The Donegal Weather Channel Monthly Long range forecast issued every week looking up to a month ahead using data from the ECMWF and GFS models.

Please note that the longer range forecasts are more uncertain and should not be used to plan outside activities from over a week out.

Extended Range Output

The output is rather different from the shorter period output of HRES and ENS products.  It provides a more general overview of the forecast up to Day 46, focusing mainly on the week-to-week changes in the weather rather than attempting to give unsupportable detail on individual days.  Output is mostly in the form of anomalies relative to ER-M-climate and is mainly shown as 7-day means for calendar weeks Monday-Sunday.   Specialised products for the extended range also include information on potential tropical cyclone activity and the MJO during the coming month.

SPONSOR THE LONG RANGE FORECAST

If you have a business and would like to sponsor our weekly month long range forecast for a period of 1 week or 1 month please do contact Donegal Weather Channel at info@donegalweatherchannel.ie or message our Facebook page . Donegal Weather Channels service relies on sponsorship/advertising. Without sponsorship/advertising Donegal Weather Channel would not be able to give so many hours and a daily service.

The forecast will be issued by myself Kenneth and i will try to keep it simple making it easy for everyone to understand. If there is a term I use in the forecast which you may not know what it means I will explain what I am talking about .

Before I start with the long range forecast I will just explain what we will be looking at and how the forecast will work.

The forecast will be broken up into 4 section Example below :

• Week 1 - Monday 26th July 2021 -Monday 2nd August 2021

• Week 2 - Monday 2nd July 2021 -Monday 9th August 2021

• Week 3 - Monday 9th August 2021 - Monday 16th August 2021

• Week 4 - Monday 16th August 2021 - Monday 23rd August 2021

Things we will look at in the forecast:

• Mean sea level pressure: Weekly mean anomalies

• 2m temperature: Weekly mean anomalies

• Wind

• Precipitation: Weekly mean anomalies (eg. rainfall and snowfall for a example.

• Dust forecast ( Only in Week 1)

• UV forecast outlook

• Potential Pollen Levels

Forecaster - Kenneth Mc Donagh

Week 1 - Monday 26th July 2021 -Monday 2nd August 2021

Mean sea level pressure: Weekly mean anomalies

Week 1 - This week will see a big change in the weather pattern across Ireland with low pressure across the country with the Atlantic dominating in a northwesterly flow.

Precipitation ( Rainfall ): Weekly mean anomalies

Rainfall amounts over the last week have been below average across the country with any rainfall coming in the form of heavy thundery rain which caused some spot flooding due to the slow movement of thunderstorms in areas and big rain rates in a short period of time. The most rain was recorded on Friday with a very active day of thunderstorms with some on the severe side which also produced hail especially across the Midlands and western half of Ireland. The Gurteen station in Tipperary recorded the most with 19.7mm all of which fell over 1.5 hours on Friday. Between 15mm to 70mm of rainfall is expected across Ireland between Tuesday the 26 of July until overnight Sunday the 1st of August. The northwest and north will see the biggest amounts.

• Tuesday is expected to be a wet day across Leinster, Ulster and northeast Connacht but drier elsewhere

• Wednesday will see heavy thundery shower which will lead to the risk of some flooding in places especially across Ulster, Leinster, north and east Connacht where the highest risk of thunderstorms will be

• Some further showery rain will fall again especially across the northern half of Ireland on Thursday with drier weather across the south but still some rain showers there also

• Further showery weather is forecast for Saturday across Ireland but these less heavy.

• Some showers again on Saturday and Sunday but there overall outlook is for a lot of dry weather for many this weekend

Rainfall amounts between Tuesday 26th July to Sunday 1st August 2021

ULSTER

Large rainfall rainfall amounts across Ulster this week with between 50mm to 70mm across west Ulster, up to 50mm across northern coastal counties of Ulster and 20mm to 35mm of rainfall across the rest of Ulster

CONNACHT

High rainfall amounts across north Connacht this week with between 40mm of rain and possibly up to 70mm across north Sligo and north Leirtim. Elsewhere there will be between 15mm to 30mm of rainfall.

MUNSTER

Rainfall amounts of between 25mm to 45 across west Munster this week with between 15mm to 30mm elsewhere

LEINSTER

Across north Leinster there will be between 15mm to 30mm and 10mm to 15mm across the rest of Leinster

Temperature: Weekly mean anomalies

Temperatures over week one will fall back to normal and below in some parts with the coolest weather in the west and northwest

Wind forecast

On Wednesday winds will be moderate and northwesterly in direction across Ireland and strong along some coastal parts.

UV forecast

UV level will be low to moderate this week

Pollen Forecast

Pollen levels will be Low to Moderate over the week with pollen levels lowest during cloudy and wet weather and highest during any sunny & dry periods. The main type of pollen will be grass this week.

Dust forecast

Dust levels will be low this week

Week 2 - Monday 26th July 2021 -Monday 2nd August 2021

Mean sea level pressure: Weekly mean anomalies

Week 2 will see low pressure remaining to dominate the weather across Ireland bring unsettled weather and a northwesterly flow.

Precipitation ( Rainfall): Weekly mean anomalies

Rainfall amounts over week 2 are forecast to be above normal in places with plenty of rain in the forecast this possibly coming in the way of thundery showers at times.

2m temperature: Weekly mean anomalies

Temperatures next week over week 2 are forecast below average across Ireland in the mid teens for many with only a few areas into the high teens

Wind Forecast

Some moderate or gusty winds will be possible at times

UV forecast

UV levels will be low to moderate in any sunshine with the risk of sun burn.

Pollen Forecast

Pollen levels will be low to moderate over the week with pollen levels lowest during cloudy and wet weather and highest during any sunny dry periods. Grass pollen will be the main type.

Week 3 - Monday 9th August 2021 - Monday 16th August 2021

Mean sea level pressure: Weekly mean anomalies

Week 3 is currently forecast to see low pressure remain across Ireland with unsettled weather but confidence is a little low for this timeframe

Precipitation ( Rainfall): Weekly mean anomalies

The latest forecast is for just above normal rainfall amounts across Ireland for the time of year which would mean plenty of wet weather

2m temperature: Weekly mean anomalies

Temperatures are forecast to be near normal this week possible just below in some parts

Wind forecast

Some windy conditions could be possible on week 3 but overall no big winds are expected

UV forecast

UV levels will be low to moderate in any sunshine with the risk of sun burn.

Pollen forecast

Pollen levels will be low to moderate over the week with pollen levels lowest during cloudy and wet weather and highest during any sunny dry periods. Grass pollen will be the main type

Week 4 - Monday 16th August 2021 - Monday 23rd August 2021

Mean sea level pressure: Weekly mean anomalies

Signals are very weak for week 4 but there are signs that high pressure may move across Ireland again turning things a little more settled but low pressure will be near by

Precipitation ( Rainfall): Weekly mean anomalies

Rainfall amounts are forecast to below average in some parts with somewhat drier weather

2m temperature: Weekly mean anomalies

Temperatures this week are mostly likely to be near normal or just above possibly around the high teens to low 20s and that bit higher in some areas.

Wind forecast

There area no strong winds signaled for this week

UV forecast

UV levels will be Moderate to high in any sunshine with the risk of sun burn even with cooler weather as the sun this time of year is stronger.

Pollen forecast

Pollen levels will be Moderate to high over the week with pollen levels lowest during cloudy and wet weather and highest during any sunny dry periods. Grass pollen the main type