Long range weather forecast for the Western Isles – 7th October 2021

Welcome to the our long range forecast for the Western Isles. This is our twice weekly update covering up to two ahead. We look at trends and patterns. Usually posted on a Thursday and Sunday.

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.

EC – Monday 11th October – Saturday 16th October

So the EC is suggesting high pressure across most of the UK with an area of rain moving across the Western Isles with a developing area of low pressure. The end of the day would be fine and dry with sunshine and cloud as the area of low pressure clears away. Tuesday high pressure dominates across the UK with sunshine and cloud. For us in the Western Isles it would be mainly fine and dry with sunshine and cloud along with light winds and scattered showers. Into the Wednesday and high pressure slides away southwards with brisk winds for us in the Western Isles along with rain and showers these heavy at times. For Thursday high pressure across the South of the UK but an area of low pressure far to the North of the UK will bring heavy rain and blustery winds across Scotland staying unsettled for us in the Western isles with rain and blustery winds. Friday and Saturday high pressure develops across Northern Scotland which would result in fine and dry conditions with sunshine and cloud along with light winds. But light rain moves in later in the day with increasing winds late on the Saturday.

GFS – Monday 11th October – Wednesday 20th October

So the GFS is suggesting that high pressure develops across the UK with a wet start to the day on Monday across the UK with rain clearing away to sunshine and cloud later in the day. Into Tuesday, Wednesday and Thursday very little change as high pressure develops across the UK with sunshine and cloud for us in the Western Isles with some light rain at times. Winds would be brisk as we sit on the edge of the high pressure. Lighter winds for the Tuesday. For Friday we are likely to see heavy rain move across the Western Isles as an area of low pressure moves in from the North West along with blustery winds. High pressure sits across the far South of the UK. Into Saturday and Sunday with brisk winds across Scotland with sunshine and cloud across the Western Isles with some scattered showers along with high pressure across most of the Southern half of the UK. For the final two days of the time period high pressure still persists for the many but a band of rain will move across the UK and gradually weaken this would bring rain to the Western Isles for a time before coming drier later.

Thanks for reading any feedback is welcome. Featured photo taken by Màiri Robertson Carrey

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