As we head into the hot days of summer, the lack of moisture begins to drive the fire danger up. Tuesday we are expecting highs temperatures to reach 93 in the Denver metro area before a brief cool down begins but by Saturday those temps will be back up to the mid-90’s.

Much of the western slope once again finds itself under Red Flag Warnings. Frisco in Summit County and Guffey in Park County have recently battled small blazes. With the long holiday weekend approaching, lots of folks will be heading to the high country. More people means there is a greater chance for fire so everyone should be careful.

Closer to the Front Range, while we are not currently under any fire related advisories, we are still very dry and the danger exists. Just yesterday a grass fire near Wiggins quickly blew up and consumed 2,500 acres and took six hours to contain.

Please be aware of the danger and leave the fireworks to the pros! Remember that fireworks are illegal in Thornton and can get you a $1,000 fine if you are caught using them.

Your intrepid Weather Examiner is back from vacation, relaxed, tanned and ready for summer!  What makes a good vacation for a weather geek?  Severe storms of course and I saw a doosy while in northeastern Colorado last week. 

Weatherwise my vacation started out pretty boring with mild days, cool nights and I suppose what most people would consider beautiful weather.  Last Friday started out much the same as the week with a calm, beautiful day on the eastern plains of Colorado but it is after all severe weather season and the chances of something brewing over a week are pretty good. 

By the mid-afternoon, more clouds started to roll in and by late afternoon, I was watching a storm cell with great potential develop to the northwest of me.  Soon the weather radio was beeping warning of a Severe Thunderstorm Watch being issued for my location and that was upgraded to a Warning before too long. 

Soon those clouds started to darken and spots of green were showing - sure signs of something major brewing.  A band of rain was clearly visible and moving our way.  A quick check of the weather radar software on my laptop showed great potential with the cloud tops exploding over 30,000 feet above.  Before long the rain started mixed with a touch of pea sized hail.  That rain got pretty heavy and the wind was getting pretty vicious.

Being in an RV in severe weather is not always the wisest place but I was pretty confident we were okay although we did have a plan to escape to more secure shelter about 75 yards away. After dumping a good inch of rain in less than 20 minutes the storm passes. However, that same storm cell did spawn a tornado 10 miles to the southeast after it passed me. Even more notably, the cell was so powerful, it continued churning out severe weather for an additional 90+ miles before disappating!  
 
In the end, having the one day of severe weather while on vacation made it pretty danged fun!  The desire to chase the storm cell was strong but my better half would probably not have approved me leaving the family behind at that point. 

We recently wrote about systems which provide severe weather alerts to the general public.  In writing that, we extolled the virtues of having a “weather radio” - a specialty radio that allows you to listen to and monitor the NOAA Weather Radio All Hazards (NWR) system.

We just read on KMGH channel 7’s website that all Front Range area King Soopers are offering a very good deal on a Midland WR-100 radio.  These are similar to the WR-300 model we discussed previously - just with fewer bells and whistles.  The WR-100 retails for $49.99 but through September at area King Soopers stores you can buy one for $29.99. 

You can find more information on channel 7’s website including a list of area King Soopers stores and even a video that walks you through how to set the radio up.  This is a great deal and we would encourage everyone to take advantage of it. 

Now this is just about perfect!  The forecast shows just about ideal weather if maybe a touch warm.  Friday we will have a high temperature of 82 under clear skies.  Saturday will be the warmest day of the weekend hitting near 90, again under clear skies.  Sunday follows up with a high of 85 with a few clouds around. 

The first part to the middle of next week could see a slight change as a series of cold fronts moves across eastern Colorado.  Afternoon and evening thunderstorms could be a possibility. 

Get outside and enjoy this weather! 

The National Weather Service has completed their tornado assessment of the Windsor tornado and determined the twister was rated an EF3 on the Enhanced Fujita scale.  See below for details and here for a map of the path the twister took. 

