Archive For The “Hurricane Season Facts” Category

2017 Atlantic Hurricane Season Predictions

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The 2017 Atlantic Ocean hurricane season could have an above-normal number of hurricanes this year. The Climate Prediction Center at NOAA predicts a 70% likelihood of 5 to 9 hurricanes with 2 to 4 of them being major hurricanes (Category 3, 4 or 5).

2017 Hurricane Season Outlook

Strong wind shear reduces the development of the number and strength of tropical storms that grow into hurricanes, whereas weak wind shear increases hurricane development. There is a significantly reduced upper atmosphere wind shear predicted for the 2017, which points to more numerous and stronger hurricanes this season.

2017 Atlantic Tropical Storm / Cyclone Names

Arlene: Tropical Storm off Newfoundland (April 19 – April 21)
Bret: Tropical Storm from Mid-Atlantic Ocean to Venezuela (June 19 – June 20)
Cindy: Tropical Storm from Honduras to Louisiana (June 20 – June 23)
Don: Tropical Storm off Venezuela (July 17 – July 19)
Emily: Tropical Storm passed through Florida (July 31)
Franklin: Category 1 Hurricane passed through Southern Mexico (August 6-10)
Gert: Tropical Storm off Bahamas (August 13)
Harvey: Tropical Storm passes through Caribbean and Central America. Category 4 hurricane hits Texas (August 18-26)
Irma: Category 5 hurricane in Caribbean (August 31 – September 8)
Jose: Tropical Storm in Eastern Atlantic (September 5)

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Hurricane Hermine (2016) First Florida Landfall Since 2005

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Hurricane Wilma Florida Landfall 2016Hurricane Hermine made landfall just east of St Marks near Tallahassee Florida on September 2, 2016. Maximum sustained winds were near 80 mph, which would make it a Category 1 Huuricane. Hermine brought devestating winds to the Big Bend of Florida area which resulted in extensive downed trees and power lines causing significant power outages lasting for days. Hurricane Wilma was the last hurricane to hit Florida, which was in 2005.

Hurricane Hermine Damage in Florida

Insured losses to property damage in Florida by Hurricane Hermine reached US$80 million with 14,890 claims. Preliminary assessments indicated hurricane related damage in excess of US$300 million. Ahead of the hurricane’s landfall, a station south of Apalachicola reported wind gusts of 79 mph (127 km/h) at an elevation of 115 ft (35 m). At sea level, sustained winds reached 52 mph (84 km/h) at Keaton Beach, with gusts 67 mph (108 km/h). While moving ashore, Hurricane Hermine produced a 5.8 ft (1.8 m) storm surge at Cedar Key. Heavy rainfall occurred across western Florida, reaching 22.36 in (568 mm) over 72 hours at the Lake Tarpon Canal in Pinellas County. The outer rainbands of Hurricane Hermine spawned an EF0 tornado just southwest of Windermere with a width of 450 ft (140 m) and 80 to 85 mph (129 to 137 km/h) winds. On the ground for 1.2 mi (1.9 km), the twister damaged about 100 trees, along with several fences and windows.

High winds from the hurricane knocked down many trees in northwestern Florida, some of which fell onto power lines and roofs. The resulting power outages affected about 325,000 people, affecting 1% of all homes and businesses in the state. In Leon County, where the state capital Tallahassee is, 57% of homes lost power, including approximately 80% of the city proper, as well as Florida State University. Strong winds in the Tallahassee area caused trees to fall onto several houses, injuring a number of people. Hermine was the first hurricane to affect the city since Hurricane Kate in 1985.

