Tuesday, July 22, 2014

Tropical Depression Two - May Become Hurricane Bertha

A storm is forming in the North Atlantic, known as Tropical Depression Two, moving to the west at 16 MPH. It is presently a tropical depression, with winds of 35 MPH. Its path should take it to Puerto Rico on Thursday into Friday and into the Dominican Republic. If it continues on its present course, it will pass over Cuba, then enter the Gulf of Mexico. It can affect either Texas or Louisiana if it continues on its present course. This may be the first storm that may impact the mainland of the United States this hurricane season. As this storm moves forward, its progress will be reported here. If it turns into a hurricane, it will become Hurricane Bertha. 

Tropical Typhoon Matmo Nears Taiwan

Tropical Typhoon Matmo, located in the Western Pacific has cleared the Northern Territory of Luzon of the Philippines, and is now continuing on a northwestern course to directly hit Taiwan. ..... It then will continue in a Northwestern direction to arrive on mainland China directly centered on Tannan and Haitan Bays. The typhoon is expected to rapidly loose strength as it passes over Taiwan because of the very mountainous terrain that makes up the island nation. There are currently 197 mountains making up the island country, more than any other country in the world. If there were any landmass that could really damper the forward direction and strength of a storm, it would be Taiwan.  Taiwan is definitely the buffer that protects mainland China.
Mountains clearly visible in the screenshot above
Once on the mainland of China on its present course, it will pass over Changle and the main city of Fuzhou. It is expected to turn to the north and pass just directly east of Shangrao, pass through Huangshan and Xuancheng, weakening on the way into a tropical storm, still dumping inches of rain on the affected areas. As it turns to the northeast, it is expected to head out to the East China Sea. If the storm reaches the sea, speculation has it that it will be so weakened at that point that it will just completely fall apart. But there is still a chance that it can gather strength if it makes it out to the East China Sea. As Typhoon Matmo passed the Philippines, it traveled through very warm waters of approximately 85 degrees Fahrenheit which fueled the storm. The waters may be a little cooler as it enters the East China Sea. If the typhoon gains strength and stays on course, it most likely will come ashore possibly at North or South Korea. If it continues more to the east, it is possible that the storm will affect the country of Japan from the southwest, but this is highly unlikely. 
The storm is now a Category 1 typhoon as it heads towards Taiwan, the 50th largest country in the world. The population of Taiwan over 23 million people as of 2012, but before the storm reaches Taiwan because of the high water temperatures, it is expected to gain strength as a category 2 storm prior to reaching Taiwan. It is the 16th most densely populated country in the world. Taipei City, which is the capital of Taiwan has a total population of over 7 million. After going through the mountainous terrain of Taiwan, it will pass over water again before reaching China, and then it may strengthen again, possibly entering China as a category 2 typhoon, but this gain of strength is not expected. It is just a possibility. 
This storm will clearly not be one of the strongest storms to affect the Philippines, Taiwan and China, but the 
rainfall that is expected from this storm will cause major flooding in areas that already are flooded from torrential rains. It is noted that this area of the oceans is now the warmest of waters in the oceans today. It is expected that continuing storms, turning into typhoons will continue to plague the nations in these waters for some time.

Friday, July 18, 2014

Typhoon Rammasun Enters China - Category 4 - New Storm Approaching The Philippines

- Typhoon Rammasun weakened slightly while moving over the Leizhou Peninsula and Hainan Island Friday.
- Made final landfall early Saturday (local time) near China/Vietnam border.
- Storm surge flooding, destructive winds, flash flooding and mudslides are expected.
- 64 dead, over 26,000 homes damaged in the Philippines

Typhoon Rammasun's eyewall came ashore at 3:30 p.m. Friday, local time (Thursday overnight, U.S. time) on south China's island province of Hainan, with maximum estimated sustained winds of 155 mph, according to the Joint Typhoon Warning Center based in Pearl Harbor, Hawaii.

