Articles related to "Keith C Heidorn"
How Do Clouds Float?
A frequent question we meteorologists get is: "If water drops are heavier than air, why do clouds float?" With lovely forms of cumulus clouds popping up all around me on this summer's day, that is the question I will tackle this month.
weather • meteorology • keith c. heidorn • science of the sky • clouds
A frequent question we meteorologists get is: "If water drops are heavier than air, why do clouds float?" With lovely forms of cumulus clouds popping up all around me on this summer's day, that is the question I will tackle this month.
weather • meteorology • keith c. heidorn • science of the sky • clouds
A Record Setting Day
For those who love weather in all its varied forms, extreme or rare weather events often hold great allure. Spawned by our love of statistics, one extreme event that catches our attention is the breaking of daily temperature records. Whether a record hot day or record cold day, it is sure make local news headlines. If today's weather set a record for either maximum or minimum temperature, you would likely respond with a modicum of interest. If I told you that this day broke both the daily maximum and minimum temperature record, you might exhibit degree of incredulity. I call such days: double record days.
weather • meteorology • keith c. heidorn • science of the sky • a record setting day
For those who love weather in all its varied forms, extreme or rare weather events often hold great allure. Spawned by our love of statistics, one extreme event that catches our attention is the breaking of daily temperature records. Whether a record hot day or record cold day, it is sure make local news headlines. If today's weather set a record for either maximum or minimum temperature, you would likely respond with a modicum of interest. If I told you that this day broke both the daily maximum and minimum temperature record, you might exhibit degree of incredulity. I call such days: double record days.
weather • meteorology • keith c. heidorn • science of the sky • a record setting day
Superior Moisture Gain
Large water bodies have major influences on the weather,impacting the weather and climate of their shoreline regions. But unless we are involved with the maritime industry or sport sailing, we tend to overlook the weather and climate over the water body itself. Herein, we look specifically at one aspect: on-lake condensation on Lake Superior.
weather • meteorology • keith c. heidorn • science of the sky • lake superior
Large water bodies have major influences on the weather,impacting the weather and climate of their shoreline regions. But unless we are involved with the maritime industry or sport sailing, we tend to overlook the weather and climate over the water body itself. Herein, we look specifically at one aspect: on-lake condensation on Lake Superior.
weather • meteorology • keith c. heidorn • science of the sky • lake superior
The Flavour of Lows
Often in the weather reports we hear of tropical lows, subtropical lows, extratropical lows, and thermal lows. What distinguishes these various flavours of "lows" from one another?
weather • meteorology • keith c. heidorn • science of the sky • low pressure
Often in the weather reports we hear of tropical lows, subtropical lows, extratropical lows, and thermal lows. What distinguishes these various flavours of "lows" from one another?
weather • meteorology • keith c. heidorn • science of the sky • low pressure
Why Are Lightning Bolts Not Straight?
If you've ever watched a spark of static electricity jump from an object like a doorknob to your finger, you perhaps noted that mini-bolt followed a fairly straight-line path from the object to your finger. Lightning bolts are essentially the granddaddy version of that static spark, so why do lightning bolts generally appear so jagged and forked? The answer for lightning's jaggedness arises in its size and formation process.
weather • meteorology • keith c. heidorn • science of the sky • stepped leader
If you've ever watched a spark of static electricity jump from an object like a doorknob to your finger, you perhaps noted that mini-bolt followed a fairly straight-line path from the object to your finger. Lightning bolts are essentially the granddaddy version of that static spark, so why do lightning bolts generally appear so jagged and forked? The answer for lightning's jaggedness arises in its size and formation process.
weather • meteorology • keith c. heidorn • science of the sky • stepped leader
Frost Pockets
The lengthening nights during the late summer and autumn bring noticeably colder minimum temperatures across most of North America. If such nights have clear skies and fairly calm regional winds, the potential for temperatures to fall below the freezing mark increases as the days move on toward winter. This is especially true in low-lying terrain, hollows and drainage bottoms where cold air can pool. Such areas are more susceptible to frost than the surrounding terrain and are therefore known as frost pockets.
