Hundreds of weather balloons like this are released daily by the National Weather Service. (NOAA)
A 12-year-old boy reportedly received a bit of a shock when he touched a National Weather Service balloon that had landed near Niver Creek Middle School in Thornton. The balloons which are launched twice daily from the old Stapleton International Airport facility and other locations across the nation are essential instruments for forecasters.
The boy complained of numbness in his hands after touching it and school officials called the fire department as they were unsure what the device was. Upon closer inspection they read the labels that said the unit belonged to the National Weather Service and was a weather instrument. The boy was transported to a hospital as a precaution and his father told Channel 7 Wednesday morning that he was fine.
Weather balloons are launched daily from 102 locations across the United States, Caribbean and Pacific and are essential forecasting instruments (see below for a map of sites in the contiguous United States). The six foot diameter balloons are launched twice daily and simultaneously at all the sites at midnight UTC and noon UTC (5:00am MDT and 5:00pm MDT). Once launched, the units can attain an altitude of 115,000 feet and travel up to 200 miles before they burst and fall harmlessly to the ground.
Called a radiosonde, the balloon’s payload measures air pressure, temperature, humidity, wind direction and wind speed. The data is transmitted in real time to receivers on the ground which is then fed into National Weather Service computers and monitored by forecasters. Information obtained by the units is essential for forecasters to evaluate and predict atmospheric conditions for forecasting, severe weather alerting and more.
A funnel cloud near Thornton on Sunday, June 7, 2009. Knowing where to get information on developing weather could save your life. Image courtesy John Wagner, Warrior Legacy Foundation.
We recently updated our weather links page (available from the menu at the left) with dozens more links to a wide array of weather related website. From sites that provide statistical information and historical data to ones where you can become your own weather forecaster, we have it all.
Certainly weather is one of the things that every single person on the globe has in common. It can impact almost every aspect of our daily lives in a myriad of ways. It can make or break that outdoor event, determine whether or not the kids have school today and most notably it can change lives in an instant when it turns severe.
Knowing where to find information about weather can help to educate, inform and possibly save lives – possibly even your own. We have accumulated this extensive list of Internet resources devoted to weather topics on everything from climatology to tropical weather and winter weather.
Denver & Thornton Climatological Preview - September 2009
As temperatures start to drop, September reminds us that summer is at an end and fall is now here. Sunshine is predominant though as the month actually has the highest percentage of sun out of any month. Sunny days and clear, cool nights are the standard weather pattern for the month.
Normal highs on the first of the month are 82 degrees with a low of 53. By the end of the month we see those high temperatures drop to an average of 73 and the lows get to a chilly 42. Overall the month averages 62.4 degrees.
Hurricane Bill on Thursday morning is seen as it nears the United States.
Wind shear helped to slow Hurricane Bill’s wind speeds to Category 3 levels of 125 mph over the last 24 hours. However, the National Hurricane Center cautions that some strengthening is expected in the next 24 hours and Bill may return to Category 4 levels.
The storm now has hurricane force winds extended out 85 miles from its center and tropical storm winds extending out 230 miles. Moving toward the northwest at 18 mph, the effects of the season’s first major Atlantic hurricane will begin to be felt in the next 72 hours.
The Bahamas and Bermuda will begin to experience large swells in the next 24 to 48 hours. Portions of the United States east coast will also feel similar effects Friday into Saturday. The National Hurricane Center is cautioning residents of these areas that ocean waters will be “extremely dangerous” with “life-threatening rip currents.”
Denver has record setting cool temperatures and snow arrives in the Rocky Mountains. Image courtesy Victor Lewis.
While some parts of the nation experience record setting heat, on Thursday Denver had the opposite problem. The high temperature as measured at Denver International Airport reached a mere 64 degrees. This was two degrees below the previous record low maximum temperature of 66 degrees for this date set in 1925 and previous years. That is also an amazing 24 degrees below the normal temperature for this time of year!
Here in Thornton, we were even cooler than the official temperature on Thursday as the mercury climbed to a mere 61.3 degrees!
The unseasonably cold weather has also brought an unusual sight to the Colorado mountains in July – snow! Some northern parts of the Rocky Mountains in the state above 12,000 feet received a couple inches of snow.
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.
At the start of the month Denver usually averages around 88 degrees for a high temperature. By the end of August that drops to 82 degrees. Similarly, nighttime lows drop from 60 to 53 from the start to the end of the month. Generally clear skies can be expected between midnight and noon but the afternoon often brings showers and thunderstorms. These storms typically develop over the foothills then bring precipitation to the Denver metro area.