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List of Florida Islands by County

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Broward County

Hillsboro Island

Collier County

Airplane Island
Albert Island
Alpha Key
Bear Island
Bear Island
Beta Key
Big Corkscrew Island
Big Key
Big Morgan Island
Brush Island
Buttonwood Island
Camp Key
Camp Lulu Key
Cannon Island
Cape Romano Island
Carr Island
Catherine Island
Charity Island
Charlie Fewl Hammock
Chokoloskee Island
Cochran Island
Coconut Island
Coon Key
Corn Dance Hammock
Curry Island
Currys Island
David Key
Dickmans Island
Eagle Island
East Hinson Island
East Morgan Key
Flinthead Island
Forth Island
Foster Key
Four Brothers Key
Fred Key
Gullivan Key
Halloway Island
Helen Key
Henry Key
Hog Island
Hog Key
Hogan Island
Horrs Island
Indian Key
Jackfish Island
Jenkins Key
Johnson Island
Keewaydin Island
Kice Island
Little Corkscrew Island
Little Marco Island
Little Tide Key
Lone Chicken Island
Marco Island
Margaret Key
Morgan Island
Morgan Key
Munlin Island
Neal Key
Owl Hammock
Panther Island
Panther Key
Pass Key
Picnic Island
Picnic Key
Pig Key
Platt Island
Pretty Island
Railroad Islet
Ramsey Key
Rattlesnake Hammock
Rock Spring Island
Rookery Island
Rosse Key
Round Key
Rousse Key
Royal Palm Hammock
Ruess Island
Russell Key
Sandfly Island
Sea Oat Island
Shell Island
Shell Key
Sick Island
Smallwood Island
Stingaree Island
Stop Keys
Ten Thousand Islands
The Woods
Thompson Pine Island
Threemile Island
Tiger Key
Tripod Key
Turtle Island
Turtle Key
Twin Palms Island
Umbrella Island
West Morgan Key
White Horse Key
Wiggins Island

Miami-Dade County

Arsenicker Key
Key Biscayne

Monroe County

Archer Key
Ballast Key
Barracouta Key
Big Coppitt Key
Big Mullet Key
Big Pine Key
Big Torch Key
Boca Chica Key
Boca Grande Key
Boot Key
Conch Key
Cottrell Key
Craig Key
Crawfish Key
Crawl Key
Cudjoe Key
Duck Key
East Rockland Key
Fat Deer Key
Fiesta Key
Geiger Key
Grassy Key
Indian Key Historic State Park
Joe Ingram Key
Key Largo
Key West
Knights Key
Knockemdown Key
Lignumvitae Key
Little Conch Key
Little Mullet Key
Little Torch Key
Lois Key
Long Key
Long Point Key
Lower Matecumbe Key
Lower Sugarloaf Key
Man Key
Middle Torch Key
Molasses Keys
Mule Key
Mule Keys
No Name Key
Ohio Key
Palm Key
Pigeon Key
Plantation Key
Ramrod Key
Rockland Key
Saddlebunch Keys
Shark Key
Sigsbee Park
Stock Island
Sugarloaf Key
Summerland Key
Sunset Key
Tea Table Key
Upper Matecumbe Key
Upper Sugarloaf Key
Vaca Key
Windley Key
Woman Key

Palm Beach County

Bingham Island
Everglades Island
Fisherman Island
Halifax Banks Island
Hunters Island
Hypoluxo Island
Ibis Isle
Kreamer Island
Little Munyon Island
Munyon Island
Padgett Island
Peanut Island
Pelican Island
Ritta Island
Singer Island
Tarpon Island
Torry Island

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Path of Hurricane Arthur 2014

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Path Hurricane Arthur 2014

Path Hurricane Arthur 2014 in Canada

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Path of Tropical Storm Bertha 2014

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Path of Tropical Storm Bertha 2014

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Important Math, Chemistry and Physics Equations

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Algebra Equations

(ax)^y (ax)^z = (ax)^(y+z) = a^(y+z)x^(y+z)

Geometry Equations

Circumference(circle) = 2pi x radius
Volume (rectangular prism) = Length x Width x Height
Quadratic Formula (ax^2 + bx + c = 0) -> [-b +- sqrt(b^2 – 4ac)]/2a = x

