21st September

Hi All,

After a beautiful late summer (early autumn ?) walk around Rutland Water’s peninsular at the weekend, everything looked rosy from a weather perspective with high pressure, misty mornings and pleasant temperatures…..Sadly life isn’t to be that way as no sooner than I said last week that the jet stream looked stable and sitting high then the GFS chart turns on its head and we see a cold, northerly low turn up in our forecast this week. This will drag the temperatures down from the early part of the week and leave us feeling very much in autumn mode not just for this week but extending beyond that as well. For the people sitting in areas with 2 mm of rain all of September this will be a welcome break, for those who’ve already endured a wet end to summer (Ireland, north west England and Scotland), it’ll be more of the same I am afraid.

This situation neatly highlights the limitations of forward weather forecasting when a week ago everything looked rosy but now we look to go into a trough pattern in the jet stream and that’ll plunge us into a cooler, unsettled outlook for the foreseeable. The behaviour of the jet stream and our meteorological inability to forecast / predict it beyond 7-10 days is a major limitation to forecast accuracy.

Uncanningly the rain will start on the 23rd of September, exactly the same date last year that a dry September gave way to a wet one.

How weird is that ?

Next year I’ll be getting all of my holidays done by the 3rd week of September !!!

General Weather Situation

Looking at the innocuous GFS output above for this week, all looks fine and indeed as forecasted last week but it is from mid-week that things start to get messy, cooler and wetter.

So Monday looks like being a beautiful autumn day with light winds, plenty of sunshine and only the tip of a rain front nudging into north west Scotland to provide a blemish on an otherwise clear weather chart for the day. This front will push some cloud and a fresh westerly wind into Scotland and in so doing peg back temperatures to the mid to high teens, Further south in the sunshine, temperatures will rise quickly once the early mist has burnt off and most areas will see high teens / low twenties for the day. Not much more to say about it other than enjoy it. I will, I’m going get a dry path run in p.m. with a bit of luck if my legs will tolerate it 🙂 Onto Tuesday and that band of rain over north west Scotland begins to drop south and east to push rain into the north west of Ireland from around lunchtime Tuesday, this will then move slowly south and east over Ireland and Scotland as we progress through the 2nd half of Tuesday. England and Wales hang onto that lovely autumnal theme for just a bit longer with another beautiful day. Lots of sunshine, temperatures in the low twenties but with a freshening south westerly wind, a portent of things to come. So increasingly wet for Ireland and Scotland with temperatures struggling into the mid-teens with the cloud cover and rain 🙁

Wednesday morning sees that rain band over Wales, the north of England whilst Scotland and Ireland should start dry, dull and cool. Through the course of the morning this rain will consolidate into more widespread rain across east Wales and southern / Central England / The Midlands and the east of England, the first rain in some locations for close on 3 weeks. Together with the rain comes a freshening south westerly wind that turns northerly later on in the day bringing temperatures down into the mid-teens in these areas. Ireland looks to have a largely dry, if dull and cool day save for some blustery showers kicking off along the west coast for the 2nd half of the day. These will push inland as well. Scotland should be largely dry, with some sunny intervals but noticeably cooler with temperatures only just the right side of double figures. Dry though so that’s a blessing.

Overnight into Thursday sees a low-lying, Atlantic low push into Ireland introducing rain overnight. The Meteoblue graphic above for Thursday shows the two low pressure systems that we will have in place towards the end of the week, one over The Irish Sea, one over The North Sea. No great surprises then that Thursday is a wet and unsettled day for Ireland as that low slowly crosses the country pushing rain into The South West and Wales during Thursday morning. This rain will quickly cover the whole of the southern half of the U.K, really from The Pennines south meaning Scotland will miss the worst of this again with another largely dry if cool day. So wet, windy and cool despite a breezy southerly wind for the southern half of the U.K and Ireland really sums up Thursday with that low pushing across Wales as we approach dusk. The leading arm will spin the rain further north into The Borders at the same time. Cool everywhere with a noticeable nip in the air as temperatures sit in the low teens at best, maybe lower 🙁

Closing the week off on Friday we see that low now over The North Sea heading for my motherland, Denmark. The trailing edge of the low will pull down unwelcome northerly winds so not only will it be wet and unsettled at the end of the week, we will continue that cool feel from a temperature perspective. At this stage Ireland should miss most of the rain and plenty of sunshine on Friday save for some showers affecting the west and north west coast. It will be pretty windy though. So a north wind, sunshine and heavy blustery showers type of forecast for Friday with the heaviest of the showers always on the east of the country, closer to the low pressure system. Scotland will be similar, drier and brighter across the west with any showers down central and eastern parts. Temperature-wise, low double figures nudging into the teens across the south of England but feeling especially cool in that wind.

The weekend is a real west-east split with Ireland looking to have a quite miserable Saturday with overnight rain pushing slowly across the country during Saturday and even when it clears it’ll leave behind thick cloud. The U.K looks to have a dry Saturday on the whole with varying amount of cloud and some sunshine. Through the afternoon that rain will push across The Irish Sea into The South West and also Wales before fizzling out overnight. A new front of heavy rain will push across Ireland overnight into Sunday clearing most of the country by dawn with that rain already into the west of England and Wales early doors on Sunday. This vertical band of rain will stretch the length of the U.K and will move eastwards during Sunday morning, a nice one then for me to try and get in an early jog, put my feet up with fresh coffee, some toasted Rundstykker and watch MotoGP 🙂

It’ll take most of Sunday for this rain to move west-east and clear the U.K so the east will stay driest the longest on Sunday. A better day for Ireland and Scotland, though the west will still be blustery and showery in both countries. Temperature-wise, low double figures / teens is the order of the weekend with a bracing northerly wind on Saturday swinging round to westerly on Sunday and losing a bit of its bite as a consequence.

