Long range weather forecast for the Western Isles – 10th January 2021

Good afternoon and welcome to our long range forecast. This is posted either once or twice a week covering from 4 days ahead to 10 days ahead. In this update coving from Thursday 14th January until Saturday 23rd January.

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 which is based in Reading and the GFS 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.

Thursday 14th January

Some good model agreement for next Thursday with some early morning rain clearing away. A mainly fine and dry day with sunshine and cloud. Winds will be brisk. Some patchy rain but mainly dry. Both the EC and the GFS have high pressure over the UK and fairly mild day.

Friday 15th January

Fairly good model agreement with next Friday with high pressure in charge across the UK. The EC keeps conditions settled during the day before heavy rain moves in as we go overnight into Saturday. The GFS keeps things settled across the Western Isles fine and dry and with sunshine. Light winds. Both models have high pressure centred close to London on Friday.

Saturday 16th January

Model differences once again. The EC has rain moving across the islands this will be heavy to start the day but clears it away later in the day. Becoming dry and settled. Windy start. Low pressure tracks across the UK and across the leading edge could bring some snow showers. The GFS keeps high pressure firmly in charge with some patchy rain across the Western Isles. A deep area of low pressure approaches the South West of the UK and runs into the high pressure and sinks Southwards away from the UK.

Sunday 17th January

Some good model agreement once again with high pressure in control across the UK. The EC brings in some patchy light rain. The GFS keeps conditions fine and dry. We would likely see clear skies and settled conditions so once again a risk of frost and ice. The EC has low pressure South East of the UK and high pressure out in the Atlantic. The GFS has high pressure firmly across Ireland.

Monday 18th January

Solid model agreement with a slack airflow. We are likely to see some rain and showers. These wintry at times as the cold air comes down from the North again. Breezy conditions. Both the GFS and the EC are on board with this happening. Low pressure over Northern Europe and High pressure in the Atlantic helps to drive down the colder airflow.

Tuesday 19th January

Again good model agreement with high pressure over the East of Scotland. An area of low pressure slides down from the North West across the Western Isles. This would bring some patchy rain and drizzle with brisk winds. Both the EC and GFS suggest this.

20, 21st, 22nd and 23rd January

Now this is the really long range. So take it with a large amount of salt and is the silly range. So with the GFS it suggests fine dry and settled weather for the first two days and then rain and showers for the final two days. With some stronger winds.

Thanks for reading any feedback is always welcomed.

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