In my early 20s as a student and then as a young professional, it was my twice-daily task to copy the coded weather station observations onto a map and then draw the isobars, isotherms, isopleths and other contour lines. My first effort took about three hours, but after a few months, I could easily plot and analyze a weather map of the Great Plains and Upper Midwest in half an hour.
It became a pleasure to draw those lines. I would never be confused for being an artist; my handwriting is barely legible, but my maps were a thing of beauty, at least to me.
A ripple in adjacent lines could be a place where a thunderstorm would develop. A weakening high pressure might signal a place to watch for fog. Computers do most of the analysis in today’s world, but hand-analysis is still the best way to learn how weather works.