Mike's Blog Archive: September 2009

A very active severe weather season will get some extra legs over the next couple of days as a very potent storm system moves across the country. Large hail, strong winds, and isolated tornadoes will be possible Wednesday and Thursday from Kansas into Missouri and Arkansas.

Wednesday's storm potential rests across western Kansas and Nebraska as the system starts to interact with the moist atmosphere. A strong cap, or warm air aloft, may prevent storms from forming til well after dark across the region, but if storms are able to form in this region early on, supercells are likely to develop with very large hail and a few tornadoes.

Thursday looks to be the more potent day. The strong cold front that will drop our temperatures here in Colorado will be sweeping across the plains and will trigger a large damaging squall line for areas in eastern Kansas, northeastern Oklahoma, western Missouri, and western Arkansas. A few supercells may form early before the cold front plows through causing those storms to quickly merge into a fast moving wind driven line of heavy thunderstorms.

While not likely, the setup Thursday may produce a very significant outbreak of severe weather, including the potential for a few strong tornadoes. However given the speed of the cold front, its not likely that storms will be isolated long enough to produce such strong tornadoes.

After a very successful season, 7News Weather Producer and Storm Chaser Tony Laubach will give it one more go as he will be out chasing this event Wednesday and Thursday. Tony will be blogging during his trip with pictures and status updates and you can keep track of him and Corey at http://www.tornadoeskick.com. There you will find a live updated map showing Tony's location as well as his blog updates from the field. Tony's videos and reports will also be aired on 7News shows over the next couple of days, so definitely stay tuned as they cover this potential autumn severe weather outbreak.

The weather was pretty chilly early today, with lows in the upper 20s to low 30s across northeastern Colorado. A weak cold front slipped through the state last night, bringing in cooler air, but very little clouds cover and no precipitation. High temperatures held in the low 70s for today, with 60s in the mountains. The cooldown will not last long, as southwesterly winds will sweep across Colorado Tuesday and Wednesday. High temperatures will bounce back into the 80s at lower elevations, with 70s in the mountains.

The weather will begin to shift on Wednesday as a strong cold front moves toward Colorado from the northwest. The weather will be warm ahead of this front, but showers and thunderstorms will be developing later in the day. By Wednesday night and Thursday, a chilly airmass will descend upon the state, with chilly rain on the plains and snow for the mountains.

The chilly weather will linger into Friday and there is a chance for some frost in Denver and over the northeastern plains Friday morning. By the weekend, the weather will rebound with warmer and drier conditions returning.

Attention local gardeners! The Horizon House is a local care center for people with cancer and other terminal diseases. Every year, they make salsa from home grown green tomatos and sell them to raise money for their organization. Unfortunately, the July 20th hailstorm took out most of the garden and they are in search of green tomatoes. So if you are in your garden and have some extra green tomatos to pass along, please contact Harry Lester at harrylester@q.com.

The Autumn color is still looking very good in the central and southwestern mountains where brilliant gold remains in abundance. The northern mountain areas still have pockets of good color, but are past the peak. The next few days will offer very good weather and no driving problems, so if you can get to the mountains, here are some of our favorite routes.

1) Steamboat Springs, Elk River country north on County Road 129. Also check the view on Rabbit Ears Pass and Buffalo Pass east.

2) Colorado 14 through the Poudre Canyon west of Fort Collins

3) Trail Ridge Road (US 34) through Rocky Mountain National Park

4) Flat Tops country between Buford and Newcastle

5) Tennessee Pass, US 24, from Leadville to Vail

6) Boreas Pass between Como and Breckenridge, a 23 mile road cresting at 11,481 feet.

7) Guanella Pass between Georgetown and Grant - Normally a great route, but this year there is major road construction above Georgetown!!

8) Grand Mesa, Colorado 65 east of Grand Junction and north of Delta.

9) Maroon Bells near Aspen, a classic Colorado view!

10) Independence Pass, Colorado 82 between Twins Lakes and Aspen.

11) Colorado 135 between Crested Butte and Gunnison. Also try Kebler Pass west of Crested Butte on Gunnison County Road 12!

12) Cottonwood Pass, Colorado 306 between Buena Vista and Taylor Park

13) Monarch Pass, US 50 from Salida to Gunnison.