As of 11 p.m. EDT Friday, Rammasun's maximum sustained winds had decreased to an estimated 115 mph, according to the JTWC. This made Rammasun the equivalent of a Category 3 tropical cyclone on the Saffir-Simpson Hurricane Wind Scale. Super typhoons are those whose maximum sustained winds reach at least 150 mph.
Rammasun made its fourth and final landfall at 7:30 p.m. EDT Friday when the center of Rammasun's circulation crossed over southern China's Guangdong Province, Xinhua News Agency reports.
According to Xinhua News Agency, Rammasun was Hainan's most powerful storm in at least nine years and possibly since 1973.
In the 24-hour period ending 2 a.m. EDT Friday, Rammasun had intensified from a high-end Category 1 to a high-end Category 4 equivalent tropical cyclone. Neoguri also became a super typhoon earlier this month, but that occurred well south of the southwest Japanese islands. Unfortunately, Rammasun did so as it was making landfall.
At 2 a.m. EDT Friday, as the center of Rammasun was over the northeast coast of Hainan, the University of Wisconsin Advanced Dvorak Technique estimated a central pressure of 921 millibars.
Super Typhoon Rammasun
Infrared satellite image of Super Typhoon Rammasun as eyewall was raking Hainan and Leizhou Peninsula on July 18, 2014 at 2:28 p.m local time. Eyewall where deepest convection was occurring denoted by yellow ring around the eye. (NRL-Monterey)

South China, Vietnam Impact

China Central Television reported Friday night 1300 people were trapped in Wenchang, Hainan, with rescue work underway. Virtually all brick-and-tile houses in the town of Wengtian were either destroyed or had their roofs removed and at least one death was confirmed, according to CCTV. 
Over 40,000 were evacuated from Wenchang and Qionghai prior to the storm, according to the Hainan Daily.
Weather observations in the city of Haikou (population 830,000) sampled peak sustained winds of 78 mph, with a gust of 100.7 mph at 6 p.m. local time (Despite the country's immense size, all of China is officially 12 hours ahead of U.S. Eastern Daylight time.). Gusts from 55-65 mph continued for several hours after the peak, as Rammasun's south and southeast eyewall raked the city. 
Flying debris and broken glass injured dozens of residents in Haikou, and vehicles were flooded, according to CCTV.

Forecast Path

Forecast Path

According to the latest forecast from Joint Typhoon Warning Center, Rammasun's center will make its final landfall from the Gulf of Tonkin in coastal Yunnan province, China and far northern Vietnam early Saturday, local time. Rammasun may still be a Category 3 or stronger equivalent typhoon by its final landfall.
Rammasun's strongest winds are confined to a relatively compact area near the center of the storm. As of late Friday morning (U.S. time), JTWC said sustained winds of 74 mph or greater (the minimum threshold for hurricane or typhoon) extended no more than 35 miles from the center of the storm in any direction.
The China Meteorological Administration has issued a "red warning for typhoon" for parts of its coastline. A red warning is the second-highest level in China's four-tier warning system. 
Vietnam's National Center for Hydro-Meteorological Forecasting has issued a typhoon warning for portions of northern Vietnam.

Typhoon Impact In Metro Manila

In and near Manila, the nation's capital and the center of a metropolitan area with a population of 12 million people, its effects were felt most strongly Wednesday morning.
PAGASA said the center of Rammasun passed south and then west of the city shortly after sunrise, cutting through the provinces of Batangas and Cavite just south of Metro Manila, and Bataan just northwest of the city across Manila Bay.
Numerous social media users posted photos and videos of the wind whipping through streets and past buildings. Many reported blackouts and brownouts.
Damage around the capital included numerous downed trees, roofs torn off, overturned vehicles and at least one collapsed building. Flooding also occurred in parts of the metropolis. 
High winds also destroyed shanty homes along Manila Bay. Thousands of people in Metro Manila live in makeshift shanty towns, highly vulnerable to high winds and flooding from tropical cyclones, according to a 2013 Daily Mail article.
Ninoy Aquino International Airport reported a peak sustained easterly wind of 41 mph with gusts to 70 mph as the barometric pressure bottomed out at 988 millibars (29.18 inches of mercury). The airport is just south of central Manila. Winds began to decrease considerably a few hours later as the eye of the typhoon moved away.
Subic Bay Weather Station, northwest of Manila, clocked a 57-mph gust at 10 a.m. local time as Rammasun's eye approached, and a 53-mph gust three hours later as it departed.

