Well, not really a puppy, but usually when frontal systems come in from the Northwest they head in from the Atlantic, turn to snow across higher ground of Scotland and perhaps the Pennines before making their merry way into the North Sea and the sun comes out and everyone is happy.
But, the frontal system which comes in on Saturday is a little bit different and it's causing a few scratching heads here at Metcheck HQ with regards to how the models are handling it.
First of all, the system comes in from the Atlantic on Friday with rain across Northern Ireland and Western Scotland before turning to snow across the Grampians and Northern Scotland. Nothing strange or untoward at this point. But then the scratching heads scenario starts overnight on Friday and into Saturday as the front begins to stall as it crosses the UK. What happens, is that a frontal wave develops on the system. In fact, the actual wave develops somewhere down near the Bay of Biscay and then runs Northward up the frontal system and begins to develop. This does a couple of things, the first is to slow down the front even more, the second is to introduce some form of rotation along the front which then develops into a low pressure area and starts to move Southeast.
When this happens, a circulation develops where the centre of the low pressure starts. This then draws in colder air on the Northern edge of the low which then undercuts the front and the rain starts to turn to snow. At the moment, the best guess for this to happen is around the North Pennines and Southern Uplands some time during Saturday morning.
Once the low pressure is created, it will then start to head Southeast and bring a mix of rain, sleet and snow South across the UK. Where it develops and when is still open to interpretation and it's something which we will be taking a closer look at during Thursday and Friday. But if you do have travel plans on Saturday then just keep an eye on the weather at the moment with regards to this little puppy which we expect to develop.
If you take a look at the GHX model below, you can see the rain turning to snow and the front in question if you run it forward to Friday.
METEOROLOGIST : MARSH
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