Let's go surfing in the sky!

A large crashing ocean wave is a surfer's dream.  It's something they can ride their surf board on and potentially through, if they are really good!  But now imagine surfing in the sky?  Where would you get those amazing waves to ride, and what would they look like?  Well, wonder no more!



This picture was taken the morning of Friday, December 16th overlooking Birmingham, Alabama.  Large cresting waves were seen on the horizon and they really confused many of the locals.  The local television stations had many people calling in wondering what exactly was going on.

What they were actually seeing are "Kelvin-Helmholtz waves".  These waves form when a fast-moving layer of fluid slides over a slower and thicker layer of fluid, thereby dragging its surface.  For example, water waves form when the air (yes, air is considered a fluid) is moving faster than the water below.  When the difference between the wind and water speed is great enough, the waves "break" (their crests lurch forward) and they take on the classic shape of a Kelvin-Helmholtz wave as seen above!

So what happened here is that there was more than likely a slow moving cold layer of air near the surface (as evident by the thick cloud layer).  A warmer, faster moving layer of air aloft rode over top of it.  And since the cold air is denser and slower than the light, fast-moving warm air, the warmer air dragged and began scooping up the top of the cold layer, resulting in the cresting waves that appeared in the cloud!  Pretty cool, right!

Is it Partly Cloudy?

I often get  questions from people regarding how meteorologist define certain sky conditions.  You often here the phrases Cloudy, Mostly Cloudy, Partly Cloudy, Partly Sunny, Mostly Sunny, Mostly Clear, and Clear in weather forecasts.  But many don't know the distinction between some of these terms, especially between Partly Cloudy and Partly Sunny.  These two terms seem to confuse people the most, but I will go through them all, just for your knowledge.  So here we go!

Cloudy
This one is an easy one that most people can recognize.  The sky is cloudy when it is completely covered in clouds, typically when an area of low pressure moves through the region.  Many meteorologists define a cloudy sky as one where there is less than 10% of clear sky visible, while others state that it must be absolutely free of clear sky.  I'm one of the type that say where there is less than 10% clear sky, it is cloudy!

Mostly Cloudy
This one too is easy to recognize but can be a bit tricky on one end of the spectrum.  I typically define a mostly cloudy sky as one where there is between 10% and 30% clear sky visible.  That's right, a mostly cloudy sky can have a few breaks here and there.  But it can get a bit tricky with the more clearing you get, as it becomes partly sunny!  (However, at night time there is no problem as night can not be partly sunny!)

Partly Sunny
This term is one of those that can easily confuse people since it's right between mostly and partly cloudy.  It has more sun that a mostly cloudy sky, but more clouds than a partly cloudy sky.  Generally, a sky with 25% to 40% of clear sky can be described as partly sunny (unless it's night).

Partly Cloudy
This one I like to divide into day and night portions since it actually has a wider range at night.  During the day, a partly cloudy sky typically has about 40% to 75 % of clear sky visible.  However, at night that range increases to 30% to 75%.  Why?  Well, a sky that is 30%  to 40% clear during the day is considered Partly Sunny, but since there is no sun at night, it becomes Partly Cloudy!

Mostly Clear/Mostly Sunny
These are days that everyone seems to love.  Plenty of sunshine with just a hint of a few clouds scattered here or there.  They allow for quick warming during the day, but also quick cooling at night - the reverse of their mostly cloudy counterpart.  A mostly clear sky can be defined as one with 75% to 95% clear sky.

Clear/Sunny
No clouds.  No rain.  No problems.  Well... not exactly.  Clear skies can be a delight, but they also accompany extreme heat waves and cold air outbreaks across the globe.  They obviously let in a lot of sunlight during the day (plus during the winter, all that sunlight is reflected off of the snow!), but also release a lot of heat at night!  A clear sky is one where there is less than 5% cloudiness in the sky (a.k.a. barely a wisp of a cloud).

I hope this clears things up a bit, but if it doesn't just let me know and I can try to go into further detail!  Until next time, keep your eye on the sky!

2011 - 2012 Winter Weather Outlook

Hello everyone!  As meteorological winter (December through February) approaches, I though it would be good to give you a heads up as to what you may expect for the next several months - at least weatherwise. 