weather • meteorology • frost pockets • cold air drainage • katabatic winds
The lengthening nights during the late summer and autumn bring noticeably colder minimum temperatures across most of North America. If such nights have clear skies and fairly calm regional winds, the potential for temperatures to fall below the freezing mark increases as the days move on toward winter. This is especially true in low-lying terrain, hollows and drainage bottoms where cold air can pool. Such areas are more susceptible to frost than the surrounding terrain and are therefore known as frost pockets.
weather • meteorology • frost pockets • cold air drainage • katabatic winds
The Other Side of the Mountain: Rainshadows
Mountain ranges have a major impact on moist air moving over them. On the windward side, upsloping air leads to a region of heavy precipitation near the summits. But in the descent on the ridge lee, descending air and decreased precipitation forms what we term the rainshadow.
weather • meteorology • rainshadow • mountain meteorology • mountain weather
Mountain ranges have a major impact on moist air moving over them. On the windward side, upsloping air leads to a region of heavy precipitation near the summits. But in the descent on the ridge lee, descending air and decreased precipitation forms what we term the rainshadow.
weather • meteorology • rainshadow • mountain meteorology • mountain weather
Winds of the City
Walk around any city where buildings rise more than a few stories, and you will experience areas with stronger and gustier winds than felt outside the urban area, at airports, or on sports fields. The prime cause of such urban winds is the redirecting of the over-ridding wind field by the structures themselves.
weather • meteorology • urban winds • urban weather • urban wind field
Walk around any city where buildings rise more than a few stories, and you will experience areas with stronger and gustier winds than felt outside the urban area, at airports, or on sports fields. The prime cause of such urban winds is the redirecting of the over-ridding wind field by the structures themselves.
weather • meteorology • urban winds • urban weather • urban wind field
Arctic Outbreaks
Arctic Outbreaks. They happen in all months of the year and can rate headlines during spring, summer, or early autumn if they bring extreme drops in temperature or killing frost. But it is during the winter that they receive the most attention because arctic outbreaks can drop air temperatures to hazardous levels, increase demands for home heating fuels, produce lake/sea effect snows, or in their deepest southern penetration kill sensitive fruit and vegetable crops in the southern American states.
weather • meteorology • arctic outbreaks • winter cold • arctic air masses
Arctic Outbreaks. They happen in all months of the year and can rate headlines during spring, summer, or early autumn if they bring extreme drops in temperature or killing frost. But it is during the winter that they receive the most attention because arctic outbreaks can drop air temperatures to hazardous levels, increase demands for home heating fuels, produce lake/sea effect snows, or in their deepest southern penetration kill sensitive fruit and vegetable crops in the southern American states.
weather • meteorology • arctic outbreaks • winter cold • arctic air masses
Avalanche!
The snows of winter bring many hazards to humans and wildlife. In urban areas, these hazards are usually manifested as transportation- or power-transmission-related hazards. But in mountainous terrain, another danger arises: the avalanche.
weather • avalanche • snow • mountains • mountain snow
The snows of winter bring many hazards to humans and wildlife. In urban areas, these hazards are usually manifested as transportation- or power-transmission-related hazards. But in mountainous terrain, another danger arises: the avalanche.
weather • avalanche • snow • mountains • mountain snow
Edmonton Alberta Tornado 1987
Named as Black Friday, a sunny and humid day in Edmonton, Alberta turned into a barrage of thunderstorms, hail and a destructive tornado.
edmonton alberta tornado 1987 • second deadliest twister canada history • black friday edmonton alberta thunderstorms hail • funnel touched down leduc alberta • clareview extensive damage evergreen mobile home p
Named as Black Friday, a sunny and humid day in Edmonton, Alberta turned into a barrage of thunderstorms, hail and a destructive tornado.
edmonton alberta tornado 1987 • second deadliest twister canada history • black friday edmonton alberta thunderstorms hail • funnel touched down leduc alberta • clareview extensive damage evergreen mobile home p
April Showers
April showers bring May flowers. Rain showers are very common weather events during April across most of North America. Showers are a distinct form of precipitation, whether falling as rain or snow or ice pellets.
weather • meteorology • showers • rain showers • rain
April showers bring May flowers. Rain showers are very common weather events during April across most of North America. Showers are a distinct form of precipitation, whether falling as rain or snow or ice pellets.
