# Why does wind direction change in a front? [duplicate]

Plenty of answers answer the question that it happens but I can't find a good answer as to why the wind shifts during the passing of a front. For an extreme example see:

(in Dutch, x is hours and y is wind direction in degrees)
Where a passing cold front moved the wind directon from south to northwest.

The other question provides a very broad answer as to why wind changes in general and the answers there are applicable in general. My question is about the specific circumstances of a thermal front and what causes the change in the balance of forces to suddenly allow or force the direction of the wind to change direction.

• @gansub sadly no, that answer is about the regular wind inside a system without fronts passing. Dec 15 '20 at 14:55
• a front is not some extraordinary phenomenon. It has to obey the NS or primitive equations with some balance condition rolled in. Dec 15 '20 at 17:01
• So yeah, what is that balance condition? It seems that a front either provides or releases some form of friction to, quite suddenly, change the balance of forces that makes the wind blow in a certain direction. Is it just the boundary between two air masses that provides this resistance? Dec 15 '20 at 17:41
• Dec 16 '20 at 2:24
• Mate if a wikipedia article answered my question I wouldn't be here. You seem to know the answer, please walk me through it. Dec 16 '20 at 11:45

## 1 Answer

An answer I got on Reddit which seems to make sense is that fronts are usually accompanied by a pressure change which locally reinforces the "normal" geostrophic wind which changes the wind direction.

If anyone has a more in depth answer I'd love to hear it.