the National Weather Service, a great document prepared by the Thornton Fire Department about winter safety and information about the city’s snow removal plan.

We do have to make note of a couple of things on the page.

First, there is no link to ThorntonWeather.com.  We are not affiliated with the city in any way however we are the only source of truly local weather news and information.  The city must be careful of who they put out there as a recommended resource but ThorntonWeather.com is well-established having been around for more than five years and being well known and highly regarded in the community.  We pride ourselves on the wealth of information we provide, an amount that far surpasses any other.

Second, it is somewhat ironic that one of the links provided on the city’s page is for Emergency Alert Information from the Colorado Division of Emergency Management.  This is a great resource page but as we have pointed out repeatedly, neither the city nor Adams County has any sort of emergency alert system.  This is a serious deficiency that the city has chosen not to address at this time.


Thornton Weather

Thornton goes from record high temps to heavy snow in a few short days

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Denver saw a big change in the weather in a very short period of time.
Denver saw a big change in the weather in a very short period of time. Click the image for a slideshow of images from the snowstorm.

The weather in Colorado is famously variable and in a span of a few short days this was fully evident.  We went from record high temperatures to a winter-like snowstorm and back to sunny skies in four days.

On Monday, October24, Denver set a record high temperature of 80 degrees, besting the record high for the date of 79 degrees last set in 1999.  Thornton was just a touch cooler for the day with a high of 79 degrees.

Tuesday was a day of transition as we started with sunny skies but clouds rolled in during the afternoon and rain was falling by the evening.  As darkness descended and temperatures fell, the rain changed to snow and we started our first snowstorm of the season.

In the Denver metro area, snow totals ranged from a few inches to as many as 9 in the western and northwestern suburbs. Denver International Airport recorded 8.5 inches, more than double the 4.1 inch average for the month of October.  Here in Thornton, we lagged a bit with 6.6 inches of the white stuff.

Across Thornton and much of the Front Range, the heavy wet snow caused its share of problems.  Many trees had yet to lose their leaves and branches broke under the weight of the snow.  Power outages were seen across the region including many in Thornton.

The majority of Xcel Energy customers should have power restored tonight with some having to wait till tomorrow afternoon.  Click here for the Xcel Energy power outage map.

As the storm settled in, five participants at the sparsely occupied Occupy Denver protest suffered hypothermia according to organizers.  Denver Police continue to arrest those that defy the law against camping in Civic Center Park and adjacent areas.

Slideshow - Snowstorm covers Denver in blanket of white. (Examiner.com)While the storm moved out before nightfall Wednesday, it left clearing skies which led to bitterly cold temperatures.  Denver International Airport recorded an early morning low of 14 degrees, the coldest temperature the city has seen since March 5th. Here in Thornton we dropped to a low of 12.8 degrees.

The latest forecasts show we are in for a gradual warm up but one that will keep temperatures below normal through the weekend.  Beyond that, we may be getting our next shot of snow as soon as late in the day next Tuesday.

The video below was captured by our west facing webcam.  You can see as the snow builds the trees start sagging and struggle under the weight of the snow.

Weather History

October 23 to October 29 – This Week in Denver Weather History

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October 22 to October 29 - This Week in Denver Weather History
October 22 to October 29 - This Week in Denver Weather History

It’s not quite Halloween but leading up to the holiday we see plenty of  ‘scary’ weather in our look back at this week in Denver weather history. High winds are relatively commonplace and so too are major snowstorms. One recent event in 1997 dumped 14 to 31 inches of the white stuff on the metro area.

From the National Weather Service:

18-23

In 2003…an extended warm spell resulted in 5 new temperature records. The high temperature of 84 degrees on the 18th equaled the record high for the date. High temperatures of 86 degrees on the 19th…83 degrees on the 21st…and 84 degrees on the 22nd were record highs for the dates. Low temperature of 49 degrees on the 23rd was a record high minimum for the date. Low temperatures during the period were in the 40’s and lower 50’s.

19-23

In 1906…heavy snowfall totaled 22.7 inches in the city over the 5 days. Rain changed to snow on the evening of the 19th…and snow continued through the late afternoon of the 23rd. The heaviest amount of snowfall…16.0 inches…fell from 8:00 pm on the 20th to 8:00 pm on the 22nd. The most snow on the ground was 13.3 inches on the evening of the 23rd. This was the first snow of the season and the only snow of the month. Winds during the storm were from the north at sustained speeds of 20 to 30 mph each day. Temperatures during the storm were generally in the 20’s.

