Term of the day!
3/24/22
isobars
WW2010, Isobars: lines of constant pressure
isobars are lines on a weather map that join places of equal atmospheric pressure at a given time, reduced to sea level to ignore altitude differences
they are isolines, or contour lines, similar to those on topographic maps that can never touch each other
BBC Bitesize, Weather systems
isobars are typically drawn at intervals of 2 or 4 millibars (mb), a unit of air pressure in the metric system — 992mb, 996mb, 1000mb, 1004mb, etc.
the usual worldwide range in sea-level pressure is 970mb – 1040mb — anything lower towards 890 would be a strong Low like a hurricane, and anything around 1030 and higher would be a strong anticyclone High
isobars closer / tighter together on a map indicate stronger winds and turbulent conditions, while isobars spread far apart mean light winds and calmer conditions