Trigonometry Equations

tan(θ) = sin(θ)/cos(θ)
csc(θ) = 1/sin(θ)
sec(θ) = 1/cos(θ)
cot(θ) = 1/tan(θ)
Law of Sines -> Sin(A)/a = Sin(B)/b
sin^2(x) + cos^2(x) = 1
cos(2x) = cos^2(x) – sin^2(x) = 2 cos^2(x) – 1 = 1 – 2 sin^2(x)

Calculus Equations

Determine Arc Length:

Chemistry Equations

Ideal Gas Law (PV = nRT)
Pressure x Volume = Moles x Constant (0.08205746 L atm K−1 mol−1) x Temperature

Physics Equations

Potential Energy (height) = mass x gravity (9.8 m/s^2) x height
Kinetic Energy = 1/2 mass x velocity^2 = 1/2 inertia x rotational velocity^2
Angular Velocity (w) = Angle (theta) / time = linear velocity / radius

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Different Cloud Types and Precipitation

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Common Cloud Classifications

Clouds are classified into a system that uses Latin words to describe the appearance of clouds as seen by an observer on the ground.

cirrus – thin wispy high level clouds
stratus – thicker layer of clouds
cumulus – vertically developed clouds
nimbus – raining clouds

Further classification identifies clouds by height of cloud base. For example, cloud names containing the prefix “cirr-“, as in cirrus clouds, are located at high levels while cloud names with the prefix “alto-“, as in altostratus, are found at middle levels. This module introduces several cloud groups. The first three groups are identified based upon their height above the ground. The fourth group consists of vertically developed clouds, while the final group consists of a collection of miscellaneous cloud types.

High-Level Clouds

High-level clouds form above 20,000 feet (6,000 meters) and since the temperatures are so cold at such high elevations, these clouds are primarily composed of ice crystals. High-level clouds are typically thin and white in appearance, but can appear in a magnificent array of colors when the sun is low on the horizon. Cloud types include cirrus and cirrostratus.

Mid-Level Clouds

The bases of mid-level clouds typically appear between 6,500 to 20,000 feet (2,000 to 6,000 meters). Because of their lower altitudes, they are composed primarily of water droplets, however, they can also be composed of ice crystals when temperatures are cold enough. Cloud types include altocumulus and altostratus.

Low-level Clouds

Low clouds are of mostly composed of water droplets since their bases generally lie below 6,500 feet (2,000 meters). However, when temperatures are cold enough, these clouds may also contain ice particles and snow. Cloud types include nimbostratus and stratocumulus.

Vertically Developed Clouds

Probably the most familiar of the classified clouds is the cumulus cloud. Generated most commonly through either thermal convection or frontal lifting, these clouds can grow to heights in excess of 39,000 feet (12,000 meters), releasing incredible amounts of energy through the condensation of water vapor within the cloud itself. Cloud types include cumulus and cumulonimbus.

Other Cloud Types

Cloud types include contrails, billow clouds, mammatus, orographic and pileus clouds.

A contrail, also known as a condensation trail, is a cirrus-like trail of condensed water vapor often resembling the tail of a kite. Contrails are produced at high altitudes where extremely cold temperatures freeze water droplets in a matter of seconds before they can evaporate. Contrails form through the injection of water vapor into the atmosphere by exhaust fumes from a jet engine. If the surrounding air is cold enough, a state of saturation is attained and ice crystals develop, producing a contrail.

Billow clouds are created from instability associated with air flows having marked vertical shear and weak thermal stratification. The name for this instability is Kelvin-Helmholtz instability. These instabilities are often visualized as a row of horizontal eddies aligned within this layer of vertical shear.

Mammatus are pouch-like cloud structures and a rare example of clouds in sinking air. Sometimes very ominous in appearance, mammatus clouds are harmless. Mammatus are usually seen after the worst of a thunderstorm has passed.

Orographic clouds are clouds that develop in response to the forced lifting of air by the earth’s topography (mountains for example).

