Autumn Color - Viewer Photos

Viewers have captured autumn's beauty through the lens of their digital cameras recently. It's certainly a beautiful time of the year as our fall foliage peaks. Send your best shot to our Viewer Scrapbook.

--SkyTracker7 Meteorologist Jay Webb

Welcome Eagle Rock Elementary School!

The WeatherBug is getting bigger and bigger thanks to great schools and businesses who are joining the network. The newest is Eagle Rock Elementary School in Botetourt County. What's fantastic is that this is one of the smallest schools in the county, but have managed to raise the money to bring weather and science into the classroom.

The school is located in the northwestern portion of Botetourt County. Welcome students, faculty and parents. We hope you will use the weather data to help plan your day and to broaden your knowledge of this amazing science of weather.

Click here for the Eagle Rock Elementary Live data.

Click here for Eagle Rock Elementary School homepage.

--Meteorologist Brent Watts

La Nina Means Mild Winter Weather.

NOAA forecasters are calling for above-average temperatures over most of the country and a continuation of drier-than-average conditions across already drought-stricken parts of the Southwest and Southeast in its winter outlook for the United States. The report was released Tuesday (Oct 9th) and paints a bleak picture for southwest Virginia.


Movie of sea surface temperatures, January 1, 2007 - October 3, 2007. Purple and blue colors represent lower-than-average sea surface temperatures.

It appears La Nina is to "blame" for the mild winter that is forecast for the south and mid-Atlantic. La Nina is marked by abnormally cool ocean water in the equatorial Pacific. You can read the full report/forecast here, but here are some of the highlights:

• In the Northeast and the Mid-Atlantic,temperatures are expected to be above average in response to the long-term warming trend. Snowfall for the region will depend on other climate factors, which are difficult to anticipate more than one-to-two weeks in advance.
  
• The drought-plagued Southeast is likely to remain drier-than-average due to La Niña, while temperatures are expected to be above average.

With this said, this certainly doesn't mean we won't see any snow. Also, despite forecasting above average temperatures, you can count on some very cold periods this winter. This is a forecast, an educated prediction of what will happen 2 to 4 months down the road. Don't let your snow shovels hibernate this winter. Chances are you'll need them at least once.

--Meteorologist Brent Watts

Learn more about La Nina

Winter Weather Outlook

It's hard to think about winter when the temperatures outside have been in the 80s for much of the week. But if you're already dreaming of making snowballs and building snowmen, you might want a back-up plan.



While much of the nation is still in summer mode, the folks at the National Oceanic and Atmospheric Administration's Climate Prediction Center have been busy running models forecasting winter weather. What are they saying?

• Long-range weather forecasts are predicting a warmer than average winter with less precipitation for much of the United States except the Pacific Northwest.
  


• NOAA forecasters believe the emergence of a La Nina condition -- unusually cold ocean temperatures in the equatorial Pacific Ocean -- will be the main factor behind the anticipated warmth for much of North America.

If you remember, the winter of 2006-07 was extremely mild for southwest Virginia, with very little snowfall and record warmth in January. Roanoke only saw 3.4" of snowfall last winter, which fell in February. A typical winter would bring an average of 23 inches of snow to the Roanoke Valley.

I don't know about you, but I'd love to see us have a big winter with lots of snow. We need all the help we can get to make up for an extremely dry summer and fall.

--Brent

Ragweed Remediation

Early fall is prime time for allergies, and in Roanoke, ragweed is the primary allergen at work right now. Ragweed plants, which only live for one season, mature as nights get longer in late summer and early fall, releasing up to one billion pollen grains per plant!

Seventy-five percent of Americans who are allergic to pollen-producing plants are allergic to ragweed, of which there are seventeen different species growing throughout the United States.

There are easy ways to reduce your exposure to outdoor allergens, including ragweed:

1) Minimize your outdoor activity in the early morning (5-10am), when pollens are usually emitted, and avoid raking leaves or cutting grass, which can stir up pollens.

2)While it may be tempting to open windows on cool nights, keeping them closed can reduce pollen concentrations inside your home.

