The mini long range forecast for the Western Isles – 29th July 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 2nd August to Saturday 7th August

A slack airflow across the UK for us in the Western Isles we are going to see a day of sunshine and cloud with scattered showers for the Monday. Tuesday and high pressure dominates across the UK but showers move across the Western Isle which will be on the periphery of the high pressure system. Next Wednesday looks mainly fine and dry across the Western Isles but a rash of showers moves across much of the UK with a developing area of low pressure moves into Ireland which would bring increasing winds and rain here. For the Thursday the low pressure moves across the UK brining rain here but staying fine and dry for us in the Western Isles with sunshine and cloud. For the Friday and Saturday I am expecting mainly fine dry and sunny weather with brisk winds across the Western Isles as one area of low pressure departs away from the UK and the next one moves in.

GFS Monday 2nd August to the Wednesday 11th August.

The first day of this time period for the GFS is Monday showing light winds and high pressure dominating with some decent and prolonged sunshine across the Western Isles after a cool start becoming warmer as the day progresses. For the Tuesday, Wednesday and Thursday we are expecting to see sunshine and showers across the Western Isles with brisk winds. Winds would ease for the Friday we are going to see a fine dry day with some decent and prolonged sunshine. For the Saturday a band of rain heavy at times would move across the Western Isles. Winds would increase. For the final 4 days of the time period a succession of low pressure systems are currently forecast to move across the islands before becoming fine dry and settled for the final day of the time period. Lots of uncertainty as yet.

Thanks for reading any feedback is welcome. Our featured photo taken by Liz Sutherland at Scalpay

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