This weekend we got a clattering…..
Definition – Clattering (noun)
a) a continuous sound as of hard objects falling…
b) a flock of Choughs (I didn’t know that)
Quite a weather weekend and one where you might have enjoyed some sunny intervals and the odd shower or alternatively you could have been sat under a diagonal line of slow-moving, heavy rain that stretched from East Anglia, through the Midlands, north-west of England and across to Northern Ireland, and got a clattering…
31.5mm in a day is our highest rainfall day this year with just shy of 50mm for the weekend !
All thoughts of last week’s heat wave are quickly forgotten but spare a thought for the grass, one day heating up to close on 37°C with near 7 mm of E.T, the next sitting under 30 mm of rain and day time temperatures over 20°C lower. It’s one adaptive plant.
Last week gave us conditions that U.S Superintendents managing grass in the transition zone face for months of the year, every year. Guys you have my utter respect, you genuinely do.
Opening my curtains to the sunshine today may indeed prove to be a rare glimpse of summer because as this Meteoblue graphic below shows, we have more rain on the way from yet another Bay of Biscay low pressure system. A common feature of ‘summer 2019’….
General Weather Situation
So we start Monday with that band of rain still not quite clear of the U.K and currently bringing rain to the north-west of England and Lake District. I can remember some errant camping trips in North Wales and The Lakes as a lad, shivering under canvas whilst rain pinged off the bonnet of my Dad’s Austin Maxi, never again to return. Elsewhere away from this rain band we see some more rain over the far north-west of Scotland, north of The Moray Firth but in-between those two bands of rain we will have some pleasant morning sunshine after a cool night where temperatures dipped into single figures. As you can imagine from the above graphic, this state of play is transient at best. This low pressure is slow-moving and won’t make landfall across the south-west of Ireland and England until later this afternoon, so enjoy the nice weather whilst you have it. By dusk that rain will be into south Munster / Leinster, The South West and Wales before moving north and east overnight. A nice day before the rain with temperatures pushing up into the low twenties with long spells of pleasantly warm sunshine. Scotland will see that sunshine short-lived as that northern rain sinks south into central areas through the afternoon. So low to mid-twenties for England and Wales, high teens with more cloud cover for Ireland and the same, with rain, for Scotland. Winds will be light to moderate and from the south-west.
Onto Tuesday and any thoughts of the sun are soon forgotten as that low pressure sits over the south-west of England and slowly moves north and east through the course of Tuesday morning reaching eastern parts by the early afternoon. By lunchtime then the rain will be affecting east Leinster and the whole of the U.K up to the Scottish border giving significant rainfall totals across the south-west and west of the U.K through Tuesday. Ireland will see an east-west divide with the east wet and the west drier and a bit brighter. Scotland will have a pleasantly warm, dry day, if a little dull before that rain eventually arrives during the early evening. So a wet, dull day for England and Wales with temperatures down in the high teens and it’ll also be windier with the wind swinging from south-west to south-easterly as that low passes through. Scotland will be marginally warmer in the low twenties with Ireland down in the high teens due to the cloud cover and rainfall across eastern counties.
Onto Wednesday and that low pressure system is really slow-moving with its centre over northern England overnight so we will see rain continue overnight into Wednesday for northern England, The Midlands, The South West, Wales and west of England. By the morning rush hour, that low pressure is moving east pushing rain into eastern England and The North East. So a drying picture behind it for The South West, south of England and Wales. Ireland should dry up as well with some sunny intervals pushing through and possibly some rain over the coast of south-west / west Munster. Scotland looks to start off dry but during the morning that rain pushes north into The Borders and Central Scotland. With the low pressure sat squashed between two high pressures it isn’t going anywhere fast and by Wednesday evening, its centre will be sitting just off the North Norfolk coast, so a soggy evening queuing up at French’s at Wells-next-the-Sea is on the cards 🙁
By evening we will still see rain, some of it heavy across The Midlands, north of England and Scotland. Further south and west across most of Wales and Ireland, we should be dry. As with the weekend just gone another day of contrast temperature and rainfall-wise with Ireland , Wales and The South West recovering temperature as the low clears away so low twenties here. For the rest of England and Scotland under that rain, only mid to high teens is likely. Ireland should have a pleasant day after that rain moves off with spells of sunshine and temperatures just nudging up into the low twenties. It’ll be a windy one as well if you’re under that low pressure but quieter further west and north.