3)Keeping the air conditioner on can help filter and dry the air, which will also help to reduce exposure.

4)Don't hang laundry items outside to dry, where pollens and molds can collect on them.

Fun Fact: Ragweed pollens can travel considerable distances on breezy days - pollens have been found up to 400 miles out to sea, and two miles up in the atmosphere!

Learn more about the environment at earthguage.net

Can the sun be different sizes?

A recent question from a viewer is related to the sun's size, and could it possibly change sizes throughout the day:

Question: Why does the sun appear so much larger in the morning when it rises than in the middle of the day, and then gets large again when it sets? Could it change size during the day?

A: This apparent change in size of the sun and the moon is merely an illusion. While there are numerous competing theories to explain this illusion, most involve optical processes of viewing distant objects.

One way to convince yourself that the apparent change in size is merely an illusion is to do the famous finger test. Use the moon because it's dangerous to look directly at the sun. Just extend your arm and compare the size of the moon at its zenith (the highest peak) to a finger or thumbnail. Do the same when the moon is at the horizon. The moon will be the same size.

It's amazing how optics can fool you. In fact, I'm still searching to find the end of the rainbow to claim my pot of gold. :)~

For an interactive look at the sun go to this link: http://www.spaceweathercenter.org/SWOP/Interactives/1.html

Weather Radios Recalled

Just wanted to pass along some important weather information regarding NOAA Weather Radios. First off, anyone who receives alert signals from the Roanoke, Lynchburg, Hinton or Mount Jefferson transmitters will notice the radio broadcast will be off-the-air Tuesday, September 25th from 10am to 4pm.

The National Weather Service in Blacksburg will be conducting a computer software upgrade. Again, the radios should be back up by 4pm Tuesday.

NO severe weather is forecast for Tuesday, so the timing is impeccable. Nice job NWS Blacksburg!
-------------------------------------------

Also, weather radio manufacturer Oregon Scientific has recalled over 66,000 of their NOAA weather radios, as they fail to receive alert signals in certain areas of the country. Click the link below for model names.

Click Below For The Press Release:
Weather Radios Recalled by Oregon Scientific Due to Failure to Receive National Weather Service Alerts

Hope you have a great 1st week of autumn! --Brent

Why I'm Not A Pilot

I love flying, and have a great appreciation for anyone who can take a piece of machinery and navigate it through an active atmosphere while at the same time knowing you have hundreds of people's lives in your hands. Just couldn't do it. Pilots have so many variables to deal with...wind, rain, storms, ice and fog. The video below shows a Boeing 737 landing in thick fog at London's Heathrow Airport without visibility. You can hear the computer instrumentation guiding the pilot through the landing process. Amazing to see!



There are many rules when it comes to flying an aircraft under certain weather conditions. Here's some of the lingo.

Visual Flight Rules (VFR) - the pilot has the responsibility for seeing and avoiding other aircrft, towers, mountains, etc.

Marginal Visual Flight Rules (MVFR) - conditions between VFR and IFR. Generally defined as visibility between 3 and 5 miles, and ceilings between 1,000 and 3,000 feet.

Instrument Flight Rules (IFR) - the pilot may be in clouds, flying solely by instruments, and therefore unable to see other aircraft. The controller takes the responsibility for aircraft separation.

Low Instrument Flight Rules (LIFR) - ceiling below 500 feet AGL and/or visibility less than one mile.

Sounds like a topic for BTF. --Brent

Humberto Brings Hope

The spanish meaning for Humberto is "bright." Sure enough, the rain from this record-setting storm brightened the spirits and the lawns of southwest and central Virginia. While not everyone received the 5-8 inch totals as Patrick and Henry counties did, everyone got at least some rainfall. Below are some of the rainfall reports from the National Weather Service in Blacksburg. These come from the IFlows automated rain gauge network. You can find a link to all these guages on our weather page, look under "Weather Extras" and click on "Rainfall Totals from area Gauges."