weather • meteorology • showers • rain showers • rain
Cloudbursts
Have you ever gone out for a long walk, run, or bike ride on a gorgeous summer day and been caught in a torrential cloudburst? Bad enough to be caught in the rain, but cloudbursts can leave you drenched to the bone. But have you ever watched the approach of a thunderstorm darken the sky and then been surprised at how bright the day became during the heaviest downpour?
weather • meteorology • rain • rainshowers • cloudbursts
Have you ever gone out for a long walk, run, or bike ride on a gorgeous summer day and been caught in a torrential cloudburst? Bad enough to be caught in the rain, but cloudbursts can leave you drenched to the bone. But have you ever watched the approach of a thunderstorm darken the sky and then been surprised at how bright the day became during the heaviest downpour?
weather • meteorology • rain • rainshowers • cloudbursts
Dry Thunderstorms
When you hear the word thunderstorm in the daily weather forecast, you automatically think of thunder and lightning accompanied by rain, often as a drenching cloudburst, and wind, gusty at times. Not all thunderstorms are wet, however, and that worries those watching for or fighting wildfires. These thunderstorms are called dry thunderstorms.
weather • meteorology • thunderstorms • dry thunderstorms • fire weather
When you hear the word thunderstorm in the daily weather forecast, you automatically think of thunder and lightning accompanied by rain, often as a drenching cloudburst, and wind, gusty at times. Not all thunderstorms are wet, however, and that worries those watching for or fighting wildfires. These thunderstorms are called dry thunderstorms.
weather • meteorology • thunderstorms • dry thunderstorms • fire weather
Hurricane Hazel 1954
Hurricane Hazel left a path of destruction in Grenada, Haiti, Bahamas, South and North Carolina, Virginia, West Virginia, Maryland, Pennsylvania, New York, and Toronto.
hurricane hazel 1954 • worst storms 20th century eastern north america • october 12 1954 hurricane hazel haiti death toll e • hurricane hazel bahamas october 13 1954 great inag • october 14 1954 hurricane hazel landfall north sou
Hurricane Hazel left a path of destruction in Grenada, Haiti, Bahamas, South and North Carolina, Virginia, West Virginia, Maryland, Pennsylvania, New York, and Toronto.
hurricane hazel 1954 • worst storms 20th century eastern north america • october 12 1954 hurricane hazel haiti death toll e • hurricane hazel bahamas october 13 1954 great inag • october 14 1954 hurricane hazel landfall north sou
Snowrollers
Looking across the open, snow-covered cornfield, they appear, on first glance, as if someone started to build snowmen or a snow fort then left the rolled balls of snow randomly across the field. And, although they each have a distinct "roll-up" track, close inspection show no footprints in the surrounding snow. Are these the winter version of crop circles, the work of winter spirits, or a curious product of nature? Such naturally formed snowballs are called snowrollers,cylindrical rolls of snow produced by the wind and shaped like a muff, rolled carpet, or jellyroll.
weather • meteorology • snow • snowrollers • snow rollers
Looking across the open, snow-covered cornfield, they appear, on first glance, as if someone started to build snowmen or a snow fort then left the rolled balls of snow randomly across the field. And, although they each have a distinct "roll-up" track, close inspection show no footprints in the surrounding snow. Are these the winter version of crop circles, the work of winter spirits, or a curious product of nature? Such naturally formed snowballs are called snowrollers,cylindrical rolls of snow produced by the wind and shaped like a muff, rolled carpet, or jellyroll.
weather • meteorology • snow • snowrollers • snow rollers
The 46-Degree Halo
A halo around the sun often means rain, but not all come full circle.
weather • nature • weather watching • weather phenomena • atmospheric phenomena
A halo around the sun often means rain, but not all come full circle.
weather • nature • weather watching • weather phenomena • atmospheric phenomena
The Glory and the Brockenspectre
Glories appear as a full circle, their coloured rings centered on the observer's shadow. Prior to the advent of regular high-altitude flight, the glory appeared only to those who ascended to high mountain elevations. Today, we can see glories regularly from aircraft flying in the sunlight above uniform cloud decks. A glory is only visible when sunlight is at the observer's back; therefore, they are always exactly opposite the sun.
