Satellite imagery of the “1993 SUPERSTORM” on March 13, 1993.

This week, back in 1993, was one of the most intense East Coast Storms ever seen. Early on March 13, 1993 an unusually severe extratropical low moved ashore from the Gulf of Mexico hitting western Florida with hurricane force winds and a hurricane like tidal surge of up to 12 feet. Along Florida’s Gulf Coast this storm is remembered as the “No-Name Storm”. Elsewhere this intense storm is known as the “1993 SUPERSTORM”, “White Hurricane” and “The Blizzard of 1993”. The system began on March 12th and blasted the East Coast through March 15th with heavy snow, hurricane force wind gusts and record low barometric pressures.

NOAA US Surface Analysis 13 March 1993

The storm developed as a 1002mb low on March 12th off Brownsville, TX and tracked east to northeast deepening very rapidly while still over the north-central Gulf of Mexico dropping to 984mb just south of the Mississippi Delta and making landfall along the Florida Panhandle during the early morning hours of March 13th as an intense storm low with a minimum pressure of around 975mb. Hurricane strength winds and a tidal surge as high as 12 feet were reported along the Florida Gulf Coast damaging or destroying 18,000 homes and causing more than $500-million in property damage.

The associated strong cold front then swept across Florida and Cuba producing an intense squall line. The squall line produced a serial Derecho (pronounced “deh-RAY-cho” – a widespread and long lived windstorm that is associated with a band of rapidly moving showers or thunderstorms) as it swept across the Florida, Cuba, and adjacent waters producing hurricane force wind gusts and several tornados.

Sea conditions over the eastern Gulf of Mexico were incredible causing the sinking of the 200-ft. freighter Fantastico some 70 miles off Ft. Myers killing 7 crewmembers. Ten miles from Key West, the 147-ft. freighter Miss Beholding ran aground on a coral reef and several charter fishing vessels and sailboats sank.

The storm continued to strengthen as it turned north-north eastward becoming the most powerful storm to affect the continental US since the blizzard of 1888. The storm brought high winds, tornadoes, record cold temperatures, coastal flooding, and heavy precipitation including blizzard conditions as far south as northern Georgia and Alabama. Heavy snow in Atlanta forced officials closed the airport, stranding 3,000 people while snow drifts of over 20ft were reported in Boone, N.C and 4.5 ft. of snow fell in Mount LeConte, TN.

In the North Atlantic, the 586-ft. freighter Gold Bond Conveyor 200 miles south of Nova Scotia reported that 90-mph winds and 100-ft. waves were battering the ship, and it was beginning to list. Later the ship was hit by a huge swell and went down with the loss of 29 crewmembers.

At the time of this storm I was living in Lodi, NJ and recorded 12.5 inches of snow and ice during the 13th. Heavy snow fell during the morning of the 13th becoming mixed with sleet and freezing rain and later changing to rain as temperatures climbed to 36 degrees. As the trailing cold front moved through New Jersey, early on the 14th, light snow and snow showers added another ¾ of an inch of snow on top of the ice crusted snow from the day before.

When I checked back through my records I also noticed that earlier the same month another intense low had moved through the area on March 4th. My records show that I estimated that the winds during the 4th had gusted to Beaufort Force 10-11 (55-73mph) with numerous trees down, power outages and some minor structural damage. My records indicated that during the storm of the 13th-14th the winds were not as high.

The NOAA Storm Data for Dec. 4th 1993 stated that “A low pressure system moving northward along the Appalachians developed into a major late winter storm. The storm struck the area with howling onshore winds that drove tides upward to five feet above normal. The high winds, which gusted frequently between 50 and 60 knots, downed hundreds of trees and power lines throughout the region leaving hundreds of thousand without electricity.”