Pileus (Latin for “skullcap”) is a smooth cloud found attached to either a mountain top or growing cumulus tower.

Types of Precipitation

When cloud particles become too heavy to remain suspended in the air, they fall to the earth as precipitation. Precipitation occurs in a variety of forms: hail, rain, freezing rain, sleet or snow.

Rain and Hail

Rain develops when growing cloud droplets become too heavy to remain in the cloud and as a result, fall toward the surface as rain. Rain can also begin as ice crystals that collect each other to form large snowflakes. As the falling snow passes through the freezing level into warmer air, the flakes melt and collapse into rain drops.

Hail is a large frozen raindrop produced by intense thunderstorms, where snow and rain can coexist in the central updraft. As the snowflakes fall, liquid water freezes onto them forming ice pellets that will continue to grow as more and more droplets are accumulated. Upon reaching the bottom of the cloud, some of the ice pellets are carried by the updraft back up to the top of the storm. As the ice pellets once again fall through the cloud, another layer of ice is added and the hail stone grows even larger. Typically the stronger the updraft, the more times a hail stone repeats this cycle and consequently, the larger it grows. Once the hail stone becomes too heavy to be supported by the updraft, it falls out of the cloud toward the surface. The hail stone reaches the ground as ice since it is not in the warm air below the thunderstorm long enough to melt before reaching the ground.

Freezing Rain

Ice storms can be the most devastating of winter weather phenomena and are often the cause of automobile accidents, power outages and personal injury. Ice storms result from the accumulation of freezing rain, which is rain that becomes supercooled and freezes upon impact with cold surfaces. Freezing rain is most commonly found in a narrow band on the cold side of a warm front, where surface temperatures are at or just below freezing.

Freezing rain develops as falling snow encounters a layer of warm air deep enough for the snow to completely melt and become rain. As the rain continues to fall, it passes through a thin layer of cold air just above the surface and cools to a temperature below freezing. However, the drops themselves do not freeze, a phenomena called supercooling (or forming “supercooled drops”). When the supercooled drops strike the frozen ground (power lines, or tree branches), they instantly freeze, forming a thin film of ice, hence freezing rain.


Progressing further ahead of the warm front, surface temperatures continue to decrease and the freezing rain eventually changes over to sleet. Areas of sleet are located on the colder side of the freezing rain band. Sleet is less prevalent than freezing rain and is defined as frozen raindrops that bounce on impact with the ground or other objects.

Sleet is more difficult to forecast than freezing rain because it develops under more specialized atmospheric conditions. It is very similar to freezing rain in that it causes surfaces to become very slick, but is different because its easily visible.


Progressing even further away from the warm front, surface temperatures continue to decrease and the sleet changes over to snow. Snowflakes are simply aggregates of ice crystals that collect to each other as they fall toward the surface. Since the snowflakes do not pass through a layer of air warm enough to cause them to melt, they remain in tact and reach the ground as snow.

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Air Masses, Warm and Cold Fronts

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Air Masses

Global Air MassesAn air mass is a large body of air that has relatively uniform temperature and humidity. The regions where air masses form are referred to as air mass source regions. If air remains over a source region long enough, it will acquire the properties of the surface below. Ideal source regions are regions that are generally flat and of uniform composition. Examples include central Canada, Siberia, oceans and large deserts.

Air Mass Classification

Air masses are classified according to their temperature and moisture characteristics. They are grouped into four categories based on their source region. Air masses that originate in the cold, polar regions are designated with a capital “P” for polar. Air masses that originate in the warm, tropical regions are designated with a capital “T” for tropical. Air masses that originate in the arctic region are designated with a capital “A” for arctic. Air masses that originate over land will be dry and are designated with a lowercase “c” for continental. Air masses that originate over water will be moist and are designated with a lowercase “m” for maritime.