weather • meteorology • glory • brockenspectre • atmospheric diffraction
Glories appear as a full circle, their coloured rings centered on the observer's shadow. Prior to the advent of regular high-altitude flight, the glory appeared only to those who ascended to high mountain elevations. Today, we can see glories regularly from aircraft flying in the sunlight above uniform cloud decks. A glory is only visible when sunlight is at the observer's back; therefore, they are always exactly opposite the sun.
weather • meteorology • glory • brockenspectre • atmospheric diffraction
"Watching" Thunder
Knowing how sound travels through the atmosphere allows us to "watch" thunder and deduce something about the lightning that causes it.
weather • thunder • lightning • thunderstorm • atmospheric sound
Knowing how sound travels through the atmosphere allows us to "watch" thunder and deduce something about the lightning that causes it.
weather • thunder • lightning • thunderstorm • atmospheric sound
A Jet Stream Runs Through It
High above the Earth's surface, rivers of air rush their way around the globe in a high speed current that often spawns side eddies that we on the ground call cyclones. Knowledge of the position of these streams, known as the <i>jet stream</i> because of their speed, is vital to accurate general weather forecasts and severe storm predictions. Knowledge of the location of the jet stream is also important to airlines and other long-distant air transportation.
weather • meteorology • jet stream • polar front • polar jet stream
High above the Earth's surface, rivers of air rush their way around the globe in a high speed current that often spawns side eddies that we on the ground call cyclones. Knowledge of the position of these streams, known as the <i>jet stream</i> because of their speed, is vital to accurate general weather forecasts and severe storm predictions. Knowledge of the location of the jet stream is also important to airlines and other long-distant air transportation.
weather • meteorology • jet stream • polar front • polar jet stream
Air Masses: A Taste of Weather
An air mass is a large dome of air which has similar horizontal temperature and moisture characteristics. At any given time, about fifty distinct air masses are scattered across the Earth. Some are newly born entities and strongly reflect their place of birth. Others are old and travel-scarred with only the slightest hint of their place of origin remaining.
weather • meteorology • air masses • weather fronts
An air mass is a large dome of air which has similar horizontal temperature and moisture characteristics. At any given time, about fifty distinct air masses are scattered across the Earth. Some are newly born entities and strongly reflect their place of birth. Others are old and travel-scarred with only the slightest hint of their place of origin remaining.
weather • meteorology • air masses • weather fronts
Blizzard!
While the media rush to call any severe or heavy snowstorm a blizzard, true blizzards have a strict definition according to meteorologists, and snow need not even fall in a blizzard. Blizzards take on different characteristics when they rage around North America, combining wind and temperature and snow into a variety of recipes, though they all start as low pressure systems.
weather • meteorology • blizzard • winter storms • winter
While the media rush to call any severe or heavy snowstorm a blizzard, true blizzards have a strict definition according to meteorologists, and snow need not even fall in a blizzard. Blizzards take on different characteristics when they rage around North America, combining wind and temperature and snow into a variety of recipes, though they all start as low pressure systems.
weather • meteorology • blizzard • winter storms • winter
Cumulus Humilis: A Fair Weather Cloudscape
The dawn brought clear sky But, in a few hours, the warm sun would break the morning chill, and by mid-morning the perfectly clear sky would begin to lose its fair complexion as small buds of whiteness pop up hither and yon. So started a day when cumulus humilis, the most basic of the cumulus cloud family, would fill the skyscape. This cloud type often is the forerunner to larger, more developed cumulus varieties that fill the afternoon sky. But today, these fair-weather cumuli dot the sky within the large high-pressure cell that sat over the region.
weather • meteorology • science of the sky • keith heidorn • cumulus
The dawn brought clear sky But, in a few hours, the warm sun would break the morning chill, and by mid-morning the perfectly clear sky would begin to lose its fair complexion as small buds of whiteness pop up hither and yon. So started a day when cumulus humilis, the most basic of the cumulus cloud family, would fill the skyscape. This cloud type often is the forerunner to larger, more developed cumulus varieties that fill the afternoon sky. But today, these fair-weather cumuli dot the sky within the large high-pressure cell that sat over the region.
