December 4 to December 11 – This week in Denver weather history

December 5, 2010 Thornton Weather Leave a comment

December 4 to December 11 - This week in Denver weather history

While Denver still waits for its first significant snowfall of the season, in years past it has been much easier to come by. Looking back we see one five day storm that dumped snow that was measured in feet and many other smaller ones that were significant in their own right.

1-5

In 1913…the 1st marked the start of the heaviest 5-day total snowfall in the city’s history. During this period snowfall totaled 45.7 inches. Starting on the 1st…snow fell intermittently for 3 days and accumulated a little over 8 inches. On the 4th and 5th…an additional 37.4 inches of snow fell. At Georgetown in the foothills west of Denver even more snow fell…86 inches over the 5 days with the most…63 inches…on the 4th. In Colorado…snowfall was heavy along the eastern slopes of the mountains from the Palmer Divide north. High winds during the storm caused heavy drifting…which blocked all transportation. Snow cover of an inch or more from the storm persisted for 60 consecutive days from the 1st through January 29…1914. Additional snowfall in December and January prolonged the number of days. This is the third longest period of snow cover on record in the city.

2-17

In 1939…more than 2 weeks of unseasonably warm weather made the month the 3rd warmest on record. Seven daily temperature records were set…including the all time record high temperature for the month of 79 degrees on the 5th. Daytime highs were balmy with 14 days in the 60’s and 70’s. Low temperatures dipped to freezing or below on only 5 days. The period was dry with only a trace of snow on the 12th.

3-15

In 1972…a protracted cold spell held an icy grip on metro Denver when maximum temperatures never reached above freezing for 10 consecutive days from the 3rd through the 12th and minimum temperatures dipped below zero on eleven consecutive days from the 5th through the 15th. Daily low temperature records were set with 15 degrees below zero on the 5th…17 degrees below zero on the 6th… And 18 degrees below zero on the 10th. Daily record low maximum readings were set with 3 degrees on the 6th and 6 degrees on the 9th. The very cold temperatures were caused by 3 to 5 inches of snow cover and a Canadian air mass.

Continue reading December 4 to December 11 – This week in Denver weather history →

Climatology, Thornton Weather

Thornton’s November weather recap – Month ends drier and warmer than normal

December 4, 2010 Thornton Weather Leave a comment

November 2010 goes down in the books as drier and warmer than normal. (iStockphoto / johnnyscriv)

November 2010 was most notable not for what weather condition occurred but rather for what it lacked – snow. Historically November is Denver’s second snowiest month but 2010 saw us receive very little of the white stuff as we start out the season far behind where we average.

At the official Denver weather monitoring station at Denver International Airport a mere 1.5 inches of the white stuff was recorded. That is 9.2 inches below the historical November average of 10.7 inches. Despite that, the month fell short of the top 10 least snowiest Novembers as number 10 on that list is 1971 with 1.4 inches. Given that no snow was recorded in September or October, the 2010 snow season is off to a dismal start at more than 15 inches below normal.

In terms of precipitation, only 0.5 inch was collected in the rain bucket – barely more than half of the normal of 0.98 inch. While dry, it wasn’t enough to put the month into top 10 driest November status. Three years in Denver history have recorded only a trace of precipitation and the number 10 slot is held by 1989 when only 0.15 inch of precipitation was recorded. No precipitation or snowfall records were set or tied during the month.

Here in Thornton we fared drier than the official Denver tallies on all fronts. We recorded only 1.14 inches of snow and 0.33 inch of precipitation.

Temperature-wise Denver ended the month warmer than normal with an average temperature of 38.3 degrees. This was 0.8 degrees above the normal of 37.5 degrees. Temperatures ranged from a high of 77 degrees on the 6th down to a low of 4 degrees on the 25th. There were 24 days with low temperatures below the freezing mark which is normal. On only one day, the 29th, did we fail to hit a high temperature of at least freezing as the thermometer only climbed to 31 degrees that day. No temperature records were set or tied during the month.

Overall Thornton’s average temperature for the month was cooler than Denver’s. The average temperature was 36.8 degrees with the warmest day hitting 78.7 degrees and the lowest temperature being 9.0 degrees.

Wind is of course a fact of life on the plains and November 2010 did set a new peak wind gust for the month of 55 mph on the 16th. This easily broke the old record of 49 mph set in 1990.

