Just a little over a year ago, the simple idea of a community shaped around the core concept of learning more about the weather and its impacts on our everyday lives sparked the creation of this blog. In just a short amount of time, TWZ has reached thousands of visitors spanning all corners of the globe.
In celebration of the big anniversary, I thought I would share some of the most popular posts from the past year. No big surprises in the fact that some of the site’s most-viewed posts had to do with severe weather and significant snow events, the weather phenomena that tend to have the most impact on the general public. TWZ Interviews and our continuing “The Weather Explained” series also were very popular. Here is a list of the most popular posts from the past year:
TWZ Interviews: James Morrow – The very first of the TWZ Interviews series has proven to also be the most popular. My good friend James and I sit down to discuss all things related to the National Weather Service and its interactions with the general public.
Winter Storm Update – A simple video explaining what to expect from the biggest snow storm of the winter. It was short, sweet, and to the point and proved that snow typically is the biggest attention-grabber in the world of meteorology.
July 13th Update – An enhanced risk of severe weather from the SPC also turned into one of the heaviest traffic days here on TWZ.
September 30th Update – Hurricane Joaquin turned out to be one of the bigger weather events of 2015 as evidenced by this post outlining the potential effects of the storm on our region.
The Weather Explained: “Why is the Weather in the Mountains so Unpredictable?” – May have cheated a bit on this one, but snow storms and Hurricane Joaquin already have spots on this list. The Weather Explained series is really the reason why I started this blog. I had a dream of taking the complex science behind some of the most fascinating facets of meteorology and communicating them in a way that everyone can understand and appreciate.
As always, I want to hear from you heading into the future. What topics are you interested in learning more about? What things do you like and what could you do without? Do you want more forecasts or like the feature pieces? This feedback will help me grow this blog into something you will actually want to use. Please get into contact with me through the About page, because I love hearing from you!
It is truly amazing to think just how far and wide this humble blog has reached, and for that I truly want to say thank you for coming along for the ride and making The Weather Zone what it is today. I also want to give a big thank you to all of the people who contributed to the blog in the past year for helping us get this far. With your help, we can continue to grow TWZ into a welcoming community focused on learning about all things weather.
13 hours. That’s roughly how long it took for the first Hokie Storm Chase team of 2013 to reach our destination on the first day of a two-week long trip. Our sole purpose on the trip was to gain even the smallest glimpse of nature on its worst behavior. I couldn’t have been more excited to be invited to go on the trip, but I wasn’t anywhere near prepared for the long hours on the road that would trademark each remaining day of our excursion. Considering how most of the general public wouldn’t even dare think of chasing a tornado for “fun”, or even for education for that matter, looking back on my trip I wouldn’t have had it any other way. The things I witnessed and learned on that trip further ignited a passion for the weather that occurs over our head and being able to experience that first hand, regardless of how long it took to get there, was completely worth it.
Trevor White
Virginia Tech meteorology professor David Carroll has been taking interested students out west with him for years to chase storms, even before a meteorology program at the university was even dreamed of. This year is no different, as a group of prospective meteorologists are currently out west continuing the tradition at the time of this writing. The Hokie Storm Chase is now a vital part of any meteorologist’s education at Virginia Tech. This unique “field study” opportunity allows for students to learn about the things they discover in the classroom and apply them to a real-world environment. After seeing some of their adventures over the past, very active week (if you are interested to see more of their endeavors, be sure to check the bottom of this post) and thinking back on my trip, the question of why storm chasers do what they do popped into my mind and thus this post was born.
There are a myriad of different answers to that question that run anywhere from educational to people who solely want an adrenaline fix. As far as the Hokie Storm Chasers are concerned, our sole purpose out west is to become better forecasters of severe weather and get to see that weather from a perspective that can’t be matched anywhere else. There are some chasers that chase simply for the purpose of entertainment. Chasing in certain parts of Oklahoma can be an utter nightmare, for example, because it is popular for people to go out and watch the storms as they blow through. While it is great that people are so interested in the atmosphere over their heads, this can cause potentially deadly traffic jams when a storm decides to take an unexpected turn. Whatever the reason may be that specific chasers do what they do, it is undoubtedly clear that there is a fascination with severe storms and I believe that is because there is a sense of mystery to them.