14) Cochetopa Pass between Saguache and Gunnison.

15) Gold Camp Road - Colorado 67 between Divide and Cripple Creek.

16) Lizard Head Pass, Colorado 145 between Dolores and Telluride.

17) Slumgullion Pass, Colorado 149 between Lake City, Creede and South Fork.

18) US 160, Navajo Trail, between Pagosa Springs and Cortez.

19) Platoro Reservoir, south of Del Norte and west of Conejos.

20) Cucharas Pass, Colorado 12, from Trinidad to Walsenburg.

21) CO 103 from Evergreen Parkway west to Echo Lake.

22) McClure Pass - This is a spectacular 8,755 foot pass south of Carbondale along Colorado 133 and the Crystal River.

Be sure to send us your digital images of the aspen. I will try to show as many as possible on TV and we will put them together into slideshows right here on TheDenverChannel.com!

After a very cool, cloudy, and wet week, Nature will make up for it and then some this weekend with a gorgeous stretch of days. As the lingering storm system hobbles it's way off to the east, a ridge of high pressure is developing over the region, resulting in much warmer temperatures and the sun.

The showers moved in on Monday and were still wandering over eastern Colorado five days later. Scattered thunderstorms rumbled over the Denver area and across the eastern plains in the early morning hours of Friday, but dry weather is now on tap. Temperatures will warm into the 70s to low 80s.

The fall colors took a beating in the northern mountains from snow this week, but there are still some great areas of across the central and southwest mountains.

Here is a good website, with info on the fall color...

www.parks.state.co.us.

Here are some great places to view the aspen gold!

1) Steamboat Springs, Elk River country north on County Road 129. Also check the view on Rabbit Ears Pass and Buffalo Pass east.

2) Colorado 14 through the Poudre Canyon west of Fort Collins

3) Trail Ridge Road (US 34) through Rocky Mountain National Park

4) Flat Tops country between Buford and Newcastle

5) Tennessee Pass, US 24, from Leadville to Vail

6) Boreas Pass between Como and Breckenridge, a 23 mile road cresting at 11,481 feet.

7) Guanella Pass between Georgetown and Grant - Normally a great route, but this year there is major road construction above Georgetown!!

8) Grand Mesa, Colorado 65 east of Grand Junction and north of Delta.

9) Maroon Bells near Aspen, a classic Colorado view!

10) Independence Pass, Colorado 82 between Twins Lakes and Aspen.

11) Colorado 135 between Crested Butte and Gunnison. Also try Kebler Pass west of Crested Butte on Gunnison County Road 12!

12) Cottonwood Pass, Colorado 306 between Buena Vista and Taylor Park

13) Monarch Pass, US 50 from Salida to Gunnison.

14) Cochetopa Pass between Saguache and Gunnison.

15) Gold Camp Road - Colorado 67 between Divide and Cripple Creek.

16) Lizard Head Pass, Colorado 145 between Dolores and Telluride.

17) Slumgullion Pass, Colorado 149 between Lake City, Creede and South Fork.

18) US 160, Navajo Trail, between Pagosa Springs and Cortez.

19) Platoro Reservoir, south of Del Norte and west of Conejos.

20) Cucharas Pass, Colorado 12, from Trinidad to Walsenburg.

21) CO 103 from Evergreen Parkway west to Echo Lake.

22) McClure Pass - This is a spectacular 8,755 foot pass south of Carbondale along Colorado 133 and the Crystal River.

Be sure to send us your digital images of the aspen. I will try to show as many as possible on TV and we will put them together into slideshows right here on TheDenverChannel.com!

The deep upper level low pressure system that has been swirling over eastern Colorado for the last few days is done finished with us. The sluggish storm is still spinning over the Colorado-Kansas border and will sweep more clouds and showers over the I-25 Corridor, the mountains along and east of the Divide and the eastern plains. Western Colorado will be a different story, with mostly sunny skies and mild weather today.

The snow threat will be low, as the temperatures will be in the low 50s, but it will still be quite cool for early Autumn - about 15-20 degrees below normal. There will be some scattered showers on the plains today, with snow mixing in above 9,000 feet. A few more inches of slushy snow will fall in the higher mountains.