Read more at Ocean Weather Services blog…

NOAA OPC Surface Analysis 06Z 25 Feb 2013

The hurricane force storm that was over the western North Atlantic shipping lanes Feb. 23rd-24th has weakened and turned northward towards Greenland, however, a second storm has developed off the US East Coast over night moving eastward and is also producing storm to hurricane force winds (50-65 knots) with waves forecast to build also up to over 11 meters (38 feet) by this evening over the shipping lanes between Northern Europe and the Mediterranean sea and US east and gulf ports

NOAA OPC Wave Forecast 00Z 26 Feb 2013

ORIGINAL (Feb 22)

NOAA OPC Surface Analysis 18Z 22 Feb 2013

An intense storm low over the west-central North Atlantic was producing storm to hurricane force winds (50-65 knots) and waves building up to 11 meters (36 ft.) during the next 18-24 hours within 300 NM southwest of the center. This system is developing along the shipping routes between Northern Europe and the Mediterranean Sea to/from US East and Gulf Ports and will likely cause some delays.

NOAA OPC Wave Forecast 12Z 23 February 2013

Via Ocean Weather Services Blog

Cover image (c) Matt Trommer/Shutterstock

An intense hurricane force storm is forecast to move from south of Iceland towards the coast of Norway on Monday with a large area of winds forces 10-12 (50-70 knots) which will cause waves to build upwards of 14 meters (46 ft.). Over the northeastern North Atlantic.

This storm is not as deep as the recent 930 mb storm, however due to strong high pressure near the Azores there will be a strong pressure gradient that will result in a fairly large area of storm force or higher winds.

Update: Monday February 4th:  The intense storm low is producing significant wave heights of up to 17 meters (about 56 ft).  The significant wave height is the average of the 1/3 heights so individual waves could be much higher!  Not a good time to be departing westbound via north of Scotland….

Visual at 12Z 4 February

NOAA IR Satellite 1145Z 26 January 2013 showing 930 mb hurricane force storm.

Last weekend saw an unusually intense hurricane force extratropical storm low over the North Atlantic.  An active weather pattern started showing up on computer models more than a week earlier and by the 21st, the official NOAA “96 hour North Atlantic surface forecast chart” showed a rapidly deepening 977mb storm low over the central North Atlantic for 12Z Friday January 25th moving northeastward with a forecasted central pressure dropping to 933mb by 12Z on Saturday the 26th!

NOAA OPC Surface Analysis 12Z 24 January 2013 showing fast moving low passing off the coast.

This particular system began as a weak 1023 mb disturbance along an Arctic front that was moving south and east across the Central US on the afternoon of the 23rd.

By Thursday, the 24th the rapidly moving disturbance had passed off the Middle Atlantic coast and had deepened to 1013mb. By Thursday night it was becoming apparent that this storm could approach historic strength during the following 72 hours and the official NOAA forecasts predicted that this storm would deepen to near 977mb by 12Z Friday (Jan. 25th) and as low as 920 or 924 mb by 12Z Saturday with hurricane force winds up to 75-80 knots possible.

NOAA OPC Surface Forecast 12Z 25 January 2013 showing developing hurricane force storm

Once off the coast the developing disturbance moved very rapidly (at nearly 50kts) towards the east-northeast deepening quickly to 984mb by 12Z Friday.

NOAA OPC 500MB Analysis 12Z 25 January 2013 showing strong winds high above the sea surface.

The stage was set for very rapid (explosive) deepening and over the next 24 hours the central pressure of this now large hurricane force storm dropped 54 mb to 930mb!

NOAA OPC Surface Analysis 12Z 26 January 2013 showing 930 mb hurricane force storm low.

This generated huge waves of up to 18 meters (59 feet) as depicted on the NOAA OPC Sea State Analysis on the 26th.  Wave heights on the NOAA chart here are significant wave heights which are defined as the average of the 1/3 highest waves.  This means that there was a 1 in 10 chance for a wave of almost 23 meters (75 ft.) and a 1 in 100 chance that a wave could have been as high as 30 meters (98 ft.).

NOAA OPC Wave Analysis 12Z 26 January 2013 showing significant wave heights to 17 meters (59 ft.)

