Steering of Midlatitude Cyclones

(a) Notice that the cyclone (low) moved almost in a straight southeastward direction on March 21 and March 22. On the morning of March 23, it abruptly turned northward. This change in direction corresponds to the change from (b) rather straight contours on the upper-air chart for March 21 to (c) curved contours on the chart for March 23.