...PATRICK COUNTY...8.12" CIRCLE M IFLOWS

...HENRY COUNTY...
5.58" SMITH RIVER SG

...ROANOKE...
1.44" MILL MOUNTAIN

...CITY OF DANVILLE...
1.63" DANVILLE

...BATH CO...
1.32" DOUTHAT ST PARK

...BOTETOURT CO...
1.00" DALEVILLE

Not only did this storm provide benefitial rain to areas in a moderate to extreme drought, it also made history. We have never seen a tropical depression intensify this rapidly into a hurricane just prior to making landfall. Here's the details from the National Hurricane Center:

"BASED ON OPERATIONAL ESTIMATES...HUMBERTO STRENGTHENED FROM A 30 KT (35 mph) DEPRESSION AT 15Z (10 am) YESTERDAY TO A 75 KT (85 mph) HURRICANE AT 09Z (4 am) THIS MORNING...AN INCREASE OF 45 KT (50 mph) IN 18 HOURS. TO PUT THIS DEVELOPMENT IN PERSPECTIVE...NO TROPICAL CYCLONE IN THE HISTORICAL RECORD HAS EVER REACHED THIS INTENSITY AT A FASTER RATE NEAR LANDFALL. IT WOULD BE NICE TO KNOW...SOMEDAY...WHY THIS HAPPENED."

Thanks Humberto for your rain, and we hope there are more where you came from. We have a long way to go to make up for what we've lost. Now I need to go mow my lawn. The first time since July!

--Brent

A Cool Find!

Every once in a while it'll happen. Someone out there will stumble upon a bright orange parachute with a cardboard box attached to it by lots of string.

On Monday, nine year old Devin Browder found such an object while walking in Hillsville on Hayfield Road. What he found was a weather balloon, which was launched by the National Weather Service. There are a few places this could've come from, including Morristown, TN, Charleston, WV, or likely Blacksburg. These weather instruments (called radiosondes) measure important weather aloft. Meteorologists gain valuable information like temperature, humidity, pressure and the wind profile of the atmosphere.

Weather balloons were first used by the U.S. Weather Bureau in 1936. They are launched twice daily from roughly 90 weather service offices around the country. The balloons are filled with Helium, and while they are big before the launch (around six feet in diameter) they get about as large as a two story house once the Helium interacts with cold air around 20 miles above the earth. Temperatures there are around -130 degrees Fahrenheit! Each radiosonde costs the government around $200 - and meteorologists at the NWS office in Blacksburg tell me they only get back around 2% - 4% of the balloons they launch every year. Devin didn't tell me if he plans on returning his balloon or not, but I bet it makes it to a few "show-and-tells" at his school this year. Thanks for sending us your photo Devin! --Jay

Just Our Luck ~ No Rain

Even with a subtropical storm to our east, and a cold front loaded with moisture to our west, we're not getting a drop of rain this weekend. Instead, hot and humid weather will be the rule. The image above shows the zones of precipitation Sunday morning through Monday morning. As you can clearly see, the coastal Carolina's will pick up a few inches of rain courtesy of Subtropical Storm Gabrielle, and the front stretching from Maine to Texas will have areas of heavy rain. But just our luck, the sinking, dry air between the systems to our east and west will win out, which means more lawn watering (unless you're like me and you've given up on that!) The WDBJ7 DayPlanner offers a few rain chances next week. Thanks for checking out our weather blog! --Jay

Everything you need to know about weather!

Research shows the average viewer knows little about the atmospheric processes. As meteorologists, we try to put the complex world of weather forecasting into simple terms most people can understand. While it sounds like a simple task...it's not. So, as a crash course in weather, I'm requiring all my students to view this simple, yet educational video presentation.



This is actually Peter Weatherall's music video about the weather. He writes songs geared toward children. Peter was born in Australia, and grew up in England, the United States, and New Zealand and currently lives in Japan. So he knows his international weather. For more info on the weather song and Peter's music, visit www.kidsinglish.com

In the next class, we will examine the effect of coriolis force on vorticity covariance in MHD turbulent flow of dusty fluid.

