Weather Routing For Your Yachting Needs

Beautiful boats, gorgeous skies, and that yacht life ambiance fully in place  at the 2017 Fort Lauderdale International Boat Show.

We at Weather Forecast Solutions provide can provide your yacht with both images and forecast analyses to help you safely get from point A to B.  Interested?  Let’s talk!

 

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Weathering Through the Yachting Season

Weather conditions are generally what drive the popularity of yachting season around the world. Most voyages are seeking the moderately warm breezes, long days, and pleasant waters.  Suffice to say, no one is pursuing 15 ft waves, freezing temperatures, or torrential rains.  While other determining factors such as cultural events, boat shows, and festivals also factor into intended routes, the weather is the general dictator on the scene.

Global pressure patterns will determine where and how wind patterns work, which ultimately control the associated wave heights and relative positioning of ocean currents.  Much like the phrase “work smarter not harder”, yachting also follows the same train of thought:  work with the elements and not against!  Riding with the currents can often save on fuel and can ensure a speedier ride.  It’s no coincidence that many of the global routes follow the natural flow of the water.

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Transoceanic voyages often follow the major ocean currents

Another major factor is precipitation patterns, as regional monsoon seasons can make for an extended wet ride. A seasonal wind pattern shift, such as ENSO (El Niño Southern Oscillation), is defined as a longitudinal shift in pressure patterns and winds which occur on average, every 2-7 years.

ELNINOJPEG
El Niño typically weaken or reverse the easterly trade winds to become westerly, as seen in this image.  This enhances warmer water to reach the Eastern Pacific, which further increases rain potential.

In the warm phase of ENSO, El Niño, easterly winds weaken or reverse.  This causes the warmer waters to shift from the Western/Central Pacific towards the Eastern Pacific, piling up along the South America coast. The warmer waters instigate thunderstorm development, so in turn, higher precipitation occurs.  Another side effect of the excess water is that it reduces upwelling, which is the ability of the deeper, colder, more nutrient-rich water to make its way to the surface. Ocean currents are related to water temperatures, so this shift alters the local currents.

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La Niña enhances the easterly trade winds, forcing water mass to pile into the Western Pacific. As a result, this elevates precipitation in the Western Pacific.   Meanwhile deeper (cooler) water upwells in the Eastern Pacific, which can limit thunderstorm activity.

Conversely, during the cool phase of ENSO, La Niña, the exact opposite occurs:  The easterly winds strengthen, which piles the warmer waters towards the West Pacific.  This migration of water from the East to the West makes it easier for upwelling to occur along South America.  The repositioned warmer waters over the West Pacific increase thunderstorm activity, and therefore precipitation potential.

Further examination of popular global destinations reveal that prime yachting season aligns with capitalizing on the best weather that each location has to offer:

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Peak months for yachting around the world, often follow the seasons.

The tail ends months of peak seasons tend to be the most financially affordable, as they occur while seasons are still transitioning from undesirable winds/rain/temperatures to the more preferred conditions.  While the weather can still somewhat be iffy, this is generally when dock space, berths, and anchorages are plentiful and tourists are minimal.  As yacht owners and charters seek sublime weather, peak seasonal time also brings overwhelming tourists and limited availability, hence higher prices.

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Global boating tracks, created via OceanPassages

Of course some locations are blessed with a year round type yachting season, such as Florida or the Caribbean, maritime SE Asia, or generally anywhere that is located near the equator.  Approximately 12 hours of daylight bless the equatorial regions, with daylight decreasing as you head north of south of this line.  While that ideally works for most of the year, the real caveat occurs when this excessive heat produces or strengthens tropical cyclones.  Rapid intensification or a change in track may force a yacht to redirect its route with minimal notice, or scurry towards an available hurricane hole.

Predicting and tracking the development and movement of tropical cyclones can be very tricky, as it involves a working knowledge of a four dimensional science: How things are changing 1) from east to west 2) from north to south 3) from the surface of the earth throughout the atmospheric column 4) with time. Recent activity surrounding Hurricane Harvey was a prime example of how a tropical system can intensify in a very short amount of time, as it went from a category 1 [74-95 mph] to minimum category 4 [130-156mph] in less than 24 hours.

The open ocean is a nautical playground for many, to which weather writes the rules.  Knowing the best time to take to the high seas is important, to make the best of your adventure and your time!

Severe Weather on the High Seas

Nothing makes a body feel as protected from the elements as a solid set of four walls and an up-to-code reinforced roof, but these protective features may not be present when active weather strikes.  Many seafarers find themselves subjected to harsh elements, putting them at the mercy of the skies above and the waves alongside their trusted vessels.

When it comes to the ocean, nothing “stirs the pot” like the wind; and the winds are a response to pressure differences.  More specifically, winds move from high to low values of pressure, and the greater the differences between the pressure fields, the faster the wind moves.  A good way to visualize this process is to imagine a ball rolling down a hill: the steeper the slope of the hill, the faster the ball will roll. Oh gravity, thou are a heartless force.

Ball Trajectory
The steeper slope will yield a faster speed as a result of gravity.

High pressures can ultimately be thought of as “hills”, the low pressures as the “dips”, and the ball is the “wind”.  So when analyzing atmospheric pressure patterns, much like a contour elevation map would indicate the steepness or grade to a hiker, tightly spaced pressure contours indicate a steep pressure change pattern, hence higher winds.

3D render of Pressure
Winds will flow from high to low pressures, and the steeper the slope, the faster the winds.
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Tightened pressure contours between a high and low pressure indicates a steep slope, which yields faster moving winds.