Although this was a very intense storm, it was not a record.  The all-time record for North Atlantic extratropical storms was the Braer Storm of January 1993 that reached a min pressure of 914 mb (26.99 in Hg) on January 10th. The 1993 storm caused blizzard conditions across much of Scotland and also led to the final breakup of the oil tanker MV Braer, which had been stranded in rocks off the Shetland Islands by a previous storm.

Wunderground meteorologist Jeff Masters listed 5 storms in his blog that reached central pressures between 920 and 926 mb since the late 1800s, as cataloged by British weather historian Stephen Burt.

 NOAA Verification

NOAA OPC has a web page where you can verify how good or bad their graphical forecasts were.  For this storm the NOAA OPC 48 hour forecast was  for 924mb min pressure at 12Z on the 26th which turned out to be a bit too aggressive as the actual storm verified at 930mb. Given that this was a system at the very deep end of the pool, the forecast was not too far off.

Verification NOAA OPC Jan 26th showing the 48 hour forecast chart and the actual analysis chart

Via Ocean Weather Services Blog

Satellite view of storm, 26 Jan 2013 – UK Meterological Office

click for animation

16 January Update: 

A major hurricane force storm continues over the western North Pacific with winds up to 65 knots and significant wave heights up to 20 meters (about 66 feet)! The significant wave height is the average of the 1/3 highest waves which means that some waves will be higher. Given a significant wave of 20 meters, about 1 in 10 waves could be 25 meters (82 feet) and 1 out of 100 could be as high as 33 meters (108 feet)!

Previously reported on 15 January:

A very dangerous 936 mb storm peaked today over the western North Pacific with a min pressure of 932 mb and is moving northeast at 25 knots with hurricane force winds and very high sea and swell conditions.  Hurricane Sandy, by comparison, reached a minimum pressure of 940 millibars and was the largest Atlantic hurricane in recorded history.

At 12Z 15 January the center of the storm was near 42N/163E with winds of Force 11 or higher (60-85 knots) and waves 12-18 meters (39-59 feet) within 300NM west and southwest of the center and winds forces 9-11 and waves 5.5-14 meters (18-46 feet) up to 540NM from the center.

This storm and will now weaken slowly as it moves northeastward.

Keep in mind that the wave heights here are the significant wave height which is defined as the average of the 1/3 highest waves. This means that some individual waves could be up to twice the significant wave height!

This storm appears to be an example of a rapidly deepening “bomb” low that is often associated with some winter season storms over both the North Atlantic and North Pacific oceans. These systems are associated with what is known as a warm air seclusion where the warm surface air is lifted up during the occlusion process and then wrapped around the low center into its cold southwestern quadrant.

932 millibars!

Gale force winds are predicted to extend from 36N to 60N, over 1,400 nautical mile wide swath of ocean.

click for larger

“The shipping industry is in constant change and the needs of fleet managers change with it. To respond accordingly, AWT has worked closely with its customers to develop its fully customizable fleet management system,” said Skip Vaccarello, president and CEO of AWT. “With FleetDSS, we provide a range of practical tools which give fleet managers the flexibility they need to manage their ships safely while simultaneously enhancing vessel performance.”

According to Captain Michel Cochennec, Deputy Director, Fleet Navigation Center, CMA CGM, “Working with AWT’s knowledgeable development team to customize the Fleet Decision Support System has been very rewarding. With FleetDSS, we can now compare actual vessel performance to our pro forma that results in quick, proactive management during the voyage. We can easily determine confidence levels of a route, and with the alarm dashboard we can assess risks such as pirate attacks in time to properly manage them. Coupled with AWT’s exceptional routing service, CMA CGM is better able to manage its fleet to improve efficiency and safety.”

Quick and Easy Access to Important Data

Ships are displayed in a Global Mercator projection map with full-screen capability. FleetDSS has an extensive filtering capability that allows companies with large fleets to focus on the few vessels that need the most attention for safety or performance reasons.

The dashboard feature allows operators to easily manage the vessels based on the filters selected. This makes it quick and easy for an operator to address those vessels with the highest risk first. Reports can also be exported to an Excel spreadsheet and used in meetings or company reports.