To many people’s surprise, we still have a ton to learn about tornadoes and the environments/storms that produce them. For example, it is possible to forecast a few days out where potential areas of the best mix of ingredients for storm development will arise. It is very hard, however, to forecast very far out at all just where a tornado will touch down. Not only that, but the scales on which tornadoes operate (both temporally and spatially) are so small compared to other weather systems which in turn further complicates things. Considering these facts and that the areas primed for storm initiation can often cover hundreds of miles it becomes easy to see why the chasers who chase for educational and research purposes do what they do. It is all done in an attempt to learn more about these storms so that we can better warn those people who are directly impacted by them.
Knowing that, you may be asking, “Well, why don’t we just build better technology that allows us to better study and forecast tornadoes then?”, and the short answer is that we are! It is just that the very nature of tornadoes themselves makes it very hard to study them. A typical tornado is only on the ground for 30 minutes tops and occurs in the lowest part of the atmosphere. This means that it is even difficult to sometimes see tornadoes on radar products. The radar output that you see on TV and in your weather app are a product of a fancy piece of technology known as a radar dome that looks like this:
NOAA
Inside the dome is a transmitter and receiver that shoots off energy into the atmosphere surrounding the dome. The energy beams then bounce off objects in the atmosphere (the idea is for the beams to hit precipitation, but things such as dust, smoke, and even animals like birds and bats have shown up on radar before) to give us an idea of the location and strength of precipitation in a specific area when those energy beams return to the dome. This technique can also give us an idea of what types of precipitation are on the way, as each precipitation type has a specific energy return (lower energy amounts for things like drizzle and snow and higher energy amounts for things like hail and heavy rains). It is amazing technology that is really one of our main “eyes in the sky” during weather events. While radar is great, it does have one downfall when it comes to tornadoes. The energy beams leave the radar dome at an angle, meaning that as the beams travel farther and farther away from the dome, they send back “pictures” of the atmosphere that are higher and higher in elevation. This becomes a problem when tornadoes form in the lowest parts of the atmosphere. A tornado that forms pretty far away from the radar dome won’t be imaged as well as a tornado that forms closer to the dome. You also run into a problem known as the “cone of silence” with radar. Since the transmitter revolves in a circular manner, the area directly above the radar dome goes without any scans of that particular part of the atmosphere. Say, for example, a storm that produces a tornado moves directly over a radar dome. Images of that storm simply would not be available for a period of time due to the nature of the radar itself. Due to these things, radar, although incredibly useful and vital to the field of meteorology, is not a perfect instrument.
Taking into consideration these facts, the primary goal of chasers within the field of meteorology is to get a closer view of these storms than those possible with radar alone. Just eyes on a storm that produces a tornado is incredibly helpful, but there have also been advancements such as UCAR’s DOW project (or “Doppler on Wheels”) that have allowed radar to become mobile in an attempt to better map these storms. While it may seem crazy to the general public to chase these dangerous storms, it has become incredibly vital to do so in order to learn more about them. As I have said before, the best way to be prepared for something is to learn more about it. I can’t speak for every “storm chaser” out there, but for those in the science and field of meteorology, that is the sole reason for why chasers chase.
UCAR’s “Doppler on Wheels” project, which is an attempt to create a mobile “eye in the sky” to track severe weather in real-time on location. (UCAR)
The idea of chasing something that could potentially kill you is definitely borderline crazy, but in this instance it is a “necessary evil.” I’ve said it countless times before, but the driving factor behind a meteorologist and the work that they do is to prevent the loss of human life and property damage, and it continues to drive many of us out west in search of learning more. As technology continues to advance and we learn more about the development of tornadoes, the practice of storm chasing will most likely become less popular, at least as far as the scientific and research communities are concerned. Storm chasing likely will never completely go away, however. Not as long as the practice continues to develop stunning images as these:
Check out the Hokie Storm Chasers over at their blog and on their Twitter page. They’ve seen some truly incredible things on their trip, including a record-setting 17 tornadoes (possibly even more) near Dodge City, Kansas yesterday. If you like the pictures in this post, be sure to check them out for more.
You can also follow some of the first trip’s leaders here for more details and images:
Any good meteorologist must also be a good communicator. It is so incredibly important within this field to be able to effectively communicate the complex weather scenarios that occur over our heads. We as meteorologists must be able to relay important information to the general population in a way that everyone can understand and promptly respond to a potential coming threat. In this field it is very easy to get caught up in the science behind the weather; the complex physics and mathematics used to describe the inner workings of the atmosphere. It is our duty as meteorologists to take that information and display it in a way that anyone can use.