--Brent

An August for the Record Books

There's no surprise August was an extremely hot month. But would you believe over 56 records were set this month? That's an astounding number of broken records. In fact, so odd, the National Weather Service office in Blacksburg compiled and released a list of August heat facts. Here's a summary.

+August 2007 will be the hottest on record for Roanoke, Blacksburg, Danville & Bluefield

+Over 56 records have been set for both high maximum and high minimum temperatures combined. (High minimum is considered the warmest low temperature for that date).

+There were numerous days 90+ degrees. Here's the breakdown by city: ROANOKE: 23 days
LYNCHBUG: 16 days
BLACKSBURG: 11 days
DANVILLE: 24 days

Total Lunar Eclipse

As the moon passed through the earth's shadow early this morning, few locally were able to see it. Clouds obstructed the view of the year's second Total Lunar Eclipse. For those that didn't get to see it, here's a look at the total eclipse that took place March 3rd of this year.



Aside from the clouds, a couple things got in the way of making this a spectacular viewing. The eclipse took place a bit too close to moonset OR sunrise (however you look at it). So, by the time the moon became totally immersed in the moon's shadow, the morning twilight interfered with its visibility. Also, the moon blended in with the clouds and haze we had in the atmosphere.

If you weren't able to see it this time, perhaps try next year. The next Total Lunar Eclipse will be February 20, 2008.

Meteorologist Brent Watts

Gustnado vs Tornado

Tuesday's severe storms that rolled through parts of the region created swirls of debris that appeared to resemble a tornado. Several folks reported seeing a funnel cloud. However, many weather features can create a tornado-like swirl. One of those is the gustnado.
A gustnado is a short-lived swirl of wind (whirlwind) that develops on a thunderstorm outflow boundary called a gust front.


Gustnados develop from the ground up as winds interact with land and begin to swirl, picking up dust and debris. The result is similar to a small tornado. However, if you're brave enough to look closely, you'll see the gustnado is not attached to the cumulonimbus cloud or related to the storms rotation, unlike its cousin the tornado.

It CAN produce damage due to its straight-line winds that can reach over 70mph. Gustnado damage is typically limited to small trees, windows and tossing around of loose objects, but can be worse in a very strong storm.

Thankfully, we're not accustomed to seeing these acts of nature in these parts very often. So, being able to differentiate between the two while finding shelter is fairly difficult. Regardless of the culprit, wind damage was reported and the daily plans were disrupted for a short period of time. Had this been a strong tornado, this may be a different story.

Send your weather questions to: bwatts@wdbj7.com

--Meteorologist Brent Watts

Space Station and Shuttle

Mark Hodges from the Science Museum of Western Virginia sent us this cool photo of the International Space Station and Shuttle Endeavor.

In his email he writes: "I shot this this evening at 9:30pm from the 5th floor parking deck at Center in the Square passing over the Hometown Bank building. The Space Station is first with the shuttle just passing over the top of the building."

This photo was time-lapsed and is very good considering the amount of ambient light in Downtown Roanoke at night.

The image was taken just in time, as Endeavor will be returning to earth this afternoon, a day earlier than expected. Staff at mission control in Houston was concerned that Hurricane Dean might impact the weather there, causing communication issued between the shuttle and ground staff.

Today's landing of endeavor will take place around noon in Florida. Endeavour's first landing path would take the crew over the Pacific Ocean, Central America and Cuba before touching down at Cape Canaveral in Florida.

If bad weather forces NASA to scrub that landing attempt, the shuttle's second opportunity would include flying over Mexico's Yucatan Peninsula, which was battered Tuesday morning by Hurricane Dean. If the shuttle crosses above the hurricane, it will be too high to feel its effects, according to NASA.

Pretty interesting. As always, thanks for the photo Mark.

--Brent

Mean Dean Gets Meaner

It was a phrase I jokingly used on the air last week. "Mean Dean." At the time, Dean was merely a cluster of storms that had reached tropical storm status. We had already seen three of those this season with little major impact. Dean however is certainly different.