PUBLIC INFORMATION STATEMENT…UPDATED…
NATIONAL WEATHER SERVICE DENVER CO
430 PM MDT FRI JUN 6 2008

..WELD COUNTY TORNADO OF MAY 22 2008 RATED AN EF3 TORNADO…

On Thursday May 22 2008 a wide and powerful tornado swept north northwestward for 34 miles from northeast of platteville in Weld County at 1126 AM MDT to 7 miles east northeast of Fort Collins in Larimer County at 1216pm MDT.   The National Weather Service tornado damage assessments conducted on Friday May 23rd and Saturday May 24th documented large areas of damage.  On the enhanced Fujita scale there were pockets of EF3 damage especially near the Missile Silo Park Campground west of Greeley and to homes and businesses in eastern Windsor.  Wind estimates in the heavily damaged areas were as high as 130 to 150 mph. 

The tornado was as wide as one mile at times along its path.  There was one fatality and 15 to 20 injuries.   Damage estimates are not finalized, but preliminary numbers from FEMA are 850 homes damage, with nearly 300 homes signficantly damged or destroyed.  Privately insured damages total 174 million dollars…and the Poudre Valley Rural Electric Association reported one million dollars of damage to electric transmission facilities.  

One question frequently asked is how unusual was this event.  Certainly it was not unusual in time of year (May and June are the peak tornado months in Colorado).  It was not unusual in location (more tornadoes are reported in Weld County than any other county).  It was slightly earlier in the day than normal, as we usually see tornadoes in the mid afternoon to early evening.  The track was longer than most, the tornado was moving fastern than most,  and a track moving north northwest is very unsusual.  Since 1950 there have been a total of 20 tornadoes of f3 and higher within Colorado.  This was the second f3 tornado reported in weld county since 1950.   On May 15, 1952 an F3 tornado injured 5 people within the county. 

For reference…the Enhanced Fujita Scale classifies tornadoes into the following categories:

EF0…wind speeds 65 to 85 MPH.

EF1…wind speeds 86 to 110 mph.  

EF2…wind speeds 111 to 135 mph.

EF3…wind speeds 136 to 165 mph. 

EF4…wind speeds 166 to 200 mph. 

EF5…wind speeds greater than 200 mph.

One thing that is consistent about Colorado weather is how inconsistent it can be!  Yesterday evening we saw some metro area thunderstorms with some rain and a pretty good lightning show.  Further east on the plains, four tornadoes were reported but all were in open areas.  Today the state will see it all. 

Flood watches / warnings are in effect for a good part of the western slope.  Also out west there are actually snow advisories issued for the Gore and Elk Mountain Ranges and a few other spots as the snow level will drop to around 9,000 feet.  Much of the eastern third of the state is under thunderstorm watches until around noon and those could very well be extended.  Severe storms out there are a real possibility. 

Click here to see what advisories / warnings are currently issued for the state. 

This morning in the metro area we woke up to overcast skies and light rain in many areas.  Showers will continue on and off throughout the day and a thunderstorm or two are a possibility.  Temperature wise we will be about 20 degrees below the normal of 79 and that is a pretty dramatic difference from recent days.  Expect temps around the metro area to reach around 60 today. 

There is good news though.  The rain and cool weather will move out of the Front Range after midnight tonight and we will see a quick warm up and a beautiful weekend.  Look for 77 degrees on Friday and 85 degrees on Saturday and Sunday. 

If you didn’t read our June weather preview, you may find it interesting to know that snow has actually been recorded in Denver as late as June 11th (1947).  It is pretty unlikely anything like that will happen this year but if you don’t like the rain, just remember that it could be snow! 

The National Weather Service has issued a Tornado Watch for much of northeastern Colorado including the Denver Metro area.  Counties under the watch include Adams, Arapahoe, Denver, Douglas, Elbert, Kit Carson, Lincoln Logan, Morgan, Phillips, Sedgwick, Washington, Weld and Yuma.  This watch is in effect until 8:00pm tonight. 

Tornado Watches are issued when weather conditions are favorable for the development of severe thunderstorms that are capable of producing tornadoes. A tornado watch therefore implies that it is also a severe thunderstorm watch.

As we all saw two weeks ago in Weld County, conditions can quickly deteriorate and the weather can present a very real danger to life and property.  Now would be a good time to run through tornado emergency procedures in your mind. 

Please remember, should the tornado threat increase:  Get in, get down and cover up!  A well built structure with a basement is ideal shelter but if that is not available, an interior bathroom or closet is next best.  Modular and mobile homes are NEVER a good option nor are vehicles.  If you are in a vehicle and a tornado is near, abandon it immediately and seek shelter in a low lying area such as a ditch. 