Thursday sees that low finally move off across to The Netherlands to give us a largely dry start to the day but rain is never far away this week and by lunchtime we will see some showers trigger off across Scotland and the north of England. Further south and west of these showers, Thursday morning looks to be pleasantly warm with sunshine. Through the morning those showers will combine into longer spells of rain across Scotland and the north of England, maybe pushing down later into The Midlands. Ireland looks to have a dry, pleasant day with sunny intervals and temperatures in the high teens. So the south of England and Wales should have a dry and warm day with temperatures in the low twenties away from that rain. Through the course of Thursday evening those showers will dissipate leaving a dry night for most. Winds will be light to moderate and from the north / north-west.
Closing out the week, Friday sees a similar start to Thursday with a largely dry picture across the U.K and Ireland. Through the course of Friday morning we will again see some showers pop up across Scotland and the north of England, more scattered than on Thursday, so some areas staying dry all day with some nice spells of sunshine pushing temperatures up into the low twenties. Similar for Ireland maybe with more in the way of cloud cover though so that’ll peg back temperatures to the high teens but dry nonetheless. Through the course of Friday evening we will see those showers from The Humber up to The Lakes and into southern Scotland. We may also see some showers further south across The Midlands later in the evening.
So how does the weekend look ?
The graphic above shows how we are caught between another weak Bay of Biscay low and a low on the continent. Sandwiched between them is a weak high pressure which will keep central and eastern areas largely dry for the weekend. So we are likely to see showers for Ireland and the west / south west / south coast of England push in later on Saturday afternoon / evening, dry till then and pleasantly warm if a little dull. These showers remain through Saturday night into Sunday morning and will continue to affect Ireland and The South West / Wales as well. East and north of this you should be largely dry with sunny intervals building and pleasant temperatures on Sunday with a chance of some showers popping up on north-western coasts later in the day. A tricky one to call where and when you’ll get the showers but they will largely be confined to the south of Ireland, Wales and The South West. Away from the thicker cloud base in these areas we will see sunny intervals and temperatures climbing into the low twenties for most of England and Scotland.
So will August be a departure from this changeable summer we have had or will we continue the pattern of no one weather system dominating for any length of time ?
Well my money is on the latter and has been since the end of May 🙂
So next week looks like being a sunshine and showers type of week with showers initially across eastern areas on Monday and Tuesday but spreading westwards by mid-week. No great rain deluge looking likely during the week but as we head to weekend after next, we could see a deep Atlantic low push into Ireland and track slowly eastwards affecting all areas by the latter part of the weekend. If it does come to pass I can see this being a dominant player through the middle of August bringing high winds and rainfall. No great shakes temperature-wise, high teens and low twenties is nothing to complain about either as I’ll take it any day over 30°C plus. It is after all good growing weather 🙂
E.T, G.P and Clipping Yield…
For some it’s already long forgotten but last week’s heat wave put grass on the back foot big time with the highest daily E.T of the year so far recorded at The Oxfordshire on Thursday 25th July at 6.8 mm.
We also saw a big drop off in growth rates as predicted in the Growth Potential formula but I’m interested in all you guys who measure their clip yield, how did it chart out last week assuming you were cutting every day (which you may or may not have during that heat ?)…Did you see a big reduction on the 25th ?
A graph of daily G.P vs. E.T for July so far shows the big dip in growth potential and its relationship with E.T…
You can see how the G.P dropped to 0.26 on the 25th July because of the high day (and night-time temperatures) with 37°C and 17°C recorded respectively. You can also see how the E.T ramped up on the 23, 24, 25th July peaking on the 25th at 6.8mm of moisture loss in a day.
