December 12 to December 18 – This week in Denver weather history

December 12, 2010 Thornton Weather 1 Comment

December 12 to December 18 - This week in Denver weather history.

We all know weather can be dangerous but usually we don’t associate that with winter weather conditions. However, our look in Denver weather history for this week shows that the common winter conditions of wind and cold can not only cause injure, it can lead to death.

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.

8-12

In 1932…the second longest sub-zero period on record in Denver occurred. The temperature fell below zero shortly after 1:00 pm on the 8th and remained below zero for 92 hours until 9:00 am on the 12th. The lowest temperature recorded during this period was 13 degrees below zero on both the 9th and 11th. That temperature on the 11th was a record low for the date. High temperatures of 4 on the 8th…5 below zero on the 9th…1 below zero on the 10th… And 6 below zero on the 11th were record low maximum temperatures for those dates. Light north winds at 5 to 10 mph were accompanied by occasional light snow…which totaled only 2.2 inches.

9-13

In 1961…cold arctic air produced a protracted cold period. The temperature plunged to 16 degrees below zero on the 10th…establishing a new record for the date and the coldest reading since 25 degrees below zero on February 1… 1951. Low temperatures dipped below zero on 5 consecutive days with 9 degrees below zero on the 9th…16 below on the 10th…10 below on the 11th…and 12 below on both the 12th and 13th. High temperatures reached only 3 degrees on the 10th and 6 degrees on the 11th.

11-12

In 1903…a sharp cold front on the 11th plunged temperatures from a high of 59 degrees to a low of 15 degrees…produced northeast winds sustained to 42 mph along with gusts as high as 60 mph…and produced 1.3 inches of snow overnight. The high temperature on the 12th was only 25 degrees.

In 1968…strong winds buffeted the eastern foothills and plains and caused light…but widespread property damage. Wind gusts of 50 to 75 mph were reported. West winds gusted to 52 mph at Stapleton International Airport.

Continue reading December 12 to December 18 – This week in Denver weather history →

Thornton Weather

Thornton WinterFest forecast – Dry, cool and windy

December 11, 2010 Thornton Weather Leave a comment

The detailed forecast for Thornton's WinterFest.

A full day of events highlights Thornton’s annual WinterFest on Saturday and the weather should cooperate for the most part. It will be a bit cool and windy but there is nothing weather-wise to keep everyone from coming out to this great event.

The outdoor activities start at 9:00 with a community walk around the multipurpose fields (108th & Colorado Blvd). Temperatures will be right around the freezing mark at the start with northwest winds at 5 mph creating a wind chill of 28 degrees. It will be chilly but certainly tolerable.

WinterFest gets started in earnest at 10:00 with a full slate of events. By then the mercury will have climbed to 35 degrees with light winds of 7 mph. Skies overhead will be partly cloudy today but there should at least be intermittent sun to help warm things up.

As the day progresses the thermometer will rise but the winds will also be picking up. The high today will hit 41 degrees by about 1:00pm and hold steady there through 4:00pm when the sun starts to go down. Winds will gradually increase through the morning peaking by 2:00pm at 15 to 20 mph, gusting to 25 mph. After that they should start to die down and by 7:00pm they will be mostly calm.

Fireworks will close out today’s events at 8:30pm and the weather will be chilly but otherwise it should be a great display. Temperatures by then will be down to 30 degrees but the winds will be calm.

The City of Thornton has plenty of activities for the whole family today. From the community walk to Santa’s village, ice skating, food and a concert from the Thornton Community Band. Be sure to come out and join your Thornton neighbors!

You can get more details including a complete schedule of events on the city’s website.

Thornton Weather

Heading to Thornton’s WinterFest this evening? Expect cool temperatures, blustery conditions

December 10, 2010 Thornton Weather Leave a comment

Cool and slightly breezy for Santa's arrival in Thornton tonight. (ThorntonWeather.com)

Thornton’s annual WinterFest kicks off this evening at 6:30pm with the arrival of Santa and Mrs. Claus. The weather will certainly not be a factor and Santa should be able to arrive without any problem and enjoy their time in our city.

Look for temperatures at the recreation center fields to be around 43 degrees when Santa arrives. Temps will drop to around 39 degrees by the time tonight’s festivities end at 9:00pm.

Winds are a bit gusty right now from 10 to 20 mph as a cold front moves through and unfortunately those won’t ease much. Some higher gusts to 30 mph are possible so it will be a bit blustery.

Snow is one thing that Santa won’t really find in Thornton this year. A few flakes may fall this evening but no real accumulation is expected.

Be sure to check back tomorrow for a complete look at Saturday’s weather for tomorrow’s events!

Thornton Weather

Lenticular clouds appear over Denver

December 9, 2010 Thornton Weather Leave a comment

These stacked lenticular clouds hovered over Denver on the evening of December 8th. View more photos in the slideshow by clicking on the image. Photo: Alycia Gilliland

Colorado is home to many weather phenomena which is certainly part of its appeal. Our topography and geographic location allow us to experience a true four seasons and every type of weather.

