 DISCUSSION: Lightning is one of the most dangerous types of weather phenomena. As of September 3rd, 2018, according to the National Weather Service, in 2018 alone there have been 20 deaths from lightning strikes in the United States so far. It is recommended to stay inside when there is an upcoming thunderstorm. The National Severe Storms Laboratory (NSSL) has a page that lists and describes the different types of lightning. Lightning is formed by energy transferred from positive and negative charges in clouds or the ground. There are three primary types of lightning which include: cloud-to-ground (the most commonly known type), cloud-to-air, and cloud-to-cloud. With cloud-to-ground lightning, the rapid discharge of lightning is a channel of negative charge that is attracted to the positively charged ground. Once the two charges are connected by the stepped leader (the initial invisible connection between the two charges) and a positive return stroke from the positively charged ground, the electrical current that is seen as lightning forms. Sometimes, the cloud can be positively charged, and the ground negatively charged, but this doesn't occur as often. The NSSL states that cloud-to-air and cloud-to-cloud lightning have 5 to 10 times more lightning strikes than cloud-to-ground. (Below is a picture of cloud-to-ground lightning.)  Cloud-to-air lightning is described by the National Weather Service (NWS) as “lightning that occurs when the air around a positively charged cloud top reaches out to the negatively charged air around it.” In other words, these lightning strikes are an attraction between clouds and air that are opposite charges and never reach the ground. Most of the time though, the positive charge forms atop of a storm cloud and is attracted towards a negative charge in the air nearby. (Below is a picture of cloud-to-air lightning.)  Lastly, there is cloud-to-cloud lightning. The NWS describes this type of lightning as “lightning that occurs between two or more separate clouds.” This lightning forms by one cloud being a mostly negative charge and another being a mostly positive charge, causing the attraction between the two. The NSSL explains that a type of cloud-to-cloud lightning called a “spider lightning” are formed underneath stratiform clouds (low-level, thin clouds that may produce a light drizzle) and flashes travel horizontally. (Below is a picture of cloud-to-cloud lightning.)  There are a few more lightning types that aren’t necessarily categorized as part of the three main types of lightning. These lightning types include: red sprites, blue jets, and elves. Red sprites usually occur above a large thunderstorm and are normally a red color. Red sprites usually occur during a cloud-to-ground lightning strike. They can be seen from space as they extend up to 60 miles above a cloud top. They can reach all the way to the mesosphere! Blue jets also form above a storm cloud but, unlike red sprites, they are not associated with cloud-to-ground lightning. They reach up to 22-35 miles above a cloud and can be seen by aircraft. They can sometimes just reach the stratosphere. Lastly, elves are described as a glowing disk that can extend up to 300 miles. This upper-atmospheric lightning can reach the ionosphere. The Space Shuttle discovered elves in 1992. (Below is a diagram provided by the NSSL of red sprites, blue jets, and elves.)  Lightning is important to understand and a weather phenomenon that happens constantly on this planet. Knowing what types of lightning occur at what height in the atmosphere is important to assure aircraft and spacecrafts have safe travel paths. Lower-atmospheric lightning is a life-threatening danger to humans and being more cautious when lightning is forecasted could save lives.
To learn more about other important educational topics in meteorology from around the world, be sure to click here! © 2018 Weather Forecaster Brittany Connelly
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Storm Surge Impacts from a Tropical Cyclone....Why Worry? (credit: Meteorologist Jordan Rabinowitz)9/7/2018  DISCUSSION: As the National Weather Service's National Hurricane Center office in Miami, Florida continues to work on the track as well as intensity forecasts for a number of current as well as potential storms in both the tropical Eastern and tropical Atlantic Ocean basins, there are still people who have their doubts about the rest of the respective seasons. Having said that, there are a few things that everyone should be aware of when it comes to tropical cyclone impact potential. First and foremost, tropical cyclones are a unique danger to both life and property and often across very large regions due to their size and power.
