Hi All,

Well what a difference a day makes…yesterday here we had clear blue skies and a cracking autumn day, the leaves on the turn, the mist in the valleys and the dew on the ground.


As I walked yesterday I noted the absence of Swallows and House Martins in the sky and thought they must have all have left to head south and follow the sun but was pleased to see a flock of Martins still filling the air over Hallaton, proving summer is still clinging on by the very tip of its fingers.. 🙂

Things are very different this morning however, it’s rained (and raining), the skies are leaden and the wind is up. It’s also 5°C warmer than it was at the same time yesterday morning and that’s going to cause some agronomic issues I think in terms of disease development. (More on that later)

I was shocked seeing yesterday’s pictures from the south-east of France where they had 6 inches of rain in 2 hours leaving towns and cities devastated and people dead, that’s a huge amount of rain to fall in such a small space of time and shows the power and energy of our climate as its worst.

General Weather Situation

So we have low pressure in charge as predicted for the start of this week and I think we’re now set in a pattern of short-term, intense low pressure systems pushing in from The Atlantic and then interspersed by quieter, settled periods when high pressure takes charge. So how’s Monday shaping up ? well mild and with some moisture around for sure.

Currently we have some heavy rain around, specifically over Ireland and the west of England / Wales. This will push northwards propelled by a southerly wind and it’s this that’s bringing the higher temperatures and humidity. By early afternoon the worst should have cleared all but the northern counties of Ireland, but they’ll still be significant rain over northern England and this will push up into The Borders during the afternoon and into Scotland in general by late afternoon. A new pulse of rain will push into the south coast of England early afternoon and this will then move northwards though I think tracking east of a line up from the Isle of Wight to Birmingham. This rain will intensify to heavy bursts during the late afternoon over Hampshire and Surrey before moving across London and into The East Midlands / Eastern counties. It’ll feel humid with temperatures touching the high teens and winds will be moderate to blustery.

As we progress overnight into Tuesday, another band of heavy rain is into the south of Ireland late Monday night and also the south west of England. The heaviest rain looks to be along the west coast of Kerry, Mayo and Sligo through Tuesday morning, but it’ll also be potentially heavy in the southern part of the U.K and over Wales as well through Tuesday morning. That overnight rain will also be sitting over Scotland during Tuesday morning so we’ll have two distinct rain pulses, one over the south of the U.K, the other over Scotland and between them it’ll be dry and potentially sunny. For the second half of Tuesday that rain looks to clear Ireland, push across the north of England and then concentrate across Wales and the west coast of northern England as we see out Tuesday. Again it’ll feel mild with temperatures in the mid-teens courtesy of a mainly southerly airflow.

Into Wednesday and we have a potentially better picture for most areas with rain still featuring along the west coast of the U.K and pushing into northern England and Scotland through Wednesday morning. Over to the west across Ireland it looks drier with only some isolated showers along the west coast of Munster and Connacht later on in the afternoon / evening. The same is true south of Leeds / Manchester where it looks to be a drier and significantly, a cooler day as the wind swings round to the north west moving the warm, humid air away. So temperatures in the low to mid-teens for Wednesday, but they’ll be some breaks in the clouds across the south west and central England through the course of the day. As we progress to Wednesday evening the rain over Scotland pushes more eastwards and potentially finishes off with some heavier bursts across the north east of Scotland as we see out the day.

Onto Thursday and two things you’ll notice, firstly the winds will be much lighter and it’ll be a much drier weather picture. Sadly not for everyone as we have some rain likely to push into Kerry and track north and east across Ireland through Thursday afternoon, though it’ll be decreasing in intensity as it does so.  It’ll feel cooler again with temperatures in the low teens, but they’ll be some periods of sunshine around across the east coast mainly of the U.K and across Ireland before that rain arrives. Winds will remain westerly in nature but are set to change through Friday.

Overnight into Friday we have high pressure settling in over the U.K and Ireland so dry on the whole save for some scattered, light showers affecting the west coastline of the U.K. By late afternoon we have a new pulse of rain pushing into the south west of Ireland and moving across the country through Friday evening into Saturday, though it looks like it’ll track along the west coast so some areas may miss this entirely. For the U.K, we look cool and settled with light winds now coming from the east and low to mid-teen temperatures depending on whether you see any breaks in the cloud cover. This is likely to be more on the west coast as our old friend Haar will probably come calling along the eastern coasts and central areas.

Onto the all-important weekend and though high pressure looks to be in charge, it won’t be a calm one because those easterly winds will ramp up through the course of Saturday and Sunday. This is because we have two southerly low pressure systems trying to get in on the act and you remember what happens when a low and a high meet, the winds get funneled between them. That rain over the west of Ireland will slowly move northwards through the day into Donegal and then off into The Atlantic by close of play Saturday. Elsewhere it’ll be a dry, breezy day, dull on the whole as the wind brings cloud cover off The North Sea. Sunday looks more of the same, dry for all areas I think, windier than Saturday, but also with the promise of some sunny intervals through the morning and afternoon. All in all, not bad really.

