Long range weather forecast for the Western Isles – 13th January 2021

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 Sunday 17th January until Saturday 26th January.

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.

Sunday 17th January

Good model agreement for next Sunday with low pressure close to Shetland and a brisk airflow across the Western Isles. Showery conditions with some heavy rain as we go overnight into Monday. Winds gusting 20 to 40 mph. The GFS has the low pressure a bit further North then the EC but again the same brisk airlow and feeling colder. Some wintry showers are possible.

Monday 18th January

Some model differences for next Monday with the EC showing low pressure to the North of Scotland and this will bring spells of rain heavy at times possibly wintry at times. Brisk winds. The GFS has low pressure to the South of us moving across Ireland and central Scotland. This would bring us some morning rain but keeping us mainly dry with a few showers drifting into Barra. Winds will ease

Tuesday 19th January

Big model differences for next Tuesday. The EC has low pressure still slow moving to our far north with rain and showers and brisk winds. A high pressure system develops across central Scotland. The GFS develops a deep and broad area of low pressure centered over Wales. This would bring some heavy snow across Scotland. Rain and wintry showers with blustery winds over the Western Isles.

Wednesday 20th January

Some good model agreement for next Wednesday with both the EC and GFS bringing low pressure over the UK bring rain and snow to large parts of the UK. The area of low pressure would results in rain and wintry showers across the Western isles with winds gusting 30 to 40 mph. Possibly some stronger winds and feeling cold. EC has the low centred close to Newcastle and the GFS has the low near edinburgh so depending on the position of the low will determine how windy it will be for us.

Thursday 21st January

Good model agreement for next Thursday with the low pressure moving out into the North Sea. However both move it at different paces. The EC moves it slower and this would result in it staying windy with further wintry showers and spells of rain heavy at times. The GFS moves the low pressure system out into the North sea quicker. Spells of scattered showers but mainly dry with lighter winds.

Friday 22nd January

Model difference for the Friday with the EC slowing the low down and keeping it down in the North sea with rounds of rain and wintry showers moving across the Western isles and staying windy. The GFS moves the low away and moves the next low into England and Wales. Mainly fine and dry across the Western Isles with a few scattered showers. Fairly light winds for most.

23rd, 24th, 25 and 26th January

Now this is the really long range. So take it with a large amount of salt and is the silly range. So with the GFS it suggests that we will see further spells of rain and wintry showers and blustery winds with additional spells of low pressure moving in. Becoming drier for the end of this time period.

Thanks for reading any feedback is always welcomed.

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