As of this blog entry, Hurricane Dean, a Category 4 with winds topping 150mph, has already devistated parts of the Caribbean Islands, completely wiping out precious banana crops in St. Lucia and Martinique.

The dangerous hurricane is being guided by a low pressure system that was over southern Florida. That low has now taken a westerly move and will be replaced by a ridge of high pressure over the east. This should keep Dean on a southerly route through the Yucatan, and into the southern Gulf of Mexico. Most of the models have the northern Gulf "in the clear." This spaghetti plot (below) that meteorologists look at as forecast guidance, takes all the various computer model runs and compares the forecast track. The one on the left shows most of the models are now coming together on a southern Gulf route to Dean, which takes him either into southern Texas or northern Mexico.

As a result of a possible Texas landfall. NASA has decided to bring the space shuttle home early for fear mission control in Houston could be disrupted. The photo on the right was taken from the shuttle. It shows Hurricane Dean with the Space station in the foreground.

With several thousand oil rigs in the Gulf of Mexico, even without a US landfall, we will likely feel the impact in a gas price increase. A simple trade-off for being spared so much devistation. We'll continue to monitor Dean. You can too in our Hurricane Center section. You can find it by returning to the main weather page and click on the hurricane center icon.

So long for now! --Brent

Heat, Humidity and Water Woes

"It's not the heat, but the humidity." We hear it all the time. But we are living that phrase this week. Last week, air temperatures reached 100 and dew points (measure of amount of moisture in the air) were extremely high (60s & 70s), which made it feel like a sauna each time you stepped outdoors.

This heat wave is different in that our moisture source is cut-off, so our air is very dry, almost like the desert. At one point Wednesday, the dew point was 49 and the relative humidity was 27%. That's almost as dry as Death Valley.

We're in desperate need of rain. Roanoke Regional Airport has a deficit of -7.98" for 2007. In the middle of a moderate drought, Danville is even worse, down -8.15" for the year. It's not unusual that summer is dry, with mainly scattered storms being the main source of precipitation. We typically see a return of wetter weather in the fall as the tropics get active and also when the jet stream returns a bit farther south. One could only hope we can make up for some of the lack of rain as we did at the end of 2006.

Below is the temperature and precipitation outlooks for September-November, based on climate and current models. This data comes from NOAA and the National Weather Service.

THE TEMPERATURE OUTLOOK FOR SEPTEMBER-OCTOBER-NOVEMBER 2007 CALLS FOR ABOVE NORMAL TEMPERATURES OVER MOST OF THE UNITED STATES. THE CHANCES OF ABOVE NORMAL TEMPERATURES ARE SOMEWHAT HIGHER THAN NORMAL FOR THE SOUTHWEST DUE LARGELY TO THE LONG-TERM TRENDS AND ONGOING DROUGHT CONDITIONS.

ABOVE NORMAL PRECIPITATION IS EXPECTED ALONG THE GULF AND ATLANTIC COASTS PARTLY DUE TO AN EXPECTED ACTIVE TROPICAL ATLANTIC STORM SEASON AND ALSO DUE TO THE LONG-TERM TRENDS.

What does this all mean? Conserve water, drink water, and pray for water. --Brent

Waterspout Photos

Our weather intern David Wolters just came back from a Florida vacation. Aside from the vacation stories of wild parties, surf and sand (OK, at least 2 out of 3), he shared some of the coolest photos he took while there.

Florida is known for its abundance of storms. Over land they can produce tornadoes. But over water, those same formations are called waterspouts. Here are some of the photos he took. He would estimate the spout was about 10 miles from land. Luckily, it stayed there. Thanks for the photos. --Brent

Supercell Storms

We've certainly had our share of stormy weather over the past several weeks. A fellow employee (thanks Debra) sent me this video of a supercell storm time lapse from Oklahoma.

You might define a supercell as a thunderstorm with a deep rotating updraft (mesocyclone). In fact, the major difference between supercell and multicell storms is the element of rotation in supercells. As you will see in the video below, these storms do have quite the rotation, and if conditions are right, can produce tornadoes.

Learn more about supercells here...after watching the video :) --Brent