Typhoon Rammasun Reaches Hainan and Mainland China - Strengthened Again to Category 4

Typhoon Rammasun has finally reached Hainan (population of 9 million) at around 1:30 p.m (1:30 am ET) and Guangdong provinces in southern China. The storm originally appeared as it was not going to be a very strong storm, similar to its traits before slamming into the Philippines. But again for the second time, the storm gained strength again over the South China Sea and is now battering Hainan, with its inner eye wall hugging the island's coast.

The storm is now categorized by the China Meteorological Administration as a super typhoon. The local weather agency issued a 'red' typhoon warning, which is the highest of four color-coded warning levels. As the storm approached Hainan, it carried winds of more than 200 kilometers per hour. Officials claim that this is the strongest storm to hit Hainan in 40 years. 

The evacuation of 26,000 people had taken place on Hainan ahead of the storm. The storm carries violent winds, high waves and torrential rain to southern China, where dozens already have been killed by floods in recent days. 

Back in the Philippines in the city of Manila and surrounding areas, there are millions of people in the city and surrounding areas that have no power, as downed power lines and trees continue blocking roadways in many areas. 

Damages and casualties to Hainan and to mainland China, along with Northern Vietnam, are expected to be very high. Presently, the storm has entered the mainland as a category 4 typhoon, and all that's left now is to wait for the storm to pass. In very densely populated areas, there really is nowhere to go or to hide, but people do their best. Storm surge along the coast has been devastating, and there already is major flooding in Hainan and in mainland China. Details of the storm will be provided once the storm passes. 

Typhoon's Trek Across the Philippines - 64 Known Deaths - 7000 Homes Destroyed

Satellite image of Typhoon Rammasun (Glenda) as its eye moved over Polangui, Albay province in the Philippines around 1000 UTC (6 p.m. local time) Tuesday, July 15, 2014. Thousands of homes were reportedly damaged in Polangui.
Rammasun, known as 'Glenda' in the Philippines, made its first landfall Tuesday morning (U.S. time) over Albay province in the southeastern part of the northern Philippines.
According to the National Disaster Risk Reduction and Management Council, the first landfall occurred at 5 p.m. local time over the municipality of Rapu-Rapu. This was followed by a second landfall at 6:30 p.m. in nearby Tabaco City, on the main island of Luzon.
After emerging over the Ragay Gulf, the typhoon's eye made a third landfall on Luzon over the Bondoc Peninsula of Quezon province near Catanauan, about 115 miles southeast of Manila, at midnight local time Tuesday night.
A fourth landfall appeared to occur near Lucena in Quezon province shortly before sunrise Wednesday, and a fifth landfall appeared to occur on the Bataan Peninsula around 9 a.m. Wednesday after the eye crossed Manila Bay.
The Philippines are 12 hours ahead of Eastern Daylight Time in the U.S.
Storm chaser James Reynolds traveled to Legazpi, the provincial capital of Albay, and experienced both the eye and eyewall of Rammasun (Glenda) Tuesday.

The typhoon caused at least 64 deaths in the Philippines, as well as damage to property and infrastructure across Luzon, the largest island in the archipelago, according to the Philippines News Agency, citing of Office of Civil Defense. The agency said most victims were struck by falling trees or other debris. At least 103 injuries were reported and five people reported missing.
The typhoon damages more than 26,000 houses -- about 7,000 of those destroyed, the agency said.
James Reynolds, a freelance journalist and videographer who was in Legazpi when the typhoon made landfall in the Philippines, said in a twitter post that Rammasun looked "immensely powerful -- one of the strongest I've seen in the (South) China Sea for a long time. 