Despite that moisture, the chance for severe weather decreases considerably compared to the first two months of summer. Cooler air near the surface helps to create a stable atmosphere thus keeping thunderstorms from usually becoming too intense. After the middle of August, tornadoes and damaging hail are pretty rare. The slow movement of storms this time of year are more likely to produce potentially heavy rain.
Do these clouds have the potential to bring a tornado? Learn more at National Weather Service storm spotter training.
We have written before about the great opportunity the National Weather Service provides by giving storm spotter training during the start of the severe weather season. Normally these sessions are held in the spring but in response to the very active severe weather of early June, and the increased interest in severe thunderstorms, the National Weather Service in Boulder has added to additional spotter training session next week.
When: Saturday, July 11
Time: 10:00am
Where: Broomfield, CO.
Exact location: Rocky Mountain Metropolitan Airport, Terminal Building, 11755 Airport Way (formerly Jefferson County Airport)
The storm spotter program is a nationwide program with more than 280,000 trained spotters. These volunteers report weather hazards to their local National Weather Service office providing vital information when severe strikes. Data from spotters include severe wind, rain, snow measurements, thunderstorms and hail and of course tornadoes.
Storm spotters are part of the ranks of citizens who form the Nation’s first line of defense against severe weather. There can be no finer reward than to know that their efforts have given communities the precious gift of time–seconds and minutes that can help save lives.
By completing one of these training classes you can become an official storm spotter. When severe weather strikes, you can report it by calling a special toll free number or submit your report via the National Weather Service’s website.
Taking the training though doesn’t obligate you to being a storm spotter. These are great sessions for anyone wanting to learn more about the severe weather we experience in Colorado, whether you want to be an official spotter or not. All training is free. Topics include:
This funnel cloud was seen on Tuesday from the Thornton Civic Center (looking north) on June 10th. Image courtesy Lisa Wilson, the City of Thornton.
June 2009 went down in the history books as one of the more unusual June’s on record. Residents are all of course well aware of the string of severe storms but the Mile High City also were unusually cool and certainly very wet.
In terms of precipitation, a whopping 4.86 inches of rain fell at the official measuring site at Denver International Airport during the month – the second wettest June since recordkeeping began here in 1872. We missed out on breaking the record by only a tenth of an inch as the all-time wettest was back in 1882 when 4.96 inches fell in the rain bucket. Nevertheless, we easily exceed the normal rainfall total for the month which is 1.56 inches. In fact, we beat that in one day on June 23rd when 1.64 inches fell at DIA. Here in Thornton we didn’t measure near as much precipitation having recording 3.44 inches for the month. This is more in line with what areas closer to the actual metro area recorded than what was recorded at DIA. See below for details on the controversy about Denver’s climate records.
Temperature wise, we were very cool as well, never breaking the 90 degree mark during the month. Two days, the 29th and 30th, came close with 89 degrees being recorded as the high temperatures on those days. This was the first time since 2003 no 90 degree days were recorded in June. Before that, you would have to go way back to 1972 to find another June when that happened. The average temperature for June 2009 was 64.4 degrees, 3.2 degrees below the normal of 67.6. That may be cool but it was nowhere near the record low average for June which is 60.6 set in 1967. Thornton was just a touch warmer than the official stats from DIA as we recorded 90.0 degrees on the 29th. Similarly, Thornton’s average temperature was just a bit cooler at 63.2 degrees.
Then of course there were the storms. Tornadoes, funnel clouds and hail will probably be the most memorable events of the month, especially the twister that struck the Southlands Shopping Center in Aurora. In all, DIA recorded 18 days with thunderstorms – eight more than normal. 15 days had precipitation versus the normal of nine. All those storms also took a toll on what is normally a sunny month. On average Denver has 70 percent of possible sunshine during the month. This year we only recorded sunshine 51 percent of the time.
All that rain we have received in the last two months, especially in June, helps to make one other statistic a bit more tolerable. Colorado’s snow season runs from July 1 to June 30 each year and for the 2008 – 2009 snow season, we recorded a meager 38.1 inches of the white stuff. That is a whopping 29 inches below the normal of 67.1 inches. Thornton fared a bit better on the snowfall front but not by a lot having recorded 48.5 inches for the season.
There is always a ‘but’…
As always, we would like to remind everyone that all official Denver weather statistics are now taken out at Denver International Airport. As we outlined a few months ago, moving the official monitoring station 13 miles away has made quite a difference in Denver’s climate records. Evidence suggests that temperatures and precipitation as measured at DIA differ greatly from what would have been recorded at the old site at Stapleton or near downtown Denver.
