A weather related question

[chump]

Last few days its been 20 degrees or so where I am. Today the maximum temp was 12 degrees. It occured to me that whenever there is a large temperature 'swing' like this it always seems to happen overnight. That's to say the swing doesn't happen half way during the day. I'm especially confused as this swing is supposedly due to the jet stream shifting again - surely this doesn't happen only at night?

It was the same when I was in adelaide, Australia. One day it was 40 deg the next 18 degrees. But again this happened overnight.

Can someone enlighten me why this happens or am I missing something obvious?

 

[John]

sun goes down, it gets cold. sun doesn't come out again, it stays cold

 

[njdbaxter]

sun goes down, it gets cold. sun doesn't come out again, it stays cold

cant believe they didn't know that.

isn't the sahara desert supposed to get really cold at night

 

[gibbsy]

Weather is dictated by weather fronts, mainly warm fronts and cold fronts and there is a third type an occluded front. When a front comes through the country the warm or cold air usually floods in behind it. Warm fronts, at this time of year are usually Atlantic fronts, sometimes bringing very warm air from the Azores. Cold fronts usually come in front the north west or as was the case during the spring continental Europe.

All this weather is driven by the jet stream. If it is to the north of the UK our weather will usually be warm and dry. When over the UK or close by we can be hit by weather front after weather front such as last summer. To the south we can expect very cold weather as we have recently experienced.

Why does it go cold overnight? A cold front passing through the country during recent days will not see a dramatic fall in temperature during daylight hours, the sun at this year is getting stronger and heats up the land. The following night however the warmth of the land escapes into the atmosphere and the air gets colder, hence what seems like a dramatic drop in temperature overnight. Remember at this time of year the seas around the UK are cold and the Artic air is still a big player when weather systems drags in the air from the north.