Wednesday, July 16, 2014

Typhoon Rammasun 'Glenda' Predicted Path Through the Philippines

As predicted, the central path of Typhoon 'Glenda' introduced itself to the Philippines by entering the Albay Gulf. It continued in a steady Northwest direction and passed directly over Cagraray Island and into Luzon. The path took it directly over Tabaco City, back out into Ragay Gulf into Luxon once again. The typhoon, traveling at a Category 3 strength, passed by Lucena, Sariaya, Poblacion and into Taal Lake. Continuing on the same path, it passed directly north of Taal Volcano Island and directly North of Nasugbu before heading out into the South China Sea as a Category 2 storm. Noted here was that the storm did loose a little definition concerning the eye of the typhoon, but now back in the very warm waters of the South China Sea, the storm is expected to continue in its path to enter land again once reaching China. Presently, the storm is expected to enter Hainan at Fengjia Bay and exit at Yugu Harbor. It is expected to reach the North Vietnam at 3AM on Saturday China time. Before reaching the mainland, the storm is expected to weaken abit, but then continue to re-strengthen as a Category 3 storm. But predictions now have it weakening again after passing over Hainan. The storm band is so large, that even though the storm will enter the mainland of North Vietnam, as the eye should pass just to the north of Hanoi. The NorthEastern band of circulation which is the strongest presented from the storm, will be over China. Cities such as Nanning and Kunming in Southern China along with smaller towns like Chixiong and Yuxi. These China towns have a considerable amount of time to prepare, and word should be spread now in Hanoi, Vietnam and other neighboring communities of the pending storm.

Tuesday, July 15, 2014

Typhoone Rammasun - Category 3 Bearing Down on Manila, Philippines

It is now believed that Typhoon Rammasun, which is known as "Glenda" in the Philippines, made landfall near Sorsogon, Philippines, which is located on the southeastern part of Luzon Island. at approximately 2 PM Tuesday, July 15 local time. It entered the country as a Category 3 storm with sustained winds of about 125 miles per hour. 

This storm is expected to directly hit Manila, which is the home of approximately 12 million people. It is expected to be over the capital city before noon local time on Wednesday. Many have fled their homes in provinces outside of Manila, and others have decided to stay. The city should expect to see a storm surge of at least 10 feet or more. 

The local weather service in the Philippines, PAGASA, has placed metro Manila in a Signal 3 warning, which is the country's highest typhoon warning designation. 

Just 12 hours ago, the storm was expected to hit the Philippines as a Category 1 storm, but to everyone's surprise, it rapidly gained strength and now plowing through the country as a Category 3 storm. It is now weakening as it passes over mountainous areas of the Northern Philippines, but still on a direct course to Manila. 

The country is expected to see at least 15 inches of rainfall in the Philippines from this storm which is equivalent of a month's worth of rainfall in just one to two days time. 

Typhoon Rammasun, a.k.a. Glenda, intensified rapidly as it approached landfall, with its central atmospheric pressure dropping from 965 millibars to 945 millibars in just 3 hours. 
Track Forecast 

