SWAT Chasers at the Dayton Hamvention today and tomorrow. Stop by, say hi and check out the SWERV.
As of 8:00 AM, Hurricane Irene was a strong Category 2 hurricane with 110 mph winds. Hurricane Irene is likely undergoing what we call an eyewall replacement cycle (ERC) where the old eyewall dissipates while a new eyewall develops and becomes the dominate center of circulation. This is likely the cause for Irene’s weakening, however strengthening will likely resume later today and Irene will likely regain major hurricane status (category 3).
Outer rain bands from Hurricane Irene are already impacting portions of the Eastern and Southeastern South Carolina Coast. Folly Beach, SC has already reported 2,600 people without power and I’m sure that is just the beginning in terms of power outages! Increased wave heights can also be expected this afternoon along the Florida, Georgia and Carolina Coast as Irene continues to move North at 14 mph.
As Irene draws closer to the North Carolina coast, the atmosphere associated with Irene will become more favorable for tornadoes, which is fairly common in hurricane and tropical type storms. For that reason, the Storm Prediction Center has outlined Eastern North Carolina in a slight risk (5%) for tornadoes this afternoon and this evening.
Hurricane warnings are in effect for much of the South Carolina and North Carolina Coast. Hurricane Irene is a very large hurricane with a very large wind field and strong tropical storm force and hurricane winds will reach the coast long before Irene makes landfall. Rapidly deteriorating conditions are expected along the Carolina Coast by late this evening.
My forecast track for Irene is very similar to the National Hurricane Center’s official forecast track. Irene will likely make landfall between Morehead City, NC and Hatteras, NC sometime Saturday Afternoon. Irene will then move back into open waters and make a second landfall on Sunday near Atlantic City, NJ. Here is the official National Hurricane Center forecast track and the latest hurricane watches & warnings.
Besides the hurricane force winds and potential tornadoes, the other extremely dangerous threat with Irene will be the potential for massive amounts of rainfall and dangerous and deadly flooding due to the large amounts of rainfall and storm surge. Irene has a significant moisture influx feed with her and she will bring heavy amounts of rain to the entire East Coast. 8-16 inches of rain will be possible from North Carolina all the way to New York.
Our thoughts are with all of those that will be impacted by Hurricane Irene. Hurricane Irene has the potential to be one of the most destructive hurricanes and for that matter disasters to impact the United States in decades. Residents in the path of Irene from North Carolina to Long Island, New York should be taking their hurricane precautions/preparations and heeding any warnings given by public safety/emergency management officials.
SWATChasers is just now entering Western North Carolina and we are enroute to Morehead City, NC to get set-up and prepared for Hurricane Irene. We will continue to bring you live updates on our facebook page (www.Facebook.com/SWATChasers), on twitter (www.Twitter.com/SWATChasers) and you can watch our live streaming video later today at http://www.SWATChasers.com!
SWAT will also have live video coverage/interviews on the following stations:
WLIO – Lima, Ohio
Local 12 – Cincinnati, Ohio
ABC 22 – Dayton, Ohio
NBC WDTN 2 – Dayton, Ohio
Fox 45 – Dayton, Ohio
WCIA 3 – Eastern, Illinois (Champaign – Urbana)
Fox 59 – The Indianapolis News Leader
Since there has been some speculation that a gustnado may have developed along the gust front as it struck the Indiana State Fair causing the stage collapse and mass casualty incident, I figured I would take time to post a weather wise blog explaining what gustnadoes are!
While there are some theories that a gustnado may have struck the Sugarland stage at the Indiana State Fair causing the stage collapse, that is neither here nor there as far as this blog entry is concerned. I will tell you however that there were several documented gustnadoes across Central and Western Indiana on Saturday Evening, August 13th, 2011.
A gustnado is a specific type of a short-lived, low-level rotating cloud that can form in a severe thunderstorm. Gustnadoes form due to non-tornadic cyclonic features in the downdraft from the gust front of a strong thunderstorm, especially one which has become outflow dominated. While they often look similar, gustnadoes have very little in common to their big brother, the tornado. Gustnadoes are outflow dominated and often form along gust fronts, while tornadoes form from a rotating supercell and mesocyclone.