Operators can view alerts when any issue comes up with the voyage, ensuring that their attention is focused where it is needed most. These alerts are customer-controlled and customizable to meet the needs of each specific voyage. With one glance at the dashboard, operators can see which ships are at elevated risk and may need immediate attention.

Improved Vessel Performance

Pro forma graphs allow operators to compare the vessel’s expected performance with its actual performance while en route. Operators are alerted when a ship deviates from the pro forma voyage plan, enabling them to quickly spot vessels that are over consuming fuel and proactively address the problem during the voyage to minimize excessive consumption.

At the end of the voyage, operators can use the summary report to compare the ship’s performance with past voyages in an easy-to-read graphical display. They can also compare vessels on the same trade run to each other and to their pro forma requirements, making it easy to spot those vessels that are under performing.

Safety Features in FleetDSS

In addition to the customized alerts, FleetDSS includes several safety alerts.  Operators can see alerts when there has been a recent pirate attack within the vicinity, if vessels are entering a war risk area, and if there are any hazards nearby.  Operators are also easily able to view dangerous weather conditions such as rogue wave risk areas, iceberg areas, significant wave height, tropical cyclones and more.

“Today, an operator’s biggest barrier to ensuring efficient voyages is a lack of concise information to make quick and informed decisions,” said Rich Brown, AWT’s vice president of product management. “With FleetDSS, AWT built a true decision support system that gives operators custom data to identify and manage vessels in need of attention en route. The result is improved vessel performance and safety, in addition to increased efficiency on shore.”

About AWT

AWT (awtworldwide.com) is the leading provider of shore-based ship routing services, BVS onboard voyage management software, Fleet Decision Support System and its award-winning GlobalView™ Fleet Management System. The company’s mission is to provide decision support solutions and services that enable companies in the maritime industry to increase effectiveness, improve profitability, maintain safety, and minimize environmental impact. Focused solely on the maritime industry, AWT is staffed by world-renowned experts in ship routing, meteorology, IT, maritime science and former mariners. AWT’s 24/7 personalized customer service and integrity have made AWT the trusted fleet optimization provider to more than 1,000 shipping companies. Founded in 1996, AWT is headquartered in California’s Silicon Valley with worldwide offices located in the UK, Germany, Hong Kong, Shanghai, Korea, Japan, Singapore,New York, and New Jersey.

There are five types of ocean waves:

1. Wind generated
2. Tides
3. Seiches
4. Tsunamis
5. Pressure induced

1. Wind-Generated

Wind-generated waves are the most common waves found on the ocean and are the result from stress on the water surface caused by the wind. The smallest of these are capillary waves which can be quickly brought back to equilibrium solely by the cohesion of the individual water molecules. Most wind-generated waves, however, are referred to as gravity waves since it is gravity that acts to restore them to equilibrium. Wind driven waves are the waves that have the greatest impact on ships.

2. Tides

Tides are the rise and fall of sea level caused by the gravitational attractions of the moon and sun and by the centrifugal force of the spinning earth.

When the solar and lunar gravitational forces are in line they combine to create the highest of the high tides and lowest of the low tides which are referred to as “spring tides.” When the forces are perpendicular to each other, the forces are pulling the water in different directions so the difference between high and low tides are minimized and is referred to as a “neap tide”.

A illustrated guide to tides can be viewed HERE.

3. Seiches

Image Credit: Keith C. Heidorn, PhD The Weather Doctor’s Weather Almanac Sloshing The Lakes: The Seiche

A seiche is the sloshing of water back and forth in lakes and other large bodies of waters. Seiches can be caused by a disturbance such as an earthquake or landslide, changes in air pressure, or changes in the wind. The most common cause of seiches are persistent strong winds blowing along the long axis of large water body causing a rise in the water level at the down-wind side and a lowering of the water level at the up-wind end.