Click here to view the 2010 Thornton Climate Summary.

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
745 AM MST FRI DEC 3 2010

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

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF NOVEMBER 2010... 

CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2010

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              80   11/08/2006
 LOW              -18   11/29/1877
HIGHEST            77   11/06        79      -2       77  11/05
LOWEST              4   11/25       -18      22       16  11/16
AVG. MAXIMUM     52.6              51.5     1.1     56.4
AVG. MINIMUM     24.0              23.5     0.5     28.8
MEAN             38.3              37.5     0.8     42.6
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX = .01         6               5.6     0.4        3
DAYS >= .10         2                MM      MM        3
DAYS >= .50         0                MM      MM        0
DAYS >= 1.00        0                MM      MM        0
GREATEST
 24 HR. TOTAL    0.15 11/16 TO 11/16         0.33 11/14 TO 11/15

SNOWFALL (INCHES)
RECORDS
 TOTAL           42.6  1946
TOTALS            1.5               10.7

DEGREE_DAYS
HEATING TOTAL     793               826     -33      664
 SINCE 7/1       1128              1408    -280     1479
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        870               696     174      533

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

WIND (MPH)
AVERAGE WIND SPEED              9.7
RESULTANT WIND SPEED/DIRECTION   2/228
HIGHEST WIND SPEED/DIRECTION    45/310    DATE  11/16
HIGHEST GUST SPEED/DIRECTION    55/320    DATE  11/16

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM

NUMBER OF DAYS FAIR            9
NUMBER OF DAYS PC             17
NUMBER OF DAYS CLOUDY          4

AVERAGE RH (PERCENT)     51

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       1
LIGHT RAIN                2     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                1     SNOW                       4
LIGHT SNOW                9     SLEET                      0
FOG                      13     FOG W/VIS

Thornton Weather

Record high temperature set for December 3rd

December 3, 2010 Thornton Weather Leave a comment

Not since Grover Cleveland was president has Denver had as warm of a December 3rd as today.Not since Grover Cleveland was president has Denver had as warm of a December 3rd as today.

If you looked at a thermometer late this morning or early this afternoon you might have found yourself wondering if the calendar that says it is December is correct. Not since 1885 when Grover Cleveland was inaugurated as the 22nd president of the United States and the Washington Monument was completed has Denver had as warm of temperatures on December 3rd as today.

At 11:41am this morning the temperature at the official Denver weather station at Denver International Airport reached 69 degrees. Thornton topped that slightly as we recorded 70.2 degrees at 12:13pm.

As is often the case, the warmer temperatures have been brought on my strong winds. Gusts this afternoon to 45mph are possible, particularly along the usual wind-prone areas in the foothills like Highway 93 between Boulder and Golden.

The warmth will be short-lived however as those winds bring in a cold front later this evening. Overnight and into tomorrow some areas of the Front Range may see a wintry mix of snow and freezing drizzle. Highs on Saturday will only reach the mid to upper 30s. For the complete local Thornton forecast click here.

Related (Examiner.com): Do Denver weather and climate records have an asterisk attached?

ThorntonWeather.com note: Some media outlets, including KMGH Channel 7, are incorrectly reporting that Denver hit a high temperature of 70 degrees today and broke the record. This is incorrect.

National Weather Service observations are initially reported in Celsius, rounded to the nearest whole degree – in today’s case, 21 degrees Celsius (70 degrees Fahrenheit). However the true temperature is recorded to the nearest tenth of a degree. Today’s actual high temperature was 20.6 degrees Celsius or 69 degrees Fahrenheit.

Yet another reason to rely on ThorntonWeather.com for your weather news and information! 😉

Colorado Weather, National Weather

Snow across western United States imaged by NASA satellite

November 29, 2010 Thornton Weather Leave a comment

Widespread snow from the Sierra Nevada to the Colorado Rockies snarled travel leading up to the Thanksgiving holiday. As the holiday weekend wraps up, NASA has released satellite imagery showing just thousands of square miles coated in a blanket of white.

November 27 to December 4 – This week in Denver weather history

November 28, 2010 Thornton Weather Leave a comment

November 27 to December 4 - This week in Denver weather history

Cold, snow and wind are part of life on the Great Plains and we see all of those events have struck in abundance during this week in Denver weather history. Many of the wind events were damaging and the snow accumulations significant.