As I have mentioned in an earlier post, the La Nina that we dealt with last winter faded away this past summer.  Unfortunately, it has made a comeback and will likely play a role in our weather patterns across the nation for this winter.  In addition to La Nina, the lesser known and less predictable Arctic Oscillation could influence our weather as well with large short-term temperatures swings.  As a result of these large temperature swings and strong shifts in the climate patterns, the Arctic Oscillation could overwhelm or amplify the impacts typically seen from a La Nina!

So here is what the scientists at NOAA are predicting for the 2011 - 2012 weather season.

The northwestern US and eastweard into the Great Lakes region will likely see wetter conditions for the winter months, which could mean more snow than normal!  In addition, much of this area, especially the Missouri and Mississippi River Basins saw massive flooding last spring due to so much snow melting from the last La Nina winter.  The increase in precipitation again this winter could once again mean another season of flooding for these river basins!  And on the flip side, areas that need the precipitation the worst are less likely to see it.  The southern US, which is already facing a drought not seen in decades in some areas (namely Texas and Oklahoma), is expected to be much drier than normal.  So the drought will likely continue into next year.  Below, you can see an image of this thanks to the folks at the Weather Channel.



As far as temperatures, that's were it gets a bit tricky.  Typically, a La Nina will bring much cooler conditions to the Northern Plains, Great Lakes, and the California coast with warmer conditions for the South Central U.S.  And this is what is expected for this winter as well (as you can see below in the image from the Weather Channel).  However, the tricky part comes from the Arctic Oscillation (remember him?... we'll just call him A.O. from here on out!).  The negative phase of the A.O. pushes cold air into the U.S. from Canada that typically lasts a few weeks and are very difficult to predict more than a week or two in advance.  The A.O. went strongly negative at times the last two winters and caused outbreaks of cold and snowy conditions across the U.S., including the ice storms that affected the Dallas, TX area before the Super Bowl last January and the massive snow storms across the East Coast the past two winters.  The strong negative A.O. also increases the snowfall amounts around the Upper Midwest as well, along will bitterly cold conditions (below -25F anyone?).  Okay... I think I just sent a shiver up your spine with that comment!



With the much cooler conditions for the Upper Midwest this winter, maybe now would be a good time to take a trip to Hawaii... it's anticipated that they will be warmer and drier than normal!  But to recap, I am expecting a cold and snowy winter for us here in Wisconsin & Minnesota with plenty of temperature swings to keep things interesting!  I hope you have your snow shovels handy!  Until next time, have a great day and stay warm!

Winter Weather Safety Reminder!

Wow.... it has been way to long since I last posted.  I guess I'm still getting use to blogging, even after a year!  Anyways, I think now would be a good time to review some winter weather terminology and safety tips.  I know most of you have heard this before, but it's something that is very vital for living in the Upper Midwest between November and late March!  So here we go!

First, lets start with the watches, warnings, and advisories you typically hear about this during the late fall, winter, and early spring months and what they actually mean!

Winter Storm Watch
A Winter Storm Watch is issued when there is a potential for a winter storm to affect the region during the next 1 to 3 days. It does not always mean the area will be hit by a winter storm, but there is still some uncertainity of the exact path or timing of the event. This is a planning stage. Use this time to ensure you have supplies at home, like some extra food, medications, baby items, etc.. If travel is planned, check ahead and see if a different route or delaying your departure may make your trip safer. Be alert for changing weather conditions.


Winter Weather Advisory
Advisories are issued for those winter weather events that are expected to be more of an inconvenience and should not become life-threatening if caution is exercised. These are often issued for 3 to 6 inches of snow, blowing and drifting snow, freezing drizzle, or a combination of these elements. It may be issued for less snow for early season events, when drivers may not be accustomed to slick roads.


Winter Storm Warning
Winter Storm Warnings are usually issued when dangerous winter weather is expected, occurring, or imminent. The weather can become life-threatening. Criteria includes snowfalls of 6 inches or more in 12 hours, 8 inches in 24 hours, or lower amounts if accompanied by strong winds or a combination of dangerous winter elements. Avoid unnecessary travel.


Blizzard Warnings
The most dangerous winter event is certainly the blizzard. Blizzard Warnings are issued when snow or blowing snow lowers visibilities to a 1/4 mile or less, wind gusts hit 35 mph or higher, and the storm lasts for 3 hours or more. Travel is dangerous and should be avoided if possible.


