Marine Weather Articles


Chicago Yacht Club Race To Mackinac - 2022
Thunderstorms seem to be attracted to sailboat racing. Perhaps it’s an affinity for fiberglass, but more likely it’s because competitors challenge Mother Nature by venturing offshore during the height of thunderstorm season. (read more....)


A Strong Cold Front Arrives
The much heralded cold front reached Lake Erie overnight. Wind quickly veered from southerly around 10 knots to westerly at 40 to 45 knots with the arrival of the front. (read more...)


A Little Too Much Excitement on Narragansett Bay
The final race of the Jamestown Yacht Club's summer series had a wild ending courtesy of a long-lived thunderstorms. (read more....)

Weather Forecast Models 101-Forecasting A High Wind Event
Several weeks ago, I published a summary of storm-force sustained winds, hurricane-force gusts, and a drop in water level approaching six feet across Lake Erie’s western basin, all courtesy of the passage of a deep low pressure system on November 27, 2019 (click here to read the summary). This article examines how the weather forecast models performed during the event. (read more...)

Weather 101-Thunderstorm Resources
Seasoned boaters know first-hand that weather conditions on the Great Lakes can change from pleasant to terrifying very quickly. From dangerous lightning to high winds, thunderstorms can ruin an outing in many ways. However, reading the marine forecast before leaving the dock and regularly checking weather radar along the way will dramatically increase your chances of avoiding uncomfortable or dangerous conditions. (read more...)


Hurricane Force Winds on Lake Erie
Wednesday, November 27, 2019 was a wild day on Lake Erie thanks to the passage of a deep low pressure system and its accompanying cold front. The surface forecasts issued by the Weather Prediction Center (WPC) suggested the powerful and fast-moving low and its cold front would reach Lake Erie’s western basin around sunrise on the 27th (Figure 1) and the eastern end of Lake Ontario by early evening (click here for forecast graphic). (read more...)

Lake Breeze Enhanced Thunderstorms
Even when the atmosphere is supportive of thunderstorms, a source of lift is necessary to provide the upward motion required by a fledgling storm’s updraft. A reliable source of lift is often found near a cold, warm, or stationary front accompanying an approaching low pressure system. (read more...)


Clearing Up Clouds
Sailors have been watching clouds since the first boat was launched. As aficionados know, clouds come in an infinite variety of shapes and sizes. The overall shape of a cloud and the altitude where it forms help tell the story of current and short-term weather patterns. (read more...)

Chaff on Radar?
On the afternoon on December 10, 2018, an area of what initially appeared to be precipitation (Figure 1) was detected northwest of Evansville, Indiana by the National Weather Service (NWS) Doppler Weather Radar station at Paducah, Kentucky (KPAH). When first detected, the blob was 100 nm northeast of KPAH at an elevation of approximately 12,000 feet. (read more...)


A One-Two Weather Punch: The Sunday Morning Cold Front
By any measure, the 2017 Chicago Yacht Club Race to Mackinac was no picnic. The Race started on Saturday under very pleasant southwesterly breezes and the fleet made good progress toward Mackinac Island. (read more...)

A Tale of Two Downbursts
Lake Michigan sailors have had a challenging summer. In mid-July, competitors in the Chicago-Mac were treated to a rare type of downburst known as heat burst (or dry downburst) near Milwaukee late on Saturday night (read more...)

A Rare Weather Event During the 2017 Chicago-Mac Race
After a challenging 2016 Chicago Mac (click here for a summary), this year’s competitors were likely hoping for an easier trip to the island. (read more...)

Doppler Weather Radar: A Boater's Best Friend
Weather-savvy mariners know the best resource for monitoring the location, size, intensity, and movement of thunderstorms is Doppler Weather Radar from the National Weather Service (read more...)

Deciphering Surface Weather Maps
Surface weather maps offer a wealth of information to the weather-savvy boater. However, the key to unlocking the vast treasure of information displayed on these maps is understanding the terminology and symbols used by forecasters... (part one --- part two)


A Little Excitement on Lake St. Clair
Whether it’s a beer can race or a top tier regatta, weather often adds a bit of excitement to sailboat racing. (read more...)