On that note, as a direct result of their often larger size (i.e., a couple hundred to sometimes several hundreds of miles across), tropical cyclones have the ability to churn up a ton of upper-ocean water content both beneath and just out ahead of their forward track. Therefore, one of the most prolific impacts from a tropical cyclone are those impacts which are delivered by a given tropical cyclone's storm surge. It is very well-known around the world that the most powerful force on Earth is indeed the power of water. Thus, it is no surprise that when a tropical cyclone drags an overstock of ocean water into shallower bays and inlets prior to and during its landfall, this can and often does have disastrous consequences for anyone and anything in its path. This is due to the fact that when water quickly piles up in shallower coastal regions, the water has no other place to go other than inland at that point and this often occurs quite violently. More specifically, it has been found that even just 6 inches of rapidly moving water can often sweep someone off their feet. Moreover, by the time you reach 1 to 2 feet of quickly moving water, the associated force can often be powerful enough to move most automotive vehicles and sweep them away. However, when it comes to a tropical cyclone's storm surge, you often are dealing with a violent rushing wall of ocean water which can be 5 feet high and counting. Hence, the reason for why inland moving storm surge impacts are often even more destructive than the strong onshore winds associated with a landfalling tropical cyclone. The points noted above or a big reason for why anyone who is ever positioned in the cross-hairs of an approaching tropical cyclone (regardless of its intensity near the time of landfall) should always treat a tropical cyclone with the utmost amount of respect. Attached above is YouTube footage from Super Typhoon Haiyan and it was captured by Nickson Genesis, a Plan Philippines Community Development Worker at 6 am on the morning of 8 November 2013. Note the massive storm surge was that moved inland in this footage at a location which was at least 1 to 2 miles away from the nearest coastline. This footage just goes to show the natural ferocity and power of an intense tropical cyclone's storm surge. To learn more about other important educational topics in meteorology from around the world, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz  Photo: Credit to The Lung Association. DISCUSSION: In a previous article, I explained how inhaling cold, dry air constricts airways and makes it harder to breathe. The same can be said for hot, humid air. The sticky, stuffy air can make everything from breathing to sleeping a challenge.
Your body is always using energy just to breathe and working to maintain a normal body temperature. Being exposed to extreme heat and humidity causes your body to use extra energy to remain cool. People with asthma and chronic obstructive pulmonary disease notice these negative effects the most. Extreme heat can cause the air to become stagnant which traps pollutants in the air. The moisture in the air helps with the absorption of oxygen. Warm, moist air is also the perfect environment for mold to spread and dust mites to grow and multiply. All of these factorsmake it hard to breathe. Respiratory issues or not, here are some tipsto project your lungs on hot, humid days in the final days of summer:
Humans are not the only mammals that get overheated and find breathing a challenge on hot and humid days. Actually, animals have their own techniques to beat the heat. If you find your pets being sluggish or acting different on hot, muggy days, make sure they are doing these things:
For more education on various weather-related topics, click here. © 2018 Meteorologist Amber Liggett  When the National Weather Service (NWS) issues a heat warning, it’s something to take seriously. There are four types of warnings that could be given within a period of consecutive hot days. But before explaining what each warning means, some terms need to be defined. Temperature is “the degree or intensity of heat present in a substance or object.” Humidity is “the state or quality of being humid. It’s a quantity representing the amount of water vapor in the atmosphere or gas.” If we put both the temperature and humidity together, we get what is called the heat index. The heat index “the apparent temperature” or “what the temperature feels like to the human body” (Merriam Webster Dictionary). This number is calculated by knowing the air temperature and relative humidity. It’s easy to figure out what the heat index is by using a chart that the NWS made. But, for example, if it is 90 degrees Fahrenheit outside, and the relative humidity is 65%, then the heat index would be 103 degrees.
So it all begins with an excessive heat outlook. These are issued when the next 3-7 days are forecasted to be upwards of 100 degrees Fahrenheit, allowing people to get prepared for the intense heat wave that is coming through. The next step the NWS would take is to issue an excessive heat watch. Watches are different from outlooks because it means that the weather is favorable for that event within the next 24-72 hours. The wide range in the 24-72 is because the exact timing of the heat or heat wave is uncertain at that point of time of forecasting, but confident enough that it will hit during the 24-72 hour period. You want to take action when a heat advisory is issued. This type of warning is released within 12 hours of the hot weather that could be potentially dangerous. In most parts of the United States, hot weather that is potentially hazardous consists of at least two days with the heat index temperature above 100 degrees Fahrenheit, and at night where the temperature doesn’t drop below 75 degrees. The NWS adds that “these criteria vary across the country, especially for areas that are not used to dangerous heat conditions.” This type of warning is sent out for people to take actions and plan accordingly so that they don’t become ill during this period of heat. The most severe heat warning issued is called an excessive heat warning. This is basically the same thing as a heat advisory, but the main difference is that heat index temperatures are expected to be upwards of 105 degrees Fahrenheit, with nighttime temperatures not dropping below 75 degrees. This again, varies for different locations across the US, as explained before. It’s essential to watch and understand all of these warnings issued by the NWS because they could impact your health. When outside, make sure that you’re staying hydrated and taking breaks from any work you could be doing. Make sure never to leave any kids or pets unattended in cars, and always check up on those who are elderly, sick, or without air conditioning. To learn more about other important education stories in atmospheric and oceanic science, be sure to click here! © 2018 Weather Forecaster Allison Finch  It’s a beautiful, hot day and you and your friends decide to head to the beach, so you pack up the car and head out. Your car is telling you that it is 85˚F outside then suddenly the temperature drops to 79˚F. What happened? Did your car’s thermometer break? Unlikely. More likely, you crossed what meteorologists call a sea-breeze front which leads to cooling near the coastline of the ocean or sea. Similarly, a lake-breeze front can occur near a large lake. On the left side of the photo above, the blue line with triangles represents the sea-breeze or lake-breeze front.
But why does this occur? Simply, it is the result of uneven heating between the land and water. Land changes temperature faster than water does. Therefore, as the sun shines and begins to heat the Earth’s surface, the land’s temperature increases faster than the water’s temperature. This leads to a temperature difference between the land and the water. The temperature difference causes the winds in the area to blow from the cold water to the warm land. The greater the difference in temperature, the faster the winds will blow. Therefore, as daytime heating increases, the temperature difference increases. This in turn leads to windspeeds increasing. As the winds increase, they begin to move the colder air that was over the water onto the shore. This causes the temperature to drop near the coast. The leading edge of the change in temperature is the sea-breeze or lake-breeze front. As the day progresses, the front moves further inland and around late afternoon is usually at its furthest point inland. Once the sun beings to set and the temperature begins to fall, the front begins to weaken and eventually disappears. Just as the land warms faster than the water, it also cools faster. Therefore, once the sun goes down, cooler temperatures are seen over the land than over the water. This results in the opposite of a sea-breeze or lake-breeze with winds blowing from the cooler land to the warmer water. When this occurs, it is referred to as a land-breeze. The land-breeze front is located where the temperature change is located. This can be seen on the right side of the above image. However, the temperature difference at night is often weaker than it is during the day. Therefore, the winds and front are also weaker. Along the fronts, clouds and thunderstorms can develop. However, thunderstorms are more likely to develop along a sea-breeze or lake-breeze front than they are along a land-breeze front. Due to a sea-breeze or lake-breeze front, the shore is usually cloudy despite the rest of the area being sunny. Another interesting meteorological phenomenon that can occur is when there are multiple sea-breeze or land-breeze fronts. Sometimes, as the individual fronts move inland, they collide with one another. As a result, strong thunderstorms and rain showers seemingly appear out of nowhere. Such a situation often occurs over the Florida peninsula. Sea-breeze fronts develop on both the east and west coast of the state and move inland. They then collide with each other over the middle of the state, resulting in afternoon thunderstorms. This is why it often storms in the middle of the afternoon when you are visiting the amusement parks in Orlando. For more information on Sea- and Lake-breezes refer to: Ahrens, D. C., 2013: Meteorology Today An Introduction to Weather, Climate, and the Environment. 