Weather Routing... sailing the 1020 isobar line... Interesting article

[Owly055]

https://www.riggingdoctor.com/life-aboard/2018/1/11/weather-routing-and-barometers

Here is a bit of this article.  The author operates a Utube channel called The Rigging Doctor.

Playing around with a few programs, I noticed a trend emerging with the route that they would suggest. They all seemed to follow the 1020mb isobar line. Any two points, anywhere on the map, the route always seemed to follow this isobar as best it could. This was my first clue into an enlightening discovery.

While 1020mb may seem like an arbitrary isobar, this region is known for having mild and steady winds. If the pressure is greater than 1020mb, you risk reaching the center of a high pressure system where the wind vanishes, and if you venture into areas where the pressure is less than 1020mb, you risk running into a low pressure system with its associated storm conditions. It seemed that there was something magical about 1020mb.

In further reading, I found a review of 5 popular (payment required) weather routing programs posted by Sail Magazine.At the end of the review, the author noted that all of these programs  "...aim for a course very close to the 1020mb pressure isobar. There's something to be said for the old-timer's simple route planning." (Source: https://www.sailmagazine.com/cruising/weather-routing-101-part-2)

That line: There's something to be said for the old-timer's simple route planning. That stuck out to me as it confirmed that the weather routing programs that charge are also following along with the 1020 isobar line!

When following this line, the winds appear to be steady and uniformed in the same direction as it revolves around a high and low pressure system. The winds circulating around a high pressure system will always rotate clockwise while the winds circulating around a low pressure system will always rotate anti-clockwise (in the Northern Hemisphere). Knowing this, it is possible to pick a downwind route from any Point A to Point B by following the 1020mb isobar around high and low pressure systems!