From the National Weather Service:

25-28

In 1952…the average coldest 4-day period in November in the previous 81 years of record occurred. Maximum temperatures of 19…15…21…and 25 degrees were recorded. Minimum temperatures were below zero each day with readings of 7 below…6 below…5 below…and 6 below.

25-29

In 1985…dense fog with visibilities as low as 1/8 mile occurred on five consecutive days at Stapleton International Airport. The fog was at times accompanied by light snow… Light freezing drizzle…or ice crystals. Fog occurred all day on both the 26th and 29th.

In 1884…a windstorm during the afternoon produced northwest sustained winds to 46 mph. Two wooden slats were blown out of the weather instrument shelter…and nearly all of the slats on the north and west sides were loosened.

In 1898…northwest winds were sustained to 50 mph with gusts as high as 80 mph.

In 1902…northwest winds were sustained to 40 mph with gusts to 48 mph. The strong apparent Bora winds warmed the temperature to a high of only 40 degrees.

In 1904…northwest winds sustained to 44 mph with gusts to 58 mph warmed the temperature to a high of 58 degrees.

In 1927…strong west winds occurred in Boulder…causing widespread minor damage. A wind gust to 65 mph was recorded at Valmont east of Boulder. The west winds possibly produced a cyclonic twist.

In 1928…heavy snowfall totaled 7.0 inches over downtown Denver.

In 1957…a vigorous cold front produced north-northeast wind gusts to 54 mph at Stapleton Airport. Light snow following the front totaled only 0.2 inch.

In 1970…strong Chinook winds reached 77 mph in downtown Boulder.

In 1978…wind gusts 60 to 90 mph were reported in and near the foothills.

In 1984…high winds of 60 to 80 mph occurred along the Front Range eastern foothills. In Boulder…the high winds blew the roof off a service station. Several trees were felled… Damaging some cars. An elderly woman was injured when she was knocked down by a wind gust and blown 20 feet into some bushes. Northwest winds gusted to 36 mph at Stapleton International Airport.

In 1994…winds gusted to 72 mph in Boulder. No damage was reported. Northwest winds gusted to 35 mph at Stapleton International Airport.

Continue reading November 27 to December 4 – This week in Denver weather history →

National Weather, Natural Disasters

Strong cold front brings tornadoes, damaging wind to Illinois and Wisconsin

November 23, 2010 Thornton Weather Leave a comment

Path of EF2 tornado in Illinois on November 22, 2010. (NWS)

November is not normally the time of year for tornadoes, least of all in states in northern latitudes like Illinois and Wisconsin. That however did not stop a mini-outbreak yesterday as at least two tornadoes struck and as many as seven were possible.

Watch video of the twister below

Severe thunderstorms were spawned yesterday by a strong cold front moving across the upper Midwest. The twisters were the first in 26 years to strike the area in November – you have to go all the way back to November 9, 1984 to find the last one.

The National Weather Service has confirmed that the strongest of the tornadoes yesterday was an EF2 packing winds of 135mph. It covered a path of 16.4 miles and had a maximum width of 200 yards. The twister overturned a bus, caused significant damage to buildings and injured six people.

Below you can see a video of the twister as it passed near Loves Park, Illinois.

Thornton Weather

Colorado mountains set to be slammed by major snowstorm

November 21, 2010 Thornton Weather Leave a comment

A major winter storm will bring heavy snow to much of western Colorado. (NWS)

As travelers prepare to hit the road to visit friends and family for the Thanksgiving holiday, a major winter storm set to strike the Western Slope may cause problems. Some areas will be measuring snow in terms of feet rather than the usual inches.

A strong Pacific trough of low pressure will begin encroaching on western Colorado today followed by a cold front on Sunday. These factors will combine to bring heavy snow to much of the western third of the state where Winter Storm Warnings have been posted.

The long-lasting storm will bring periods of heavy snow lasting from today through Wednesday. The San Juans will bear the brunt through tomorrow followed by the Sawatch and Elk mountain ranges from Monday through Wednesday. Areas farther north along the Rockies will also feel the effects.

Here in Thornton and the Denver metro area things will be much calmer but also cooler, particularly on Wednesday and Thanksgiving Day. High temperatures for those two days may not even reach the freezing mark. At the current time it does appear we will remain dry so flying into and out of Denver International Airport (DIA) should not be a problem.

Get more details including a look at current weather warnings for Colorado on the Denver Weather Examiner.

Climatology

Globe experiences eighth warmest October on record

November 21, 2010 Thornton Weather Leave a comment

Warm and dry were the key words for Denver’s October weather and that same trend was also seen globally. According to the National Climatic Data Center, October 2010’s average global temperature was the 8th warmest on record. With an average temperature of 58 degrees, the month was nearly 1 degree warmer than average.

The image below shows the areas that were warmer and cooler than the 1971 to 2000 average.

October 2010 global temperatures. (NOAA)

From the National Oceanic and Atmospheric Administration:

Global Temperature Highlights

The combined global land and ocean average surface temperature for October 2010 was the eighth warmest on record at 58.07 F (14.54 C), which is 0.97 F (0.54 C) above the 20th century average of 57.1 F (14.0 C). The range associated with the combined temperature is +/- 0.14 F (0.08 C).*
The October worldwide land surface temperature was 1.64 F (0.91 C) above the 20th century average of 48.7 F (9.3 C) — the sixth warmest October on record. Warmer-than-average conditions were particularly felt across western Alaska, Canada, northeastern Africa, the Middle East, Kazakhstan and large portions of Russia. Cooler-than-average regions included most of Europe, Mongolia and much of Australia. The range associated with the land surface temperature is +/- 0.20 F (0.11 C).
- According to the Bureau of Meteorology, Australia had its 10th coolest maximum temperatures on record for October with daytime maximum temperatures 2.12 F (1.18 C) below average. Statewide, both the Northern Territory and Queensland had their third coolest maximum temperatures since national records began in 1950.
The October worldwide ocean surface temperature was 0.72 F (0.40 C) above the 20th century average of 60.6 F (15.9 C) and was the 10th warmest October on record. The warmth was most pronounced across the Atlantic, western North Pacific and most of the Indian Ocean. The range associated with the ocean surface temperature is +/- 0.13 F (0.07 C).
For the year-to-date, the global combined land and ocean surface temperature of 58.53 F (14.73 C) was tied with 1998 as the warmest January–October period on record. This value is 1.13 F (0.63 C) above the 20th century average.
Moderate La Niña conditions continued in October, while sea surface temperatures remained below-normal across the central and eastern equatorial Pacific Ocean. According to NOAA’s Climate Prediction Center, La Niña is expected to strengthen and last at least into the Northern Hemisphere spring of 2011.

Polar Sea Ice and Precipitation Highlights

The average Arctic sea ice extent for October was 2.97 million square miles (7.69 million square km), which was 17.2 percent below average. This marks the third lowest October Arctic sea ice extent since records began in 1979 and the 14th consecutive October with below-average Arctic sea ice extent.
Antarctic sea ice began its annual retreat during October. October 2010 was the fourth largest sea ice extent on record (2.9 percent above average). The largest October sea ice extent occurred in 2006.
According to Mexico’s National Weather Service (Servicio Meteorolológico Nacional), this October was Mexico’s driest since 1941.
North and west Amazonia in Brazil was in the midst of its worst drought in the past 40 years. In October, one of the Amazon River’s most important tributaries, the Black River, dropped to its lowest level of 44.7 feet (13.6 meters) since record keeping began in 1902.

Weather History

November 21 to November 27 – This week in Denver weather history

November 21, 2010 Thornton Weather Leave a comment

November 21 to November 27 - This week in Denver weather history

Weather is a big part of the holidays. With many people hitting the road to visit friends and family the weather can make or break those holiday plans. Our look back at this week in Denver weather history shows a number of Thanksgivings when the weather put a damper on travel plans.

19-21

In 1979…a heavy snowstorm buried most of Colorado under at least a foot of snow. Snowfall at Stapleton International Airport totaled 17.7 inches…the greatest snow depth since 1946. Winds to 60 mph produced 5-foot drifts paralyzing the city as temperatures hovered in the 20’s. While small airports closed…Stapleton remained open…but with long delays that snarled Thanksgiving holiday traffic. Schools and businesses closed and postal deliveries were delayed. Almost all major highways leading out of Denver were closed to traffic for periods of time on the 20th and 21st. Most of the snow…13.5 inches…fell on the 20th. At Stapleton International Airport…north winds gusted to 35 mph on the 20th and to 38 mph on the 21st.