These letters are combined to indicate the type of air mass:
cP: cold, dry air mass – continental Polar
mP: cold, moist air mass – maritime Polar
cT: warm, dry air mass – continental Tropical
mT: warm, moist air mass – maritime Tropical
cA: extremely cold, extremely dry air mass – continental Arctic

Once formed, air masses can move out of their source regions bringing cold, warm, wet, or dry conditions to other parts of the world.

Warm and Cold Fronts

Warm, Cold Fronts, Low Pressure SystemA front is simply the boundary between two air masses. Fronts are classified by which type of air mass (cold or warm) is replacing the other.

Cold Fronts

A front is called a cold front if the cold air mass is replacing the warm air mass. The air behind a cold front is colder and typically drier than the air ahead of it, which is generally warm and moist.
There is typically a shift in wind direction as the front passes, along with a change in pressure (pressure falls prior to the front arriving and rises after it passes). Cold fronts have a steep slope, which causes air to be forced upward along its leading edge. This is why there is sometimes a band of showers and/or thunderstorms that line up along the leading edge of the cold front. Cold fronts are represented on a weather map by a solid blue line with triangles pointing in the direction of its movement.

Warm Fronts

A warm front occurs when a cold air mass is receding (i.e. a warm air mass is replacing a cold air mass). The air behind a warm front is warm and moist, while the air ahead of a warm front is cooler and less moist. Similar to the cold front, there will a shift in wind direction as the front passes and a change in pressure. Warm fronts have a more gentle slope than cold fronts, which often leads to a gradual rise of air. This gradual rise of air favors the development of widespread, continuous precipitation, which often occurs along and ahead of the front. Warm fronts are represented on a weather map by a solid red line with semi-circles pointing in the direction of its movement.

Stationary Fronts

A stationary front is a front that is not moving. Although the frontal boundary does not move, the air masses may move parallel to the boundary. Stationary fronts can also produce significant weather and are often tied to flooding events. Stationary fronts are represented on a weather map by alternating red and blue lines, with blue triangles and red semi-circles facing opposite directions.

Occluded Fronts

Generally, cold fronts move faster than warm fronts. Sometimes in a storm system the cold front will “catch up” to the warm front. An occluded front forms as the cold air behind the cold front meets the cold air ahead of the warm front. Which ever air mass is the coldest undercuts the other. The boundary between the two cold air masses is called an occluded front. Occluded fronts are represented on weather maps by a solid purple line with alternating triangles and semi-circles, pointing in the direction of its movement.

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Hurricane Season Facts Content

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Hurricane & Storm Preparedness

Hurricane Preparedness mp3 by CDC
Hurricane Emergency Preparedness and Response: CDC
Miami-Dade County Hurricane Emergency and Evacuation Plan
Broward County Hurricane Preparedness Guide and Emergency Shelter Map

Atlantic Hurricanes Predictions, History and Information

2014 Atlantic Hurricane Season Predictions
Pacific Typhoon and Atlantic Hurricane Names 2014
Category 5 Atlantic Hurricanes List
Top 10 Seasons with the Most Hurricanes

Hurricane Science, Meteorology

Sunspot Activity, Sunspots Cycle Definition
What is Atmospheric Pressure
What is Coriolis Effect, Force
How Hurricanes Form, What Causes, Hurricane Models
Air Masses, Warm and Cold Fronts
Different Cloud Types and Precipitation

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2014 Atlantic Hurricane Season Predictions

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Global Weather Oscillations Inc. (GWO), a leading hurricane and climate prediction company with the best predictions record in the last 5 Years and the only organization that was correct in predicting the weak 2013 season, recently issued its hurricane predictions for the 2014 through 2017 Atlantic hurricane seasons. The 2014 Atlantic basin hurricane season will be stronger and more dangerous than last year (2013) with 17 named storms, 8 hurricanes and 3 major hurricanes (Category 3, 4 or 5). An average Atlantic hurricane season has 12 named storms, 6 hurricanes and 3 major hurricanes.

Upper atmospheric wind shear coupled with sand blowing off Africa and over the eastern Atlantic Ocean stifled developing tropical systems similar to an El Niño, and was one of the key reasons for the 2013 Atlantic hurricane season being the third weakest hurricane season since 1956.

