Undercutting.

[feb1991blizzard]

Just a quick question here, maybe ive got it wrong but back in the day in the 80s, the BBC forecast team used to describe undercutting in winter as cold air from the East circulating around a scandi high dipping to a lower altitude than the air approaching behind a front from the West, but a lot of people on here say its the low 'undercutting' the block? which is actually the correct terminology?

Edited October 23, 2013 by feb1991blizzard

[knocker]

I think it's a term that can be used in various stuations when cold air undercuts warm air. The obvious example would be a cold front. The idea that cold air wedges, or undercuts, the warm air is often used to depict how advancing cold fronts force warm air to rise along the sloping cold air. I doubt there is a strict definition but I've been known to be wrong.

[Mark Neal.]

Undercutting- The idea that cold air wedges, or undercuts, the warm air is often used to depict how advancing cold fronts force warm air to rise along the sloping cold air, much like a snow shovel scooping up snow, creating instability. Provided with sufficient moisture, the rising air would thus condense, creating storms, clouds, and/or rain. While this concept is used to generally describe frontal precipitation patterns, it is technically incorrect.

[feb1991blizzard]

Thanks for the response.