When the wind abates, the water is released as a seiche wave. Flooding and erosion can occur at one end of the lake, while at the other end the decreased water depth can cause hazards to ship navigation.

4. Tsunami

Recent events in Japan have focused our attention on tsunamis. Tsunamis are long-period waves generated by undersea earthquakes, volcanic eruptions and landslides. In the open deep oceans a tsunami will have extremely long wavelengths with small amplitudes and might go unnoticed by ships. Tsunami waves travel at very high speeds, often at hundreds of miles per hour through deep water but as the tsunami waves reach shallow water near the coast, they begin to slow down while gradually growing steeper, due to the decreasing water depth and can grow to tens of meters or more as they reach the shoreline. The effects can be further amplified where a bay, harbor, or lagoon funnels the waves as they move inland and well document during Japan’s recent event. Another potential cause of a tsunami is an asteroid impact in the deep ocean which could produce a tsunami waves of over 100 meters (more than 330 feet)!

5. Pressure Induced

The 5th but less significant type of wave develops as air pressure perturbations move over the water surface. The sea surface height rises or falls slightly as the atmospheric pressure changes. Low air pressure within a strong storm can elevate the ocean’s surface up to 0.5m (1.6ft), creating an atmospherically forced pressure wave beneath the storm.

Wave Definitions

Wave definitions: Image credit NOAA

A wave crest is the highest point in the wave and a wave trough is the lowest point in the wave.
Wave height (H) is the vertical distance between the wave crest and the wave trough.

Wavelength (L) is the distance from one crest to the next crest or from one trough to the next trough.

Wave period (T) is the time it takes successive wave crests or successive wave troughs to pass a fixed point. In the real world, the wave period is actually a spectrum of periods scattered about a mean wave period.

Wave steepness (S) is defined as wave height divided by wavelength (S = H/L). Therefore, the same wave height will result in high steepness if the wavelength becomes smaller. A small height divided by a large length will produce a low steepness. When the wave steepness exceeds about 1/7 the wave will begin to break or “white cap.”

Wave speed (C) is the speed an individual wave moves through water. If the wave period (T) and wave length (L) are known, then the wave speed (C) can be determined by C=L/T

Other Wave Facts:

Deep Water or Shallow Water
A wave is considered to be a deep water wave as long as water depth exceeds 1/2 the wavelength. A wave is considered to be a shallow water wave as long as water depth is less than 1/20 the wavelength. The area between deep and shallow water is transition zone.

Wave Energy
Wave energy increases by a factor of 4 as the wave height doubles so a 10ft wave is four times more powerful than a 5 ft wave.

The significant wave height (Hs) is the mean height of the highest one third of the waves passing a point. This is of interest as this wave height correlates best with the wave height a trained observer reports after examining a group of wave heights from a ship or platform. The averaged periods of the waves used to compute significant wave height is known as the significant wave period.

Statistical distrubution of wave heights

Useful wave height relationships:

Hm (Mean wave height) = 0.64 times Hs
Hs or H1/3 = Significant wave height
H1/10 (Highest 10% wave height) = 1.27Hs
H1/100 (Highest 1% wave height) = 1.67Hs
Hmax (Max probable wave height for a large sample) = about 2.0Hs

Ocean Swell is defined as any wave that has moved out of its wind generation source region. Swells characteristically exhibit smoother, more regular and uniform crests and a longer period than wind waves.

Combined Seas describes the combination or interaction of wind waves and swells in which the separate components are not distinguished. Combined Seas (CS) is the square root of the square of swell plus the square of wind waves: The National Weather Service considers the combined seas as being the same as significant wave height.

 

A wall of water approaches the Stolt Surf in Oct. 1977 Photo: Karsten Petersen, www.global-mariner.com

Rogue waves

Rogue waves (sometimes called freak waves) are simply unusually large waves appearing in a set of smaller waves. A rogue wave will have a height of at least twice the size of surrounding waves, often come from a direction different than the prevailing waves, and they are unpredictable. Most reports of extreme storm waves say they look like “walls of water,” and are seen as steep-sided with unusually deep troughs. The USS Ramapo reported one such wave with a height of 112 feet in the Pacific in 1933.  Another report of a freak wave occurred when one struck the Queen Mary amidships, south of Newfoundland, at the end of World War II, rolling her to within a degree or two of capsizing.