22-23

In 1914…post-frontal rain changed to snow. Precipitation totaled 2.72 inches…most of which was in the form of moist snow which melted as it fell in the business section of the city. About 3 inches of snow was measured on lawns in the residential areas on the morning of the 24th. Official snowfall totaled only 0.4 inch downtown… But an estimated 8.0 inches of snow melted as it fell. North to northeast winds were sustained to 29 mph with gusts to 30 mph on both days.

In 1975…a vigorous cold front moving across metro Denver followed by strong northeast winds gusting to 52 mph produced billows of blowing dust and plunged the temperature 21 degrees in an hour. The surface visibility was reduced to 1/4 mile in blowing dust at Stapleton International Airport. The temperature cooled from a daily record high of 81 degrees to a low of 38 degrees by day’s end. The first snowfall of the season totaled 2.7 inches on the 23rd. This was the only measurable snow of the month at Stapleton International Airport.

In 1995…heavy snow fell on the Palmer Ridge south of Denver and in the foothills west of Denver where snow amounts ranged from 4 to 8 inches. Sedalia…south of Denver… Received 8 inches of snow. Winds strengthened on the plains and produced blizzard conditions…reducing surface visibilities to less than 1/4 mile. I-70 was closed from just east of Denver at Gun Club Road to the Kansas border. Ten inches of snow fell at Strasburg east of Denver where north winds at sustained speeds of 35 to 45 mph with gusts as high as 60 mph produced 2 to 4 foot drifts. Snowfall totaled only 2.2 inches at the site of the former Stapleton International Airport. North winds gusted to 51 mph at Denver International Airport.

23

In 1876…skies were fair…but winds were sustained to 48 mph.

In 1942…a major storm dumped 10.2 inches of snow over downtown Denver. Post-frontal northeast winds were sustained to only 13 mph.

In 1955…the first snowfall of the season and the only measurable snow of the month dumped 4.1 inches of snow on Stapleton Airport. This was the single heaviest October snowfall in 13 years since 1942. The storm also brought the first sub-freezing temperatures of the season when the temperature dipped to a low of 25 degrees.

In 1956…southwest winds gusted to 53 mph and produced some blowing dust at Stapleton Airport.

In 1967…a northwest wind gust to 51 mph was recorded at Stapleton International Airport. In downtown Boulder… Winds were sustained at 20 mph with gusts in excess of 40 mph.

In 1981…strong winds occurred in the foothills. Wind gusts to 70 mph were reported at Wondervu.

Continue reading October 23 to October 29 – This Week in Denver Weather History →

Colorado Weather, Thornton Weather

NOAA releases winter outlook: La Niña’s return could mean another dry winter in Thornton

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Winter weather outlook
What will this winter hold for Thornton?

Strengthening La Niña conditions in the Pacific could lead to another dry winter on the Colorado Front Range according to the winter 2011 / 2012 outlook released by NOAA.  However, as we well know, Mother Nature is never consistent and other factors could give us some help.

Last year a relatively strong La Niña made ski areas in Colorado very happy while at lower elevations we were bone dry.  The high country saw record-setting amounts of snowfall but Denver endured its second least-snowiest season on record.

While temperatures in the Equatorial Pacific Ocean are indeed cooler than normal – and getting cooler – at this point they remain warmer than they were last year at this same time.  This does help us hold out some hope that the winter won’t be as dry as last year.

It should also be noted that the effects of La Niña and El Niño in Colorado are much harder to predict and less consistent than in other places in the nation.  Our location near the middle of the country with the monstrous Rocky Mountains adjacent to us oftentimes throws a wrench in the works.

From NOAA:

U.S. dealt another La Niña winter but ‘wild card’ could trump it
Devastating drought in Southern Plains likely to continue

NOAA's winter 2011 temperature outlook.
NOAA's winter 2011 temperature outlook. Click the image for a larger view.

The Southern Plains should prepare for continued drier and warmer than average weather, while the Pacific Northwest is likely to be colder and wetter than average from December through February, according to the annual Winter Outlook released today by NOAA.

For the second winter in a row, La Niña will influence weather patterns across the country, but as usual, it’s not the only climate factor at play. The ‘wild card’ is the lesser-known and less predictable Arctic Oscillation that could produce dramatic short-term swings in temperatures this winter.