Typhoons That Affect The Philippines - Presently Typhoon Rammasun - Category 3

Typhoon Rammasun presently ravenging the Philippines above

The record of Typhoons that have ravaged the Philippines goes back to the September 1881 typhoon. During this storm, approximately 20,000 people lost their lives. In the most modern of times, Typhoon Haiyan became the strongest land-falling tropical cyclone to ever be recorded as it crossed the Central Philippines on November 7 and 8th of 2013. The wettest known tropical cyclone occured in July of 1911, as it dropped over 2,210 millimeters, or 87 inches of rainfall within a 3 day 15-hour period in Baguio City. The northern part of the country receives approximately 30% of their yearly rainfall from these tropical storms, while the southern part of the Philippines only receives approximately 10% of their total rainfall from tropical storms each year. There is no other nation on earth that is more susceptible to tropical weather than the Philippines. Luzon, which is now presently under attack by the latest tropical storm of the year, Typhoon Rammasun is spinning at a category 3 at the moment and will be passing over Luzon on its way to the China Sea before reaching China. The frequency of storms in this region is directly responsible for some of the desolate areas of the Northern Philippines. Typhoon Rammasun is expect to gather more strength as it enters the China Sea. In comparison to Hurricane Arthur that just skirted up the United States Coastline within the last week, this storm is at least 5-6 times stronger and will definitely affect any person in its direct path. 
So again, it doesn't matter where you live in the world, it is best to always try to stay away from such tropical storms. Most of the time, residents of affected areas are given ample notice of the storms and when it should be designated to leave any affected area to protect yourself. Many people heed the warnings of their local governments, but many do not. One of the purposes of this blog, www.hurricanefollower.com is to help bring up the awareness of these types of storms. Storms located around the world, especially in this region surrounding the Philippines will be reported on whenever newsworthy information can be obtained. 

Live satellite loop of Typhoon Rammasun

Typhoon Rammasun is packing winds around 125 mph — a category 3 on the Saffir Simpson Hurricane Scale. While the typhoon’s eye is not well-defined on satellite, a band of torrential thunderstorms surrounds its core. 7.13 inches of rain fell in the city of Legaspi on Tuesday. Rammasun was intensifying as it made landfall in Luzon, and only weakened slightly after that.

Glossary of HNC Terms

The Following is a Published Glossary by the National Weather Service that can be found at:

Glossary of NHC Terms

See also: NWS Glossary
Jump to:  a - b - c - d - e - f - g - h - i - j - k - l - m - n - o - p - q - r - s - t - u - v - w - x - y - z
Official information issued by tropical cyclone warning centers describing all tropical cyclone watches and warnings in effect along with details concerning tropical cyclone locations, intensity and movement, and precautions that should be taken. Advisories are also issued to describe: (a) tropical cyclones prior to issuance of watches and warnings and (b) subtropical cyclones.

Best Track:
A subjectively-smoothed representation of a tropical cyclone's location and intensity over its lifetime. The best track contains the cyclone's latitude, longitude, maximum sustained surface winds, and minimum sea-level pressure at 6-hourly intervals. Best track positions and intensities, which are based on a post-storm assessment of all available data, may differ from values contained in storm advisories. They also generally will not reflect the erratic motion implied by connecting individual center fix positions.

Generally speaking, the vertical axis of a tropical cyclone, usually defined by the location of minimum wind or minimum pressure. The cyclone center position can vary with altitude. In advisory products, refers to the center position at the surface.

Center / Vortex Fix:
The location of the center of a tropical or subtropical cyclone obtained by reconnaissance aircraftpenetration, satellite, radar, or synoptic data.

Central North Pacific Basin:
The region north of the Equator between 140W and the International Dateline. The Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii is responsible for tracking tropical cyclones in this region.

An atmospheric closed circulation rotating counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Direct Hit:
A close approach of a tropical cyclone to a particular location. For locations on the left-hand side of a tropical cyclone's track (looking in the direction of motion), a direct hit occurs when the cyclone passes to within a distance equal to the cyclone's radius of maximum wind. For locations on the right-hand side of the track, a direct hit occurs when the cyclone passes to within a distance equal to twice the radius of maximum wind. Compare indirect hitstrike.

Eastern North Pacific Basin:
The portion of the North Pacific Ocean east of 140W. The National Hurricane Center in Miami, Florida is responsible for tracking tropical cyclones in this region.

The roughly circular area of comparatively light winds that encompasses the center of a severe tropical cyclone. The eye is either completely or partially surrounded by the eyewall cloud.

Eyewall / Wall Cloud:
An organized band or ring of cumulonimbus clouds that surround the eye, or light-wind center of atropical cyclone. Eyewall and wall cloud are used synonymously.