weather • meteorology • science of the sky • keith heidorn • cumulus
Diamond Dust: Snow Without Clouds
During the depths of winter cold, we often hear some weather sage observe, "It's too cold to snow." Truth is, it is never too cold to snow. At very cold temperatures, 40 below zero (C or F) and colder, snow can actually fall out of the clear blue sky without intervening clouds, a weather condition known appropriately enough as diamond dust.
weather • winter • meteorology • diamond dust • ice crystals
During the depths of winter cold, we often hear some weather sage observe, "It's too cold to snow." Truth is, it is never too cold to snow. At very cold temperatures, 40 below zero (C or F) and colder, snow can actually fall out of the clear blue sky without intervening clouds, a weather condition known appropriately enough as diamond dust.
weather • winter • meteorology • diamond dust • ice crystals
Gap Winds
Terrain interacts with the atmosphere in many ways to alter the weather. If winds push through the terrain in spots, rather than going over it, another set of wind phenomena arises, the gap winds. Gap winds are high-speed winds associated with gaps or low elevation areas in mountainous terrain, and whose direction more or less parallels the gap axis.
weather • meteorology • gap winds • topographical winds
Terrain interacts with the atmosphere in many ways to alter the weather. If winds push through the terrain in spots, rather than going over it, another set of wind phenomena arises, the gap winds. Gap winds are high-speed winds associated with gaps or low elevation areas in mountainous terrain, and whose direction more or less parallels the gap axis.
weather • meteorology • gap winds • topographical winds
Gulf of Alaska Storms
Storms move out of the Gulf of Alaska into the Pacific Northwest with great regularity, as many as three or four per week during the height of the winter storm season. Winter Gulf of Alaska storms typically sport winds in excess of 80 km/h (50 mph) with corresponding high waves. Some storms rival the strength of the great hurricanes/typhoons and would be considered as such if their origins were tropical rather than polar.
weather • meteorology • winter storms • gulf of alaska • aleutian low
Storms move out of the Gulf of Alaska into the Pacific Northwest with great regularity, as many as three or four per week during the height of the winter storm season. Winter Gulf of Alaska storms typically sport winds in excess of 80 km/h (50 mph) with corresponding high waves. Some storms rival the strength of the great hurricanes/typhoons and would be considered as such if their origins were tropical rather than polar.
weather • meteorology • winter storms • gulf of alaska • aleutian low
Heavenly Shades of Nighttime Falling: It's Twilight Time
While you might think that clear skies are not conducive to skywatching — unless you look past the atmosphere to the moon, planets and stars — but there are subtle changes in the clear sunset/sunrise skies that are worth looking for. Under clear skies, the twilight period can provide subtle sky beauty with its softly changing colours, particularly in the sky regions known as the <EM>twilight</em> and <EM>anti-twilight arches</em>.
weather • meteorology • sky color • twilight
While you might think that clear skies are not conducive to skywatching — unless you look past the atmosphere to the moon, planets and stars — but there are subtle changes in the clear sunset/sunrise skies that are worth looking for. Under clear skies, the twilight period can provide subtle sky beauty with its softly changing colours, particularly in the sky regions known as the <EM>twilight</em> and <EM>anti-twilight arches</em>.
weather • meteorology • sky color • twilight
Ice Storms: Beauty Amid Destruction
Residents of the eastern United States and Canada may experience freezing rain any time between late October and early May. When freezing rain falls for a long period and covers and extensive area it is called an ice storms. While ice storms may be very destructive, they can leave scenes of great beauty in their wake.
weather • meteorology • ice storms • freezing rain • winter weather
Residents of the eastern United States and Canada may experience freezing rain any time between late October and early May. When freezing rain falls for a long period and covers and extensive area it is called an ice storms. While ice storms may be very destructive, they can leave scenes of great beauty in their wake.
weather • meteorology • ice storms • freezing rain • winter weather
Icicles
Icicles are one of our strongest symbols of winter and often used to depict the cold depths of prolonged winter. In its basic form, an icicle is a tapered, hanging spike or cone of ice formed by the freezing of dripping or falling water.
winter weather • weather • meteorology • icicles • icicle formation
Icicles are one of our strongest symbols of winter and often used to depict the cold depths of prolonged winter. In its basic form, an icicle is a tapered, hanging spike or cone of ice formed by the freezing of dripping or falling water.
