Welcome to 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 8th November to Saturday 13th November
So the EC is suggesting that for next Monday the first day of the time period that high pressure will be in charge of the weather across the UK. For us in the Western Isles, a fine and dry day with plenty of cloud and some sunshine but a weather system will move in later in the day bringing rain heavy at times across the Western Isles. Into the Tuesday we are more than likely going to see a showery regime set up across the Western Isles after the previous days heavy rain has cleared away. This showers and possibly squally rain will be accompanied by windy possibly gale force winds. On to the Wednesday and it is likely that we will see more in the way of rain and showers across the Western isles. Heavy rain will move into all parts later in the day as the next weather system moves across the Western Isles. Into the Thursday and a band of heavy and slow moving rain will move across the Western Isles gradually clearing into the evening. Behind it drier and brighter weather and plenty of clouds along with brisk winds. For the Friday and Saturday, high pressure will dominate much of the weather across the UK. However, bands of rain will feed across the islands on both days bringing spells of heavy and slow moving rain as warmer air from the tropics sinks across the UK.
GFS – Monday 8th November to Wednesday 17th November
Now the GFS is suggesting that for the Monday high pressure will dominate across large parts of the UK with weather system moving across the Western Isles bringing wet and at times windy weather across our islands. Into the Tuesday and an area of low pressure moves across the UK. But for us in the Western Isles it would be a mainly fine and dry with plenty of cloud some light rain and drizzle moving in later in the day. Onto Wednesday and the GFS suggest that high pressure builds across most of the UK but for us in the Western Isles a band of rain heavy at times would move across the islands. But behind it high pressure will build in meaning a fine and dry end to the day with sunshine and cloud with light winds. For the Thursday and Friday similar to above with high pressure across most of the UK with rain feeding across the islands thanks to tropical air moving in from the South West. Into the Saturday high pressure builds in again and a fine and dry day across the Western Isles but with brisk winds. For the final four days of the time period, the GFS is showing high pressure across most of the UK with some spells of light rain.
Thanks for reading any feedback is welcome. Featured photo Bernera standing stones – Caroyln Prosser