TV meteorologists sometimes get a “bad” reputation within the public due to the “getting paid to be wrong” mentality. Whatever you may believe about that, it cannot be argued that these people’s jobs are so important because they are the key link between the incredibly complex science used to describe and forecast the weather and the people who need to be able to prepare for said weather. It is a remarkably large task to undertake, but so much can be communicated through the use of an image. The old saying “a picture is worth a thousand words” rings so true within this field. Weather graphics have long been a passion of mine since I joined this wonderful community simply because they are an incredibly powerful tool. When done right, a weather graphic is capable of telling someone exactly what they need to know about what the atmosphere will send their way on a specific day. These images can also be wonderful pieces of art. The Weather Channel, for example, produces graphics that are incredibly pretty to look at, but also tell a meaningful and informative story about a complex weather scenario. A weather graphic can become a great mediator between a science filled to the brim with difficult topics used to describe the motions of the atmosphere to a community that is directly impacted by those motions. It is one of the best tools we have to help prevent the loss of life and property damage, the main goal of all meteorologists.
With all of that being said, just what makes a good weather graphic? What is the right balance between the science and the communication of the science? What audience are you trying to reach? Are their specific colors that work better than others? What sort of language will you use? How many words will you need to place within the graphic in order to convey the message you are trying to send? Questions like these must be answered when developing a good and compelling weather graphic, which leads to an incredibly difficult task. So much, or so little, can be said with the answers to all of these questions and more. Striving and obtaining a balance within a weather graphic is so very important because you have a limited time to relay the message you need to say. You must capture the attention of your audience and display the information in an understandable and compelling fashion within a timely manner. It is an absolute vital skill to have if you want to be successful within the realm of broadcast meteorology. It is the reason why a network like The Weather Channel, who prides itself on maintaining that balance, can exist and has been so successful throughout its history.
If all of that sounds hard, it is because it simply is. That is why I am curious to see what you think is a good weather graphic. Think of any and all weather broadcasts you may have seen over the past couple of months and try to remember anything from a graphic that may have stuck out to you. If you can’t think of any specifics, maybe try to think of what colors or words may have resonated with you the most. Please be sure to share what sticks out to you in a weather broadcast or specific examples in the comment section below!
To start things off, I will share one of the graphics I did during my internship with a local TV station a few summers ago (major thanks to WDBJ7 out of Roanoke for allowing me to learn so much from their incredible staff of meteorologists and for letting me use their awesome graphics tech):
I created this graphic to help display the “cold” snap our region would experience over the span of the coming week (it may not seem that “cold”, but this was made in the middle of July, so those temperatures were pretty below average for that time of year). I happen to love this graphic because of the colors. They really pop making it easier to draw your attention in. It also doesn’t say too much, meaning that it can be used to compliment what the meteorologist on screen is saying rather than just being something the meteorologist reads verbatim. While I like this graphic, I am curious to know what you think, so let me know in the comment section below (please be gentle). Thanks as always for tuning in and I cannot wait to see the weather graphics that you like!
Moore, Oklahoma. Joplin, Missouri. Tuscaloosa, Alabama. What do all of these locations have in common? These seemingly separate locales have all been hit with a devastating tornado over the past five years. Each year tornadoes and severe weather cause the loss of countless lives and billions of dollars in property damage across the United States. It is a terrible situation and one that the entire field of meteorology is hoping to help mitigate as much as possible. It is the reason why storm chasers, people the general public see as potentially crazy, do what they do. People within this field are driven by a passion to help people be better prepared for the worst that mother nature can throw our way. Nothing says this better than the National Weather Service’s mission statement: “Provide weather, water, and climate data, forecasts and warnings for the protection of life and property and enhancement of the national economy.” I have always believed that one of the best ways to be better prepared is to be better educated, and thus this post was born. It could not really come at better time either, with meteorological spring officially started and 2016 already delivering some devastating tornadoes, locally and nationally. With all of that being said, what exactly causes a tornado?