A Challenging Start to the 2016 Chicago-Mac
Competing in the Chicago-Mac is never easy – after all, it is at least 333 statute miles to Mackinac Island. And by all accounts, the 108th running of Mac was unusually challenging. (read more...)

Doppler Weather Radar: It Isn't Live But It's Getting Better
Doppler Weather Radar is your best defense against a hair-raising and wind-blown encounter with thunderstorms. (read more...)

Understanding Meteorological Time
Weather recognizes no geographic or political borders. In order to coordinate their observations and forecasts, meteorologists around the world use a standard timekeeping system. (read more...)


Sloshing and Surfing on Lake Erie
The marine forecast for Lake Erie on Saturday, June 27, 2015 suggested conditions were going to be unusually nautical for late June. Sustained northeasterly winds were likely to reach 35 knots, while gusts approaching 45 knots were possible. Significant wave heights were expected to reach 11 feet (read more...)

Trans Superior Sailboat Race: Weather Resources
The Trans Superior International Yacht Race is sponsored by the Duluth Yacht Club and is held on a biannual basis. The 338 nautical mile race begins at Gros Cap Light near Sault Saint Marie and ends near Duluth. (read more...)

The Mills Invitation Tropy Race 2015
The 2015 Invitational Mills Trophy Race, organized by the Toledo Yacht Club and the Storm Trysail Club, was held on Friday, June 5, 2015. The race includes three courses ranging from 37.7 to 70.9 nautical miles (read more...)

Tragedy Strikes The 2015 Dauphin Island Race
The 57th annual Dauphin Island Race (DIR) was held on Saturday, April 25, 2015 on Mobile Bay, Alabama. The popular DIR offers a one-way, 18-mile course beginning in the upper Bay and ending near the Dauphin Island Bridge in the Bay’s southwestern corner (read more...)

Chicago Yacht Club's Race To Mackinac - Climatology
Reviewing the long-term average wind and wave conditions on Lake Michigan for the middle of July is great way to set the stage for your Mac weather forecast, particularly for those who are participating in the Race for the first time. (read more...)

Bell's Beer Bayview Mackinac Race - Climatology
Reviewing the long-term average wind and wave conditions on Lake Huron for the middle of July is a great way to set the stage for your Mac weather forecast, particularly for those who are participating in the Race for the first time. (read more...)


A New Spin on Waterspout Forecasting
Several waterspouts, the intense columnar vortices considered “tornadoes over water”, have been reported across the Great Lakes over the past two weeks. Waterspouts come in two varieties – tornadic and fair weather—with the fundamental difference between them being the type of storm they are associated with, and the manner in which they form. (read more...)

The Effects of Lake Temperature on Gusty Winds
The Great Lakes -- individually and collectively -- play a significant role in the region's weather. This is especially evident in the spring and early summer when cold lake waters promote the development of fog, suppress temperatures along the shore, and diminish the potential for strong thunderstorms offshore. One phenomenon of particular interest to sailors is the significant impact a relatively cold lake has on the wind well into the summer months. (read more...)

Marine Model Output Statists (MOS): A Unique Wind Forecasting Resource
Sailors spend a lot of time analyzing wind forecasts, whether they're planning a short afternoon sail, preparing for a regatta, or developing a strategy for a long-distance race. (read more...)

Feeling the Pressure: The Value of a Barometer
Every cruising boat should have a reliable barometer on board. (read more...)

Lake Erie Wind Analysis: Gay Games Sailing 2014
The 2014 Gay Games sailing competition begins Monday, August 11 on the nearshore waters of Lake Erie, just west of downtown Cleveland, Ohio. The regatta, hosted by Edgewater Yacht Club (EYC), is comprised of nine preliminary races scheduled through Wednesday August 13, (read more...)

Doppler Weather Radar-When Storms Aren't Storms
Doppler weather radar has a lot to offer a weather-savvy boater. Before leaving the security of your dock, a quick look at the wide array of radar products offered by the National Weather Service (read more...)


Superstorm Sandy and Lake Erie
The remnants of Hurricane Sandy roared ashore near Atlantic City, New Jersey at approximately 7:30 pm on October 29, 2012 with sustained winds of 70 knots and storm surge exceeding 10 feet. Dubbed Superstorm Sandy, it ravaged the coast of New Jersey and New York and produced storm force winds as far west as the Great Lakes. (read more...)

