October 4th

Hi All,

Some lovely cloudscapes and rainbows around on Sunday along with some cracking anvil clouds. This is a departing storm that drenched me through to my skin but on departure, the air was full of midges and the Swallows and Martins took full benefit. As did the Trout and as did I (The only person stupid enough to stay out there but I knew what would happen when it stopped raining!)

October has really started off with a bang weather-wise with some really heavy rain but as mentioned last week in my blog, there’s a good chance we will be into a drier spell from mid-week onwards after another heavy rain event. This will be both good and bad news (at it usually is for our industry) because I envisage it’ll also bring some pretty high disease pressure as well.(more on that later)

It doesn’t seem like 5 minutes since I saw the first Sand Martin (above) arriving on a chilly April day earlier this year and now the Martins and Swallows are gathering to begin their long trek down south to Africa. Just imagine for a moment, a bird as small and dainty as a Swallow or a Martin beginning a flight all the way to Africa, it’s quite amazing really when you think about it, crossing Europe, The Med, The Sahara desert and like, all on the power of it’s wings. Some of our Swallows take the route down the African coast to avoid the Sahara, others track east and follow The Nile valley for the same reason. Typically they’ll cover 200 miles a day with a total journey length of 8,000 miles. That’s some going….Of course as the summer migrants leave, the winter ones return and pretty soon we will hear the shrill whistle of Redwings and Fieldfares coming over from Scandinavia to plunder our berry crop. I’d say that might start this week as the wind swings eastwards.

This is the ‘Ying and Yang’ of nature that takes place irrespective of us, of Covid, of any fuel or energy crisis, Social Media and the like. I like it because currently we seem to live in an extremely volatile age and this consistency in the natural world is reassuring to me, though not to be taken for granted. Of course 90% of people in the street don’t even notice it, so pre-occupied are they with the crap that comes out of their phone that is so……’important’

GFS Output – 04-10-21

General Weather Situation

So after a pretty wet weekend, what’s in store for this week ?

From the GFS output above you can see we still have low pressure in control as we start this week so it should come as no surprise to know that Monday will see a mix of sunshine and showers for the U.K & Ireland. These will mainly affect the west of Ireland and west coastline of the U.K but already I can see some on the Netweather radar tracking across Scotland, the north of England and The South East. Through the day we will see these showers consolidate across the west of Ireland as a heavier rain front makes its presence felt, pushed along by a strong to blustery south west wind. Some of these showers across the west of the U.K will push inland across England, Wales and Scotland. So a sunshine and showers sort of day finishing pretty wet for the west of Ireland with temperatures in the mid-teens and a strong to moderate south westerly wind.

Onto Tuesday and overnight that heavy rain over Ireland has pushed into The South West, South Wales / Wales and The Midlands. The path of the heaviest rain looks to be southern half of the U.K, with the areas above likely to get the most rain. They’ll be rain up to The Borders but the heaviest stuff will be south of this. This rain will clear Ireland overnight so a dry start for Scotland and Ireland on Tuesday but for the east / south east of England you’ll have the heaviest stuff sitting over you as dawn breaks. This rain will clear most areas pretty quickly on Tuesday but The North East looks in line to stay wet through the course of the day as the centre of the low pressure rotates out into The North Sea. This could mean some flooding for this area. So a drier day for Scotland and Ireland, a very wet start for some areas of England before the rain pushes north and east. Some of the rain associated with this low pressure looks pretty heavy with localised flooding likely. No surprises then that Tuesday is a cooler day as the trailing edge of the low pressure pulls down a cooler north westerly wind so low teens is likely for most areas whether you have rain or not.

Onto mid-week and an improving weather picture you’ll be pleased to know but we aren’t totally out of the woods yet….So a dry start for most areas but although high pressure is building, the low isn’t completely finished with us yet and pushes in a new rain front across the west of Ireland by dawn. Further east across The Irish Sea it looks like a dry start for most here. This rain over Ireland pushes across country and then stops and moves northwards as building high pressure pushes it on a northerly trajectory. For this reason we won’t see this rain front across the U.K & Ireland aside from the west of Scotland that’ll pick up some heavy rain later on Wednesday night. So a drier picture for most areas of the U.K, staying cool though with a prevailing northerly wind, so low teens is the order of the day.