It has been a year filled with weather oddities and events. In fact, people are still recovering from summer events, including the big storm that plowed through the city back in July. The Horizon House is a local care center for people with cancer and other terminal diseases. Every year, they make salsa from home grown green tomatos and sell them to raise money for their organization. Unfortunately, that July storm took out most of the garden and they are in search of green tomatos. So if you're in your garden and have some extra green tomatos to pass along, please contact Harry Lester at harrylester@q.com.

By tomorrow, the upper air disturbance will swirl away across the Great Plains and will leave Colorado. Sunny skies and warmer temperatures will return for the weekend.

The fall color will have taken a beating over the northern mountains, but central and southern areas will still be gold and glorious!

Here is a good website, with info on the fall color...

www.parks.state.co.us.

Here are some great places to view the aspen gold!

1) Steamboat Springs, Elk River country north on County Road 129. Also check the view on Rabbit Ears Pass and Buffalo Pass east.

2) Colorado 14 through the Poudre Canyon west of Fort Collins

3) Trail Ridge Road (US 34) through Rocky Mountain National Park

4) Flat Tops country between Buford and Newcastle

5) Tennessee Pass, US 24, from Leadville to Vail

6) Boreas Pass between Como and Breckenridge, a 23 mile road cresting at 11,481 feet.

7) Guanella Pass between Georgetown and Grant - Normally a great route, but this year there is major road construction above Georgetown!!

8) Grand Mesa, Colorado 65 east of Grand Junction and north of Delta.

9) Maroon Bells near Aspen, a classic Colorado view!

10) Independence Pass, Colorado 82 between Twins Lakes and Aspen.

11) Colorado 135 between Crested Butte and Gunnison. Also try Kebler Pass west of Crested Butte on Gunnison County Road 12!

12) Cottonwood Pass, Colorado 306 between Buena Vista and Taylor Park

13) Monarch Pass, US 50 from Salida to Gunnison.

14) Cochetopa Pass between Saguache and Gunnison.

15) Gold Camp Road - Colorado 67 between Divide and Cripple Creek.

16) Lizard Head Pass, Colorado 145 between Dolores and Telluride.

17) Slumgullion Pass, Colorado 149 between Lake City, Creede and South Fork.

18) US 160, Navajo Trail, between Pagosa Springs and Cortez.

19) Platoro Reservoir, south of Del Norte and west of Conejos.

20) Cucharas Pass, Colorado 12, from Trinidad to Walsenburg.

21) CO 103 from Evergreen Parkway west to Echo Lake.

22) McClure Pass - This is a spectacular 8,755 foot pass south of Carbondale along Colorado 133 and the Crystal River.

Be sure to send us your digital images of the aspen. I will try to show as many as possible on TV and we will put them together into slideshows right here on TheDenverChannel.com!

The much advertised storm system has deeked and dodged and will leave Denver dry. Well, not entirely dry, just a little wet, but not white. The upper level low that was expected to move over the eastern plains has shifted into western Kansas and that will make all the difference. Instead of a moist upslope flow over the Front Range, all of the moisture is over the plains east of Denver. Along the foothills, we have had a gentle westerly flow and that is all downslope - hence very little precipitation, but a lot of egg of the faces of forecasters!

Well, it is not always easy to forecast in Colorado and this one will be a check mark against us in the accuracy column, sorry about that. The entire prediction was based on the position of the upper level low and that darn thing has wobbled off too far to the east. Instead of snow and rain in Denver and heavy snow in the foothills, we will have clouds, cool temperatures and some light showers today.

The good news, no tree damage in Denver, the aspens trees will still look pretty in the mountains and the weekend looks great!

The Fall season officially arrived at 3:19 PM today, however the new season got a major jump start as a strong cold front swept through the state early Monday. The moisture associated with the 30-40 degree drop in temperatures came in both wet and white form. Four to eight inches of snow was reported over much of the northern and central mountains and the adjacent foothills.

Temperatures in Denver went on a wild ride with highs in the mid 80s on Sunday afternoon to the low 30s with flakes flying across Denver Monday morning. But now, we may be in for the first real snow of the season in Denver. Some suburban areas did get light snow yesterday, but no snow fell at DIA or downtown. Our average first day of snow is not until October 19th, but September snows do occur about every 3-4 years. Last year, the first flakes flew on November 14.