winter weather • weather • meteorology • icicles • icicle formation
Jet Streaming Along the Polar Front
The polar front and its associated jet stream have a major influence on the weather conditions surrounding it. Many storms form along the polar front in the vicinity of the jet stream's maximum winds. Because the jet stream is associated with the polar front, media weather maps often include the jet stream's position as a rough indicator of warm and cold air masses.
meteorlogy • weather • jet stream • polar front • rossby waves
The polar front and its associated jet stream have a major influence on the weather conditions surrounding it. Many storms form along the polar front in the vicinity of the jet stream's maximum winds. Because the jet stream is associated with the polar front, media weather maps often include the jet stream's position as a rough indicator of warm and cold air masses.
meteorlogy • weather • jet stream • polar front • rossby waves
Lake Breeze Weather
On late spring and summer days when the temperature soars, a special wind system may form along the coastline of the Great Lakes or other large lakes. It is known as the lake breeze, a similar condition to the sea breeze known along ocean shores.
weather • meteorology • great lakes • lake breeze • lake breeze thunderstorms
On late spring and summer days when the temperature soars, a special wind system may form along the coastline of the Great Lakes or other large lakes. It is known as the lake breeze, a similar condition to the sea breeze known along ocean shores.
weather • meteorology • great lakes • lake breeze • lake breeze thunderstorms
Neither Rain Nor Snow
Neither rain nor snow, nor freezing rain, for that matter. That is how one must often characterize winter precipitation. Rain and snow are just the most common members of the winter precipitation congregation, but not the only ones. Others include: ice pellets, snow grains, graupel, ice crystals and ice needles and also known by local names in different regions such as sleet, hail, soft hail, snow pellets and diamond dust.
weather • winter weather • meteorology • ice pellets • snow grains
Neither rain nor snow, nor freezing rain, for that matter. That is how one must often characterize winter precipitation. Rain and snow are just the most common members of the winter precipitation congregation, but not the only ones. Others include: ice pellets, snow grains, graupel, ice crystals and ice needles and also known by local names in different regions such as sleet, hail, soft hail, snow pellets and diamond dust.
weather • winter weather • meteorology • ice pellets • snow grains
Rainbows
Rainbows have been part of human mythology and culture for millennia and have fascinated scientists through the ages as well. From two simple ingredients water drops and light, we can form the beauty of a rainbow. Here's how.
weather • meteorology • rainbows
Rainbows have been part of human mythology and culture for millennia and have fascinated scientists through the ages as well. From two simple ingredients water drops and light, we can form the beauty of a rainbow. Here's how.
weather • meteorology • rainbows
Raindrop Shape: No More Tears
When we think about raindrops, we often have a fixed image of how they look,their shape as they fall. Literature, poetry and song are filled with allusions to raindrops as heaven/sky tears. In truth, raindrops are spherical in shape initially. Then, unless they are very small, they take on shapes looking more like falling hamburger buns.
weather • meteorology • rain • rain drops
When we think about raindrops, we often have a fixed image of how they look,their shape as they fall. Literature, poetry and song are filled with allusions to raindrops as heaven/sky tears. In truth, raindrops are spherical in shape initially. Then, unless they are very small, they take on shapes looking more like falling hamburger buns.
weather • meteorology • rain • rain drops
Sun Dog Days
Sun dogs or mock suns appear on either side of the solar disk as bright bursts of light formed when sunlight passes through ice crystals at the proper angle.
atmosphere • weather • halos • sun dogs • parhelia
Sun dogs or mock suns appear on either side of the solar disk as bright bursts of light formed when sunlight passes through ice crystals at the proper angle.
atmosphere • weather • halos • sun dogs • parhelia
The Highs and Lows of Weather: Part 1 - The High
Among the most commonly recognized weather features are the roaming regions of high and low pressure, designated by H and L on media weather maps, respectively.
weather • meteorology • high pressure • high pressure ridge • anticyclone
Among the most commonly recognized weather features are the roaming regions of high and low pressure, designated by H and L on media weather maps, respectively.
weather • meteorology • high pressure • high pressure ridge • anticyclone
The Highs and Lows of Weather: Part 2 -- The Low
Low pressure areas are the centers of interest in many weather situations for they are the storms that move across the continent.