Weather Outlook

The GFS output for Monday clearly shows that cool trough pattern which extends all the way down to Greece and a new northerly Atlantic low waiting in the wings. During the course of next week this low will drop down into the trough bringing strong winds and quite a bit of rainfall with it and some even chillier temperatures to boot. Monday looks a sunshine and showers day with freshening south westerly winds and it turning increasingly wet over Ireland. Tuesday looks a pretty wet one for everyone with that rain pushing across all of the U.K before more rain arrives for Wednesday as the low pressure spins around on its axes but doesn’t move away, trapped in the trough. More rain for Thursday before we begin to break down into a more sunshine and showers type affair at the end of next week. That low isn’t finished with us yet as it moves east to west, yes I said east to west across the U.K and Ireland during Saturday / Sunday bringing more rain before finally moving away (?)

Agronomic Notes

Now I know this doesn’t apply to everybody (thankfully) being more of an issue in the drier areas of the U.K & Ireland, but Anthracnose activity has been significant since the last trigger in Mid-August and the earlier triggers in May and June. With a dry September this disease has been notable and as mentioned before it has an almost unique ability to look like its getting better, then worse, then better, then worse, dependent on the weather and the grass plant involved. I say grass plant because it is generally assumed to be a Poa-only ailment but in some countries, most notably the United States, it is happy to take out bentgrass as well.

This is a significant point because it highlights a general issue with grass cultivars which has raised its head in the past and will do so increasingly for sure in the future.

When you are overseeding, how high up in your decision-making process is the cultivars disease resistance / susceptibility ?

We know of course that there is a general practice of over-sowing bentgrass into Poa greens, sometimes with Creeping bent, sometimes with Browntop. In other areas, some golf courses are pursuing the fescue route, mostly in a links environment, but again the same criteria applies. In an outfield situation, the same question could easily be posed of  a Lolium perenne mix in terms of Leaf Spot or maybe Red Thread.

What is the susceptibility of the cultivar you’re sowing to lets say, Microdochium nivale, Colletotrichum cereale (Anthracnose to you and me) and / or  Clarireedia homeocarpa (Dollar Spot) ?

It is an area where we are woefully short of information to assist that decision-making process and one crying out for a considered approach. It can also be tricky to compare data from country to country because we know disease genetics can be different. For example, we think that the fungal species of Dollar Spot that is affecting greens in The U.S and Scandinavia / Continental Europe is not the same genetically as the one we see over here or at least it currently it isn’t to the best of our knowledge. I mean if you have Anthracnose-affected areas as detailed in the above images, in an ideal situation you’d surely want to overseed them knowing that the cultivar or cultivars you intend to use is not going to feature the same poor susceptibility to this disease ?

As we enter an age with less and less fungicides and a general decline in A.I per ha input, resistance to disease must become a key driver in the selection of a grass cultivar or grass seed mix. Currently there’s very little information this side of the pond regarding disease susceptibility of grass cultivars, be that Creeping or Browntop aside from one or two minor diseases. That must change and as an industry we need to focus our collective attention on this area. As an aside I note that in reasonably-recent trials in the U.S, a creeping bentgrass resistant to Dollar Spot made an appearance, how long before we see a Microdochium nivale resistant Bentgrass I wonder and will the E.U’s current stance on ‘genetically modified crops impede this process as it has done in the past ?

The same has to be true for ryegrass and fescue species in terms of considerations before overseeding. There’s little benefit in my mind with working so hard to produce a fescue-dominated sward say only to then increase the swards susceptibility to a disease that you didn’t have an issue with before.

I’ve used the above picture before but it graphically illustrates the increased susceptibility of Poa annua to Microdochium nivale vs. in this case a modern creeping bent cultivar.  If we can achieve a higher level of bentgrass in our Poa-dominated greens, we know we will decrease the susceptibility to our worst turfgrass disease. Now for sure we will probably see a bit more Take-all incidence as we have this year with the wet June providing a resurgence in activity of this pathogen but I’d take the above any day of the week as would most golfers.

……………………………………

A short window to act….

The arrival of cool and unsettled weather will provide a great opportunity for overseeding thin areas, disease-affected areas and the like if you can make a start and have the budget / resources to do so. Getting a granular fertiliser down this week to move these type of areas on would be opportune timing with soil temperatures still nicely up and rain on the horizon. All hands to the pumps I’d say if you want to try and squeeze in a late, light topdressing as well.

Of course we know that cooler and unsettled weather will equal more worm activity as mentioned last week and with less drying down time, a problem in terms of managing the inevitable casting.

On the plus side it is likely to lower the Microdochium nivale risk going into the autumn as the last few years have taught us that this type of weather pattern is not associated with high disease levels normally.(ending on a positive note :))

Must dash now, tempus fugit my friends for you and for me….

All the best

Mark Hunt