GFS Output – 07-10-21

Thursday sees that ridge of high pressure pushing up across Ireland and in a flick of the weather switch that will change the weather as the wind swings round to the south west and ushers warm air north and eastwards. So Thursday is a much better day for the England and Wales, warm (with temperatures in the high teens) and with plenty of sunshine. You’ll note I excluded Ireland and Scotland and that’s because a persistent rain front will push into the west of Ireland on Thursday and extend right up into the north west / west of Scotland. Through the day this rain will cross Ireland and it’ll also stay across the west and south west of Scotland, so a very wet day likely there. Across The Irish Sea and away from that active rain front, it’ll be a lovely autumn day with warm wind, spells of sunshine and warm south westerly winds. Expect high teens across all areas with the east of Ireland looking to miss most of that rain as it fizzles out crossing the country.

Closing out the week on Friday and we see that rain front still affecting the south west / west of Ireland and west of Scotland with rain pushing into Central Scotland as well. This front will slowly edge eastwards across Ireland and Scotland but the intensity of the rain will lessen as it does so. Further east and south across England and Wales we have another lovely autumn day with a light to moderate southerly wind and spells of sunshine. This will push temperatures up into the high teens for the 2nd day running. That rain across Ireland and Scotland will stay all day but break down into showers for the 2nd half of the day, clearing the west as it does so.

So how does the weekend look ?

Well we still see a vestige of that rain front across the east / north east of Ireland and stretching up into Scotland on Saturday morning. This will sink southwards and dissipate through the morning. Elsewhere a lovely autumn day as the winds lighten in intensity and push round to the east. A lovely day again with high teens temperatures across Ireland after that rain moves through and for Wales and England. Scotland will be a little cooler with more in the way of cloud cover, so mid-teens here. Sunday looks even better with more in the way of sunshine but it’ll feel a tad cooler as the wind swings round to the north and picks up a little. A dry picture just about everywhere save for some rain right along the tip of northern Scotland. A bit cloudier for Scotland but still not a bad Sunday in October for everybody.

GFS Output – 11-10-21

Weather Outlook

So here’s the projection for the start of next week. More like the middle of July than the start of October I think !

Now it kind of looks like a replay of this week but flipped the other way round because during Tuesday a low pressure trough will push down across the east of Europe and that’ll nudge the high pressure westwards back out into The Atlantic (strange one that). This will do two things – Firstly it’ll swing the winds round to the north across the east of the U.K and secondly it’ll also introduce more cloud and the chance of rain for the north of the U.K on Tuesday. Thereafter it looks like the high pressure re-asserts itself and continues to hold the fort for the rest of the week. I think it’ll be cooler next week because of the northerly aspect of the wind, so probably mid-teen sort of temperatures and more in the way of cloud for the east coast.

Agronomic Notes

Since it’s the first blog of the month, let’s look back at September and see how it fared from a GDD, G.P and rainfall perspective ?

September 2021 – GDD Summary – Thame, Oxfordshire, U.K

So September 2021 will go down as a pretty warm month and in fact the 2nd warmest since we started measuring GDD back in 2010. A total of 300GDD puts it nearly on a par with August in terms of overall warmth (300 vs. 318) and aside from 2016, our warmest September to boot from a GDD perspective.

Y.T.D though, 2021 still lags behind because of that really cool April primarily and nothing-t0-shout-about summer with a total GDD Y.T.D of 1557, a long way behind the last few years. I wonder if we will see a warm last quarter to counter-act this ?

September 2021 – U.K locations – G.P & Rainfall

For the second month in succession, you could almost run a ruler across the monthly growth potential because it is so consistent despite the fact we are sampling across the U.K with these locations. It is interesting because the weather was so consistent over August and September that it caused issues with power generation due to a lack of wind and sunlight. Wind or rather a lack of it was key and really strange for an island location. No wind means no real change in weather patterns. A good growth month for sure, September 2021, with an average of 87% of optimum growth across all the G.P’s we monitored and only Scotland came in a little lower at 76.5%, still good though.

