Isobars

Isobars and isotherms are lines on weather maps which represent patterns of pressure and temperature. This  Isobars map are shows  blue lines which connect equal pressure values based on the set from 1000 mb with an interval of 4 mb above or below that. Isobar values are labeled in blue within the isobar lines that are contained in the map area. Additionally, centers of locally highest and lowest pressures are marked by a blue H and red L, respectively.




Source:https://www.ametsoc.org/amsedu/dstreme/extras/usr_guide/Pressure.html