10th ed. Brooks/Cole, Cengage Learning, 241-243. UCAR Comet Module: Thermally-forced Circulation I: Sea Breezes. http://meted.ucar.edu/mesoprim/seabreez/print.htm North Carolina Climate Center climate.ncsu.edu/edu/Breezes To learn more about other important education stories in atmospheric and oceanic science, be sure to click here! © 2018 Meteorologist Sarah Trojniak  As if thunderstorms aren’t hazardous enough, sometimes they can combine into a large cluster known as a mesoscale convective systems (MCS). These thunderstorm clusters are smaller than our typical low-pressure systems with warm and cold fronts, but are larger in scale than a singular thunderstorm. First discovered in the mid-1970s by infrared satellite imagery, they were originally named Mesoscale Convective Complexes--larger versions of MCS’s characterized by areal coverage and persistence of their satellite signature. Like major hurricanes and low-pressure systems, MCC’s have very distinct satellite signature. These storm clusters frequently occur in many parts of the world, including the southern and central United States, South America (the equatorial and mid-latitude areas), southeast Asia, Indonesia, and northern Australia. So, why do these thunderstorms “cluster” and why are they so dangerous? The typical MCS that we see in the Midwest during the spring storm season becomes most active in the evening, lasting clear into the early morning hours. If you’ve experienced an MCS, you probably noticed an abundance of vivid lightning and multiple crashes of thunder on an otherwise peaceful evening. This may be a bit puzzling seeing as a major ingredient for thunderstorms is warm, humid air near the earth’s surface. Once the sun sets, wouldn’t you lose your main energy source? As it turns out, the cooler air near the surface at night helps with the intensification of a jet stream much lower than what a typical airliner uses. This low-level jet--roughly 1,500 to 3,000 feet above the surface, gliding atop the cooler air below--feeds the warm, humid air into the developing MCS. Thus, new thunderstorms form where the low-level jet collides with rain-cooled outflow from previous thunderstorms. MCS’s become stronger overnight due to the increased instability from cooling at the cloud-top level--as cloud tops radiate energy back into space with no incoming solar radiation to absorb--teamed up with the latent heat, heat given off from condensation of water vapor into surrounding clouds. Latent heat alone may be enough to generate an area of low-pressure aloft, but behind the main line of thunderstorms in the MCS. This circulation, known as a mesoscale convective vortex (MCV), may last well after the thunderstorms in the cluster have died off the following morning. It may also appear in the satellite imagery, occasionally resembling an inland tropical storm. Interestingly enough, this MCV can help regenerate additional thunderstorms later in the day, even forming another MCS. An MCS can track over 1,000 miles and last in excess of 12 hours. A major part of the impact of an MCS is determined by how quickly it moves. These systems can be quite difficult to forecast. In many cases, it’s pretty clear that an MCS will move in a particular direction, but forecasters may struggle to determine how long it will cast. In 2015, the PECAN (Plains Elevated Convection At Night) Field Program ventured out to collect data on nocturnal MCS’s in the Plains. Some of the data collected showed that forward propagation of an MCS versus backbuilding--standing in place--can make a huge difference in impact. While it is possible for an MCS to produce hail and tornadoes, there are three main impacts that occur when an MCS is in progress: Flooding rains, damaging winds, and immense lightning rates. If an MCS stalls or moves rather slowly, flash flooding becomes a possibility. This typically occurs when the winds in the upper-level jet stream are relatively weak, and/or the aforementioned low-level jet is oriented towards the west or southwest edge of the MCS. Rather than thunderstorms clearing an area, new thunderstorms are produced and train over the same areas, bringing multiple rounds of heavy rain over an extended period of time. It’s not uncommon to have rain rates of several inches fall within an hour, quickly triggering flash flooding that’s particularly dangerous when occurring at night. Sometimes one area can see repeated MCS’s for weeks at a time! When this occurs, major riverbed flooding can become widespread. Two notable examples of this are the succession of MCS’s plaguing the Plains in May of 2015 in addition to the Great Mississippi River Flood of 1993. Despite the flood dangers that accompany MCS’s they also provide widespread spring and summer rainfall that’s needed to sustain crops in the Midwest. Without these storms, corn and wheat would shrivel up as the hot summer sun depletes moisture from the soil. Penn State University’s 1986 study found that 30%-70% of the rainfall between April and September over much of the area between the Rockies and Mississippi River comes from MCS’s. This study, lead by Dr. Michael Fritsch, also stated