A term used in advisories and tropical summaries to indicate that a cyclone has lost its "tropical" characteristics. The term implies both poleward displacement of the cyclone and the conversion of the cyclone's primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force.

Extratropical Cyclone:
A cyclone of any intensity for which the primary energy source is baroclinic, that is, results from the temperature contrast between warm and cold air masses.

Fujiwhara Effect:
The tendency of two nearby tropical cyclones to rotate cyclonically about each other.

Gale Warning:
A warning of 1-minute sustained surface winds in the range 34 kt (39 mph or 63 km/hr) to 47 kt (54 mph or 87 km/hr) inclusive, either predicted or occurring and not directly associated with tropical cyclones.

High Wind Warning:
A high wind warning is defined as 1-minute average surface winds of 35 kt (40 mph or 64 km/hr) or greater lasting for 1 hour or longer, or winds gusting to 50 kt (58 mph or 93 km/hr) or greater regardless of duration that are either expected or observed over land.

Hurricane / Typhoon:
tropical cyclone in which the maximum sustained surface wind (using the U.S. 1-minute average) is 64 kt (74 mph or 119 km/hr) or more. The term hurricane is used for Northern Hemisphere tropical cyclones east of the International Dateline to the Greenwich Meridian. The term typhoon is used for Pacific tropical cyclones north of the Equator west of the International Dateline.

Hurricane Local Statement:
A public release prepared by local National Weather Service offices in or near a threatened area giving specific details for its county/parish warning area on (1) weather conditions, (2) evacuation decisions made by local officials, and (3) other precautions necessary to protect life and property.

Hurricane Season:
The portion of the year having a relatively high incidence of hurricanes. The hurricane season in the Atlantic, Caribbean, and Gulf of Mexico runs from June 1 to November 30. The hurricane season in theEastern Pacific basin runs from May 15 to November 30. The hurricane season in the Central Pacific basin runs from June 1 to November 30.

Hurricane Warning:
An announcement that sustained winds of 64 knots (74 mph or 119 km/hr) or higher are expectedsomewhere within the specified area in association with a tropicalsubtropical, or post-tropical cyclone. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the warning is issued 36 hours in advance of the anticipated onset of tropical-storm-force winds. The warning can remain in effect when dangerously high water or a combination of dangerously high water and waves continue, even though winds may be less than hurricane force.

Hurricane Watch:
An announcement that sustained winds of 64 knots (74 mph or 119 km/hr) or higher are possible within the specified area in association with a tropicalsubtropical, or post-tropical cyclone. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane watch is issued 48 hours in advance of the anticipated onset of tropical storm force winds.

Indirect Hit:
Generally refers to locations that do not experience a direct hit from a tropical cyclone, but do experience hurricane force winds (either sustained or gusts) or tides of at least 4 feet above normal.

A weather system for which a tropical cyclone forecast center (NHC, CPHC, or JTWC) is interested in collecting specialized data sets (e.g., microwave imagery) and/or running model guidance. Once a system has been designated as an invest, data collection and processing is initiated on a number of government and academic web sites, including the Naval Research Laboratory (NRL) and the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS). The designation of a system as an invest does not correspond to any particular likelihood of development of the system into a tropical cyclone; operational products such as the Tropical Weather Outlook or the JTWC/TCFA should be consulted for this purpose.

The flooding of normally dry land, primarily caused by severe weather events along the coasts, estuaries, and adjoining rivers. These storms, which include hurricanes and nor'easters, bring strong winds and heavy rains. The winds drive large waves and storm surge on shore, and heavy rains raise rivers. (A tsunami — a giant wave caused by earthquakes or volcanic eruptions under the sea or landslides into the sea — is another kind of coastal inundation, but should not be confused with storm surge.)

The intersection of the surface center of a tropical cyclone with a coastline. Because the strongest winds in a tropical cyclone are not located precisely at the center, it is possible for a cyclone's strongest winds to be experienced over land even if landfall does not occur. Similarly, it is possible for a tropical cyclone to make landfall and have its strongest winds remain over the water. Compare direct hitindirect hit, and strike.