Research over the past 25 years has found that each of the Atlantic and Gulf coastal zones have varying weather cycles, and within each cycle, there exists smaller weather cycles which make each zone unique. Once all of the cycles are discovered, GWO then uses the Climate Pulse Technology to accurately assess the intensity of a future hurricane season, and the probability risk for hurricane or tropical storm conditions within a prediction zone for that year.

GWO makes specific predictions for 11 US coastal zones from New England to Texas. Prediction Zones assigned a high probability risk for a hurricane are termed “Hot Spots” for that year. GWO’s hot spot predictions for the United States have been nearly 90% accurate since 2006, and instrumental for long-range planning by insurance companies and other organizations.

GWO’s recent CPT model successes include the very weak 2013 hurricane season, hot spot zone predictions of Hurricane Ike (2008), Irene (2011), and Sandy (2012). The prediction of Sandy, a high-impact hybrid storm was made 3 years in advance, and Irene 2 years in advance. The last major hurricane to strike the US was in 2005 (Wilma), but that could change in 2014.

David Dilley, a former NOAA meteorologist formed Global Weather Oscillations Inc. (GWO) in 1992 with the specific understanding that weather and climate occurs in cycles. While mankind is playing some role in climate change, David Dilley believes most climate changes are primarily attributable to weather cycles. He disputes the notion that hurricanes occur randomly and are impossible to predict. He states “There are no random hurricanes, everything occurs in cycles.”

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Sunspot Activity, Sunspots Cycle Definition

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Sunspots ActivitySunspots are regions on the solar surface that appear dark because they are cooler than the surrounding photosphere, typically by about 1500 K (thus, they are still at a temperature of about 4500 K, but this is cool compared to the rest of the photosphere). They are only dark in a relative sense; a sunspot removed from the bright background of the Sun would glow quite brightly.

Basic Features of Sunspots

The largest sunspots observed have had diameters of about 50,000 km, which makes them large enough to be seen with the naked eye. Sunspots often come in groups with as many as 100 in a group, though sunspot groups with more than about 10 are relatively rare. There are well established methods for measuring the number of sunspots. Sunspots develop and persist for periods ranging from hours to months, and are carried around the surface of the Sun by its rotation (a fact known to Galileo). A typical sunspot consists of a dark central region called the umbra and somewhat lighter surrounding region called the penumbra.

Solar Rotational Period

Historically, the first measurements of the period for solar rotation were made by tracking sunspots as they appeared to move around the Sun. Galileo used this method to deduce that the Sun had a rotational period of about a month. Because the Sun is not a solid body, it does not have a well defined rotational period. Modern measurements indicate that the rotational period of the Sun is about 25 days near its equator, 28 days at 40 degrees latitude, and 36 days near the poles. The rotation is direct, that is, in the same sense of the motion of the planets around the Sun. Sunspots have been monitored since the time of Galileo. One striking feature that emerges from the long-term data is that the number of sunspots observed in a given year varies in a dramatic and highly predictable way.

11-Year Sunspot Cycle

If one plots the total number of sunspots observed in a year as a function of the year, there is a striking variation in the number of sunspots that is cyclic, with a period of approximately 11 years. This 11 year periodicity is called the sunspot cycle. The last solar maximums (period of maximum sunspot activity) were in the years 2000 and 2012. The last solar minimum was 2009.

The Active and Quiet Sun

Sunspot maxima correspond generally to periods of high solar activity. This activity includes increased solar wind and phenomena like aurorae and magnetic storms that are correlated with the solar wind, increased flares, and increased non-thermal radio and X-ray emission. Conversely, near sunspot minima the Sun is much quieter with respect to these phenomena. In addition, as we have seen there are significant differences in the nature of the corona during periods of active and quiet Suns.