Weather Outlook

As intimated above we have a battle between a deep southerly low pressure system that is projected to be sitting over The Bay of Biscay this time next week, and a flattening high pressure sitting over Scandinavia. So although high pressure starts off the week in a similar mode to the weekend, dry but with strong easterly winds, I think it’s likely to slowly pick up some of the effects of that southerly low pressure system as the week goes on, so that means we will get some rain off the continent as we go through the week, but amounts will be light and scattered. That high pressure will be a stubborn one to go however so it’ll be a gradual capitulation rather than a quick transition. Easterly winds will be the theme of the week so that means plenty of cloud cover, cool as well and reasonably dry. I think by the time we close out next week we’ll have low pressure in the driving seat so that will mean a south westerly / westerly airflow and potentially a bit milder as well.

 Agronomic Notes

Disease Pressure

I expect the next 2 days to be a real test in terms of Microdochium disease pressure because we have combination of mild temperatures, moisture and humidity. All of these are drivers for disease and more importantly the temperatures won’t drop much as we go through Monday and Tuesday night, so conditions will very much suit fungal growth over the next 48 hours. It highlights to me yet again what a good system we have with the Growth Potential (G.P) model for expressing turfgrass growth potential.

Last week I charted out the weekly total G.P to give a definitive indication as to the potential for recovery from aeration work and to highlight why early is best when it comes to autumn aeration. This week I’ll use it to demonstrate that it provides us with an ‘early warning’ system when we link to a projected weather forecast as we do in Meteoturf. Looking at Meteoturf today you can clearly see the increase in G.P highlighted for Monday and Tuesday, directly as a result of mild day and night temperatures.


Looking at this from the start of October you can see how much of a peak it actually represents and that the driver is the two mild nights at the start of this week..


A number of key points here ;

Firstly, this peak was evident from last Wednesday on Meteoturf when the weather forecast correctly predicted the swing to a southerly airflow so we knew it was coming and had 3 good days to apply any preventative strategy from a fungicide perspective. I say we had 3 good days but that doesn’t allow for shotgun starts and the like 🙂

Secondly, trying to apply reactively rather than preventatively won’t be too much of a feasible option because we have rainfall through today and tomorrow and reasonably blustery winds.

Lastly, it’s likely to be one of those periods when the balance is tipped very much in favour of the disease even if you have what you think is an effective control already down. So don’t be surprised to see signs of potential activity even though you’re in the ‘sweet spot’ of a preventative fungicide application. It won’t just apply to Microdochium either, I expect Red Thread, maybe even Dollar Spot to raise its head and also Superficial Fairy Ring / Waitea Patch.

Thankfully this period of adverse disease pressure will be relatively short-lived because you can  see from the graph above that once you get to Wednesday we lose that humid air and consequently the mild night time temperatures and things settle down to normal. It is however unlikely to be the last G.P peak we see this month because for the last 5 years out of 7, we have seen very mild temperatures (day and night) going into November.

It graphically highlights to me how growth-predicting models like GDD and G.P can be not only useful but essential in order to make proactive turf management decisions out on the golf course. The tools are there at our finger tips, we just need to use them in a consistent manner.

The best time to aerate in the autumn according to Growth Potential

Last week I used G.P to look back at the period from July to the end of September and see how the growth compared on a weekly basis to the theoretical maximum attainable during that week. It gave (I thought) a good indication of how quickly growth drops off when we get into September and therefore how much longer recovery will take from any aeration work. This week I have added on a northern location, York (Thanks Adrian) to compare two different locations. Here’s how it looks…


You can see pretty similar trends though the northern location appears to drop off quicker as we get through week 3 in September. You can also see the potential to catch some cooler air up north even at the end of July when the weekly total G.P fell back to 66% vs. 86% further south at Thame. This was due to some wetter, cooler air coming in from the continent and primarily affecting the west and north of the U.K and Ireland. As promised I’ll carry this on through October to highlight how aeration and recovery potential during this month compares with July to September, I hope it will help some of you make a case to the powers-that-be.


Last week I wrote that I regard October as a “Steady as she goes” month nutritionally and this week highlights why this is the case. Imagine if you’d have fertilised last week with a significant nutrient input and then we have these two balmy days following on from that application. Aside from increased clipping yield and wet growth to try and manage, it’s also quite possible that you may have created a very succulent grass plant, one more easily prone to disease ingression.

Looking at this week, from mid-week I think things will settle down temperature and growth-wise and if you need to make an application the conditions should be fine for this with calmer winds and a lower likelihood of rainfall. So small amounts of available N combined with iron are I feel the way to go for the time-being, remembering that it’s not usually till the mid part of November before temperatures drop off and life becomes easier to predict.

Ok that’s all for this week, I hope my prognosis on the potential for disease development during the early part of this week is inaccurate, please as usual drop me a comment or an email on what you see out on the turf on your facility as it does help me to keep a handle on theory vs. practice.

All the best.

Mark Hunt