Major Hurricane:
hurricane that is classified as Category 3 or higher.

National Geodetic Vertical Datum of 1929 [NGVD 1929]:
A fixed reference adopted as a standard geodetic datum for elevations determined by leveling. The datum was derived for surveys from a general adjustment of the first-order leveling nets of both the United States and Canada. In the adjustment, mean sea level was held fixed as observed at 21 tide stations in the United States and 5 in Canada. The year indicates the time of the general adjustment. A synonym for Sea-level Datum of 1929. The geodetic datum is fixed and does not take into account the changing stands of sea level. Because there are many variables affecting sea level, and because the geodetic datum represents a best fit over a broad area, the relationship between the geodetic datum and local mean sea level is not consistent from one location to another in either time or space. For this reason, the National Geodetic Vertical Datum should not be confused with mean sea level.

Post-storm Report:
A report issued by a local National Weather Service office summarizing the impact of a tropical cyclone on its forecast area. These reports include information on observed winds, pressures, storm surges, rainfall, tornadoes, damage and casualties.

Post-tropical Cyclone:
A former tropical cyclone. This generic term describes a cyclone that no longer possesses sufficient tropical characteristics to be considered a tropical cyclone. Post-tropical cyclones can continue carrying heavy rains and high winds. Note that former tropical cyclones that have become fully extratropical...as well as remnant lows...are two classes of post-tropical cyclones.

Preliminary Report:
Now known as the "Tropical Cyclone Report". A report summarizing the life history and effects of an Atlantic or eastern Pacific tropical cyclone. It contains a summary of the cyclone life cycle and pertinent meteorological data, including the post-analysis best track (six-hourly positions and intensities) and other meteorological statistics. It also contains a description of damage and casualties the system produced, as well as information on forecasts and warnings associated with the cyclone. NHC writes a report on every tropical cyclone in its area of responsibility.

Present Movement:
The best estimate of the movement of the center of a tropical cyclone at a given time and given position. This estimate does not reflect the short-period, small scale oscillations of the cyclone center.

Radius of Maximum Winds:
The distance from the center of a tropical cyclone to the location of the cyclone's maximum winds. In well-developed hurricanes, the radius of maximum winds is generally found at the inner edge of theeyewall.

Rapid Intensification:
An increase in the maximum sustained winds of a tropical cyclone of at least 30 kt in a 24-h period.

A term used in an advisory to indicate that a vector drawn from the preceding advisory position to the latest known position is not necessarily a reasonable representation of the cyclone's movement.

Remnant Low:
post-tropical cyclone that no longer possesses the convective organization required of a tropical cyclone...and has maximum sustained winds of less than 34 knots. The term is most commonly applied to the nearly deep-convection-free swirls of stratocumulus in the eastern North Pacific.

Saffir-Simpson Hurricane Wind Scale:
The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's intensity at the indicated time. The scale provides examples of the type of damage and impacts in the United States associated with winds of the indicated intensity. The following table shows the scale broken down by winds:

CategoryWind Speed (mph)Damage
174 - 95Very dangerous winds will produce some damage
296 - 110Extremely dangerous winds will cause extensive damage
3111 - 129Devastating damage will occur
4130 - 156Catastrophic damage will occur
5> 156Catastrophic damage will occur

A detailed description of the Saffir-Simpson Hurricane Wind Scale is available athttp://www.nhc.noaa.gov/aboutsshws.php.

Storm Surge:
An abnormal rise in sea level accompanying a hurricane or other intense storm, and whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic high tide from the observed storm tide.

Storm Tide:
The actual level of sea water resulting from the astronomic tide combined with the storm surge.

