Long range weather forecast for the Western Isles – 21st March 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 25th March until Saturday 3rd April.

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.

Thursday 25th March

Some good model agreement for next Thursday with a brisk airflow across the UK. A day of showers and spells of rain which will be heavy at times. Some of these showers will be wintry at times. Winds gusting 40 to 50 mph. It will feel mild but there is good model agreement on this from both the EC and the GFS.

Friday 26th March

Again good model agreement for next Friday both the EC and the GFS has a low pressure to our North West. The EC has it slightly further South and closer to us. But in the weather is expected to be mainly the same. A day of sunshine and showers. These heavy at times and possibly squally. Becoming wintry in nature for a time. Some decent spells of sunshine in between. Winds will be from the West gusting 40 to 50 mph.

Saturday 27th March

Some model differences for next Saturday. We are going to see a day of sunshine and showers according to the EC with blustery winds. A band if heavy rain out West and this is expected to stay out to sea. The GFS on the other hand drives an area of low pressure across the Western Isles which would bring strong winds and risk of gales. Further bands of rain which would be heavy at times.

Sunday 28th March

Some model disagreements for next Sunday. The EC pushes the aforementioned band of heavy and persistent rain across the islands. This would be slow to clear with showery conditions in its wake later in the day. This will be accompanied by blustery winds. The GFS has a day of sunshine and showers. These heavy and wintry at times with blustery winds. The GFS also develops a low pressure to our South as we go into Monday and would bring spells of rain which could bring stronger winds to Uist and Barra,

Monday 29th March

Some good model agreement for a week on Monday. The EC and GFS both suggesting a day of sunshine and showers. These becoming heavy at times. Winds are expected to gradually ease and with winds coming from the South so it will become milder.

Tuesday 30th March

Again some model differences. The EC suggests that an area of low pressure will form and push across Scotland. This would bring further bands of rain which will be heavy at times across the Western Isles. The GFS suggests that a band of rain will move across the Western Isles with a risk of some wintry showers moving in behind on a brisk airflow.

31st March, 1st, 2nd and 3rd April

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 that we are going to see a unsettled first couple of days across the Western isles with further bands of rain heavy at times and blustery winds. Before calming down for the end of the time period.

Thanks for reading any feedback is always welcomed.

Featured photo – Gerinish Beach taken by Ronnie MacPhee

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