20-21

In 1898…snowfall totaled 4.0 inches in downtown Denver. Northeast winds were sustained to 48 mph with gusts as high as 60 mph behind an apparent cold front on the 20th… When temperatures plunged from a high of 66 degrees to a low of 9 degrees. On the 21st the high was only 24 degrees and the low was 2 degrees.

In 1970…a wind gust to 94 mph was recorded at gold hill in the foothills west of Boulder. Strong winds also swept across metro Denver. Wind gusts reached 59 mph in downtown Boulder…while at Stapleton International Airport west- northwest winds gusted to 43 mph on the 21st. Damage was minor.

In 1992…a large Canadian air mass moved into the state at the same time an upper level storm system approached from the west. The combination of cold air at the surface and very moist air aloft produced heavy snow across the entire state. Snowfall totaled 6.3 inches at Stapleton International Airport…where north winds gusted to 23 mph on the 20th. Snow was heavier in the foothills…with 14 inches at Wondervu…13 inches at Aspen Springs…Conifer… Boulder…and Gross Reservoir…8 inches at Rollinsville… And 10 inches at Golden Gate Canyon and Morrison.

In 2007…a storm system brought moderate to heavy snowfall to portions of the urban corridor. Storm totals included: 7 inches…3 miles south-southeast of Fort Collins…with 6 inches in Boulder and at Horsetooth inlet bay. Elsewhere… Storm totals ranged from 2 to 5 inches. Snowfall totaled 2.0 inches at the site of the former Stapleton International Airport.

Continue reading November 21 to November 27 – This week in Denver weather history →

Weather History

November 14 to November 20 – This week in Denver weather history

November 16, 2010 Thornton Weather Leave a comment

November 14 to November 20 - This week in Denver weather history

Henry Fenton is probably not a name many folks are familiar with however he will forever be engrained in the Denver weather history books. It was 139 years ago this week that Fenton made the first official Denver weather observations.

From the National Weather Service:

11-14

In 1970…heavy snowfall totaled 7.2 inches at Stapleton International Airport where northeast winds gusted to 22 mph on the 12th and 14th. Most of the snow… 4.2 inches…fell on the 12th.

12-15

In 1909…light snowfall totaled 6.7 inches in downtown Denver over the 4 days. This was the first measurable snowfall of the season. Northeast winds were sustained to 15 mph on the 12th.

13-14

In 1925…heavy post-frontal snowfall totaled 6.4 inches overnight in downtown Denver. Northwest winds were sustained to 27 mph with gusts to 29 mph on the 13th.

In 1974…northwest winds gusted to 52 mph at Stapleton International Airport…warming the temperature to 60 degrees shortly after midnight on the 13th. A cold front cooled temperatures into the 20’s by late morning and produced snowfall of 3.7 inches. The low temperature dipped to 14 degrees on the 14th.

In 1993…an upper level low pressure system combined with a weak but moist upslope flow to produce heavy snow across metro Denver. Snowfall amounts averaged 6 to 8 inches with up to 16 inches in the foothills at the Eldora Ski Area. Snowfall totaled 6.0 inches at Stapleton International Airport where north winds gusted to only 20 mph on the 14th. Most of the snow fell on the 14th.

In 1994…heavy snow developed rapidly along the Front Range urban corridor with the heaviest snow over northwest metro Denver. Sixteen to 18 inches of snow fell in Boulder… Lafayette…and Louisville. This was the second heavy snowfall over northwest metro Denver in 10 days. Eleven to 14 inches of snow were measured from Longmont southward into Aurora. Snowfall totaled 12.1 inches at Stapleton International Airport where northeast winds gusted to 29 mph on the 13th. Most of the snow…9.0 inches…fell on the 14th.

In 1997…heavy snow fell overnight in portions of Jefferson and Boulder counties. About 5.5 inches of snow were reported in Boulder…while 4 inches were measured 12 miles southwest of Morrison and 6 miles southwest of Golden. Snowfall totaled only 1.8 inches at the site of the former Stapleton International Airport. Northeast winds gusted to 26 mph at Denver International Airport.

Continue reading November 14 to November 20 – This week in Denver weather history →

Weather, natural disasters & climate news and information.