Storm Warning:
A warning of 1-minute sustained surface winds of 48 kt (55 mph or 88 km/hr) or greater, either predicted or occurring, not directly associated with tropical cyclones.

strike zone diagramFor any particular location, a hurricane strike occurs if that location passes within the hurricane's strike circle, a circle of 125 n mi diameter, centered 12.5 n mi to the right of the hurricane center (looking in the direction of motion). This circle is meant to depict the typical extent of hurricane force winds, which are approximately 75 n mi to the right of the center and 50 n mi to the left.

Subtropical Cyclone:
A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 n mi), and generally have a less symmetric wind field and distribution of convection.

Subtropical Depression:
subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 33 kt (38 mph or 62 km/hr) or less.

Subtropical Storm:
subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 34 kt (39 mph or 63 km/hr) or more.

Synoptic Track:
Weather reconnaissance mission flown to provide vital meteorological information in data sparse ocean areas as a supplement to existing surface, radar, and satellite data. Synoptic flights better define the upper atmosphere and aid in the prediction of tropical cyclone development and movement.

Tropical Cyclone:
A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).

Tropical Cyclone Plan of the Day:
A coordinated mission plan that tasks operational weather reconnaissance requirements during the next 1100 to 1100 UTC day or as required, describes reconnaissance flights committed to satisfy both operational and research requirements, and identifies possible reconnaissance requirements for the succeeding 24-hour period.

Tropical Depression:
tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 33 kt (38 mph or 62 km/hr) or less.

Tropical Disturbance:
A discrete tropical weather system of apparently organized convection -- generally 100 to 300 nmi in diameter -- originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field.

Tropical Storm:
tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) ranges from 34 kt (39 mph or 63 km/hr) to 63 kt (73 mph or 118 km/hr).

Tropical Storm Warning:
An announcement that sustained winds of 34 to 63 knots (39 to 73 mph or 63 to 118 km/hr) areexpected somewhere within the specified area within 36 hours in association with a tropical,subtropical, or post-tropical cyclone.

Tropical Storm Watch:
An announcement that sustained winds of 34 to 63 knots (39 to 73 mph or 63 to 118 km/hr) are possiblewithin the specified area within 48 hours in association with a tropicalsubtropical, or post-tropical cyclone.

Tropical Wave:
A trough or cyclonic curvature maximum in the trade-wind easterlies. The wave may reach maximum amplitude in the lower middle troposphere.

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Page last modified: Friday, 16-May-2014 21:13:06 UTC

What is an 'INVEST' ?

Many have heard of the term 'INVEST' when it comes to meteorology. Before a storm actually is designated as a storm, hurricane or cyclone, the region of weather or area of concern is called an 'INVEST'. It is short for 'investigation' or 'to investigate'. They have been designated by three separate forecast centers, namely the  National Hurricane Center Central Pacific Hurricane Center and Joint Typhoon Warning Center. Because the weather of concern is called an 'invest', that doesn't mean that it will further develop into an area of major concern, or actually turn into a full fledged storm. If the area of concern is in the Atlantic, the name of the storm, made up of numbers, will be followed by the letter 'L'. If the storm name contains the letters 'E' or 'C', then they would be located in either the Eastern Pacific or Central Pacific respectively. If the name is tagged with the letter 'W', then it is in the West Pacific. Some of the letters are used in different areas. For example, the Joint Typhoon Warning Center also issues unofficial warnings for the Australian cyclone region, designating tropical invests with the 'S' suffix when they form west of 135 degrees East, and the 'P' suffix when they form east of 135 degrees East. When it comes to invests in the North Indian Ocean, they are also designated by the Joint Typhoon Warning Center and are suffixed with the letter 'A', if they form in the Arabian Sea and with a 'B' if they form in the Bay of Bengal. Interestingly enough, the numbers are reused between 90 and 99. After 99, would come 90 once again. If the system develops into a tropical cyclone, it is reclassified as the next name/number on the list.

In some cases, they will be reported here along with the known storms in different regions around the world. The cases that will be reported will be the ones that have potential to affect a land mass, especially if the  'INVEST' upgrades into a storm of any magnitude.