The National Weather Service has finally acknowledged this and has setup a measuring station at the Denver Museum of Nature and Science (click here to view current conditions from it on the Weather Underground). However, they maintain that Denver’s official statistics will continue to be recorded at DIA and as a result, Denver’s climate records will forever have an asterisk next to them. If you compare June’s statistics from this new station to the ‘official’ ones at DIA, you will notice that much of what we discuss above, including the temperature and precipitation, would be much different were the statistics being kept by the new station closer to where people actually live.
Denver climate summary for the month of June 2009 – From the National Weather Service
CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2009
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 104 06/26/1994
LOW 30 06/02/1951
HIGHEST 89 06/30 104 -15 95 06/26
06/29
LOWEST 41 06/08 30 11 37 06/12
AVG. MAXIMUM 77.7 82.1 -4.4 83.9
AVG. MINIMUM 51.1 53.0 -1.9 50.9
MEAN 64.4 67.6 -3.2 67.4
DAYS MAX >= 90 0 6.3 -6.3 10
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 4.96 1882
MINIMUM T 1890
TOTALS 4.86 1.56 3.30 0.73
DAILY AVG. 0.16 0.05 0.11 0.02
DAYS >= .01 15 8.7 6.3 4
DAYS >= .10 9 MM MM 2
DAYS >= .50 4 MM MM 1
DAYS >= 1.00 1 MM MM 0
GREATEST
24 HR. TOTAL 1.64R 06/23 TO 06/23 0.70 06/04 TO 06/05
SNOWFALL (INCHES)
RECORDS
TOTAL 0.4 1919
TOTALS 0.0 T
DEGREE_DAYS
HEATING TOTAL 78 60 18 64
SINCE 7/1 5616 6128 -512 6056
COOLING TOTAL 68 136 -68 144
SINCE 1/1 94 161 -67 172
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/02/1951
EARLIEST 10/07
LATEST 05/05
.................................................................
WIND (MPH)
AVERAGE WIND SPEED 8.4
RESULTANT WIND SPEED/DIRECTION 2/147
HIGHEST WIND SPEED/DIRECTION 53/260 DATE 06/26
HIGHEST GUST SPEED/DIRECTION 68/270 DATE 06/26
SKY COVER
POSSIBLE SUNSHINE (PERCENT) 51
NUMBER OF DAYS FAIR 3
NUMBER OF DAYS PC 22
NUMBER OF DAYS CLOUDY 5
AVERAGE RH (PERCENT) 65
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 18 MIXED PRECIP 1
HEAVY RAIN 7 RAIN 10
LIGHT RAIN 17 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 3
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 14 FOG W/VIS <= 1/4 MILE 6
HAZE 10
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
Change is of course the one constant in Denver’s weather but come July, things actually get pretty consistent. The standard formula for a day in July is a sunning morning, clouds developing in the late morning and early afternoon. Come mid-afternoon, thunderstorms are rolling off of the foothills and into the metro area and the eastern plains. These storms do occasionally reach severe status containing hail, gusty winds and heavy downpours of rain.
In fact, the worst hail storm on record in Denver history hit western sections of the city on July 11th, 1990. Baseball and softball sized hail from this ferocious storm caused millions of dollars worth of property damage.
July is the most stormy month of the year in fact with thunderstorms occurring on average 11 days per month – or once every three days. These slow moving storms are one of the reasons July is Denver’s second rainiest month with an average of 2.16 inches of rain (second only to May). However, these storms are also often very localized and cause widely varying precipitation amounts across the metro area. It is not unusual for one area of down to be deluged while others remain entirely dry. With these severe storms, flash flooding remains a possibility.
From the National Weather Service: June 2009 has moved into the second wettest June since Denver weather records began in 1872. So far for June 2009, through June 26th, the Denver International Airport (DIA) has measured 4.86 inches of liquid (and there are still 4 more days left in June). The 4.86 inches of water is 3.52 inches above normal through the 26th. Last year, June 2008 had only measured 0.73 inch again through the same June time frame.
The wettest June on record for Denver was in June 1882 when 4.96 inches of moisture was collected in the rain bucket.
For the 2009 year so far, 10.38 inches of water has been measured at DIA which is a very impressive 2.51 inches above the normal through June 26th. Last year in June, only 3.04 inches had been recorded through the same time frame.
Note: The average Denver annual precipitation is 15.81 inches.
Change is of course the one constant in Denver’s weather but come July, things actually get pretty consistent. The standard formula for a day in July is a sunning morning, clouds developing in the late morning and early afternoon. Come mid-afternoon, thunderstorms are rolling off of the foothills and into the metro area and the eastern plains. These storms do occasionally reach severe status containing hail, gusty winds and heavy downpours of rain.