References

The Weather Doctor, Keith C. Heidorn: ”Weather Almanac for June 2004: SLOSHING THE LAKES: THE SEICHE”

NOAA NWS JetStream – Online School for Weather: Wind, Swell and Rouge Waves

NOAA NWS JetStream – Online School for Weather: Tides

NOAA Ocean Service Education:  Tides and Water Levels

Sailor - Global Mariner Photos by Karsten Petersen

Wikipedia, the free encyclopedia: Rogue Wave

The Eyewall Of Hurricane Katrina

When the first hurricane emerges from the Atlantic Ocean or Gulf of Mexico this season, NOAA will use a new statistical model to help predict the start of the “eyewall replacement cycle,” a key indicator that a storm’s strength and size is about to change dramatically. This new tool adds to a suite of forecast products NOAA uses to warn coastal communities of imminent threats.

An eyewall is an organized band of clouds that immediately surround the center, or eye, of a hurricane. The most intense winds and rainfall occur near the eyewall. Within a hurricane, eyewall replacement cycles occur when a second concentric eyewall forms around the original and eventually overtakes it. This phenomenon especially happens in strong, long-lived hurricanes.

“Hurricanes usually strengthen and grow gradually over time, but eyewall replacement cycles can cause very sudden changes in size and intensity,” said Jim Kossin, a scientist with NOAA’s National Climatic Data Center, who led the effort to create the model.

The model predicts the start of the developing eyewall replacement cycle by measuring key aspects of the storm’s structure and environment and relating these to the conditions observed during past replacement cycles. Kossin said skillful forecasting of these natural cycles is crucial to protecting life and property.

“As it was approaching New Orleans, Hurricane Katrina weakened but grew in size because of an eyewall replacement cycle and the huge wind field led to an enormous storm surge that devastated the Gulf Coast,” Kossin said.

The model uses data from NOAA’s Geostationary Operational Environmental Satellites (GOES) to identify hurricane structure patterns related to eyewall replacement cycles. Microwave images from NOAA’s polar orbiting satellites were incorporated extensively to create the model using past data.

“This is an important first step towards understanding how we can use the eyewall cycle to someday improve intensity forecasts,” said James Franklin, branch chief of the hurricane specialist unit at the National Hurricane Center.

This project is part of the NOAA Joint Hurricane Testbed, which is part of the Hurricane Forecast Improvement Project under the NOAA Weather-Ready Nation strategic plan.

Hurricanes Karl, Igor and Julia (from left to right on Sept. 16) were part of the onslaught of Atlantic storms in the 2010 hurricane season. Image via NOAA

By Fred Pickhardt,

With two named tropical storms already on the books before the official start of the 2012 hurricane season I wanted to review what the Mariner’s 1-2-3 Rule is and if it should be revised. The most important ship routing tactic in dealing with tropical cyclones is avoiding them in the first place. The Mariner’s 1-2-3 Rule was developed as an aid for mariners to avoid tropical cyclones by accounting for forecast track errors and is a must for any mariner to know when navigating near a hurricane or tropical storm.

The Mariner’s 1-2-3 Rule originally was an adaptation made from a US Navy training film “A Time for All measures” in use during the early 1970′s. Since the 1990’s the Mariner’s 1-2-3 Rule has incorporated a “danger zone” by adding the 10-year average tropical cyclone forecast track errors which were at the time, approximately 100 nm for each 24 hour forecast period plus the radius of forecasted gale force (34 knot or higher) winds. The 34 knot or higher wind field was chosen as the critical wind speed because at this level or higher the wind and sea conditions significantly limit ship maneuverability. When ship maneuverability is limited, then course options are also significantly reduced.