Snow will fall heavily in the mountains and foothills west of Denver, and along the Palmer Divide this afternoon and tonight. In fact - a WINTER STORM WARNING is in effect for areas above 6,500 feet for tonight. Six to sixteen inches of snow may plop down in the warning area by Wednesday afternoon. A WINTER WEATHER ADVISORY has been issued for the Palmer Divide areas with up to 10 inches of snow possible in the higher elevations of Douglas and Elbert counties.

It will be a wet, sloppy snow that will be tough on trees. You may need to get out with a broom and try to knock down as much of the snow as possible as the trees, still being in leaf, will take a pounding.

Denver prpoer, will get a mix of rain and snow, but some light accumulations are likely - perhaps a couple of slushy inches on grassy surfaces.

The chilly weather will hang around for most of this week as a deep upper air disturbance swirls on top of Colorado. This chilly air aloft makes the atmosphere very unstable and the result is the soggy, cold and sloppy weather. Gardeners will probably want to cover your tomato plants tonight. The chance for a hard freeze is low because of the clouds, but some areas may get a little frost nip during the next two nights. In addition, if you are in an area that will get wet snow, try to put some kind of support over the tomatoes to keep the weight of the snow off of the plants.

It is likely, the wet and snowy weather will completely wipe out the aspen viewing in northern Colorado. The display has been ahead of schedule this year, due to the cool summer. A couple of days of rain and snow will knock down many of the leaves.

It's all a fitting start to the season in a year filled with weather oddities and events. In fact, people are still recovering from summer events, including the big storm that plowed through the city back in July. The Horizon House is a local care center for people with cancer and other terminal diseases. Every year, they make salsa from home grown green tomatos and sell them to raise money for their organization. Unfortunately, that July storm took out most of the garden and they are in search of green tomatos. So if you're out salvaging your garden to get them in ahead of this first snowstorm and you have some extra green tomatos to pass along, please contact Harry Lester at harrylester@q.com.

By the weekend, the weather will improve dramatically, with sunshine and very pleasant early fall weather. If the leaves manage to hang on over the next 72 hours, we should have a lovely weekend to check out the aspen gold, but the best viewing will shift to the central and southern mountains.

Here is a good website, with info on the fall color...

www.parks.state.co.us.

Here are some great places to view the aspen gold!

1) Steamboat Springs, Elk River country north on County Road 129. Also check the view on Rabbit Ears Pass and Buffalo Pass east.

2) Colorado 14 through the Poudre Canyon west of Fort Collins

3) Trail Ridge Road (US 34) through Rocky Mountain National Park

4) Flat Tops country between Buford and Newcastle

5) Tennessee Pass, US 24, from Leadville to Vail

6) Boreas Pass between Como and Breckenridge, a 23 mile road cresting at 11,481 feet.

7) Guanella Pass between Georgetown and Grant - Normally a great route, but this year there is major road construction above Georgetown!!

8) Grand Mesa, Colorado 65 east of Grand Junction and north of Delta.

9) Maroon Bells near Aspen, a classic Colorado view!

10) Independence Pass, Colorado 82 between Twins Lakes and Aspen.

11) Colorado 135 between Crested Butte and Gunnison. Also try Kebler Pass west of Crested Butte on Gunnison County Road 12!

12) Cottonwood Pass, Colorado 306 between Buena Vista and Taylor Park

13) Monarch Pass, US 50 from Salida to Gunnison.

14) Cochetopa Pass between Saguache and Gunnison.

15) Gold Camp Road - Colorado 67 between Divide and Cripple Creek.

16) Lizard Head Pass, Colorado 145 between Dolores and Telluride.

17) Slumgullion Pass, Colorado 149 between Lake City, Creede and South Fork.

18) US 160, Navajo Trail, between Pagosa Springs and Cortez.

19) Platoro Reservoir, south of Del Norte and west of Conejos.

20) Cucharas Pass, Colorado 12, from Trinidad to Walsenburg.

21) CO 103 from Evergreen Parkway west to Echo Lake.

22) McClure Pass - This is a spectacular 8,755 foot pass south of Carbondale along Colorado 133 and the Crystal River.

