The mini long range forecast for the Western Isles – 19th August 2021

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 23rd August to Saturday 28th August

The EC is suggesting that high pressure will dominate the weather across the UK with plenty of sunshine across the Western Isles. Tuesday and Wednesday more of the same with sunshine and cloud with a few scattered showers as high pressure dominates with light winds. Thursday, Friday and Saturday sunshine and cloud with more in the way of cloud as high pressure dominates across the UK. Some scattered showers and these increasing in frequency on Saturday.

GFS – Monday 23rd August to the Wednesday 1ts September

The GFS is also suggesting that high pressure builds across the UK on Monday with fine dry and sunny weather conditions. It looks like high pressure will dominate for much of the week with sunshine and cloud for Tuesday, Wednesday, Thursday and Friday. Winds are likely to become more brisk later in the week for Thursday and Friday. For the final four days of the time period we could see more in the way of rain moving across the Western Isles for the Saturday and the Wednesday with brisk winds and a return to a more unsettled regime but that of course is a long way off as yet.

A little note of caution on the above as we are now in the peak of the hurricane season in the Atlantic there is a lot more uncertainty with longer range forecasts. These hurricanes can have an impact on the wider pattern of the weather across the Atlantic. Hurricane Henri will certainly be having an influence on the North Atlantic weather in the coming week. There is zero indication of any remnants heading towards the UK at this stage but even last year Hurricane Isaias helped to bring warmer and sunnier weather to the Western Isles as it influenced the flow of the jet stream as it moved towards Canada.

Thanks for reading any feedback is welcome our featured photo is Barra – taken by Carole Anne Fotte

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