For these and other tornado safety tips, please see our Severe Weather 101 - Tornadoes. 

Monday evening was a bit interesting around Thornton as hail was reported across much of the city.  Toward the northeast corner, hailstones up to 1″ in diameter were reported, including at the home of ThorntonWeather.com.  Thankfully it was shortlived and the size of the hail while notable, wasn’t big enough and didn’t last long enough to do any real damage.  The image at the right is the radar image of the storm as it passed over - click on it to view the full image.  That particular cell broke its upper cap of 26,000 feet and grew to 32,000 feet in a span of 15 minutes! 

Tuesday could bring severe storms again thanks to an abudnance of lower level moisture.  However, cooler temperatures should help to keep these from becoming quite as severe but hail and wind are a possibility.  As is typical this time of year, east of the urban corridor has the best chance to see some excitement. 

Wednesday afternoon and evening the chance for storms increases as a cold front moves through but again, the cooler temps should help to keep things a bit under control.  Locally heavy rain is possible, particularly the farther east you go.  In the mountains, there may even be some of the white stuff above 9,500 feet!

Notwithstanding last month’s tornadoes in Windsor and the northern Front Range, June is historically Denver’s real severe weather month.  Severe thunderstorms, tornadoes and hail are notorious visitors to Denver and across eastern Colorado during the month.  In fact, over 40 percent of the tornadoes that occur in Colorado are observed in June and these are typically the most destructive of the year.  Severe thunderstorms have also caused major property damage across the Front Range during the month.  Click here to read our complete June 2008 Weather Preview. 

I was recently asked how prevelant tornado sirens are in the metro area and thought that would be a good discussion to have.  Tornado and alert sirens do exist in some municipalities in the Denver metro area but not all. Boulder has a system (primarily due to flood dangers) as does the city of Denver itself. Many of the other suburbs however do not.  Unfortunately, Thornton does not which to me is somewhat odd as in 1981 Thornton was struck by one of the few tornadoes to have hit the metro area so you would think that would have caused them to consider building a system back then.  If you are reading this and live in another municipality, give them a call to find out if one is available in your area.

The sirens definitely do provide a service to the community.  However, USA Today just had an article discussing these types of systems and pointing out that they were expensive to maintain and of limited effectiveness.  Some municipalities have depended on reverse 911 systems to alert residents but it is my opinion that these to are limited because they rely on someone being home to answer the phone.  What if you are in an area park and a tornado is coming? People today are very mobile and a solution that takes that into account and can warn people wherever they are would be ideal.

The city of Dacono recently deployed a system that I think Thornton should give some thought to.  You can read more about it here but in essence residents can sign up to receive alerts on their home phone, cellular phone and email.  Within a matter of seconds, thousands of subscribers can be notified of everything from weather events to disaster updates to AMBER alerts for much less than the cost of a siren system.  ThorntonWeather.com is going to be discussing the idea of this type of system with Thornton City Council members in coming weeks so be sure to check back to see what we learn.

In the meantime, probably the best way to ensure you are warned about approaching dangers is to purchase what is commonly known as a “weather radio.” These radios are relatively inexpensive (around $40.00) and allow you to listen to and monitor the NOAA Weather Radio All Hazards (NWR) system. NWR broadcasts official Weather Service warnings, watches, and forecasts as well as other hazard information like earthquakes, avalanches, chemical spills, and even AMBER alerts. These broadcasts continually run 24 hours a day, 7 days a week and provide a great way to stay up to date with developing weather conditions.  One of these radios is actually what broadcasts our weather radio system here on ThorntonWeather.com.

Some of the nicer units even use what is called SAME - Specific Alert Message Encoding – which I would highly recommend. In essence you program in a code for the area in which you live and the radio will automatically turn on and sound an alert when something of note is in your area. These weather radios are very popular in rural areas in Tornado Alley but as we saw last week in Windsor, they definitely can be useful here along the Front Range as well. More information about the system can be found on the National Weather Service’s website and you can find these at many electronics retailers, particularly those on the Internet like Amazon or NewEgg.

Which weather radio do we use?  We are hesitant to recommend specific products but our radio of choice at the current time is the Midland WR-300.  This radio has the important SAME coding feature, a text display to show you what sort of alert is occurring, battery backup and more.  We have been pleased with the two we have.  NewEgg carries this model for $47.99.