Yesterday if you turned your eyes skyward you were treated to an amazing display of lenticular clouds, an unusual formation but one for which Colorado is a prime viewing spot.

Storm chaser and meteorology student Alycia Gilliland has captured some stunning photos in recent months of the sky and yesterday’s display provided another opportunity. As the sun began its decent late yesterday afternoon, Gilliland turned her camera skyward to capture beautiful images of “stacked” lenticulars.

Click on the image to the right to view a slideshow of Gilliland’s photos. You can learn more about lenticular clouds in our story on the Denver Weather Examiner.

Weather History

The weather and the ‘date which will live in infamy’

December 7, 2010 Thornton Weather Leave a comment

December 7, 1941. From left, the USS USS West Virginia, USS Tennessee, both damaged and USS Arizona, sunk. The weather played a key part in the attack on Pearl Harbor.

The weather that morning was beautiful over Pearl Harbor as one might expect in paradise. The USS Tennessee reported winds at 11 to 16 miles an hour and slight wind ripples on the water of the bay. The USS Oklahoma reported clear skies with “intermittent moving fleecy clouds.” Little did the men making those weather reports know that hell was about to rain down on them.

69 years ago today, the United States was forced into World War II with the brutal surprise attack on Pearl Harbor. Over 2,300 servicemen lost their lives on that fateful day, a “date which will live in infamy.” Relatively unknown in the stories of that fateful day is how the weather played a key and prominent role.

On December 4th, a Japanese intelligence officer at their embassy in Washington D.C. was listening to Radio Tokyo as he had been for the last two weeks. The weather report: “Higashi no kaze ame”, or “east wind, rain.” That seemingly innocent phrase was in actuality code to Japanese diplomats to destroy all of their cryptographic equipment, books and top secret documents as an attack was imminent. A weather report sounded the alarm that war was coming.

On Oahu, December and January are actually the cloudiest months and this was a concern for the Japanese in the planning of their attack. Timing was of the essence as winter in the Pacific can be brutal and if they were forced to wait till late December, success would be in doubt. The clouds would be good for hiding the planes on their approach to the islands but if they couldn’t see their targets, the attack could not be successful.

220 miles north of Oahu and heading east into a steady wind, the Japanese fleet launched its planes at 6:10am. The wind provided the extra lift for the bomb-laden planes and low clouds at 5,000 feet helped to provide cover for the fleet and its planes. The question remained however – would there be clouds over the target?

As the planes headed toward Pearl, U.S. code breakers intercepted a message from Tokyo to Japanese diplomats telling them to break off talks with the United States. At 7:33am, Army Chief of Staff, General George C. Marshall, believed this could be the harbinger of an attack and he sends a warning to Lt. Gen. Walter C. Short, commander of U.S. Army forces in Hawaii. Atmospheric static however prevents the message from being sent by radio and Marshall’s message is sent via commercial telegraph instead. Short’s headquarters receives the message at 11:45am and he did not see it until 3:00pm – more than eight hours after the attack had started.

Flying between 9,000 and 14,000 feet, the clouds provided the cover that the Japanese planes needed. Using a Honolulu radio station to guide them, the planes neared the north coast at 7:30am and heard the radio announcer report, “clouds, mostly over the mountains. Visibility good.” That is exactly what they wanted to hear. Their approach over the mountains of the island was concealed by the clouds and as they neared Pearl Harbor, those clear skies reported by the USS Oklahoma and Tennessee provided the bombers the visibility they needed to hit their targets. At 7:55am, metal rain began to fall on our soldiers, sailors and airmen.

Our nation was forever changed that day and as is often the case, the weather played a key role in this moment in history. After the attack, Japanese Admiral Isoroku Yamamoto said, “We have awakened a sleeping giant and have instilled in him a terrible resolve.” Indeed that was the case but the price was heavy as nearly 300,000 United States service members would lose their lives in the years to come.

Dallas City Hall, Veterans Day, November 11, 2004. Houston James, a survivor of the attack on Pearl Harbor, hugs Marine Staff Sergeant Mark Graunke Jr., a member of an explosive disposal team who lost his left hand, one leg and an eye in Iraq.

On personal note, I ask all of our readers to take the time today to acknowledge and remember not only those that paid the ultimate sacrifice on December 7, 1941 and in the following years, but also remember that more than 16 million men and women served in the armed forces during World War II. Of those, a mere 2.3 million are still with us today and 1,000 World War II veterans die each and every day. As we mourn their passing, we should also remember that which they stood for – honor, sacrifice, courage, God and country. There had never been – and there never will be – a generation like theirs. I thank them for their service and hope they may have the peace in heaven that they did not see while on earth. God bless you all.

For more information: Please help Thornton build a memorial to honor not only World War II veterans but all veterans from all branches of service and all wars. The owner and operator of ThorntonWeather.com is a significant contributor to the project and asks that our visitors consider donating to the project. Please visit the Thornton Veterans Memorial website for more information.

Weather History

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

3-15

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 →

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