Be sure to send us your digital images of the aspen. I will try to show as many as possible on TV and we will put them together into slideshows right here on TheDenverChannel.com!

The past weekend was a half and half affair over Colorado. Saturday was cool and cloudy with scattered showers and even a touch of snow over the high mountains. Sunday returned to more typical late summer weather with scattered afternoon thunderstorms and much warmer temperatures. The cause of the cool weather on Saturday was a weak upper air disturbance that settled over the region. The chilly temperatures aloft helped make the atmosphere unstable and brought showers and even some light snow. By Sunday, the upper air disturbance had moved out of the region, allowing temperatures to warm again. There was still enough moisture trapped in the mid levels of the atmosphere to bring some afternoon storms to the mountains and foothills.

The next few days will bring more late summer thunderstorms to much of the state as the winds aloft will be quite light and no major weather system will be moving into the central Rockies. There will continue to be some moisture in the middle part of the atmosphere (about 15-25 thousand feet) and that means we will continue to have scattered thunderstorms each day. The best chance for storms will be in the mountains and foothills, with only a slight chance expected over the eastern plains.

Temperatures will be slightly warmer than average across Colorado. Highs will be in the upper 70s to mid 80s on the plains, with 60s expected in the mountains. Nighttime lows will slip into the upper 40s to mid 50s at lower elevations, with mainly 30s in the mountains.

Speaking of the mountains, we are getting some good color over the northern and central mountains right now. You had better be quick this year, as the wet summer will likely mean a short season for the aspen gold. Typically moist summers tend to make the leaves turn black and fall off the trees more quickly. Once again this year, we are providing some great fall color routes to explore. Just click on the Discover Colorado button on the left side of this page.

A brief, but big change is in store for this weekend with much cooler temperatures and a showery weekend. A strong upper level storm system moving out of the Pacific northwest will move across the Northern Plains, but a surface cold front will push through Colorado bringing the start of a weekend-long change. The storm system will be too far north to make for a widespread rain event, but some upslope winds behind the front will keep showers in the forecast through Sunday.

Temperatures will be the big story with this system as we get our first taste of Fall. Friday will be 10-15 degrees cooler than Thursday, but even cooler temperatures await us on Saturday where highs won't break out of the 60s. It may feel even cooler than that with the clouds, a sign of Fall for sure. Temperatures rebound a little bit on Sunday, then bounce back to near 80 early next week.

Fall colors are starting to show in the high country thanks in part to the cooler than average summer. Unfortunately the early start to the colors may signal a shorter fall viewing season than normal. Its probably worth getting up early to enjoy the colors before the peak. Get brushed up on some of my favorite fall color routes by clicking here! I have 20 different routes filled with some of the best fall color Colorado has to offer!

Enjoy the NFL kickoff weekend! It will definitely feel like football weather!

The weather pattern that has brought so much severe weather to Denver and the eastern plains of Colorado will start to mellow out as we get deeper into September. The days are growing shorter as we now have about 12.5 hours of daylight, about 2 hours less than in late June. The shorter days mean less solar heating to help inspire thunderstorm development. We will still have some widely scattered afternoon and evening thunderstorms, but the really severe storms are just about done for the season.

We are now beginning to hear some reports of the aspen changing color in the northern mountains! It looks like we should see our peak color pretty much on schedule this year, but the wet summer may make this year's display a little less brilliant. The best years for aspen viewing are those with well-timed rains and no major fall storms. A too dry summer will send the leaves falling quickly, while a wet summer tends to make them darken to brown or black. The best color over the northern mountains should be from September 20th to the 30th. The central mountains will be about five days behind, with the southern mountain areas rounding out the last days of the month and the first ten days of October.

Usually the first signs of aspen gold tend to begin in late August over the higher forests of central and northern Colorado. By the second and third week of September, many aspen groves are well worth a day's drive. Usually the peak time to view aspen is around the last weekend of September. After that, early snows will knock down the leaves and others drop away by themselves. Aspen color does not vary nearly as much as the rich reds and purple leaves of the Midwest and East, but there is something about gold leaves against a backdrop of rich evergreen and deep blue sky that makes our fall mountains special indeed!