Hurricanes and Sunspot Activity

A recent study suggests that hurricane intensity may be linked to the number of sunspots on the Sun. A decrease in the number of sunspots may be related to an increase in hurricane intensity. After examining the past 100 year hurricane records of the United States and Caribbean, James Elsner and Thomas Jagger of Florida State University in Tallahassee conclude that their intensity may be linked to 10 to 12 year solar magnetic activity cycles. Data from the National Hurricane Center, Miami, Florida, was used in the study. Sunspots are areas on the Sun with increased magnetic activity. The number of sunspots vary during the solar cycles. Increased solar activity will allow more ultraviolet rays to reach Earth, resulting in warming of the relatively colder upper atmosphere. Decreased solar activity reverses this phenomenon. It is believed that the greater the temperature difference between upper and lower atmospheric regions, the higher the hurricane intensity. Establishing a link between sunspots and hurricane intensity can provide a valuable tool for predicting storms. Other scientists however question the statistical basis of the study and the physical processes attributed to changes in hurricane activity.

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What is Atmospheric Pressure

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Atmospheric Pressure

Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of Earth (or that of another planet). In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. On a given plane, low-pressure areas have less atmospheric mass above their location, whereas high-pressure areas have more atmospheric mass above their location. Likewise, as elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation. On average, a column of air one square centimeter in cross-section, measured from sea level to the top of the atmosphere, has a mass of about 1.03 kg and weight of about 10.1 N (A column one square inch in cross-section would have a weight of about 14.7 lbs, or about 65.4 N).

Standard Atmospheric Pressure

The standard atmosphere (symbol: atm) is a unit of pressure equal to 101325 Pa or 1013.25 millibars. It is equivalent to 760 mmHg (torr) or 14.696 psi.

Mean Sea Level Pressure

The mean sea level pressure (MSLP) is the atmospheric pressure at sea level. This is the atmospheric pressure normally given in weather reports on radio, television, and newspapers or on the Internet. When barometers in the home are set to match the local weather reports, they measure pressure reduced to sea level, not the actual local atmospheric pressure. The reduction to sea level means that the normal range of fluctuations in atmospheric pressure is the same for everyone. The pressures that are considered high pressure or low pressure do not depend on geographical location. This makes isobars on a weather map meaningful and useful tools. The altimeter setting in aviation, set either QNH or QFE, is another atmospheric pressure reduced to sea level, but the method of making this reduction differs slightly.


The barometric altimeter setting that will cause the altimeter to read airfield elevation when on the airfield. In ISA temperature conditions the altimeter will read altitude above mean sea level in the vicinity of the airfield.


The barometric altimeter setting that will cause an altimeter to read zero when at the reference datum of a particular airfield (in general, a runway threshold). In ISA temperature conditions the altimeter will read height above the datum in the vicinity of the airfield.

QFE and QNH are arbitrary Q codes rather than abbreviations, but the mnemonics “Nautical Height” (for QNH) and “Field Elevation” (for QFE) are often used by pilots to distinguish them. Average sea-level pressure is 101.325 kPa (1013.25 mbar) or 760 millimetres of mercury (mmHg). In aviation weather reports (METAR), QNH is transmitted around the world in millibars, except in the United States, Canada, and Colombia where it is reported in inches (to two decimal places) of mercury. However, in Canada’s public weather reports, sea level pressure is reported in kilopascals. The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1050.0 mbar (105.00 kPa), with record highs close to 1085.0 mbar (108.50 kPa). The lowest measurable sea-level pressure is found at the centers of tropical cyclones and tornadoes, with a record low of 870 mbar (87 kPa).