NOAA expects La Niña, which returned in August, to gradually strengthen and continue through the upcoming winter. It is associated with cooler than normal water temperatures in the tropical Pacific Ocean and influences weather throughout the world.

“The evolving La Niña will shape this winter,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “There is a wild card, though. The erratic Arctic Oscillation can generate strong shifts in the climate patterns that could overwhelm or amplify La Niña’s typical impacts.”

The Arctic Oscillation is always present and fluctuates between positive and negative phases. The negative phase of the Arctic Oscillation pushes cold air into the U.S. from Canada. The Arctic Oscillation went strongly negative at times the last two winters, causing outbreaks of cold and snowy conditions in the U.S. such as the “Snowmaggedon” storm of 2009.  Strong Arctic Oscillation episodes typically last a few weeks and are difficult to predict more than one to two weeks in advance.

NOAA's winter 2011 precipitation outlook.
NOAA's winter 2011 precipitation outlook. Click the image for a larger view.

With La Niña in place Texas, Oklahoma, New Mexico and parts of surrounding states are unlikely to get enough rain to alleviate the ongoing drought. Texas, the epicenter of the drought, experienced its driest 12-month period on record from October 2010 through September 2011.

Stormy periods can occur anytime during the winter season. To improve the ability to predict and track winter storms, NOAA implemented a more accurate weather forecast model on Oct.18.  Data gathered from the model will support local weather forecast office efforts to prepare for and protect the public from weather events. This service is helping the country to become a Weather-Ready Nation at a time when extreme weather is on the rise.

According to the U.S. Winter Outlook (December through February) odds tilt in favor of:

  • Pacific Northwest:  colder and wetter than average. La Niña often results in below-average temperatures and increased mountain snow in the Pacific Northwest and western Montana during the winter months. This may set the stage for spring flooding in the Missouri River Basin;
  • California: colder than average and wetter than average conditions in northern California and drier than average conditions in southern California.  All of the southern part of the nation are at risk of having above normal wildfire conditions starting this winter and lasting into the spring;
  • Northern Plains: colder and wetter than average.  Spring flooding could be a concern in parts of this region;
  • Southern Plains and Gulf Coast States: warmer and drier than average. This will likely exacerbate drought conditions in these regions;
  • Florida and south Atlantic Coast: drier than average, with an equal chance for above-, near-, or below-normal temperatures. Above normal wildfire conditions;
  • Ohio and Tennessee Valleys: wetter than average with equal chances for above-, near-, or below-average temperatures. Potential for increased storminess and flooding;
  • Northeast and Mid-Atlantic: equal chances for above-, near-, or below-normal temperatures and precipitation. Winter weather for these regions is often driven not by La Niña but by the Arctic Oscillation. If enough cold air and moisture are in place, areas north of the Ohio Valley and into the Northeast could see above-average snow;
  • Great Lakes: colder and wetter than average;
  • Hawaii: above-average temperatures in the western islands with above normal precipitation during the winter.  Some drought recovery is expected across the state with Kauai and Oahu having the best potential for full recovery.
  • Alaska: colder than average over the southern half of the state and the panhandle with below average precipitation in the interior eastern part of the state.

This seasonal outlook does not project where and when snowstorms may hit or provide total seasonal snowfall accumulations. Snow forecasts are dependent upon winter storms, which are generally not predictable more than a week in advance.

Weather History

October 16 to October 22 – This Week in Denver Weather History

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October 16 to October 22 - This Week in Denver Weather History
October 16 to October 22 - This Week in Denver Weather History

Snow and wind are two common conditions we see this time of year and our look back at this week in Denver Weather History certainly has those type of events. Also notable is a surprising October hail storm 13 years ago that went into the books as one of the costliest in history.

From the National Weather Service:

13-16

In 1873…smoke from several large forest fires in the mountains made the air very hazy in the city.

15-16

In 1928…a thunderstorm produced hail shortly after midnight on the 15th. Rain changed to snow by evening. Through the afternoon of the 16th…the heavy snowfall totaled 7.3 inches in the city. North winds were sustained to 23 mph on the 15th.