One of the key differences and easiest ways to determine a gustnado verses a tornado is that gustnadoes are often not attached to any cloud structure. Tornadoes on the other hand extend down from a rotating wall cloud, a cloud feature that often develops in a supercell thunderstorm. Gustnadoes, while not true tornadoes, can become quite wide and can even be long lived. Gustnadoes should be considered dangerous as they often produce winds in excess of 60 to 70 mph. Gustnadoes have and can do damage.
The picture above is a rotating supercell and associated wall cloud. Wall clouds often have that circular and lowered look and typically rotate, some times quite violently. Most tornadoes develop from wall clouds and supercell type thunderstorms.
The picture above was taken by SWAT Chasers outside of O’Neill, Nebraska on May 30th. The storms that day quickly became outflow dominant and the storms produced numerous gustnadoes all across Central Nebraska. Some of the gustnadoes became quite wide including one we chased which was over 1/2 mile wide. The picture above shows that the rotating column of air, dirt and debris was clearly a gustnado as it was not attached to any wall cloud or lowered cloud base. This particular gustnado occurred on a gust front that surged out ahead of a supercell. What was rare about this particular incident was that to the East of our location, a large gustnado was swirling on the ground. To our West under the actual mesocylone, a tornado briefly touched down under the wall cloud in an open field.
Gustnadoes are often confused and interpreted to be tornadoes by the public and even law enforcement and public safety officials. As stated above, the simplest way to tell a gustnado from a tornado is to check and see if there is a connection to a rotating cloud base. If there is, it is a tornado. If there is not, it is likely a gustnado. If you see a gustnado approaching, you should seek shelter as they can produce strong winds and cause damage.
I hope this blog gave you a little bit of a better understanding of gustnadoes so that when us weather people use the term in the future, you will have a better idea what we are talking about!
Thanks for reading!
P.S. Don’t forget that you can book your storm chase tour with SWATChasers for the 2012 storm chase season! We are offering week long tours that will offer guests a chance to see the incredible Great Plains, Severe Thunderstorms and hopefully tornadoes! You can check out our tour schedule and find more information at SWATTours.com
Hey everybody. Is it going to rain, or will it be a good day to grill out with the family? When you want to know what the weather is doing outside, the first place you probably look is up! Clouds can hint at a calm afternoon or an exciting evening of weather, and sometimes the clouds that look ominous aren’t really telling of severe weather at all. In this, the latest in a series of weather education blogs, you will learn more than you ever wanted to know about Clouds.
So lets start at the beginning. Where do clouds come from? The stories you were told as a kid are not true, like the one that goes something like this for example, “Clouds are made in a factory a far ways away and pumped out a smokestack…etc.” That is not how it works at all, and upon growing up, you probably made this discovery on your own. In fact, I found out that you couldn’t grab a piece of a cloud and put in in my pocket to take home after we booked a sight seeing flight in Myrtle Beach, back when I was 6. I reached out the plane window as we went through a cloud and tried to grab a piece, but my hand just got damp. It goes without saying that I was disappointed for the next 10 years or so. However, to this day you still aren’t sure exactly how it all works. You know that clouds are made up of some kind of water, and they get blown about by the wind. But why are they there? Why do some clouds grow into thunderstorms, while some make fun shapes that slightly resemble celebrities or animals? I’ll try my best to explain CLOUDS.
It takes a bit of heavy lifting to get a cloud to rise. Moist air must be forced up somehow, whether it be from a front, warm or cold, or from some topographical feature, such as a tall hill or mountain. As that air gets forced upwards, it cools, and that water in it’s gaseous form (water vapor) condenses and forms water droplets. Warm air is capable of holding more water vapor than colder air, so any time air is cooled, it gets closer to being saturated, or reaching it’s saturation level. The point at which air becomes saturated is known as the dew point. I explained this in the Dew Point and Humidity posting a few weeks ago. Eventually, warm air rises high enough to the point in which it becomes saturated and droplets form. These droplets are smaller than rain drops or snowflakes. Once you get enough of the warm air to become saturated, a cloud becomes visible in the sky.