NOAA
In order to understand what causes a tornado, you need to understand the driving force behind them. While we have discussed some things related to this topic before, we need to discuss what goes into making a thunderstorm, the prerequisite to a tornado. Thunderstorms come in all shapes and sizes, but they are all essentially born from one or more of these basic elements:
Instability, which is basically the atmosphere’s ability to support upward motion of air. For example, a stable atmosphere means air near the surface of the earth is relatively close to the same temperature as the air above it, meaning there is very little atmospheric motion occurring. On the other hand, an unstable atmosphere means that air at the surface is typically warmer than the air above it, allowing that air near the surface to begin moving upwards (the increase in temperature leads to a decrease in the density of the air and therefore the warmer pocket of air begins to rise). The number one thing to remember about all things weather is that when you have rising air your chances of seeing some sort of meteorological phenomenon go up. As far as thunderstorms are concerned, the strongest storms typically have the highest amounts of upward motion.
Moisture, a key ingredient to making a rain storm, especially close to the earth’s surface. It is kind of difficult to make something that rains water down on the earth without some sort of moisture already present in the atmosphere. As the saying goes, what goes up must come down, and that definitely is true for moisture in the atmosphere that is moving upwards due to the instability we mentioned above.
A “trigger”, something that will provide a “spark” to get that upward motion we mentioned above going. Boundaries are typically the most common source of lift within the atmosphere and are one of the best triggering mechanisms for storm development. For example, a cold front is basically the boundary where cooler air meets warmer air. The cold air stays close to the surface while the warmer air rides over the top of the cold air bubble. This is one of the simplest ways to get that upward motion that is absolutely vital to thunderstorm development.
While not necessary for storm production in general, Wind Shear is a big player when it comes to crossing the line between your average thunderstorm and a severe one. Wind shear is basically the term used to describe differences within the wind profile of the atmosphere as you move upwards. There are two types: directional shear (changes in wind direction as you move upwards through the atmosphere) and speed shear (same thing, but this time with changes to the wind’s speed with height).
As far as tornadoes are concerned, the storms that produce them typically have a good amount to work with in all of these categories. Thankfully, not every storm or storm type (i.e., general pop-up storm, line of storms, etc.) produces a tornado, but the storms that do often produce the most destructive tornadoes are called supercells. These very powerful thunderstorms have vast quantities of instability to build a thriving updraft within the storm sparked by some sort of triggering mechanism, a great deal of wind shear that causes the storm’s updraft to rotate and tilt, providing necessary ventilation (thunderstorms have to keep up a continuous circulation of air or they will die out; in other words, if the updraft/rising air within a storm dies, so does the storm itself) and separation from the storm’s downdraft, and finally, plenty of moisture to act as a type of fuel for the storm to work with. Long story short, the kind of storms that produce tornadoes often come equipped with the best recipe possible as far as storm development is concerned.
Once you have all of the necessary ingredients to build a strong storm in place, wind shear becomes the tipping point between a severe storm and a severe storm that produces a tornado. Like we mentioned above, winds funnel into a storm from various different directions and with different speeds at varying levels in height throughout the storm. These differences in the wind’s characteristics cause the air in the lowest portions of the atmosphere to begin rotating along the surface of the earth. A storm with a very strong updraft is then able to absorb that rotating air, causing the vertically-rotating air along the surface to transition into horizontally-rotating air withing the storm itself. This horizontally-rotating column of air is then dragged back down to the surface by the rain and hail being generated by the storm. The moisture within the column begins to condense allowing a cloud to form, often taking the shape of a funnel because of the continued rotation. A funnel cloud remains a funnel cloud until it makes contact with the ground, and at that point a tornado is born. Tornadoes come in all different shapes and sizes, but the general driving force behind them all is the same.
Images showing the life cycle of a tornado. Wind shear causes air to rotate near the surface which is ingested into a storm with a strong updraft. The now horizontally-rotating column of air moves closer and closer to the surface until a tornado is born. (NOAA)
As with most things within the field of meteorology, we still have a lot to learn about the storms and environments that produce tornadoes. There are still several questions that remain to be answered about how a strong thunderstorm can take something as simple as a rotating column of air and turn it into one of nature’s most destructive forces. The fact that a typical tornado only stays on the ground for a few minutes and in very localized instances make them incredibly difficult to study. While we have come a long way with radar technology, it is still fairly hard to keep up with a tornado on radar since they form in the lowest portions of the atmosphere. Radar beams go out from the tower at an angle, meaning that the lowest area of the earth’s atmosphere (i.e., where a tornado forms) is not accurately represented on the imagery that you see a TV meteorologist or weather app use. Combine all of these issues together and you can start to see why tornadoes are often considered one of the “last frontiers” within the weather community. We’ve gotten pretty good about pinpointing areas or regions that look like they will have the necessary ingredients in place to spark thunderstorms capable of producing tornadoes a few days out in time, but it is still practically impossible to say a certain town will see a tornado at this specific time on this specific day. It is a tricky situation for sure, but one that hopefully with the continued advancement of technology will only get better.
