Understanding Pilot Charts and How they Can Help in Planning a Cruise
When the Atlantic hurricane starts, I think of how Pilot Charts can help analyze each month storms. I consider August the beginning of the Atlantic Hurricane season, although technically, it runs from June 1 through Nov. 30. But I call it the beginning, because traditionally, there are no big storms before August. Tropical storms will develop, maybe even a Category 1 or 2, but the big storms—what they call “major storms”—develop starting in August and this continues through mid-October. The height of the season is said to be around Sept. 10-11, about mid-point of this more active storm period. Major storms never really have developed after mid-October, although times could be changing.
When I first came to Florida in the winter of 1979, I really knew nothing about hurricanes, being from the West. I had purchased a 26-foot Folkboat that I was living on in Palm Beach (yes—Palm Beach, town of the rich and famous, although most of us at the Royal Poinciana docks were lowly liveaboards) at a small marina, and I was planning to cruise the Bahamas during the summer. I needed to know more about the winds and currents in the areas I was going to be in, plus I figured I better learn something about hurricanes, and my studies led me to Pilot Charts. I can’t remember the cost, but I remember they were expensive to me. But they were so intriguing, I bought a set anyway (since I consider them bordering on sacred, I still have them to this day).
Pilot Charts cover five regions of the world’s oceans. The one of concern to our region is the North Atlantic, which goes as far south as the northeast coast of South America. Since Pilot Charts are concerned with sailing conditions, there is a chart for each month. For the North Atlantic, there is a separate chart for the northern North Atlantic (Labrador and north), the central North Atlantic (south to Guyana), and a chart showing, in a larger scale than the central chart, the Gulf of Mexico and the Caribbean Sea, which is important for those sailing and cruising the Southeast U.S., the Bahamas and the Carribean. Each of these regions have a chart for each month. You can therefore use the chart to learn about the winds and currents in each month.
Pilot Charts Show Winds, Currents and Major Hurricane Tracks of Past Storms
On each Pilot Chart are Windroses of prevailing winds – showing both direction and strength of winds. Also shown on each chart are the currents and storms for the month covered. Other monthly information is given, depending on the location and month, like wave heights, water clarity, surface pressure, air temperatures, ice limits, visibility and gales. See the Wind Roses, taken monthly from Pilot Charts, on our monthly weather page in each issue of SOUTHWINDS.
The main feature that first sparked my interest was the tropical storm tracking. The map of the Caribbean and the Gulf of Mexico shows major storm tracks going back to the early 1900s. They even have a small map of the region showing probabilities that there would be a tropical storm in different zones of a grid.
The tracks of major hurricanes shows where storms became hurricanes and where they went. The differences for each month are informative. For example, in September—height of the storm season—they were all born southeast of the Gulf, around 20 degrees latitude and moved in a clockwise curve moving into the southeast states. If you look at the November chart, there are no tracks of severe storms and the probability of any tropical storm is low. Same for June and July. The busiest months are always August and September, and some in October, but history shows that the major storms happen only in early October. These are older storms pre-dating all the information we have today. Today, we have much more thorough information on past storm tracks on the internet. To view past storms, go to this website.
Where Pilot Charts Came From
The hurricane information is interesting, but the amount of data collected on prevailing winds, currents, air temperatures and pressure is monumental. Not so much today, since there are weather buoys, weather balloons and data collection today that is live and connected to data centers electronically, but before this modern age, this data was collected from ships at sea, by entries into the ship’s log and onto charts. It was first compiled, manually, in an organized system by Lieut. Matthew F. Maury, U.S. Navy, who studied thousands of ships’ logs and charts in the mid 1800s to make the information available to ships at sea. He is considered the father of modern oceanography and naval meteorology and one of the main results of his work are the Pilot Charts.
Where to Get Pilot Charts
Below you can view and/or download the Pilot Charts for each month for the Gulf of Mexico, Caribbean Sea, the Atlantic off the coast of Florida, and the Bahamas. For the Pilot Charts of the North Atlantic and the other oceans of the world, you can download them for free as PDFs at www.offshoreblue.com. Click on “Navigation,” then “World Pilot Charts.”
The above charts in this article link to hi-res images of the downloaded charts for the month of January (also available below). To view and/or download the Pilot Chart of the coast of Florida, the Caribbean Sea, the Bahamas and the Gulf of Mexico for each month, click on the month: