Long range weather forecast for the Western Isles – 18th June 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 covering from Monday 21st June until Wednesday 30th June

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 ( European Centre for medium range weather forecasts) which is based in Reading and the GFS (Global forecasting system) 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 21st June

High pressure dominates the weather across the UK. Both the GFS and the EC agree on this. With mainly fine and dry conditions. The EC has more in the way of cloud then the GFS which has more sunshine. It should be a fine and dry day with sunshine and cloud. Winds will be light. A few scattered showers are possible.

Tuesday 22nd June

Some good model agreement for Tuesday. Both models agree that high pressure over most of the UK with some rain for South East England. An area of low pressure to the North West of the UK will bring rain and showers to the Western Isles with some sunny spells according to the EC and the GFS.

Wednesday 23rd june

Again good model agreement for next Wednesday. Both the GFS and high pressure across the UK. The area of low pressure to the North West of the UK will bring rain and showers across the Western isles with some sunny spells. The GFS brings in heavier rain into the evening whilst the EC has more showery rain.

Thursday 24th June

Again good model agreement between the EC and the GFS with low pressure to the West of the Western Isles and high pressure across the bulk of the UK. The EC has a broader area of low pressure to the West and this would bring showery conditions with sunny spells. The GFS has more heavy rain across the Western Isles with plenty of cloud and a few sunny spells with brisk winds.

Friday 25th June

Some model differences for next Friday the EC declines the area of high pressure away. We are going to see spells of rain and showers clearing away to mainly fine dry conditions with sunshine and increasing amounts of cloud with light winds as high pressure builds across the UK. The GFS has low pressure to the West of the Western Isles and this would bring showers early in the day. Before clearing away to fine dry and sunny conditions before more rain pushes in from the South later in the day.

Saturday 26th June

Some slight model differences for next Saturday. The EC has high pressure building across the UK but the cloud dominating with scattering of showers with light winds. The also has high pressure across much of the UK with fine dry weather across the Western Isles with light winds. A weather system will move into the South West of England.

27th, 28th, 29th, 30th June

Now this is the really long range. So take it with a large amount of salt and is the silly range. So the GFS is suggesting that we may see more fine dry and settled conditions across the Western Isles. Even becoming warmer for a time. A risk of showers for the last day of this time period.

Our featured photo taken by Janet Morrison of the castle grounds.

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