So the wind blows and the waves react as a result. Now depending on the size and location of the pressure patterns, winds and therefore waves of various sizes can be produced and travel away from their origin location.  Wind waves are a result of local winds blowing across the surface of the water that eventually break or reach a shoreline.

Waves

If no deterrent is present, these waves have the ability to propagate over hundreds of miles as a result of their momentum.  This is known as groundswell

Waves can often aid a vessel along its course, acting like a turbocharged engine to work in tandem with the boats own gas/diesel power.  However there are the other instances in which the waves become the foe.  Increased wave heights, including the elusive rogue waves can roll and/or even break a vessel, overpower engines or snap rudders, leaving a craft at the mercy of the winds.

While most know the tale of the RMS Titanic, other maritime disasters have encountered similar fates as a potential result of winds and their respective waves. A 656 ft German merchant ship, the MS München, departed Bremerhaven, Germany on December 7th, 1978 on a transatlantic voyage towards Savannah, GA.  In the early morning hours of December 12, the MS München sent out an S.O.S. signal, with its last reported position.  All search efforts were officially called off on December 22, with emergency buoys, life rafts, life vests and belts, and lifeboats retrieved from search operations and random encounters. The MS München was never located, but via investigations done on the salvaged lifeboats, it has been theorized that via severe weather, she likely succumbed to a series of large waves which both broke over the bow and eventually flooded the vessel, causing it to sink.

While it may be easier to associate poor conditions with big patterns, sometimes small scale phenomena can produced localized increases not seen in the big picture.  Two examples of this would be squall lines and water spouts.

Waterspouts can be sub-categorized into tornadic and non-tornadic, as a result of their formation source. The fair-weather types are most frequent, and are considered non-tornadic in nature, meaning they aren’t associated with a supercell thunderstorm as are the rarer tornadic waterspouts. Typical non-tornadic waterspouts start forming on ocean/lake surface and rise up to meet the base of a parent cloud.  They tend to last less than 20 minutes and produce winds less than 70mph, which would classify it as the equivalent of an EF-0 tornado.  Tornadic water spouts are a result of a rotating cloud which produces a tornado that then descends and connects to the surface of a body of water.  While limited in space and time, either type of waterspouts can locally whip up winds and waters, and boaters are advised to stay clear.

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Waterspouts in St. Thomas, US Virgin Islands | Photo by Erickson
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Waterspouts on the Mediterranean | Photo by Mehmet Gökyigit
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Waterspouts off the coast of Turkey | Photo by Tufancetiner

Tornadic waterspouts can also be associated with squall lines, which is a typically narrow but elongated band of intense thunderstorms.  The formation of a squall line in the near or offshore waters is usually ahead with an oncoming cold front associated with a low pressure.  While generally measuring about 10-20 miles wide, squall lines can stretch for hundreds of miles, and are capable of producing, tornadoes/waterspouts, damaging winds, and frequent lightning.  An incoming frontal boundary from the West or Northwest will alter winds in a location as follows:  Initial winds will be from the east/southeast to south, as the winds begin blowing from the local higher pressure towards the incoming lower pressure.  As the frontal boundary nears, winds will become south/southwest, finally becoming west/northwest as it departs. When a squall line approaches ahead of the frontal boundary, wind shifts can be sudden and fierce which leaves little time for vessel preparation.

From the small scale back to the large, no other weather phenomena has the power and expansive reach than that of a tropical cyclone.  The amount of energy generated during the evaporation and condensation processes that produce the clouds/rain is almost 200 times the world’s electrical generating abilities, while the amount generated via the wind is roughly half of the world’s electrical generating abilities.  The movement across the ocean basins can generate long range swells that can be felt several hundred miles away.  Navigating a vessel around the associated increases can be tricky and requires advanced knowledge of environmental factors to determine potential storm trajectories.

Tropical_Vis and RH
Visible satellite, mid-level relative humidity, and steering flow of 2016’s Hurricane Matthew.  This image was produced while Matthew was a category 3 system; less than 8 hrs later, Matthew would briefly strengthen into a category 5 system.  This system made 4 separate landfalls:  Haiti [cat 4], Cuba [cat 4], The Bahamas [cat 3 & 4], and South Carolina [cat 1]

When interaction with a system is imminent, understanding how to circumnavigating via the “Front Right Quadrant” [FRQ] becomes key.  If one was to intersect the system with a “+” sign, the FRQ is defined as the front and right side of the system, relative to the storms forward motion. This is where the storm’s winds work in tandem with the directional wind to produce the highest winds of the cyclone.  In other words, the side to be avoided if at all possible.

FRQ
The front right quadrant, relative to the direction of motion, indicates where the strongest winds of a tropical cyclone are located.  This is where the systems’ winds work in tandem with the motion.

While there are many hazards out to sea, advanced planning and a working knowledge of the science behind these risks can help minimize disasters out to sea.  Knowledge is power and coupled with a bit of luck, here’s hoping for fair winds and following seas.

Boating Conditions Along Gulf of Mexico and Atlantic

For all the #boaters in the [aquatic] house, increased conditions in vicinity of [20-25 kts] winds and [4-6 ft] seas behind the frontal boundary [white line] in the NW Gulf of Mexico.

SWH Analysis

These increases will continue to propagate eastward through the Gulf through early Tuesday, arriving along the East Gulf waters by Monday afternoon. Strong northerly winds will continue to build in behind the boundary, likely remaining in and around [10-15 kts] through early Monday morning.

Elsewhere, southerly flow along the U.S. East coast will continue to increase through midweek, with sea heights additionally increasing beyond [6 ft] as the weak low off the East Coast of #Florida lifts northwards and towards the #MidAtlantic.

NOTE: Img indicates significant wave heights in ft and winds in kts.