MCS’s are “very likely the most prolific precipitation producer in the United States, rivaling and even exceeding that of hurricanes.” In other cases, MCS’s can be pushed forward by a more vigorous upper-level jet stream. When this occurs, damaging straight-line winds can cause tornado-like damages to powerlines, small buildings, and crops. Since these instances may occur at night, victims believe their property was indeed hit by a tornado (which can occasionally occur on the leading edge of an MCS). The more extreme version of this is called a derecho. These MCS’s feature massive wind damage at least 250 miles long, often producing gusts over 75mph. One of the more recent destructive derechos occurred on June 29th, 2012, traveling nearly 800 miles from Chicago to the Mid-Atlantic coast with an average pace of 65mph! The lightning rates within an MCS can truly blow one’s mind. For example, the MCS responsible for a flash flooding event along the Gulf Coast in 2014, produced 6,076 cloud-to-ground lightning strikes in just 15 minutes--according to the University of Wisconsin-Madison’s CIMSS Satellite Blog. Another MCS occurred in Texas on June 11th, 2009, producing roughly 31,000 lightning strikes within a six-hour timeframe, including 7,500 in Dallas and Tarrant Counties alone! This is just a glimpse into the power of a large cluster of thunderstorms with thousands of collisions between graupel and ice crystals separating charge. Another dangerous characteristic of an MCS is its ability to produce lightning well after the strongest portion of the storm has passed, occasionally lingering for an hour or more. Some MCS that produce lighter rain can still produce lightning strikes that contain a more powerful current than the average lightning bolt. When your area is in the path of an MCS, it’s best to practice lightning safety: Remain indoors, stay back from windows, and avoid using electrical or plumbing equipment until 30 minutes after the last lightning flash. To learn more about other important education stories in atmospheric and oceanic science, be sure to click here! © 2018 Meteorologist Ash Bray  DISCUSSION: In the wake of what is now a departing Tropical Storm Chris after formally being Hurricane Chris over the past 24 hours or so, there still do remain one or two concerns along north-south oriented beaches along the Mid-Atlantic and the Northeast United States. Although it would now seem to appear that the primary threat this latest offshore tropical cyclone is now well offshore, there is still a very legitimate coastal concern or two which is on the mind of many. This is the threat of both rip currents as well as mild-to-moderate coastal beach erosion. Even when a hurricane or tropical storm is tens to hundreds of miles offshore from a given coastline, there is always a legitimate threat for there to be a prominent and persistent ocean swell and wave action along the chance even far away from the storm.
This is a result of the fact that closer to the storm’s immediate proximity there are much larger waves which are generated by the stronger wind’s much closer to the storm’s center of circulation. Hence, as these larger waves continue to move away from the center of what is now (as of this evening) Tropical Storm Chris, they will gradually begin to lose some energy and magnitude with increasing distance from Chris, but not nearly enough to eliminate all the potential and kinetic energy from these incoming waves. To clarify, potential energy with wave action is referring to the net amount of energy which may end up having the ability to reach a given coastline. On the flip side, kinetic energy with wave action refers to the net amount of energy which does ultimately reach a given coastline during some given period. Further, such wave action reaching a given coastline can also induce substantial amounts of regional coastal beach erosion. This a result of the unrelenting wave action acting to quite literally “tear up” coastlines and remove a lot of sand from both parts of the inner coastal shelf, beaches, and critical protective sand dunes which help to more effectively protect coastal communities. Lastly, tropical storms and/or hurricanes can also induce what are most commonly referred to as rip currents along coastal beaches normal to the axis of the incoming wave action. Rip currents occur as a result of strong incoming wave action racing back out to sea and creating locally strong undertows in the vicinity of the outgoing ocean water from the aforementioned incoming wave action. This is visually reflected the graphic attached above courtesy of the NOAA National Weather Service network. To learn more about other important education stories in atmospheric and oceanic science, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz  DISCUSSION: As the Northern Hemisphere heads deeper in the Summer of 2018, it is no surprise that thunderstorm occurrence frequency is increasing along with corresponding rising average day-time high temperatures across many parts of the world. More specifically, across the South-Central, Central, and North-Central Plains states of the United States in North America, there is no question that thunderstorm activity frequency experiences a substantial increase. Having said that, one of nature’s greatest natural dangers is the well-known lightning strike.