13 minutes. That is the average amount of time between the time a person receives a warning about a tornado and the time the tornado moves overhead. That is simply not enough time. The entire goal of the weather community is to provide the necessary information to prevent the loss of life and property damage, and when it comes to severe weather and tornadoes we still have a long way to go. Yes, storm chasers may be a little crazy and are driven by pure love for the field within which they work, but the work they do and key research they provide is vitally important to providing more warning to those directly in the path of a strong tornado. Everything we do is to help better prepare the general public for the worst mother nature can throw our way. By educating people and continuing to advance our tactics, both through technology and with the way we communicate a complex weather scenario such as a severe thunderstorm environment, we will eventually become a more-perfect, weather-ready community.
Here is a very quick update on what to expect today from our latest winter storm. Be sure to check with your local media and with the National Weather Service throughout the day for the latest updates. You can also check back here and over on my Twitter page for updates as well. Please be sure to send us your snow pictures and your snow totals to us as well. Stay safe out there everyone!
Regardless of what the groundhog may have said last week, winter is very much still around and will remind us of that fact this upcoming weekend and into the beginning portions of next week. If you thought it was cold outside now, wait until you see what is in store for the next few days. There is also the potential for another winter storm to impact our region early next week as I am sure you may have heard by now. While this storm doesn’t currently look to be near as disruptive as the storm we saw earlier this year, precautions do need to be taken. All in all, it will be a very good idea to stay in the know weather-wise over the next several days (if you aren’t a fan of reading, skip to the bottom of this page for a video update).
First things first, it is going to get downright cold this weekend. Our region will experience an impressively large intrusion of arctic air that will drop temperatures down significantly, especially across the area on the morning of Valentine’s Day. Temperatures that morning currently look to hover in single digits across the state, with the wind chill making it feel well below the zero degree mark for some locations. All things considered, if you must be out and about on Sunday, please be sure to stay bundled up and limit your time outdoors.
Very cold conditions state-wide Sunday morning. Please try to stay warm out there! (NWS)
As far as next week is concerned, there is still a great bit of uncertainty within the forecast models at this point in time. What we do know is that something should begin falling from the sky Monday afternoon/evening and continue into the day on Tuesday. The big question right now is, as always with these types of storms, what track the storm decides to take. The GFS model tends to show more of a wintry mix and rain solution, which would ultimately limit any accumulating snowfall we would see. The Canadian solution suggests that the event would begin with snow Monday before transitioning to a wintry mix and rain on Tuesday. The European model suggests a great deal of cold rain for the region. Here are some screenshots from a few different model outputs:
GFS output for around 7AM Tuesday morning. Cold rain looks to be the primary precipitation type here, which is why snow totals for the GFS are low. (Tropical Tidbits)GFS snow totals for this storm look to stay fairly low, with most of the accumulation sticking to the western fringe of the state. (Tropical Tidbits)The Canadian solution around 7AM Tuesday morning. Notice here how there is a lot more ice, which was preceded by snow starting the event on Monday. (Tropical Tidbits)Snowfall totals for the Canadian solution are a bit higher than the GFS due to the fact that this solution has precipitation starting as snow on Monday. The western fringe of the state again looks to be the bulls eye here. (Tropical Tidbits)While a different product from the ones shown above, we can see here that the European solution is the warmest of the models we have highlighted here. In other words, mostly rain with this scenario. (Tropical Tidbits)
Long story short, the various scenarios that could play out with this storm (with the latest information available) would be something like this:
Best case scenario: main precipitation type is rain (European solution)
Middle case scenario: main precipitation type is still rain, but light accumulations of snow and wintry precipitation possible (GFS solution)
Worst case scenario: precipitation begins as snow, before transitioning to a wintry mix and a cold rain on Tuesday; highest snow accumulations (Canadian solution)
For those non-reading fans out there, here is a quick video from earlier today highlighting the main details I mentioned above (thanks to Carilion Clinic Homecare for the idea!):
As always, the situation will become clearer as we progress through the weekend, so please be sure to stay tuned to local media and with the National Weather Service to get the latest details as they become available. I will also do my best to keep this page updated as well as send along updates through my Twitter page (@Nickwx92). Thanks as always for tuning in and please try to stay safe and warm out there everyone!