In 1984…the heaviest October snowstorm in several years hit eastern Colorado with a vengeance. The storm was known as the “Bronco Blizzard” since it occurred during a nationally televised Monday Night Football game in Denver. One to two feet of snow fell near the foothills in west metro Denver with 2 to 3 feet in the foothills. Wind gusts up to 55 mph whipped the snow into drifts as high as 4 feet. The storm closed schools…roads…and airports. I-70 was closed both east and west of Denver. I-25 was closed south to Colorado Springs. Flights were delayed for several hours at Stapleton International Airport. Power outages were widespread. Snowfall totaled 9.2 inches at Stapleton International Airport where north winds gusting as high as 40 mph caused frequent surface visibilities of 1/4 to 1/2 mile in moderate to heavy snow and blowing snow overnight. The high temperature of only 35 degrees on the 15th was a record low maximum for the date.

15-17

In 1989…an autumn snowstorm hit metro Denver with 2 to 6 inches of snow. Snowfall totaled 4.4 inches at Stapleton International Airport where the maximum snow depth on the ground was only 3 inches due to melting and north winds gusted to 25 mph on the 15th. The heavy wet snow caused leafy branches to sag onto power lines…resulting in a number of power outages. Five thousand homes were blacked out in Boulder on the 16th. Up to a foot of snow fell in the higher foothills with 19 inches recorded at Echo Lake.

16

In 1878…high winds reached sustained speeds of 60 mph.

In 1998…one of the costliest hail storms to ever hit metro Denver caused an estimated total of 87.8 million dollars in damage to homes…commercial buildings…and motor vehicles. At the time the storm was ranked as the 7th costliest ever. The hailstorm…rare for so late in the season…began over portions of Arvada…Wheat Ridge…and northwest Denver where mostly pea sized hail accumulated up to a depth of 6 inches near I-70. Several accidents were attributed… At least in part…to the hailstorm. Snowplows had to be called out to clear several city streets. The storm intensified as it moved to the east…into the Denver and Aurora areas. Large hail…up to 2.00 inches in diameter pounded east and southeast metro Denver. Two inch diameter hail fell in the city of Denver and at Buckley Field. Hail as large as 1 1/2 inches was measured in south Denver with 1 inch diameter hail in northern Aurora.

In 1999…upslope conditions produced snow across metro Denver with heavy amounts in the nearby foothills. Snowfall totals included: 9 inches at Eldorado Springs; 8 inches at Genesee… Golden Gate Canyon…Littleton and near Morrison; 7 inches near Nederland; and 6 inches in Louisville. Snowfall totaled 3.6 inches at the site of the former Stapleton International Airport.

16-17

In 1990…strong downslope winds raked the eastern foothills. Wind gusts from 60 to 75 mph were common. Strong winds in metro Denver resulted in wave damage to a dock used to moor several private sail boats at Cheery Creek Reservoir. Damage was confined to the dock and two anchor cables. A northwest wind gust to 43 mph was recorded at Stapleton International Airport.

17

In 1878…strong winds reached sustained speeds of 48 mph.

In 1988…a wind gust to 62 mph was recorded in central Boulder. The strong winds caused a few brief power outages. An old smoldering brush fire in the foothills west of Boulder was re-ignited by the wind gusts.

In 1994…winds gusted to 85 mph atop Squaw Mountain…5 miles south of Idaho Springs.

In 2006…a potent storm system brought heavy snowfall to the mountains and eastern foothills. Snowfall totals in the foothills included: 14 inches at Blackhawk…13.5 inches near Idaho Springs…13 inches at cabin creek…12.5 inches at Aspen Springs and Echo Lake…11.5 inches at Georgetown and Rollinsville…10.5 inches near Jamestown…and 10 inches at grant and Lake Eldora. Lesser snow amounts…from 4 to 9 inches…were recorded elsewhere in the foothills. Snowfall totaled only 3.5 inches in the Denver Stapleton area. At Denver International Airport…north winds gusted to 31 mph.

17-19

In 1908…a moist…heavy…wet snowfall totaled 13.0 inches in downtown Denver over the 3 days. Rain from early morning on the 17th changed to snow by late afternoon and continued through the late morning of the 19th. Due to temperatures in the 30’s and melting…the most snow on the ground was only 5.0 inches at 6:00 pm on the 18th. Northwest to northeast winds were sustained between 12 and 20 mph during the storm. Precipitation totaled 1.82 inches.

Continue reading October 16 to October 22 – This Week in Denver Weather History →

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