Atmospheric Pressure Records

The highest adjusted-to-sea level barometric pressure ever recorded on Earth (above 750 meters) was 1,085.7 hectopascals (32.06 inHg) measured in Tosontsengel, Mongolia on December 19, 2001. The highest adjusted-to-sea level barometric pressure ever recorded (below 750 meters) was at Agata, Evenhiyskiy, Russia on December 31, 1968, of 1,083.3 hectopascals (31.99 inHg). The lowest non-tornadic atmospheric pressure ever measured was 870 hPa (25.69 inHg), set on October 12, 1979, during Typhoon Tip in the western Pacific Ocean. The measurement was based on an instrumental observation made from a reconnaissance aircraft. The normal high barometric pressure at the Dead Sea (lowest terrestrial point below sea level), as measured by a standard mercury manometer and blood gas analyzer, was found to be 799 mmHg (1065 hPa).

Boiling Point of Water

Clean fresh water boils at about 100 °C (212 °F) at earth’s standard atmospheric pressure. The boiling point is the temperature at which the vapor pressure is equal to the atmospheric pressure around the water. Because of this, the boiling point of water is lower at lower pressure and higher at higher pressure. This is why cooking at elevations more than 1,100 m (3,600 ft) above sea level requires adjustments to recipes. A rough approximation of elevation can be obtained by measuring the temperature at which water boils.

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What is Coriolis Effect, Force

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What is the Coriolis Effect

Coriolis EffectIn physics, the Coriolis effect is a deflection of moving objects when they are viewed in a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the left of the motion of the object; in one with counter-clockwise rotation, the deflection is to the right. The Coriolis effect is caused by the rotation of the Earth and the inertia of the mass experiencing the effect. Because the Earth completes only one rotation per day, the Coriolis force is quite small, and its effects generally become noticeable only for motions occurring over large distances and long periods of time, such as large-scale movement of air in the atmosphere or water in the ocean. Such motions are constrained by the surface of the earth, so only the horizontal component of the Coriolis effect is generally important. Rather than flowing directly from areas of high pressure to low pressure, as they would in a non-rotating system, winds and currents tend to flow to the right of this direction north of the equator and to the left of this direction south of it. This effect is responsible for the rotation of large cyclones.

What is the Coriolis Force

Coriolis Force Pressure GradientThe mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology. Sir Isaac Newton’s laws of motion describe the motion of an object in a (non-accelerating) inertial frame of reference. When Newton’s laws are transformed to a uniformly rotating frame of reference, the Coriolis force and centrifugal force appear. Both forces are proportional to the mass of the object. The Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to its square. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object’s speed in the rotating frame. The centrifugal force acts outwards in the radial direction and is proportional to the distance of the body from the axis of the rotating frame. These additional forces are termed inertial forces. They allow the application of Newton’s laws to a rotating system.

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Hurricane Preparedness mp3 by CDC

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Preparing for Hurricane Season

-> Preparing for Hurricane Season – mp3 by CDC

Hurricanes are one of Mother Nature’s most powerful forces. Host Bret Atkins talks with CDC’s National Center for Environmental Health Director Dr. Chris Portier about the main threats of a hurricane and how you can prepare. Created: 9/24/2012 by Office of Public Health Preparedness and Response (OPHPR), National Center for Environmental Health (NCEH), and the Agency for Toxic Substances and Disease Registry (ATSDR). Date Released: 9/24/2012. Series Name: CDC Emergency Preparedness and You.

Evacuating the Area of a Hurricane

-> Evacuating the Area of a Hurricane – mp3 by CDC

General instructions related to evacuation. Created: 10/25/2009 by Centers for Disease Control and Prevention (CDC). Date Released: 10/25/2009. Series Name: CDC Radio.

Staying Safe in Your Home During a Hurricane

-> Staying Safe in Your Home During a Hurricane – mp3 by CDC

How to stay safe in your home during a hurricane. Created: 10/25/2009 by Centers for Disease Control and Prevention (CDC). Date Released: 10/25/2009. Series Name: CDC Radio.

Preparing for Hurricanes – Prescription Medications

-> Preparing for Hurricanes – Prescription Medications – mp3 by CDC

Reminder to take prescription medicines when evacuating. Created: 10/25/2009 by Centers for Disease Control and Prevention (CDC). Date Released: 10/25/2009. Series Name: CDC Radio.

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