Here is a quick video update on what to expect from this storm through the rest of this day and into the upcoming weekend:
I apologize for the quality of the video, but the main gist is that while we are seeing a lull in things at the moment (at least in the southwestern portion of the state), more snow is definitely on the way. Please try to stay off the roadways if at all possible today, as travel conditions will continue to deteriorate as we progress through the afternoon and evening hours. Stay tuned here and to my Twitter page throughout the day for continuous updates, as well as with the National Weather Service and local media for the latest information on the storm as it becomes available. Also, send in your snow reports and photos in to TWZ! I’d love to see them! Thanks for tuning in as always!
As you have most likely heard by now, snow is in the forecast. Over the span of the last week or so a lot of hype has been placed on this event, and it is beginning to look as if at least some of that hype was warranted. In order to give you an idea of what to expect, let’s breakdown what each of the major forecast models is saying and what that means for us over the coming days:
NAM:
The NAM seems to want to bring in a bit more sleet and freezing rain into the picture than the GFS pictured below. This would limit the amount of snow that ultimately accumulates on the ground, and you can see that in the snowfall total map. The NAM spells out less of an event for the metropolitan areas such as Richmond and D.C. If you aren’t a fan of winter weather, this is likely the “best case” scenario even though most of the western half of the state would still see over a foot of snow if the NAM’s take on things plays out.
GFS:
The GFS currently shows the storm taking a similar path to the NAM solution, but with less influence of freezing rain and sleet meaning that snow totals are higher here. The majority of the state sees at least a foot of snow with this solution. Richmond and especially D.C. would have major travel issues with this scenario. As crazy as it sounds, this solution lies somewhere between the “best case” scenario of the NAM and the “worst case” scenario that the European models are suggesting.
European:
European products are not readily available to the general public, but we can get an idea of where this solution thinks the storm will track from the picture above. This solution has the southern-most track of all of the major model solutions, meaning probably the “worst case” scenario for Virginia as far as accumulating snow is concerned. If the European solution plays out, you can expect travel conditions across the state to come to a screeching halt for several days.
In all reality, some combination of the above solutions will likely play out. Everything is dependent upon the track of the storm, which we will continue to learn about as the storm approaches the East Coast. The most impressive thing is that there is consistency among the models and that leads to a fairly high confidence level. Right now it looks as if it would be very wise to prepare for at least double-digit snowfall accumulations regardless of where you live in the state, understanding that things could still change due to some uncertainty still a part of the forecast. As always, the National Weather Service and local media outlets are the best places to go for continuing updates on the storm. I will also do my best to keep you updated with the latest information here on theweatherzone as it becomes available. Please stay weather aware over the next several days, as staying on top of the situation is the best way to be prepared. Stay safe out there everyone!
What a year! Yes, this blog has only been around since June, but I am continually amazed at just how far and wide TWZ has grown in just a few short months. In a very small amount of time, TWZ has reached so many people and catered to visitors from vast parts of the globe. That’s a kind of growth I never imagined to be possible. Thank you so much for coming along on this adventure and I can’t wait to see what 2016 will bring about for this young, but thriving community. Here’s hoping that you learned a few things about the atmosphere above our heads in 2015 and that 2016 continues to spark your interest in “all things weather”.
Be sure to follow the link below for an in-depth look at TWZ’s stats for 2015!
I have no doubt in my mind that you have at least heard the term “El Niño” before. Chances are if you have watched a news story about some meteorological happening over the past several months the phenomenon very likely was at least mentioned. El Niño in my opinion tends to be a catch-all reason behind crazy meteorological events according to the media, especially over the past several weeks and months. While some of that hype is legitimate (this year’s El Niño event will likely go down as one of the strongest on record), as with other phenomena within the field of meteorology (and in this case within the field of climatology), the situation is a bit more complex. So what exactly is El Niño and why does it seem to do some strange things to the weather, both nationally and locally? Also, what’s up with that name? I’m no climatologist, but hopefully I’ve got some answers for you.