weather • meteorology • low pressure • cyclones • lows
Low pressure areas are the centers of interest in many weather situations for they are the storms that move across the continent.
weather • meteorology • low pressure • cyclones • lows
The Highway Mirage
Driving down the highway on a recent hot day, I saw the pavement ahead of me appeared to be covered with water. I never ever reached that wet pavement because what I observed was a true <i>mirage</i> commonly known today as a <i>highway mirage</i>.
weather • mirage • inferior mirage • optics • optical phenomena
Driving down the highway on a recent hot day, I saw the pavement ahead of me appeared to be covered with water. I never ever reached that wet pavement because what I observed was a true <i>mirage</i> commonly known today as a <i>highway mirage</i>.
weather • mirage • inferior mirage • optics • optical phenomena
The Superior Mirage
We don't hear or know as much about the superior mirage, so many think it is a rare occurrence. However, one form is so common that most of us do not recognize it as a mirage. The superior mirage can make objects appear to be floating in the air or cause objects actually located below the horizon to appear above it.
weather • meteorology • mirages • superior mirage • arctic mirage
We don't hear or know as much about the superior mirage, so many think it is a rare occurrence. However, one form is so common that most of us do not recognize it as a mirage. The superior mirage can make objects appear to be floating in the air or cause objects actually located below the horizon to appear above it.
weather • meteorology • mirages • superior mirage • arctic mirage
Turning Lakes
We generally think of weather processes as occurring from the surface upward into the atmosphere, but weather has its influences downward into the soil and water bodies as well. Seasonal weather interactions play major roles in the processes and ecology of even the smallest freshwater lakes. One of the more important is the semi-annual turnover of a lake's water mass.
weather • meteorology • lakes • lake turnover • limnology
We generally think of weather processes as occurring from the surface upward into the atmosphere, but weather has its influences downward into the soil and water bodies as well. Seasonal weather interactions play major roles in the processes and ecology of even the smallest freshwater lakes. One of the more important is the semi-annual turnover of a lake's water mass.
weather • meteorology • lakes • lake turnover • limnology
Twinkle, Twinkle: September Skies and Starlight
The lower atmosphere, where we stand to view the stars, is mottled with pockets of varying density. When the local air density changes rapidly with time, the light ray's path also alters rapidly. This slight but perceptible refraction bends the path one way, one moment, slightly different the next. This constant, but random shifting results in the star's image jiving and jiggling, fading in and out, and even changing colours before our eyes. This stellar dancing is what we call "twinkling."
weather • atmosphere • stars • twinkle
The lower atmosphere, where we stand to view the stars, is mottled with pockets of varying density. When the local air density changes rapidly with time, the light ray's path also alters rapidly. This slight but perceptible refraction bends the path one way, one moment, slightly different the next. This constant, but random shifting results in the star's image jiving and jiggling, fading in and out, and even changing colours before our eyes. This stellar dancing is what we call "twinkling."
weather • atmosphere • stars • twinkle
Weather Bombs: Rapid Storm Development
Weather bombs or bomb cyclones undergo explosive changes in intensity,forming an intense winter storm over a short period when they moved off the land and into the warm Gulf Stream waters off Cape Hatteras. These storms may move up the East Coast to form major snowstorms along their path.
meteorology • weather • winter storms • bomb cyclones • weather bombs
Weather bombs or bomb cyclones undergo explosive changes in intensity,forming an intense winter storm over a short period when they moved off the land and into the warm Gulf Stream waters off Cape Hatteras. These storms may move up the East Coast to form major snowstorms along their path.
meteorology • weather • winter storms • bomb cyclones • weather bombs
Why Is It Coldest After Dawn?