Ice Storm Warning
Ice storm Warnings are issued when freezing rain will cause widespread glazing. A coating of ice is expected to reach 1/4 inch thick or more on objects and make travel nearly impossible. For lesser amounts of ice, usually a winter weather advisory would be used, but even a thin glaze of ice can make travel difficult. Avoid travel.


Wind Chill Warning
Issued when wind chills of -35 F or lower are expected with wind speeds of 10 mph or more. A wind chill advisory is issued for values between -20 and -34 F. Dress warmly and cover as much exposed skin as possible.

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Now, here are some tips to keep in mind when nasty winter weather comes your way!

Proper winter weather awareness includes preparation. Here are some things that can help you.

When Outdoors:

• Check temperatures and wind chill indicies first.
• Dress warmly, with several layers. Dress for the worst just in case.
• Use a warm coat, gloves or mittens, a hat, and water-resistant boots.
• Cover exposed skin as much as possible.
• Watch for frostbite on finger tips, ear lobes, the nose, or toes.
• Avoid over-exertion. The cold already puts a strain on the body and heart.

At Home or Work - make sure you have:

• Extra flashlights and batteries
• A battery-powered NOAA Weather Radio or AM/FM portable radio
• Extra food and water (2-3 day supply)
• Extra medicine and baby items
• First Aid supplies
• Emergency Heating source**
• Carbon Monoxide Detector

** If you use an emergency heating source, be alert for deadly carbon monoxide gases and never place it near another object that may catch on fire. Many house fires during the winter are caused by incorrect use of a space heater. Keep the space heater at least 36 inches away from other objects and turn it off if you leave the room.

On the farm:

• Move animals to a sheltered area.
• Supply extra food for animals.
• Have a fresh water supply (most animal deaths during the winter are from dehydration).

At School:

• Have an action plan.
• Monitor weather conditions closely.
• Use NOAA Weather Radio to get hourly wind chill values.
• School days may need to be delayed, cancelled, or shortened.

When Traveling:

• Winterize your vehicle. Check the battery.
• Check the forecast and road conditions ahead of time.
• Consider adjusting your route to avoid poor driving conditions.
• Carry a cellular phone for use during emergencies.
• Keep the gas tank near full.
• Coordinate with others your destination and times of travel.
• Yield to snowplows. The snow cloud they produce can lower visibilities to near zero. Stay back - Stay Alive!
• Have a survival kit in your car:
  • Extra blankets or sleeping bag
  • Flashlight with extra batteries
  • First Aid kit with pockey knife
  • Booster cables
  • A rope
  • A small shovel
  • A bag of sand or cat litter for traction
  • Plastic bags (for sanitation)
  • Extra gloves, hat, and socks
  • Non-perishable food items and bottled water
  • Road maps (for alternative routes)
• If you do get stuck:
  • Stay with your car. Do not try to walk to safety.
  • Start the car for about 10 minutes every hour for heat.
  • Keep the exhaust pipe clear of snow.
  • Tie a bright colored (red or orange) cloth to the antenna.
  • Turn the dome light when running the engine.
  • If you must venture away from the car, use a life-line or rope.
• Be careful of Dense Fog. Delay your travel if needed.
  • Do not drive into a dense fog bank. Others may be stopped.
    • In October 2002, a pile-up on Interstate 43 in eastern Wisconsin killed 10 people (see image) during dense fog.
    • In January 2008, another series of accidents in southern Wisconsin led to some fatalities due to dense fog.

 There... I know that was a really long read, but there is a lot of useful information there!  Hopefully, this will aid you this winter as the snow begins to fly around the Upper Midwest.  Until next time (which will hopefully be soon!), have a great day!

Have you ever seen a quadruple rainbow????

Rainbows are one of nature's little gifts after a shower or storm that can quickly bring a smile to your face. Many people have seen these beautiful arcs grace the sky with their presence, and several people have likely seen double rainbows as well, even though they are far less frequent. But what about a triple or even a quadruple rainbow? Many in the scientific community long believed that they were as real as the lost city of Atlantis. But believe it or not, recent photographic evidence has proved that triple and quadruple rainbows are very real.... and very rare!

A new meteorological model has allowed meteorologists to find and capture the extremely rare phenomenon known as a tertiary, or triple, rainbow. And very recently, an amateur storm chaser in Germany went even farther and found and captured the exceptional event of a quaternary, or quadruple, rainbow. You will find his picture below. Sightings of tertiary (triple) rainbows are incredibly rare. In fact, there have only been 5 reported instances in the past 250 years! But with this new method on hand, two photos have come to light in the past few months - both showing the tertiary band and one revealing the first-ever photographed quaternary band.

The first picture ever of a quadruple rainbow shows the third-order (left) and fourth-order (right) rainbows. The first two aren't included in the image.

Now you may ask yourself, where do these unique rainbow form. The answer, look where you'd least expect! Imagine yourself in an open field, seeing the bright primary and secondary rainbows before you. To see the tertiary and quaternary rainbows, you need to look back towards the sun, about 40 degrees towards it.

Like the primary and secondary rainbows, the third and fourth order bands occur when sunlight bends as it moves through water, a process known as refraction. The curvature of raindrops within storms helps to bend the colors in sunlight at slightly different angles, dispersing them and separating them into the familiar red, orange, yellow, green, blue, indigo, and violet bands of a rainbow. Most often, the multicolor bands pass right through the raindrops, but when they are reflected, they produce a primary rainbow at approximately 138 degrees from the sun. Double rainbows occur when some of the sunlight is reflected back through the raindrops and the process is repeated. However, each time the process is repeated, the resulting rainbow is fainter, which makes the tertiary and quaternary rainbows so rare.

However, the conditions to see these rare rainbows are very tricky to find. You need an pitch black sky behind the rainbows (in order to see them), you need direct sunlight, so there needs to be a break in the clouds letting the sun in (or you'll have no rainbow at all!), and it also helps to have torrential rainfall occurring. Then, you may also have to enhance the contrast of the picture enough so that the rainbow can be seen with the naked eye. It's that tricky.

But if you ever find yourself in this perfect set up and you have a camera along, be on the lookout for these elusive rainbows. The results may just take your breath away!

Welcome to Autumn!

Greetings everyone!  I realize it has been a while since I wrote on here and I'm sorry about that.  Time has really flown the past several weeks!  And the weather has changed quite a bit too!  Since my last post, we went from a summer heat wave to temperatures today struggling to get out of the 50's!  What a change!  In a way, these fall like conditions we have in Wisconsin right now is perfect to welcome in autumn with!  Autumn officially arrived to Wisconsin around 4:04 A.M. CDT this morning. 

This is known as the autumnal equinox, the time when the sun's direct rays cross over the equator into the southern hemisphere, signaling the end of winter there and our summer here.  As a result, you will likely notice the days getting shorter very quickly from day to day as we loose more sunlight thanks to the northern hemisphere tipping away from the sun.  In turn, our daily average temperatures will also start to drop, so I hope you're ready for the cooler conditions!  It's hard to believe the cold and snow of winter is just around the corner!  Until then, have a great day, and I'll try to post here more often!

2011 Hurricane Season

Wow, it's been a while since I last wrote.  Sorry about that.  Anyways, now that we are into August, we have entered the peak of the typical hurricane season.  Hurricane activity in the Atlantic Ocean is the highest between August and October.  And this year appears to be an above normal year in hurricane  activity.

NOAA is anticipating 14 to 19 named storms (which included Tropical Storms and Hurricanes, and we've already had 5 tropical storms this year - Arlene, Bret, Cindy, Don, and Emily).  Seven to ten of these storms are anticipated to be hurricanes, half of which could be major hurricanes (Category 3, 4, or 5).  These numbers are actually higher than the prediction NOAA made back in May.

So why the increase in the number of storms in the forecast?  Here's why:

"Key climate factors predicted in May continue to support an active season. These include: the tropical multi-decadal signal, which since 1995 has brought favorable ocean and atmospheric conditions, leading to more active seasons; exceptionally warm Atlantic Ocean temperatures (the third warmest on record); and the possible redevelopment of La Niña. Reduced vertical wind shear and lower air pressure across the tropical Atlantic also favor an active season." http://www.noaanews.noaa.gov

Basically, all the right ingredients are coming together at the right time, resulting in prime conditions for an active hurricane season.  So if you live or have plans along the Gulf or East Coasts between now and October, keep an eye on the latest forecasts.  Forecasts provide a lot of advanced warning when it comes to hurricances and tropical storms, so you won't get caught by surprise.  But keep checking the forecast if your going on vacation.