Long range weather forecast for the Western Isles – 22nd October 2020

Good afternoon and welcome to our long range forecast. This is posted either once or twice a week covering from 4 days ahead to 10 days ahead. In this update coving from Monday 26th October until Wednesday 4th November.

Please note there is not a lot of accuracy for this kind of time frame. Anything beyond 4/5 days out becomes really difficult and subject to change so we will be looking at trends. Mainly take with a large vat of salt. We will be using the main two computer models for this. The ECMWF which is based in Reading and the GFS which is the American based global model.

This comes from the GFS 06z run and ECMWF 00Z run. I will refer to EC to save on typing.

Monday 26th October

After a windy weekend there is some good model agreement that we are going to see winds easing down for a time. We are going to see a mixture of sunshine and showers. Some of these heavy with brisk winds from the North West. Temps in single figures. High pressure builds in with some rain moving in from the West much later.

Tuesday 27th October

A lot of uncertainty. A deep area of low pressure is expected between us and Iceland. The EC is suggesting low pressure below 940 mb to our West and we would see heavy rain and strong winds. The closer the low and the tighter the isobars the stronger the winds. This would likely bring us winds of 50 to 60 mph based on this current track. The GFS on this model runs keeps it further West and keeps it windy for us but the very strongest winds much further out to sea.

Wednesday 28th October

Good model agreement that keeps the deep area of low pressure out to sea. We would see strong and blustery winds across the Western Isles. With winds gusting 40 to 50 mph. Both models show a new area of low pressure. EC has it far West toward the end of the day. The GFS shows the low pressure over Ireland with strong winds and rain.

Thursday 29th October

Again some model differences with the EC suggesting the area of low pressure pushing past the North West of Scotland. Not that deep however we would see some strong winds for a time and showers. The GFS bring the low near Ireland Northwards it would bring rain and strong winds for us for a time. Risk of some snow over higher ground.

Friday 30th October

More differences with the EC suggesting a day of sunshine and showers. With heavy rain moving in later. The GFS suggests a deep area of low pressure moving across England and Wales into the North Sea with. Just some spells of rain for the Western Isles.

Saturday 31st October

Some more model agreement for the last day of October with high pressure building in for a time with some mostly light rain for the the Western Isles on the EC but in the GFS suggests some heavy rain for a time but becoming more settled.

1st, 2nd, 3rd and 4th November

Now this really the long range. So really is take it with a large amount of salt and is the silly range. At this long range the GFS there is some suggestion of two areas of low pressure one to the West of the Western Isles and one in the North sea for the first two days and then a Northerly showery airflow setting up behind.

Thanks for reading any feedback is always welcomed.

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