A common adage expresses the belief that it is coldest just before dawn and begins to warm with the appearance of dawn's first light, but observations and physical theory show us that the coldest hour of the day is not before dawn but often an hour or so after sunrise. Why is this so?
meteorology • weather • science of the sky • coldest before dawn • morning temperature
A common adage expresses the belief that it is coldest just before dawn and begins to warm with the appearance of dawn's first light, but observations and physical theory show us that the coldest hour of the day is not before dawn but often an hour or so after sunrise. Why is this so?
meteorology • weather • science of the sky • coldest before dawn • morning temperature
A Study in Opposites: Thundersnow
For most North Americans, the combination, known as 'thundersnow', is a very unusual event. Even where they are most common, thundersnow occurs no more than a few times per year, usually when winter storms with substantial warm and humid air sectors spawn thunderstorms along their fronts, or when air crosses a large lake or rises over a mountain range.
weather • meteorology • snow • thundersnow • thunderstorm
For most North Americans, the combination, known as 'thundersnow', is a very unusual event. Even where they are most common, thundersnow occurs no more than a few times per year, usually when winter storms with substantial warm and humid air sectors spawn thunderstorms along their fronts, or when air crosses a large lake or rises over a mountain range.
weather • meteorology • snow • thundersnow • thunderstorm
Air Masses - From The Source
Last month, we defined what air masses were and looked at some of their basic properties. Those distinguishing properties derive from the birthplace of the individual air mass, the geographical region where they form.
weather • meteorology • air masses • air mass breeding grounds • climate
Last month, we defined what air masses were and looked at some of their basic properties. Those distinguishing properties derive from the birthplace of the individual air mass, the geographical region where they form.
weather • meteorology • air masses • air mass breeding grounds • climate
Blue Jets, Red Sprites and Elves
Blue jets, red sprites, elves, sprite halos and trolls may sound like Tolkein characters, but these high-altitude entities comprise the newest members in the pantheon of atmospheric electrical phenomena, joining lightning and St Elmo's Fire.
weather • meteorology • blue jets • red sprites • atmospheric electricity
Blue jets, red sprites, elves, sprite halos and trolls may sound like Tolkein characters, but these high-altitude entities comprise the newest members in the pantheon of atmospheric electrical phenomena, joining lightning and St Elmo's Fire.
weather • meteorology • blue jets • red sprites • atmospheric electricity
Frost flowers
Nature journal for January. The temperature plummets. Fantastic ice crystals form on the windows and along the verge of the river.
frost flowers • ice crystals
Nature journal for January. The temperature plummets. Fantastic ice crystals form on the windows and along the verge of the river.
frost flowers • ice crystals
Nor'easters and Alberta Clippers
The great tropical storms roaming the world's oceans and seas have earned the right for individual names. Extratropical cyclonic storms, those forming from the clash of polar and tropical air masses, have not yet been honoured with individual names. However, some extratropical storms take on such unique characteristics that they are often recognized with a unique name for the genre: the Nor'easter along the Atlantic coast, the Alberta Clipper that races across the continent our of the Alberta plains.
weather • meteorology • storms • alberta clipper • nor'easters
The great tropical storms roaming the world's oceans and seas have earned the right for individual names. Extratropical cyclonic storms, those forming from the clash of polar and tropical air masses, have not yet been honoured with individual names. However, some extratropical storms take on such unique characteristics that they are often recognized with a unique name for the genre: the Nor'easter along the Atlantic coast, the Alberta Clipper that races across the continent our of the Alberta plains.
weather • meteorology • storms • alberta clipper • nor'easters
Snowflakes
We think snowflakes, or more correctly snow crystals, are six-sided, frilly stars and are fairly flat like a pizza. Snow-crystal structure, however, takes on many forms from flat hexagonal plates to three-dimensional small hexagonal pillars with hexagonal plates lying on each end.
weather • meteorology • snow • snowflake • ice crystal
We think snowflakes, or more correctly snow crystals, are six-sided, frilly stars and are fairly flat like a pizza. Snow-crystal structure, however, takes on many forms from flat hexagonal plates to three-dimensional small hexagonal pillars with hexagonal plates lying on each end.
weather • meteorology • snow • snowflake • ice crystal
The Chinook
They flow off the mountain ridges, rushing winds that are very hot and very dry. Along the eastern slope of the Rocky Mountains, they have been called "Snow Eaters" but today are more commonly known by their native American name: Chinook.
weather • meteorology • winds • chinook • fohn
They flow off the mountain ridges, rushing winds that are very hot and very dry. Along the eastern slope of the Rocky Mountains, they have been called "Snow Eaters" but today are more commonly known by their native American name: Chinook.
weather • meteorology • winds • chinook • fohn
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