Cut-off low

picture The cut-off low is a cold low (depression) in mid-latitudes (occasionally almost in subtropical latitudes) where air of polar origin is cut off from the main subpolar belt of low pressure and cold air, the normal track of depressions.


picture A cut-off low usually begins as a trough in the upper-air flow, which becomes a closed circulation and then extends down to the surface. Also known as closed low or cold pool. A cut-off low is marked by more or less concentric isotherms around the core of the low.


picture Cut-off lows are most frequent in periods of low index circulation . Sometimes a cut-off low occurs with a cut-off high over the higher latitudes, typically in blocking situations. Such slow-moving lows are associated with unsettled weather and, in summer, with thunderstorms.


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