Do severe storms usually develop right along and ahead of a cold front?

Question

Do severe storms usually develop right along and ahead of a cold front?

Answer 1

The answer will depend on your location.

For the United States, this is mainly true for locations east of  the Rockies.  For the Pacific Northwest, the Great Basin, the Southern Cascades, the Sierra Nevada, and the area west of the Sierra Nevada mountain range, most of the severe storms occur when the upper low moves over the region after frontal passage.  

The main reason are the hills and mountains that makes up most of the terrain in the Western U.S. These mountains and hills will keep the warm air and low level moisture from mixing out with initial frontal passage.

With clearing skies behind the cold front, the trapped low level warm air will warm even more with daytime heating behind the front.  The air aloft will continue to cool as the cold core will move in and overhead behind the front.  This will increase the instability with time behind with the initial frontal passage.  The upper jet will provide the jet dynamics and the cyclonic flow of the mid to upper level will support the development of the low level speed and directional the shear.  The main result will be an increase in CAPES and low level helicities resulting in a better enviroment for strong to severe storm development.  

Therefore, strong to severe thunderstorms will more likely occur after the cold frontal passage for the West.  So the answer to your question really depends on the area you are forecasting.  Always be aware that there are many locations in the world that do not follow what the text books teaches you.

Answer 2

Yes, a great place for severe thunderstorm development is ahead of a cold front. However, it must be strong cold front, meaning the air mass contrast must be sharp. Also, there must be plenty of moisture, high instability, wind shear, and upper air support. A dry line would be very helpful too.

Severe thunderstorms can also occur with convergent or convective lifting.

Answer 3

Yes, the majority of severe thunderstorms do develop along and ahead of a cold front. This area is prime for development due to the southerly winds bringing in plenty of moisture from the Gulf of Mexico ahead of the cold front and the larger amount of instability located ahead of the front. Behind the front, winds shift from southerly to more northwesterly and instability typically decreases due to the cooler surface temperatures.