NOAA
In order to understand a little bit more about El Niño, you first have to understand the difference between meteorology and climatology. They are two separate, but related fields. The differences between the fields can often become blurred, especially in short news stories that simply don’t have the time or space to explain the difference. Meteorology typically deals with the day-to-day happenings of the weather overhead. When trying to determine what outfit to wear on a specific day, you are going to find the information you need within the field of meteorology. Climatology on the other hand deals with much longer-term meteorological events and patterns. If you wanted to know the general type of clothing to wear during a particular season of the year, climatology is where you’d find that answer (for example, we wear heavy jackets in the winter and shorts in the summer here in Southwest Virginia, but that could be very different in other parts of the country and the world). Meteorology can go to about a week or so out in terms of accuracy, but everything beyond that point lies within the realm of climatology. Think of meteorology as current events and climatology as history class. When viewed through that analogy, you can get an idea of the differences and similarities of the two fields. Any good meteorologist must have a solid handle on the climatology of the particular area for which he or she is forecasting. For example, the majority of the snowfall we receive during the winter months here in Southwest Virginia typically arrives in late January through the month of February. With that information in the back of your mind, if you see a forecast model output churning up a foot of snow for our area in late November/early December, you can take that solution with a very healthy dose of salt simply because the history says that we just don’t see that kind of snow this early in the season. Of course, the atmosphere is very complex and that’s not to say we couldn’t see a freak snowstorm during that time period. History just says that scenario is rare and history is a very good place to start with a forecast.
El Niño is considered a climatological phenomenon due to the fact that it takes place over several weeks and months. The temporal reach of El Niño is quite impressive, but the geographical reach of the event is even more so. The long-term impacts of the pattern have the power to change and influence the short-term weather pattern over our heads. It’s truly fascinating when you think about the happenings of the atmosphere as an interconnected, global system. One change in a particular area can set off a chain of events that can affect locations around the world. While El Niño typically gets all of the love within the media, it is just one of many of this particular type of phenomena known as teleconnections. According to the American Meteorological Society, a teleconnection can be defined as follows:
“A linkage between weather changes occurring in widely separated regions of the world.”
El Niño is part of a much bigger family of large-scale weather patterns that take place over several weeks and months. The North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) are just a few of the different teleconnections that impact the United States each year, along with El Niño (which is technically known as the El Niño Southern Oscillation, or ENSO for short). Teleconnections are caused by various different things. For example, the Madden Julian Oscillation (MJO) is caused by groupings of clouds over a particular area of the Indian Ocean. ENSO is caused by changes in ocean temperatures along the equator spanning all the way from the Indonesian islands to the western coast of South America. That may not seem like a big deal, but this change in ocean temperatures leads to some major differences from the normal weather patterns of the area.
The term “El Niño” is Spanish for “the Christ child”, which is fitting considering that the phenomenon tends to take shape around the Christmas season. Once formed, an El Niño event can last for months, and in some cases well over a year. During the early 20th century meteorologists discovered some interesting changes in the atmospheric pressure over parts of the Pacific Ocean every few years. The scientists eventually traced these changes in pressure back to ocean temperatures, specifically off the coast of Peru. Fishing has always been a large contributor to the Peruvian economy due to the cold, nutrient-rich waters that lie just off the coast; a perfect combination of ingredients for a thriving fish community. These cold waters lead to a general area of higher atmospheric pressure over Peru and it’s coast, meaning that the westernmost portion of the country doesn’t typically see a whole lot in the way of precipitation. In other words, pleasant fishing conditions are typically the norm for Peru. El Niño messes with that happy norm however. The phenomenon leads to a shift in winds which ultimately leads to warmer waters off the Peruvian coast. This warm water allows for air to rise which in turn lowers the atmospheric pressure overhead. The one overriding rule of meteorology is that rising air equals precipitation in some way, shape or form, and that rule holds true here as well. Peru, which is normally a fairly dry place, becomes home to rain and thunderstorms during an El Niño period. Warmer waters also mean less fish and a big hit to the Peruvian economy (another topic for another time, but clearly the weather can have a big impact on more than just what you should wear on a specific day). The effects of El Niño may begin with Peru, but they certainly reach to other places of the world.