There has been a significant improvement in cyclone track forecasting in recent years and we should now revise the Mariner’s 1-2-3 rule to better reflect this improvement. According to Lee Chesneau, owner of Chesneau Marine Weather and former Ocean Prediction Center meteorologist we should consider revising the rule as follows:

“The overall skills scores of the NHC for track location which the wind radii extends from, has vastly improved. The 1-2-3 Rule today should include the more accurate skill score data that adds up to about 1 degree of latitude (60nm) at 24 hours, 2 degrees (120nm) at 48 hours, and 3 degrees (180NM) at 72 hours.“

Tropical Cyclone Track Errors

For example, at 24 hours (1 degree of latitude or 60 nm) would be added to the right and left of the track. At 48 hours the error is (2 x 1 degree or 120nm) and for 72 hours the error is (3 x 1 degree or 240nm). In addition to the allowance for track error, the forecasted radius of gale force (34 knot or higher) wind field is also added. Therefore, if the 24 hour forecast shows gale (34 knot or higher) winds will extend out to 120 nm, then the radius of danger would be 60nm (the 24 hour average track error) plus 120 nm (radius of forecasted gale or higher winds) or a total of 220 nm danger zone left and right of the forecasted track and position.

This then becomes the minimum distance to maintain from the hurricane center in 24 hours. Keep in mind that larger safety zones should be considered whenever there is a high degree of forecast uncertainty, limited crew experience, or limits on vessel handling. The rule also does not account for sudden & rapid intensification of hurricanes that could result in significant expansion of the 34 KT wind field or to the typical wind field expansion that occurs when a hurricane transitions to an extra-tropical storm.

Proposed New Mariner's 1-2-3 Rule by Lee Chesneau of Lee Chesneau’s Marine Weather

The National Hurricane Center currently produces a “Tropical Cyclone Danger Graphic” depicting the “1-2-3 Rule” danger zone for tropical cyclones in both the North Atlantic and Eastern North Pacific oceans but this graphic still uses the older average track error of 100NM per 24 hours Perhaps it is time for NOAA to update this.

References

Hurricane Avoidance Using the 34-Knot Wind Radius and .1-2-3.Rules - Michael Carr George Burkley Maritime Institute of Technology and Graduate Studies Vol. 43, No. 2 August 1999 - Mariners Weather Log

A PREPAREDNESS GUIDE – U.S. DEPARTMENT OF COMMERCE, National Oceanic and Atmospheric Administration, National Weather Service Revised March 2011

Lee Chesneau’s Marine Weather Website

NOAA Tropical Cyclone Danger Graphic explanation

About Fred Pickhardt

I am a marine meteorologist with many years of experience in optimum ship routing, vessel performance analysis and weather event reconstructions.

The article originally appeared on Fred Pickhardt’s OceanWeatherServices.com blog and is republished here with permission

At the top of Lifehackers’ list (and ours too) is Weather Underground…

Founded in Ann Arbor, Michigan in 1995 it’s perhaps the web’s oldest weather site , yet hasn’t rested on it’s past performance in providing the most up-to-date and accurate weather information.  For this reason, it took the top spot on Lifehacker’s survey with close to 41% of the votes cast. The site is also well known in the technology community for being Google’s earliest and best friend, mentoring the young website through periods of rapid growth. It continues to lead innovation with new features like FullScreenWeather.com, a web tool launched to integrated mapping and mobile devices.  Combining official weather information (including live NOAA feeds) with personal and corporate weather station data, the site is virtual treasure trove of weather information.

Behind it with 20% of the vote was Weather.gov, the weather site from NOAA and the National Weather Service, and the source for many of the other contestant’s weather information and forecast data—clearly many of you prefer to go right to the source!

In third place with 19% of the vote was Weather.com, the site from the Weather Channel followed by WeatherSpark and finally Accuweather.

What we like most about Weather Underground is that, unlike so many new weather sites, they haven’t ignored the mariner. The site’s marine maps section contains vital information for routing your ship around storms and is used by mariners worldwide, including the gCaptain editors, for this very purpose.