Good evening all and welcome to the shorter version of our long range forecast. The full in depth forecast will be posted on 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 16th August to Saturday 21st August
The EC is suggesting that low pressure that has dominated the UKs weather clears away on Monday for us in the Western Isles we are expecting to see mainly fine day with sunshine and cloud according to the EC. For Tuesday the EC has fine dry settled weather across most of the UK low pressure in the North Sea with a fine dry day with sunshine and cloud for us in the Western Isles. For Wednesday a slack airflow across the UK with an overcast day with sunny spells for us in the Western isles with some light rain and drizzle. Thursday and Friday a slack airflow continues across the UK with spells of light rain and drizzle. Some heavier rain for overnight into the Saturday as a shallow area of low pressure forms. For the final day of the period a slack airflow across the UK with low pressure systems to the West of the UK one of the areas of low pressure would bring spells of rain but clearing later in the day.
GFS – Monday 16th August to the Wednesday 25th August.
The GFS is suggesting for the Monday that high pressure will be in charge to start the day across North Scotland but a brisk North Westerly airflow sets up with light rain and drizzle for later in the day. For Tuesday with high pressure to the South West of the UK a North Westerly airflow with sunshine and cloud with rain and drizzle for us in the Western Isles. Wednesday, Thursday and Friday will see the same brisk airflow from the North West according to the GFS with spells of light rain and drizzle for us in the Western isles with some sunny spells. An area of low pressure forms to the North of Scotland on Friday night. This will bring spells of rain heavy at times as we progress overnight into Saturday. This would then bring spells of rain which would be heavy at times during Saturday. The final four days of the time period and the GFS is indicating high pressure across North West Scotland would bring brisk winds at times sunshine and cloud with occasional spells of mostly light rain. Some decent and prolonged spells of sunshine. A long way off as yet but worth keeping an eye on.
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