The warming trend that El Niño brings to the Pacific basin allows for an alteration of the typical Pacific jet stream pattern of the northern hemisphere. Lower pressure off the Peruvian coast allows for the Pacific jet stream to take a dive towards the south. Here is a pretty good diagram that shows the differences El Niño can bring about as opposed to “normal”:
NWS Blacksburg
Ripples of energy ride along the Pacific jet meaning more precipitation than usual for the southernmost portion of the U.S. You also can see in this diagram the term La Niña, which is essentially El Niño, but in reverse. La Niña events don’t typically get as much love within the media as their El Niño siblings, but they certainly have widespread effects too. A La Niña event leads to warm ocean temperatures on the opposite side of the Pacific, leading to a whole new set of widespread changes to weather patterns around the world. This is why most teleconnections have the term oscillation in their names. There are varying degrees of ENSO (along with other teleconnections), with conditions typically oscillating back and forth between each phase or ending up somewhere in the middle each year. Here is another diagram that shows how both phases of ENSO (El Niño and La Niña) typically cause the Pacific jet stream to interact with the northern Polar jet stream and what that means for the United States:
NWS Blacksburg
Here is a basic rundown of each phase’s effects within the U.S.:
El Niño:
Wet conditions for the bottom half of the country
Cool conditions from Texas to Florida and into the Mid-Atlantic
Warm conditions for the top half of the country
Dry conditions for the Ohio Valley and parts of the Northern Midwest
La Niña:
Dry conditions for the bottom half of the country
Warm conditions from Texas to Florida and the Mid-Atlantic
Wet conditions for the Ohio Valley
Cool conditions from Washington state to about Minnesota
Wet conditions for the Pacific Northwest
These are of course just generalizations that give us a good idea of what to expect during each respective phase of ENSO. The atmosphere is a constantly changing beast where several factors must be taken into consideration when trying to compile an accurate forecast, but hopefully this gives you an idea as to the general impacts ENSO can have on the United States. It is also important to know that these generalizations show each phase’s offset from the climatological norm. For example, during an El Niño event, parts of Florida are typically cooler than conditions that have been recorded over the past 30 years or so for those same parts of Florida. Florida would see cooler than the average conditions during that particular time of year when an El Niño event is taking place.
The fact that we have these generalizations is telling to how much we still have to learn about the El Niño Southern Oscillation. What makes an El Niño (and transversely, a La Niña event) event occur every 2-7 years at seemingly random intervals? Why is the interval between events sometimes longer or shorter than the ones experienced in the past? Why do some events exceed others in strength and longevity? These questions just speak to the fact that while we have come a very long way in terms of learning about the atmosphere over our heads, we still have a long way to go.
Hurricane Patricia before slamming into the Mexican mainland. (NOAA)
While we are still learning about El Niño’s inner workings, it is obvious that the event has serious potential to mess with the “normal” workings of the atmosphere above us. I mentioned before that this year’s El Niño will likely be one of the strongest we’ve ever seen. Considering this, it would come as no surprise that this year’s Pacific hurricane season was one of the worst on record (16 hurricanes, 11 major hurricanes, and 10 Category 4-5 hurricanes, all of which are new records). Hurricane Patricia was the strongest hurricane to ever make landfall, with sustained winds of around 200 MPH right before it moved inland over Mexico. All of this can be attributed to the fact that hurricanes thrive over warm ocean water, which this year’s El Niño was more than happy to provide. While the Pacific season was filled to the brim with strong storms, the Atlantic season on the other hand was fairly calm when compared with previous years. This is a fairly common trait of an El Niño event, where warm waters needed for hurricane development just aren’t as prevalent within the Atlantic basin. This feature shows how connected the global system can be and the impacts a small change can have on two very distant locations.
While El Niño can certainly cause some funny things to happen weather-wise here in the U.S., it probably shouldn’t be the catch-all term that it can be within the media today. We have to take into account the entire atmosphere as a whole. With that being said, you hopefully now have a better grasp of just what that term means and how it can bring vast changes to the United States and areas around the world. The next time you hear the term in a media report, just remember that the phenomenon is a climatological event known as a teleconnection that can help shape the meteorological happenings over our heads. While there is still a lot to learn, we do know that El Niño is typically characterized by abnormally warm ocean waters along the Pacific basin, specifically off the Peruvian coastline. These warm waters cause changes in the usual atmospheric pressure of the area which leads to changes in weather patterns around the world. We’ve already seen some incredible weather events that were caused by this year’s El Niño event and only time will tell what more “the Christ child” could have in store over the coming months and into the future.
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