Instability, or when an air mass becomes unstable, describes an increased likelihood that a cloud will continue to grow and eventually precipitate. Obviously you have been told that warm air rises, and cold air sinks, so when you find yourself with an area of warmer air near the ground and colder air above it, voila! You have instability. That warmer moist air will want to rise high into the sky, forming a plethora of clouds.
Clouds come in many different shapes and sizes, and they even “reside” at different heights. The names of clouds are given by their appearance. The clouds that look similar to one another were created by the same process, whether it was by a cold front or an ocean breeze. Knowing how certain clouds formed is a grassroots method of forecasting. A British man by the name of Luke Howard devised the system of cloud classification nearly 200 years ago that we still use to this day. Once you get a grasp of the names, it becomes easier to understand. Unfortunately, Latin was popular in that day and age, so all of the classifications are in that language. Just remember the following… there are 3 main types of clouds, cotton balls, feathers and bed sheets. Also, let it be known that there are generally 3 heights that clouds float around in, high, somewhere in the middle, or low to the ground. These 6 categories all come with a Latin prefix or suffix except for the lowest ones, which have no prefix. To learn more about English, and what a prefix and suffix are, please see some other blog. Alto means “middle” and describes those clouds riding along high in the sky, but not too high. Cirro in latin means “a curl of hair.” You might ask, well what does this have to do with clouds? Well, Cirro is used to describe the highest clouds in the atmosphere, made up of mostly ice crystals. They are generally wispy in nature and if you use your imagination, they slightly resemble wavy hair. Now onto the suffixes… Generally any cloud that has a uniform, sheet like appearance is known as a Stratus cloud. You can have them at a low level, known as stratus, or a mid level, known as altostratus, or a high level, which we call cirrostratus. Now you can see that cloud descriptions aren’t that complicated after all. The cotton ball or generally fluffy clouds are called Cumulus, which means “heap” in Latin. Again, you can find this particular type of cloud in all three height levels. The last classification is not actually a different type of cloud, but if the particular cloud you are looking at is precipitating, if then gets the suffix Nimbus, which by no surprise means “rain.” At any time, you can have different clouds in all three layers occurring at the same time and this is common.
Nearly 4 miles up in the atmosphere, the air temperature is too cold for moisture to retain it’s liquid state. Tiny ice crystals form the clouds instead. This can make the appearance of these cirrus clouds very different than their lower counterparts. They appear to be semi-transparent and every once and a while if the angle is right, you might be able to make out a sun dog caused by the visible light from the sun being split into the visible spectrum, aka a rainbow, but one not caused by rain. These clouds generally mean fair weather, however sometimes they can indicate the arrival of bad weather. Generally the “bad weather” cirrus clouds are called “mares’ tails.” They are just feathery cirrus clouds with one end rolled up.
Cirrocumulus clouds are very high, fluffy clouds. Sometimes they can appear to look like fish scales, or “mackerel skies.” These clouds are formed when wind shear is taking place in the atmosphere. Wind shear is a component of severe weather, so when these clouds are seen, sometimes there might be bad weather on the way. This is the second component to the folklore I placed in the caption above. Basically all it is saying is that the combination of mares’ tails and the mackerel skies is a good indication of bad weather on the horizon, so ships will then take down their sails to not capsize.
Cirrostratus clouds, the last form of high level cloud, is a transparent sheet of ice crystals similar to a silky wedding veil. Sometimes this thin layer will thicken. This can be the signal of an approaching warm front, which could bring precipitation to an area within the next half a day to 24 hours. Eventually the cirrostratus clouds will get replaced by lower and lower clouds.
Somewhere in the middle, or 1.5 miles and 26,000 feet, you’ll find the middle layers of clouds with the alto prefix. The water droplets that make up these clouds are “supercooled,” meaning that they are able to remain in the liquid state since they are made of pure water and their size is very small. This sets them apart from their wispy neighbors above them.