Now we have talked about this before but it doesn’t mean you would have needed to replace 6.8mm of moisture through the irrigation system, more likely 60-70% of that figure depending on your grass species, rootzone, greens aspect, etc…In practice most clubs use a combination of overhead and hand watering to manage moisture loss in the summer with the latter more and more frequently used now to give more control and / or sometimes to make up for deficiencies in the irrigation system in terms of coverage 🙁
Poa stress and Anthracnose triggers…
Without a doubt Poa annua was on the back foot last week with the very high day and night temperatures and daily E.T. Monday to Friday. The total E.T loss over that period was 24 mm with only 2.6 mm of recorded rainfall so that makes a net moisture loss of 21.4 mm by my maths.
As predicted in last week’s blog we clearly hit the criteria necessary for spore germination of Anthracnose…
With high humidity and rainfall in some areas following this trigger we now have a perfect storm for this disease.
From now on the interesting thing to observe is if we actually see symptoms of Anthracnose develop over the next 14 days or so depending on whether the fungus switches from Biotroph to Necrotroph as discussed last week.
A lot of that depends on Mother Nature and your BMP’s. We will for sure have plenty of moisture to allow the fungus to develop and a wet plant leaf to boot, but I can’t see any great heat building at the moment to put the plant under stress.
Out of curiousity I took the time to look back at summer 2014 to try to understand why it gave us such a hit of Anthracnose. The similarities between summer 2019 and summer 2014 actually make for uncomfortable reading.
This is when data is so so useful and again I raise my hat to all of you that keep me posted with your weather data and stats. Thank you. A big additional thumbs up to Sean at The Oxfordshire without whom I wouldn’t be able to look back at this issue and compare data so efficiently, cheers.
So below is the maximum air temperature vs. rainfall patterns across summer 2014…
You’ll note the dry end to July 2014 and the peak in temperatures noted in the last week of July that clearly hit that Anthracnose trigger. If anything the heat was more sustained in 2014 so the plant was under more stress than in 2019 possibly ?
We then saw a dump of rain in early August and a pretty wet month to boot with lower than average air temperatures and consistent rainfall, some of it heavy. So we had plant stress, a clear trigger event for spore germination and then consistently wet surfaces to allow the fungus to develop.
Jumping forward to this year we have had a shorter stress period, a clear trigger event for spore germination followed by for some areas (under that weekend rain belt), a dump of rainfall leading to saturated surfaces. If the forecast is right we will see more high daily rainfall events during August so the scene is set I think in some areas of the U.K and Ireland.
What can we do BMP-wise ?
As discussed at length last week and in prior blogs, maintaining adequate plant leaf tissue N and K levels is critical. Some of that comes down to fertilisation frequency and to a certain extent type as well because if (and it’s a big ‘if’ ) we do get dumps of rainfall, liquid fertilisation will not be efficient. Leaching in a golf course scenario as we know from many documented studies is minimal but applying a liquid fertiliser close to heavy rainfall will not provide consistent nutrient availability as some of it will be washed through the rootzone (depending on rootzone type).
If we have cooler temperatures (likely) with that rain, then release of the nitrogen will also be slower than normal. So my advice is either to use a light rate, low N granular fertiliser (if the weather shapes up as projected in August 2019) or tighten your applications through this period and mix and match your N sources with the weather. Both I know have management implications in terms of cost and resources but it is only for a short period. It’s worth remembering that the level of Anthracnose was so severe in 2014 that we saw a big drop off in playing surface quality through into September, traditionally one of the busiest months for golf revenue.
My apologies for being a bit doom and gloomy but fore-armed is fore-warned 🙂
With high temperatures and humidity we can expect a similar scenario to June this year in terms of lots of fungal diseases coming out of the woodwork including Waitea, Fairy Ring, Red Thread and Dollar Spot (Whose new latin name is Clarireedia homeocarpa)
I saw my first Dollar Spot last week on fairways and this coincided with a sharp peak in the Smith’s Kerns Dollar Spot Prediction Model last week.
It is also likely that we will see some Microdochium nivale activity, nothing too drastic as our growth rate (as denoted by G.P) is back up to optimum again after the dip of last week.
If we do get a cool, wet August then we can expect to run into the autumn with higher Microdochium inoculum levels than previous years and that may be one thing to think about in terms of control. Early days yet though so we can cross that bridge when we get to it….
Ok that’s it for me this week, all the best for the coming week…..