An Unexpected Wind: Memorial Day 2012
Boaters clearly understand the dangers of being in a thunderstorm, but what about being near a thunderstorm? How close is too close? Are you too close if you can see the storm? Are you too close if you can hear the thunder or see the lightning? Are you too close if you can feel the rain? On Sunday, May 27, 2012, Lake Erie boaters learned that even sixty miles can be too close. (read more...)

Opti National Regatta Waterspout
Early on a Saturday morning in late July 2012, nearly four-hundred junior sailors were assembled at the Sandusky Sailing Club (SSC) in Sandusky, Ohio to participate in the Optimist Dinghy National Championship Regatta. Saturday was the third day of the Open Championship which was held on the protected waters of Sandusky Bay, east of downtown Sandusky and west of the Cedar Point causeway. (read more....)


Chicago Yacht Club Race To Mackinac - 2011
The Chicago Yacht Club sponsored the first sailboat race to Mackinac Island, Michigan, in 1898, earning it the distinction as the oldest freshwater race in the world. Over the next twenty-three years, the race was held sporadically and the course altered due to a variety of circumstances, including a hiatus prompted by World War I. (read more...)

The Forces Governing The Wind
The speed and direction of the wind is governed by three forces; the pressure gradient force (PGF), the Coriolis Force and friction. PGF is the force produced by differences in barometric pressure between two locations and is responsible for the flow of air from an area of high pressure to an area of low pressure. (read more...)

A Wet Spring in Northern Ohio
Residents of northern Ohio will remember the extraordinarily wet and gloomy spring of 2011 for many years. (read more...)

An Interesting Local Wind
Sailors are never entirely satisfied with the wind. Either there's not enough wind and they are forced to rely upon a noisy engine, or it's too strong and they are forced to seek refuge in a protected harbor. (read more...)

2010 and Earlier

Lake Ontario 300 Challange - 2010
Nearly 180 sailboats assembled on the morning of July 17, 2010 for the start of the Lake Ontario 300 Challenge (LO300). The boats were organized into several fleets (based upon their size and sail configuration) and were scheduled to start at 5-minute intervals beginning at 11:00 am local time (1500Z). (read more...)

Echo Tops on Doppler Radar Imagery
Radar is an excellent short-term forecasting tool, particularly during outbreaks of severe weather. (read more...)

Lake Erie Ice Transitions
The Buffalo office of the NWS posted two MODIS images showing the transition in ice cover on Lake Erie from February 8 to February 15, 2011. (read more...)

A Marina Takes A Hit
When thunderstorms threaten the Great Lakes, forecasters at the National Weather Service (NWS) traditionally conclude their marine forecasts with the following phrase -- Winds and Waves Higher In And Near Thunderstorms. (read more...)

A Stormy Trip: July 17, 2009
On Thursday, July 17, 2009 we were enjoying the final evening of our 2009 annual summer cruise at the recently remodeled Middle Bass Island State Park marina in Lake Erie's western basin. (read more...)

Chaff on Doppler Radar Imagery
The series of images below are Doppler radar base reflectivity scans from 1511Z to 1550Z on March 5, 2007 from the National Weather Service (NWS) Key West site. At first glance, it appears that a collection of unusually linear bands of precipitation were present over southern Florida and the Keys. (read more...)

Concentric Rings On Doppler Radar Imagery
The composite radar image below was produced at 2156Z on November 6, 2007 by the National Weather Service (NWS) site located at Caribou, Maine. (read more...)

World War II, Radar, Astronomy & Sun Spikes on Doppler Weather Radar
World War II, a time of extraordinary upheaval and untold human suffering, prompted a wealth of scientific discoveries and technological development. (read more...)

Ship Tracks on Visible Satellite Imagery
The unusual features in the lower left corner of the visible satellite below are referred to as ship tracks or ship plumes. Considering the number of large ships departing from the ports of San Diego, Los Angeles and San Francisco (read more...)

Lake Erie Displacement: December 23-24, 2007
The Great Lakes are a important natural resource and a study in contrasts. The largest, Lake Superior, contains approximately 3,000 cubic miles of water, has an average depth of 500 feet (1,332 feet at its deepest) and nearly 2,800 miles of shoreline. (read more...)

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Mark A. Thornton