Altocumulus clouds are white and gray puffs, sometimes forming waves and streets (or cloud bands.) They do not have a wispy appearance and the borders are well defined. These are generally fair weather clouds that rarely precipitate. However, they do indicate an area of unstable air aloft. This particular type of cloud forms with lift which could signal the near arrival of a cold front. (If they appear on a summer morning on a hot and humid day, the atmosphere is probably ripe for afternoon thunderstorms.)
Altostratus clouds are the other mid-level cloud other than altocumulus. These clouds are a mix of ice and liquid water and are generally a light grey on an otherwise sunny day. They are much thicker than their cirrostratus cousins, and let less light through. Generally the thicker the cloud, the darker it gets since less light is able to pass through. Altostratus clouds indicate the arrival of widespread precipitation.
Finally we have reached the group of clouds found closest to the ground. Stratus clouds generally have a dark, flat base. If they are precipitating, you can throw the nimbus suffix on the end. If you have ever tried to drive through fog, you are actually driving through a stratus cloud that is reaching the ground.
Cumulus clouds are your basic, low level, fair weather clouds. They can take on various shapes, but for the most part, they appear to be a fluffy, oversize cotton ball. Don’t let the fluffy appearance fool you however… these clouds way tons, literally. The average cumulus cloud is 1 cubic kilometer, with air density of 1.007 kg/m3. The density of the water in the cloud is roughly 1.003 kg/m3. That is why the cloud is able to “float” in the air. Using a fancy equation, one is able to calculate the the cloud contains nearly 1,000,000 cubic meters of water droplets, weighing roughly… a lot. Anywhere from hundreds of thousands to millions and even billions of pounds depending on the cloud. So if they decide one day that they don’t want to float anymore, we will all be crushed. Of course, I don’t see this day ever coming.
Some clouds have a low base but extend extremely high into the atmosphere. These can be described as “vertical” clouds, or those that are taller than they are wide. A good example of a vertical cloud is the Cumulonimbus. These are your thunderstorm clouds, and the bricks and mortar of any supercell or hurricane. A supercell thunderstorm can reach heights of 60,000 feet or more. That is over 10 miles high! Airplanes normally fly at around 30,000 to 40,000 feet, so you usually have to divert around these monsters. These are heavy rain and hail producers, and on some occasions they can even spur tornadoes. If you find cumulonimbus clouds on the open seas between the months of June and November, they might even grow into a hurricane.
Hopefully you have learned a thing or two about all types of clouds, from high to low and fair weather and bad weather. As always, if you have any questions, comments, complaints or suggestions, email them to me at Brad@SWATChasers.com. Some people are weather wise, some people are otherwise. Don’t be the latter.
Unless you have lived under a rock this year, it has been pretty obvious that the 2011 tornado season has been extremely violent and historical. The Storm Prediction Center has just released some confirmed tornado statistics for the year so far.
While the entire year has had an extremely high number of confirmed tornadoes, the most impressive tornado outbreaks occurred during the month of April. The Storm Prediction Center has confirmed that 753 tornadoes touched down across the United States during the month of April. The old April Tornado Record was 267 tornadoes which occurred in 1974. 2011 had over 3times as many tornadoes as the previous record! April 2011’s tornadoes were also much more violent than normal with 4 EF5 tornadoes occurring all during the Super Tornado Outbreak across the South on April 27th. There were also 364 fatalities during the month of April. That’s the most tornado related fatalities for any month since April 1936 when there were 509 tornado deaths!
Outside of April, the entire year has had an extremely high number of tornado touchdowns. The preliminary number of tornadoes to touch down so far this year is 1,676. This number will likely decrease some as local National Weather Service Offices submit their official storm surveys and duplicate reports are “weeded” out of the database. So far, 2011 has brought us 55 killer tornadoes which have resulted in 546 direct deaths so far in 2011. 157 of those deaths occurred on May 22nd, 2011 as a result of the EF5 Joplin, Missouri tornado.
Here is a map showing all of the locations where tornadoes have occurred from January 1st, 2011 through July 31st, 2011.
Don’t forget that you can book your 2012 Storm Chase & Tornado Tour with us today! Just go to SWATTours.com for the latest information.
