Monthly Long Range Forecast Update Ireland - 29th June until 26th July 2021
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.
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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 28th June 2021 - Monday 05th July 2021
Week 2 - Monday 5th July 2021 -Monday 12th July 2021
Week 3 - Monday 12th July 2021 -Monday 19th July 2021
Week 4 - Monday 19th July 2021 -Monday 26th July 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 28th June 2021 - Monday 05th July 2021
Mean sea level pressure: Weekly mean anomalies
Week 1 across Ireland will see high pressure dominate the weather across Ireland with a ridge of higher pressure of the west of Ireland early this week but that high moving northwards and sitting to the north and northwest of Ireland come the end of the week and over this weekend. Low pressure to the south of Ireland this weekend will bring some unsettled conditions Saturday through Sunday but not for all parts
Precipitation ( Rainfall ): Weekly mean anomalies
Rainfall amounts over the week gone by where below average for many areas of Ireland apart from the northwest and north of Ireland where they were slightly above normal and normal across the parts of the east and northwest Connacht. Amounts range from trace 3.4mm to 24mm.
It will be dry for a bulk of the country up until this weekend Saturday. Rainfall amounts will be below average for many parts of Ireland.
A few scattered showers will be possible across some eastern parts on Thursday but mostly dry as cloud develops over the day due to the heat with some convection
Friday will be a largely dry day again with good sunny spells but s few scattered showers may develop in parts of the northwest and north during the evening as cloud develops and further convection takes places due to the heat
Friday night a spell of rain will move into the southwest of the country with dry weather elsewhere. At present on Saturday morning and afternoon rain looks set to move northwards but stall over west/south Connacht ,Munster and south Leinster and fizzle out with drier weather elsewhere but again those areas that will see the drier weather may see the risk of a few scattered showers during Saturday afternoon due to the heat and warmer weather across Ulster, north Connacht and Leinster during the day. The latest outlook is for good sunny spells across the northern half of Ireland on Saturday.
There are strong signals from the European & American weather forecasts models that Sunday will see the risk of thunderstorms with some possibly giving the risk of very heavy downpours , flooding and hail. Donegal Weather Channel is watching this period closely as weather warnings could well be needed
Some uncertainty on this weekend with two mixed scenarios showing on both the American and European forecast models. The European model shows the risk of some showers across Munster and South Leinster with the risk of thunderstorms but drier across the rest of the country with the northern half of Ireland receiving the best of the weather. The American weather model shows a wider risk of thundery showers on Saturday followed by a drier day nationally.
Rainfall amounts between Tuesday 29th June to Monday 5th July 2021
ULSTER
Rainfall amounts will range between 5mm to 30mm with the most of that rain currently forecast for this Sunday coming in the way of heavy downpours from thunderstorms. Locally amounts will vary due to the localized falls of rain Thunderstorms can give.
CONNACHT
Across Connacht rainfall amounts will range between 5mm to 20mm with again the most of that rain forecast for next Sunday with the weather staying dry for much of Connacht until Saturday when a little rain is expected mainly across the southern half of the provenance.
MUNSTER
Again rainfall amounts will range between 10mm to 30mm across Munster with much of the provenance receiving over 5mm of rain over the weekend.
LEINSTER
Rainfall amounts are currently forecast to be lowest across Leinster over the coming week with around 2mm to 20mm forecast with those higher amounts across the Dublin and Wicklow mountains. Again much of the rain coming on Sunday across the provenance.
Temperature: Weekly mean anomalies
Temperatures will be 1C to 2C above normal for the time of year but near normal at the start of the week across the northwest and north coastal areas.
Wind forecast
There are no risk of any strong winds this week. There will be some gusty winds in southern parts of Ireland on Friday afternoon into Saturday morning with a southerly wind.
UV forecast
UV levels will be high this week will be high to very high in places in sunshine
Pollen Forecast
Pollen levels will be high to very 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.
Pollen levels could increase to very high this weekend in places
Dust forecast
Dust levels will be low across Ireland during week 1.
Week 2 - Monday 5th July 2021 -Monday 12th July 2021
Mean sea level pressure: Weekly mean anomalies
The outlook for next week (week2) is rather mixed with no real domination of higher pressure or low pressure. Lower pressure at the start of the week will bring some rain but some higher pressure near the end of the week may bring drier weather.
Precipitation ( Rainfall): Weekly mean anomalies
Rainfall amounts next week will be near normal or just above with with average rainfall amounts forecast across the northwest and north of Ireland
2m temperature: Weekly mean anomalies
The trend on weather forecast models including the long range ECMWF model which is used for this forecast shows temperatures average to just above in the high teens to low 20s.
Wind Forecast
There are no signs of any strong winds during week 2 but some gusty southwest to southerly winds may effect some places.
UV forecast
UV levels will be high to very high in any sunshine with the risk of sun burn.
Pollen Forecast
Pollen levels will be high to to very high 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 12th July 2021 -Monday 19th July 2021
Mean sea level pressure: Weekly mean anomalies
Confidence in this week is a littler lower and more uncertain the latest outlook is for a much more settle pattern again across the country
Precipitation ( Rainfall): Weekly mean anomalies
Rainfall amounts are also currently forecast to be lower than average due to the possibility of higher pressure sitting near or over Ireland.
2m temperature: Weekly mean anomalies
Air temperatures are also forecast to be just above average across Ireland with temperatures possibly in the high teens to low 20s and possibly into the mid 20s in places under the right set up.
Wind forecast
There are no strong signals for windy conditions over week 3
UV forecast
UV levels will be High to very high in any sunshine with the risk of sun burn.
Pollen forecast
Pollen levels will be high to very high 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 19th July 2021 -Monday 26th July 2021
Mean sea level pressure: Weekly mean anomalies
Higher pressure to the north of Ireland and lower pressure over Iberia indicates that the week may be rather settled but confidence is low for this period.
Precipitation ( Rainfall): Weekly mean anomalies
Below average rainfall amounts are signaled for week 4 across Ireland with settled weather. There may be the risk of some thunderstorms this week with lower pressure near the Bay of Biscay.
2m temperature: Weekly mean anomalies
Again confidence in this week is rather low but the latest long range forecast from the ECMWF model indicates temperatures near normal for this time of year in the low 20s possible into the mid to high 20s.
Wind forecast
No strong winds are signaled for this week
UV forecast
UV levels will be High to very 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 high to very high and possible very 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