Historically, native tribes used the aspen bark to make medicinal teas to alleviate fever. The inner bark was sometimes eaten raw in the spring, and the outer bark occasionally produces a powder that was used as a sunscreen. Aspen is a favorite of Colorado wildlife too. Beaver use aspen for food and building; elk, moose, and deer eat the twigs and foliage. Other names for quaking aspen are golden aspen, mountain aspen, popple, poplar and trembling poplar.

Many people have asked why we have had such a wet summer and if it has anything to do with climate change. The basic answer is no - the wet summer of 2009 does not negate the long term outlook of hotter and drier weather for the west. The impact of man made climate change is on a very long time scale and cannot be assigned to any particular storm or short term weather event. We have had a wet summer because of the jetstream conditions this year. The winds aloft have been very active and have brought a greater than normal amount of thunderstorm activity to the Rocky Mountain region. Our soils were full of moisture which meant more evaporation and thus, more thunderstorms.

The wet weather has help refill our reservoirs and greatly decrease the need for urban irrigation. The cooler weather has also meant less need for air conditioning and thus a lower energy usage - all good news for this season. Over the long term, however, the increase in carbon dioxide and other "greenhouse" gases will mean a gradual warming of the annual temperature for the western United States in particular and the world in general. It is incorrect to try and correlate temperature trends over a matter of months or even a few years with the trends expected over the course of decades.

One of the additional factors in our wet weather across Colorado and surrounding states has been the shift from a cool La Niña pattern in the Pacific to a warmer El Niño condition. After three years, a fledgling El Niño has developed and is expected to last through this winter. The last El Niño was back in 2006 and while it brought drenching storms to the West Coast, Colorado didn't feel as many effects as it normally would. This new El Niño is still very weak, but it may still have a fairly profound impact on our weather in the coming months.

As we enter the season of Autumn, the weather will likely continue to be slightly wet across eastern Colorado and New Mexico as the El Niño tends to inspire a stronger flow of moisture into the southwestern United States. Keep in mind, however, that the early fall weather pattern is not particularly stormy, so the amount of precipitation may only be an inch or two through October.

The term El Niño became familiar to the public's ear back in the early 1980s when a very strong El Niño event during the winter of 1982-1983 hit California with heavy, wet storms causing flooding and mudslides. El Niño typically occurs every two to five years and usually lasts for 12 months.

El Niño's impacts depend on a variety of factors such as the time of the year and how much the ocean temperature increases. This change in ocean temperature can cause a variety of effects. El Niño can suppress Atlantic hurricane activity, bring much needed winter precipitation to the arid Southwestern states, more mild winters in the North, and can decrease the risk of wildfires in Florida.

In Colorado, we typically see the most significant changes in the Southwest and Central Mountains where they tend to receive increased amounts of winter precipitation. On the Eastern Plains, the winters are usually more mild and the Spring has an increase in precipitation. In late summer, we often see an increase in monsoonal moisture giving us more storms through those dry months. Although in Autumn, El Niño is not usually very noticeable, although the big snowstorm in October of 1997 was during an El Niño year!

In a El Niño diagnostic discussion released recently by the NOAA National Weather Service Climate Prediction Center, scientists noted that eastern equatorial Pacific sea surface temperatures were at least 1.0 degree C above average at the beginning of July. From this, NOAA expects this El Niño event to continue developing over the next few months, with further strengthening possible.

According to Klaus Wolter of the University of Colorado- CIRES Climate Diagnostics Center NOAA-ESRL Physical Science Division, we were under weak-to-moderate La Niña conditions since fall of 2008. These conditions continued through last winter keeping Colorado dry and mild. Over the summer, however, conditions have changed toward a weak El Niño pattern in the Pacific. The current status of the El Niño / La Niña pattern could be considered "neutral", as the transition takes place. Many Colorado observations from the past few decades indicate that even a neutral condition tends to bring more moisture to Colorado.

If you would like to see more information from Klaus Wolter and his Executive Summary check out the Earth System Research Laboratory Web page.

For more details on El Niño, you can check out NOAA's El Niño site at http://www.elnino.noaa.gov

For more information about aspen leaves, El Nino, climate change and Colorado, please check out a copy of my book - THE COLORADO WEATHER ALMANAC. I cover these topics in much more thorough detail. THE COLORADO WEATHER ALMANAC is available at most local bookstores or you can search and order it from Amazon.com.

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