Monthly rainfall totals were variable and don’t really tell the whole story.

For example, Okehampton came in the highest at 113.4 mm for the month but when you look at the pattern of rainfall it tells more of that story.(see below)

Rainfall – September 2021 – Okehampton, Devon

So of the 113.4 mm, 49.4 mm fell in 3 days in the first part of the month and 57.2 mm in the last 5 days of the month. So that’s 94% of the monthly rainfall over just 8 days.

That’s the rub nowadays with our rainfall, big packets over short periods that wash out bunkers and saturate rootzones and then not a lot in-between.

September 2021 – Irish locations – G.P & Rainfall

A similar picture in terms of consistent G.P when it comes to the Irish locations for September 2021 reflecting the stability in the weather for both the U.K and Ireland last month. Again a good growing month when you look at the average G.P being around 82% of optimum. Of course rainfall was variable, (like the U.K) with the south and south west of Ireland picking up the highest figures and the east, the least. If we compare Dublin with Dooks (Kerry), we see how the pattern and amount of rainfall was / is so different.

One mans dry September is another’s pretty wet one eh ?

Disease Pressure

Whilst the transition from a very wet start to October to a warm, settled and dry one is to be looked forward to, one area where it will bring unwelcome consequences is in disease pressure. Warm southerly winds combined with predicted heavy dew formation means only one thing I think, Microdochium nivale…well O.K, two things because it wouldn’t surprise me if we see more Dollar Spot as well on courses that were affected by the September outbreak. One thing Dollar Spot absolutely thrives on is dew / a wet plant leaf.

Thinking about it make that three things (!) and maybe one for you winter sports types with high ryegrass swards but I wouldn’t also be surprised to see Leaf Spot as well.

Commonality of drivers and all that….

Here’s how the projected disease pressure looks from two locations, one in Wales and one in Ireland….


You can see how the patterns are different in terms of when the disease pressure builds and to what extent…..For the South Wales location, we see pressure building from Thursday and then extending into the weekend as that high pressure builds and temperatures ramp up. It begins to drop off from Sunday because of a predicted lighter dew formation and then as the northerly winds kick in next week, temperatures drop and so does disease pressure. With this type of disease model it is both the number of hours and the magnitude of disease pressure that counts.

For Kanturk, Ireland, the number of hours of constant disease pressure is higher but it doesn’t quite get to the same level. For both I expect this to manifest itself as quite a challenge…

Guttation fluid on Poa annua

There are two primary drivers behind this disease pressure peak. The first is obviously the warm overnight temperatures that are forecast and the second, dew formation. With a very wet spell of weather predicted for Tuesday, it is likely that we will see formation of both dew and Guttation fluid (because the ground will be saturated) in the latter part of week / weekend and ultimately I think this combination is worse because we know Guttation Fluid has a stimulatory effect on disease. Not just that but it continues to reform even after physical removal and therefore presents more of an issue.

So you may want to think about dew / guttation fluid removal prior to and through this period even if you have a fungicide down providing preventative cover.

Of course it’s a bit of a perfect storm because the peak occurs prior to and over the weekend and many clubs are struggling to get reliable weekend cover since the Covid outbreak 🙁 I wouldn’t want to put a specific number on it (well not in this blog anyway) but I think plant leaf wetness has an equal weighting when it comes to driving / ramping up disease pressure at this time of year compared to temperature.

For that reason, management of plant leaf wetness will I think become more and more important as we go forward into the new world with less and less effective A.I fungicides. Think about which of your surfaces is usually hit hardest with disease, how you might want to prioritise dew formation on these areas and perhaps how you need to change your strategy going forward in this area between manual and surfactant-based dew removal ?

OK that’s it for this week, I’ll be interested in a weeks time to hear how you coped with this disease peak, if it actually manifested itself for that matter and the like…

All the best.

Mark Hunt