As I type this clouds are once more gathering to the west with the promise of yet more rain. It is already my wettest January here in Haytor since I started recording in 2002. As of 1800 GMT 20/1/14 my rainfall total stands at 274.5mm. If you add this to the December total of 407.7mm you get 682.2mm for the winter so far. A whopping 1000mm (1 metre) of rain is certainly possible for the whole winter period. Of course this is the last thing folk on Dartmoor need as the ground is completely saturated, so what of the future?
Well I can see no end in sight to this onslaught. Drier and very cold air is sitting to our east over Scandinavia but has been reluctant to move west and early next week deep Atlantic lows will dive southeast into Britain. Some cold air from the east will be drawn in, so there is a risk of some snow but there is also great uncertainty in the detail. The chart below shows one of many possibilities.
This chart (click on it to enlarge) is from an American numerical weather prediction model and is valid for 0000 GMT next Tuesday, a week ahead forecast. The low pressure system over south Wales will give a lot of rain over Dartmoor as it tracks southeast and the pale blue line indicates that cold air is not far away highlighting the risk of snow. Other models give a different evolution but all of them give rain. Outside chance that once the low moves away south then it could turn dry and frosty for a while, but I’ll believe that when I see it. Interesting times ahead once again for us meteorologists, but not good news for our beautiful landscape and pot-holed roads up here on Dartmoor. Unless it snows of course!