Hey everybody! Have you ever been curious how a small thunderstorm in the open ocean can intensify and become a swirling force of nature capable of wreaking havoc on an entire coast line? In this, the latest posting in a series of weather education blogs we like to call Weather Wise, we’re gonna take a closer look at one of the most powerful forces of nature, Hurricanes.
Hurricane research, tracking and forecasting has come a long way in recent years. New technology has allowed us to spot these storms looming in open waters long before they come ashore. In 1900, Galveston, Texas was blindsided by a category 4 hurricane with winds estimated at 145 mph. The storm surge on that particular storm was responsible for the deaths of nearly 8,000 Texans. The Galveston Hurricane is still known as the deadliest natural disaster to ever strike the United states. Fortunately, our technology has improved enough over the last century so that hurricanes like this one will not go unnoticed. Satellites allow us to keep eyes on these monsters from space, 24 hours a day, 7 days a week. Computers help to process the large amounts of weather data and produce models to tell the meteorologists where the hurricane will track. These technologies and others like them, in partnership with several scientists have helped to increase the warning times and pinpoint the long stretches of coast lines that will be affected, days before the hurricane strikes. This has helped to cut back on needless deaths in recent years.
So what is a hurricane exactly? When the oceans near the Equator get hotter than a $2 pistol, and other atmospheric conditions become favorable, thunderstorms form with ease in what you can call a breeding ground for hurricanes. Compare it to a college house party — when the music gets turned on, (and I’m not talking about Bob Segar’s Greatest Hits,) before too long you have a living room that gets transformed into a dance floor. Those party animals start bumping into friends and inviting others nearby and before long, you have a raging kegger on your hands. The same goes for the tropics. Once water temperatures near 80°, the slightest breeze can easily send some of that low level moisture mixing into the atmosphere. Once that moist air parcel rises and condenses, a cloud forms. It may sound silly, but the first step in hurricane formation is a cloud.
The general area of thunderstorm formation is a meteorological mouthful. The Intertropical Convergence Zone, or ITCZ for short, is an area primed for thunderstorms. In this same area just north of the equator (June-Nov), the southward and northward flowing tradewinds come together to form a crease in the atmosphere. At the same time, a jet of air flows across the Atlantic Ocean from north western Africa. Sometimes, this causes a kink to form in the crease, a beep in the boop, or we could just make things easy and call this a Wave. These atmospheric waves help to get our simple clouds and small thunderstorms to intensify and form tropical disturbances, the next big step in hurricane formation.
Fast forward from your lonely cloud, through the simple thunderstorm phase and all the way to a small cluster of thunderstorms known as the disturbance. This small shapeless blob may begin to form a closed circulation, or simply put, the thunderstorms start to tango and spin around one another. The cause of this spin is the Earth’s rotation on it’s axis, similar to why the water in your toilet bowl spins counterclockwise in the northern hemisphere, (or clockwise in the Southern Hemisphere.) Soon enough, the pressure in the center of these thunderstorms begins to drop, forming a center of Low Pressure. The storms spinning around the low begin to organize further and winds become sustained from 29-39 miles per hour, and what began as a small cloud has now turned into a tropical depression.
The National Hurricane Center starts to take note of the further organizing system and they might begin to start dispatching Hurricane Hunters to investigate. The probes they release into the storm are not containers filled with Prozac to treat the depression, * Que Rim Shot*, rather they are chock full of instruments to gather data on the impending threat. Sure enough, they note a closed circulation and that the overall shape is now more circular and that they are clearly rotating around an increasingly lower pressure center. The winds now pick up to sustained speeds greater than 39 miles per hour, and thus a Tropical Storm is born. At this time, the National Hurricane Center gives this developing monster a name.
Tropical Storms alone can drop torrential downpours and cause massive amounts of flooding inland if they make landfall, but they still pose a smaller threat than a hurricane in most cases. A hurricane is just a glorified tropical storm. Pressures in the center continue to drop and satellite images continue to show a developing “eye.” So what separates a tropical storm from a full fledged hurricane? If this spinning top of thunderstorms contains sustained winds of 74 miles per hour or greater, the tropical storm gets upgraded to hurricane status.
