Long range weather forecast for the Western Isles – 11th November 2020

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 12th November until Saturday 21st November.

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 12th November

Some model disagreement the EC keeps us fine and dry with brisk winds which would gust 30 to 40 mph. Low pressure out to the West of the Western Isles. The GFS brings the low pressure closer to the Western Isles again brisk winds and would push in heavy rain during the evening after a mainly dry day with some early morning rain.

Friday 13th November

Again model differences with EC a showery airflow with brisk winds. most of the rain in the North West of Scotland. The GFS bring the above area of low pressure across the Western Isles. The rain will be heavy at times. Winds would be gusting 40 to 50 mph. The low pressure at its deepest 965 mb.

Saturday 14th November

Good model agreement with both the EC and the GFS showing areas of low pressure to the North West of the UK bringing spells of rain which will be heavy. Again would be expecting winds gusting 40 to 50 mph. The EC has the low pressure deeper. The GFS has it more broad.

Sunday 15th November

An improving picture for Sunday. In between areas of low pressure things are expected to settle with some light rain and breezy conditions. There is good model agreement on this with the low pressure moving away. Some sunshine.

Monday 16th November

Some model disagreements once again. The EC brings in a deep and vigours area of low pressure across the Western Isles. This would bring gales or severe gales for a time. With heavy and persistent rain. However the GFS is in disagreement with a brisk winds and some rain but the area of low pressure far to the South West. Something to keep an eye on.

Tuesday 17th November

More model disagreements. The EC moves area an area of high pressure across the Western isle which would settle conditions right down with light winds and sunshine. With rain moving in later in the day. The GFS has brisk air flow with an area of low pressure to the far North West. A sunshine and showers day.

18th, 19th, 20th 21st November

Now this is the really long range. So take it with a large amount of salt and is the silly range. Some rain and showers for the 18th before high pressure builds for the last few days of this long range period. Introducing some colder air.

Thanks for reading any feedback is always welcomed.

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