Use of the 500 mb Chart at Sea

The 500mb forecast chart is an excellent tool for mariners to estimate where to anticipate the heaviest sea and swell conditions as well as a guide to the expected surface storm tracks and intensities.  The closer the height contours on the 500mb chart, the faster the upper level wind flow, the stronger the temperature contrasts and the more active is the surface weather below. The development and strengthening of surface lows and the associated bad weather most often occurs on the eastern side of 500mb troughs while surface high pressure and good weather is associated with the western side of these troughs.  Without even looking at the surface pressure charts, a mariner can estimate what areas might be best to avoid.

Today’s 500 mb chart of the North Pacific is a good example.

NOAA OPC 500 mb Analysis Dec

Note the actual significant wave height analysis 

Click here to read more about using the 500 mb chart at sea.

About Fred Pickhardt

I am a marine meteorologist and sailed briefly with American Export Lines in the Far East trade after graduating from State University of New York Maritime College. I have extensive experience in weather analysis, weather forecasting, optimum ship routing, vessel performance evaluations and forensic weather event reconstructions. I founded Ocean Weather Services and as Owner and Chief Consultant currently provide optimum ship routing services and forensic marine weather reports to the maritime industry.
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2 Responses to Use of the 500 mb Chart at Sea

  1. Sailing Infidels (@Sailing_Infidel) says:

    Thank you for this.

  2. Greg says:

    Very usefull , thank You! Gretting from Poland Fred!

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