Hurricanes contain a wide variety of hazards that pose a danger to us as humans. Whether it’s flooding from the rains above, or flooding from the storm surge, winds toppling the trees or the embedded tornadoes tossing them, hurricanes really can pack a punch. Some people call tornadoes, “Fingers of God.” If that’s the case, a hurricane should be known as “God’s Fist.”
The most dangerous and deadly hazard presented by hurricanes that make landfall is the storm surge. Simply put, a storm surge is a large dome of water that rises under a hurricane due to the low pressure that moves over the shoreline causing extensive damage to beaches and structures. Like I stated at the top of this post, this is what wreaked havoc in Galveston over 100 years ago. Obviously the damage reaches it’s maximum potential if the hurricane also makes landfall at the same time as a high tide. There are 3 factors to determine the intensity of the surge. Wind speeds, water depth and the intensity of the low pressure center all determine the height of the surge. For a larger storm surge, you would look for high wind speeds, an intense center of low pressure and shallow waters. Category 5 winds combined with the other factors can produce a towering storm surge 25 feet high. The most intense surge of water occurs near the low pressure system and in the quadrant of the hurricane where the winds are blowing towards the shore. The surge is powerful and comes ashore like a small scale tsunami, destroying everything in it’s path. This is why forecasting lead times and coast line evacuations are extremely important.
The winds alone in an average sized hurricane, 74 mph or greater, can spread out over 100 miles and the tropical strength winds, 39-73 mph can extend several hundred miles from the center of the storm. The hurricanes are categorized by their sustained wind speeds. The Saffir-Simpson Scale rates these storms from 1-5 with a Category 1 storm having winds from 74-95 mph and a Category 5 hurricane having sustained winds 155 mph and higher. The winds are measured by the anemometer, which can resemble a model airplane without wings, or 3 spinning ice cream scoops. The wind damage itself is exponential as it increases in speed. 120 mile per hour winds are not going to do twice the damage as 60 mph winds, rather they will do almost 100 times the damage.
Embedded within the spiral rain bands are another, usually small scale threats… tornadoes. As the hurricane spins on it’s axis, there are usually isolated cases of some “spin-ups” or small tornadoes. Most of the time these do not go reported due to the limited visibility and the fact that the damage is hard to disseminate from damage the hurricane itself caused.
The final punch that the hurricane packs is torrential coastal and inland flooding. If a roaring storm surge, hidden tornadoes and winds so strong you can’t walk weren’t bad enough, add to the mix rainfall rates of more than a few inches an hour and you have a lot of cleaning up to do when it’s all said and done. The slower the hurricane is moving, the more potential for flooding you have. It’s very difficult to accurately predict the amount of rainfall locations will receive that are impacted by a hurricane, but generally an average storm will drop anywhere from 6-12 inches of rain or more over a 12 hour period depending on speed.
So from disturbance to depression, from tropical storm to category 5 hurricane, the easiest way to avoid any and all of the above risks is simple. Move inland. The storms rely on the warm ocean surface to fuel their growth and sustainability. You will often notice that when a hurricane moves over a large land mass or onto the United States mainland, the storm rapidly deintensifies. So if you are wanting to avoid such risks, pass on buying the ocean front property.
Always Remember, some are Weather Wise and some are otherwise… don’t be the latter. Again, if you have any questions, comments, complaints or suggestions, please email them to Brad@SWATChasers.com. If your questions are good enough they may be featured in the next Weather Wise segment!
A Hurricane Hunter Aircraft found a closed low level circulation in the tropical wave that is now Tropical Storm Emily. Tropical Storm Watches and Warnings have been issued for the Leeward and Windward Islands and Puerto Rico. Emily currently has winds of 40 mph and is moving West at 17 mph. Emily should continue to gradually strengthen and turn to the Northwest. The ultimate track of Emily continues to be in question due to land interaction with Hispaniola, however all residents along the Eastern Seaboard should closely monitor the progress of Emily over the next several days.
SWAT will be closely monitoring the progression of Emily as there is a chance we may hurricane chase if she comes close to the United States Coast!
Don’t forget to check out SWATTours.com for the latest on our 2012 Storm Chase Tours!