Cold Polar Maritime Air MassesAdded : Saturday at 14:10 One of the main characteristics of the weather across Britain and Ireland this winter has been frequent bursts of west/north-westerly winds bringing Polar Maritime air to our part of the world. The next couple of days will see another period of winds coming in from the west or northwest, and these winds will bring some unusually cold air with them although it will still have been modified by the milder waters of the North Atlantic Ocean.
So why are they bringing some unusually cold air? Basically the polar vortex has been located over towards Canada and Greenland during the last couple of weeks or so, as can be seen by the dark blues on this chart from lunchtime today:
During the next 24 hours or so a secondary area of low pressure will be pushing eastwards across Britain and Ireland, better seen on the high resolution Arpege model:
Not only will this feature bring a spell of wet and very windy weather (wind gusts of up to 60-70 MPH possible in exposed spots on its southern flank for a time) during Saturday night, but it will then pave the way for those cold west/north-westerly winds to return. A look at the pressure chart for tomorrow shows where those winds are originating from:
Yes, direct from Greenland and north-eastern Canada. So although the air will have warmed up a touch by the time it gets here, it will still be very cold and cold enough for most of the precipitation to be falling as snow:
Most of the precipitation will be in the form of showers so it will always be northern and western regions of the UK and Ireland that see the heaviest and most frequent of the hail and snow showers, but that's not to say some of the showers won't filter further inland at times. The snowfall accumulation chart from the Arpege model sums up well the areas likely to catch the most snow:
Despite all the showery activity and the strong winds, a widespread frost will form on Sunday night too so wherever you are there will be a wintry flavour to the weather in the next couple of days:
The rather cold and changeable theme continues well into next week too so no sign of any early springlike weather just yet.
METEOROLOGIST: BARBER |