With severe weather, many people across the United States and many other parts of the world know first-hand about how dangerous lightning can be. First off, it is important to note that an average lightning strike can have a maximum instantaneous temperature of around 53,000 degrees Fahrenheit as opposed to the surface of Earth’s Sun which has a temperature of around 10,000 degrees Fahrenheit. Second, lightning which is most commonly found directly in association with strong to severe thunderstorms in places all over the world can also sometimes strike many miles away from a given thunderstorm cell. Sometimes the reasons for such a displaced electrical discharge away from a given thunderstorm are not perfectly clear, but, the bottom line here is that it can and does happen at times. Thus, when you may have the curiosity during this Summer to go outside and watch an incoming thunderstorm, remember that lightning can strike both unexpectedly and unpredictably in many cases. Hence, always be sure to have the utmost respect for the natural power of thunderstorms during any season regardless of when they may occur. Remember the old phrase from the NOAA National Weather Service network: “When thunder roars, go indoors.” It may initially seem comical at the face of that phrase, but at some point in your life, this may just end up being a phrase which separates you from encountering a potentially life-threatening experience due to a run-in with one of Mother Nature’s most intense weather phenomena on the planet. Remember that you can always replace a memory card in a camera for the next thunderstorm event, but you can never replace a life. To learn more about other important educational topics in global atmospheric science topics, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz  Analyzing the entirety of the atmosphere is vital in studying weather, understanding synoptic systems, and ultimately, providing forecasts. However, when studying smaller mesoscale phenomena, the atmospheric boundary layer (ABL) is the way to go. The ABL is the layer of the atmosphere which is directly influenced by the surface of the earth through exchanges in energy, moisture, and turbulence. To give an idea of its size, the troposphere (where almost all weather occurs) in mid-latitude regions is on average 12 miles high, but the ABL is only about a tenth of that. Two subsets of the ABL, each with their own distinct processes and functions, will be investigated in depth to understand its importance in the weather world. The Land Boundary Layer The boundary layer over land, also known as the land boundary layer (LBL) is one that almost everyone sees and interacts with every day. This boundary layer forms by growth with the diurnal cycle. The sun heats up the ground which in turn destabilizes the lower part of the atmosphere, generating dry convection. This convection mixes the air vertically elevating the boundary layer as it does so. In addition to heightening the LBL, this creates low level turbulence. The height of the boundary layer depends on many different weather processes that occur daily, not just convection on a sunny day. For example, fronts, deep moist convection, precipitation, temperature and moisture advection, amongst others can significantly impact the height of the LBL. For a typical summer sunny day, with no significant weather features in the area, heights of the LBL extend up about 1-2 km with extreme cases such as in desert environments up to 4-5 km. How do we know where to spot the boundary layer on a typical day? There are a few ways to go about this. One visual way is to look at the sky. Fair weather cumulus clouds, if present, will typically give an estimate of the LBL’s elevation. Below these clouds lies the mixing of the air from convection and hence a turbulent environment of varying intensities. Above these clouds exists an inversion, essentially the best way to pick out the LBL depth. Another method utilizes a vertical profile of the atmosphere. In the sounding below from North Platte Regional Airport on the 27th of June 2018 at 00Z, the boundary layer is shown to be around 1.2 km above ground level (AGL) (the surface elevation is about 850 m, meaning the boundary layer is from the surface to 1.2 km above this). The temperature around this height shows a distinct increase for the next few hundred meters while the moisture significantly drops off above this increase in temperature. What this physically signifies is the almost uniform air below the inversion because of the mixing from thermals, shown by the unvarying moisture throughout the LBL. The widely varying moisture above this level is a testament to the mixing not being present and hence the boundary layer ceasing to exist at and above, in this case, 1.2 km AGL.  The LBL and its processes are very important to the Plains and Midwest United States, especially during the nighttime hours. Essentially a nocturnal increase in winds develops around 850mb after the sun goes down and lasts into much of the overnight providing moisture, instability, and wind shear to support thunderstorms during the nighttime hours. More on this process and the physics behind it will be provided in a future article to further explain the LBL’s importance in the weather world. The Marine Boundary Layer Switching gears, the marine boundary layer (MBL) chiefly differs that of the land boundary layer in that it has direct contact with the ocean instead of the land, allowing for large amounts of heat and moisture to be exchanged. However, the MBL is harder to study than the LBL for a few reasons. First off, there is a lack of observations due to the difficulty of studying the atmosphere over the ocean. Even on an island, local influences from the land can affect soundings. Consequently, little is known about the MBL. Whereas cumulus clouds can usually be seen above the LBL, stratocumulus clouds are more likely to be seen over the MBL. These flat, low-lying clouds are very important to the earth’s radiation budget, since these clouds essentially act as a white blanket over large swaths of the ocean. This large blanket has a very high albedo (high reflectivity), meaning that these clouds will globally cool the earth’s surface. See below for a satellite image of a swath of these clouds.  The stratocumulus clouds in this layer are formed top-down. An air parcel on the top of the cloud will become negatively buoyant and stable by the cooling of the stratocumulus cloud. This will cause the parcel to sink; therefore causing surrounding parcels to rise (imagine dropping a rock in a cup of water, the water level will rise to make room for the rock as it sinks to the bottom). This process in the MBL creates a well-mixed layer with lots of turbulent air (see here for a great article on turbulence). This turbulent air allows water vapor and heat to be transported up to the cloud, which the cloud needs to stay alive. Note the difference in boundary layer formation from the LBL. To recap, the MBL develops via stability and sinking air (top-down process) whereas the LBL develops in pretty much the exact opposite way; destabilization and convection (bottom-up process) matures the LBL. Another important phenomenon that occurs in the MBL is decoupling. Essentially, decoupling occurs when the air that sinks below the cloud base does not reach the ocean surface; this is usually due to intense sunlight. The warming of the sun allows the stable air to retain some buoyancy, and therefore does not completely sink to the bottom of the ocean surface. This will cease the turbulence halfway up the cloud layer, meaning there is little to no air movement. As a result, this disallows the warm water vapor at the ocean surface to reach the cloud surface. Due to this lack of water vapor reaching the cloud, the cloud therefore thins and evaporates. Therefore, this diurnal process of decoupling essentially dissipates the cloud. See below for a comparison of a well-mixed and decoupled MBL.  As a whole, the planetary boundary layer is one of the most important aspects of the climate system. It is in direct contact with either the land or ocean surface, making boundary layer research essential to more accurate forecasting. Many important processes occur in the boundary layer, such as convection, turbulence, and decoupling, making it a vital part of our atmosphere to study and understand.
To learn more about the boundary layer, both over land or water, stay tuned in to GWCC and be sure to click here! ©2018 Meteorologist Joseph DeLizio(Land Boundary Layer) ©2018 Meteorologist Joseph Fogarty (Marine Boundary Layer)  For every summer that I can remember, I remember going outside and catching fireflies in the backyard. These cold-blooded bugs are bioluminescence, which means there is a chemical reaction between luciferin and luciferase. Luciferin is an enzyme which brings oxygen and luciferin together. This creates a lot of energy; to which they emit 100% of its energy by giving off light.
During the winter, fireflies are usually in the larval stage and hibernate by burrowing underground until they emerge in the spring. Larvae live underground in the winter, mature during the spring and emerge in the early summer. When they emerge, it ranges from the third week of May to the third week of June. In years when summer-like weather arrives before June, they tend to appear earlier than usual – like late spring. The air temperature and rainfall play a huge role in when they emerge. Since they feed on snails, slugs, and pill bugs, which are brought out by the rain and moist environment, fireflies like the muggy weather. Cold-blooded bugs like fireflies slow down when it gets cold. As the weather gets colder, the flash in the fireflies will flash at a slower rate. But once the air temperature reaches 50 degrees Fahrenheit and lower, that’s when they will stop flashing and flying around. An Ideal night for these insects is when it’s warm and muggy. If it rained during the day, an ideal environment would be present during the nighttime hours for their prey. If it is a cloudy night, the clouds act as a “blanket” over the surface, keeping the warm air from the day close to the surface. Since the moon doesn’t give off any radiation/heat, the clouds have stored energy from the day that they give off to the Earth’s surface during the night. This acts as a “blanket” to the surface keeping it warm throughout the night and not letting the heat escape. So, if you are trying to look for fireflies, then your best bet would be to do so on a warm and muggy night. To learn more about other interesting educational stories in atmospheric, oceanic, or climate science from around the world, be sure to click on the following link: www.globalweatherclimatecenter.com/education. © 2018 Weather Forecaster Allison Finch |
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