September 3rd

Hi All,

After a glorious autumnal weekend (well for some in central and eastern areas anyway) with temperatures hitting 26.5°C here, it was simply beautiful weather, everyone seemed to be out enjoying it. That said, we are definitely tipping a hat towards autumn because the night temperatures dipped down into single figures on some nights with heavy dew and mist first thing.

Lots of talk about an extended heatwave through September, obviously people have read the usual rubbish in the media. People’s attitude to the weather constantly amazes me, one chap asked me this weekend as I was setting up my fly rod, “What do you think the weather will be like on the 21st of September Mark ?”, “Haven’t a clue” I replied “and nor has anyone else for that matter”. So anyone thinking we will have an extended heat wave should look towards this coming weekend when low pressure may be in charge bringing cooler temperatures and rainfall.

If I took a punt at September as it looks at the moment I think we will have a similar pattern to August with alternating periods of high and low pressure and no one weather system dominating, it is a punt though…

General Weather Situation

So Monday starts off with a west-east divide as we have a vertical band of rain positioned across the west side of the U.K and extending from mid-Wales all the way up to the east coast of Scotland which is currently receiving some heavy rain as I type this at 8.38 a.m. We also have some sharp showers over The Midlands following the Fosse Way kind of like. Ireland looks to start off dry and cloudy but crucially nice and dry. As we progress through the day we will see that line of showers sink slowly south and east but it’s unlikely to progress far into central areas. That said we may see more of the sharp showers through the day across Leicestershire and Warwickshire. Scotland is another case of west-east divide but this time western areas look to stay largely dry whereas the rain over the east will linger through the day and be slow to clear. Through the afternoon we will see that Scottish easterly rain formation drift south into The North East so a dull and wet end to your day here. So central and southern areas along with Ireland look to get the best of the weather and late summer sunshine. Temperature-wise, I expect the south to hit low to mid-twenties again in that sunshine but a more normal high teens for Ireland, Scotland and Wales, the latter two with more cloud cover pinning temperatures back. Winds will be very light and from the north-east strengthening as we close out the day.

Tuesday looks to be a pretty dull day everywhere across the U.K, with the exception of the south coast which should see the majority of the sun. Ireland likewise, sunny and pleasant across the west, more cloud across the east. There may still be a vestige of that rain across The North East through Tuesday morning but eventually it’ll fizzle out leaving thicker cloud behind. Not a bad day really with pleasant temperatures ranging from high teens across Ireland and Scotland, a degree or two higher for Wales and again low twenties for the south of England if you see the sun. Winds will be moderate and northerly.

Wednesday looks a messy day forecast-wise with rain and thicker cloud pushing into the north-west of Ireland (Donegal, Connacht) through the morning. There’s also likely to be the same combination of thick cloud and potential rainfall associated with it for Ease Anglia and The South East. So at present the driest, sunniest weather looks like being across The South West, the north of England, Midlands and South Wales. Through the afternoon we see the rain front over Ireland push slowly eastwards and this same rain front will also introduce thicker cloud and rain into the north-west of Scotland. As we head towards dusk we see most of the rain slowly fizzle out across Ireland but it’s likely to stay wet and dull for the north-west of Scotland and the south-east of England. With a stronger north-east wind in situ it’s likely to feel cooler across all areas with high teens probably the best we can hope for.

Image courtesy of Meteoblue

Thursday sees a change in temperature to much cooler conditions as a trough of cool air feeds down across the U.K and Ireland (see image right) This cold front will introduce some rain into Scotland, The North East and north of England overnight into Thursday but by the morning rush hour this may only be affecting the latter. Thick cloud will push southwards through the morning especially along The North Sea coastline and that’ll knock the temperatures down a tad more. Ireland will also see thicker cloud pushing south after a dry start so cooler and fresher everywhere. As we go through the afternoon, that rain across The North East will sink south into northern England leaving clearer and fresher conditions behind it. So much cooler on Thursday with temperatures in the mid-teens across Ireland and Scotland and a couple of degrees higher elsewhere.

Projected weather for Saturday…courtesy of Meteoblue

Closing out the week on Friday we see a low pressure system drop into that trough pattern and that’ll dictate the weather through the end of the week and the start of the weekend, so much for the heat wave right 🙂 So a dry start for most on Friday but by dawn that low pressure will begin to introduce rain to The North East initially and then later in the morning, Scotland, The North West and Mid-Wales. You can see the isobars are packed tightly across the north and north-west so a windy day here I’m afraid.  As we go through the afternoon, this rain will push into the north of Ireland, north of England and North Wales before pushing south and inland overnight into Saturday. A cool day on Friday with that cold low pressure dominating the weather so remember those layers with low teens for Scotland, Ireland and Wales and only mid-teens for England. As that low sinks south the wind will change from north-west to south-west.

No big surprise then that the forecast for the first part of the weekend looks decidedly average with that low pressure projected to sink south over the U.K overnight Friday into Saturday. This will bring significant rain into northern, western and central areas overnight and through Saturday though Scotland could end up missing it as the low will be further south. Ireland likewise though South Munster and possible East Leinster may catch some rain with the chance of further rain later in the day extending out into Kerry.  So Saturday looks to be a bit of a wash out away for the afore-mentioned areas with a strong westerly wind accompanying that rain. That said, it’s 5 days away at present so the timings of the rainfall could change. Sunday is likely to be drier for most areas as that low pushes south and east though there’s still rain likely to be associated with it across East Anglia first thing on Sunday. So a dull but pretty dry outlook for Sunday after the wet end of the week and with lighter winds, it’ll feel a bit better. Don’t expect much more than mid to high teens over the weekend with the south picking up some warmer, more settled conditions through the latter part of Sunday.

Weather Outlook

So after an unsettled end to this week and first half of the weekend, how does next week look ? Well not bad actually as we have high pressure pushing in from The Atlantic so a warmer and drier start to the week for central and southern areas though there may still be some rain across these areas on Monday. Cooler and more unsettled for the north of the country and north-west of Ireland as a rain front is projected to cross the north of Ireland and Scotland through Tuesday. I expect the heat to build in most areas through Tuesday and Wednesday before it begins to cool a little on Thursday as low pressure begins to push the high away into continental Europe. For the east side of the U.K you may pick up cooler conditions associated with this high because of northerly winds and more cloud cover. Beyond that is tricky, some projections suggest the high will persist into the weekend, others that low pressure will dominate.

Agronomic Notes

OK since this is the first blog of September, we can look back at August from a GDD and rainfall perspective across Ireland and the U.K and see how we fared ?

August, from a GDD perspective, was one of the highest August totals we have measured and this explains why so many people have mentioned the flush of growth they experienced once rainfall was forthcoming after the heat of July. August 2018 was (for this location) a ‘typical’ August of fine weather with some rainfall through the month and this contrasts strongly with a ‘trough pattern’ August that brings us much cooler weather and consequently lower GDD.

With the heat of July and August, 2018 is now right up there with 2017 as the highest GDD year we have measured. When you look back and take into account how far back we were in April and even May, it illustrates just how hot the summer has been. We have 4 months of the year remaining and as commented upon earlier this summer, it won’t surprise me if 2018 runs out as the highest GDD year we have measured. That would make it two record years in a wow, an ominous sign of things to come ? let’s hope not.

GDD & Rainfall – UK Locations

Looking at the rainfall totals first we can see that The South West picked up the highest level of rainfall from the stats provided and this would have been very well-received no doubt. Mid-country and the east of England were the driest with 32 – 38mm of rain from The Midland locations up to York with Fife picking up 62mm over the course of the month. GDD-wise, quite a variation with Fife recording 16% less GDD than York and 25% less GDD than Northampton.

GDD & Rainfall – Irish Locations

Over the Irish Sea for a comparison of how their locations fared during August…

From a rainfall perspective we see another case of west-east divide with the west side of the country receiving the majority of rainfall not surprisingly. The exception being Limerick which seems to have done a good job of dodging most of what The Atlantic sends their way..GDD-wise we see the usual variation with the wetter locations pulling in the lowest GDD figures with Claremorris  recording 16% less GDD than across the country in Dublin. There’s less difference between north and south locations across Ireland in August compared to west-east. Limerick comes through with the highest GDD and that makes it two significant high scores as I understand it during August with their Hurling team taking their first All-Ireland win since 1973 ! 🙂 (Cue lot’s of requests to unsubscribe from the blog from every other county in Ireland 🙂 )

Is the drought forgotten then ?

It is always interesting to note the comments of golfers and players alike and how quickly they forget the weather we have just endured. It’s almost like everyone expects grass to flick a switch from totally dormant to green and growing. When I came into Heathrow airport on my return from Alaska it was interesting to note how dry some of the cricket outfields, winter season pitches and golf course fairways looked from the plane across the west side of London.

For this reason, I thought I’d continue the E.T / Rainfall / Moisture Deficit / Surplus work from our Thame location to see the pattern through August…

Comparing 2018 with 2017 continues to show the contrasting difference between the two summers in terms of rainfall, loss of moisture by E.T and the resulting moisture surplus / deficit in the soil. You can also see the fluctuations of low and high pressure through this August with decreases in the soil moisture deficit when we have rainfall and increases when we have hotter, drier weather.

All things considered though the soil moisture deficit grew in August 2018 from -225mm at the start of August to -275mm at the end of August, so the drought isn’t over despite the fact that we have had some rainfall during the last month. I expect this situation to continue through September with alternating periods of rainfall and settled, dry and warm conditions.

Of course the E.T loss will be reducing on a daily basis because the hours of daylight are less and night temperatures are lower, the former is becoming really noticeable now as the evenings draw in. So in a sentence, we are not completely out of the woods yet.

What does this mean for growth, recovery and disease pressure ?

Well despite people’s relatively short memory as to why outfield areas look patchy, it’s likely that we should be able to continue to recover turfgrass swards through September with I know plenty of you out there renovating and overseeding. For most you’ll have areas that are recovering quickly, some recovering slowly and some where only aeration / renovation and overseeding will provide grass cover. For this reason surfaces will appear inconsistent, in fact less uniform than they were when they were droughted out unfortunately. This inconsistency will continue through September and gradually fade as we move into the autumn. A faster turnaround is only gained with renovation / aeration and overseeding and in that respect the potential run of warm, dry and settled weather followed by rainfall and then a repeat of the same should be fine.

Disease-wise, we have a number of diseases doing the rounds, Microdochium nivale from the wet and humid weather in mid-August, Anthracnose (Colletotrichum cereale) that has been an issue since June / July and if anything is increasing in severity as we move into September and finally Dollar Spot (Clarireedia sp.).

The more observant of you will notice that I have not used the name, Sclerotinia homeocarpa for Dollar Spot and this is because the causal fungus has been re-classified according to research into the genetical diversity of the pathogen. If you’re really sad you can read about it here (must be careful as I know this is a pet subject for Kate E :)) but essentially they have now split the pathogen into four different species and a new family, Clarireedia (probably pronounced in some airy fairy scientific way intended to make the less educated people like me stick out like a sore thumb). The species differ in their geographical distribution and sometimes with respect to the host grass species they attack.

Dollar Spot for me has always been a weird disease because in some instances it attacks grass species on greens, tees and fairways and in others only outfield turf. It’s likely then that the difference between the genetical make up of the disease will dictate how it behaves and where it occurs on your turf facility (if it does at all). From my experience, in the U.K and Ireland it attacks mainly outfield turf and the same in Scandinavia but in Germany, Switzerland and the more southern countries of Europe, it attacks greens as well as outfield. STERF have done some good work on this pathogen although their paper references the old latin name (so last year you know). The best way to combat the disease once you have apparent symptoms is to grow it out so nutrition is key as is reducing plant leaf wetness (dew control) and dropping PGR’s so the plant can grow away from the effects of the disease. An up-to-date article on combating Dollar Spot from the U.S can be found here

Etiolated Growth

Etiolated Growth has been around for years now but feedback in 2018 is that it’s been the worst ever with actual turf loss noted in some areas of extreme etiolation. It’s a tough one this because in the U.S they have isolated a number of bacterial (not fungal) species said to be the causal agent and have demonstrated the fact by inoculating healthy turf with the bacteria and re-creating the symptoms. The problem in the U.K is that so far we haven’t been able to isolate the same bacterial species, so the causal agent is as yet unidentified. It’s kind of a blessing in disguise really because even if we had, the solution would mean applying an antibiotic like Streptomycin to your turf and that isn’t realistic or advisable in my books. I was asked why it might have been more of a problem this year and a number of potential reasons spring to mind.

Firstly, as it principally affects Poa annua species and this year Poa has been under a lot of stress, I think it has been more vulnerable to pathogens in general (Anthracnose, Microdochium and Etiolated Growth). It may also be that the climate has played an additional role because warmer temperatures would theoretically increase fungal and bacterial populations. Solutions, well I suppose reducing plant stress would be the obvious one but this summer that wasn’t exactly easy. I’d be interested in feedback on this phenomenon and if you feel it has been more or less prevalent in 2018, wherever you hail from.

Ok that’s it for this week, time for a cuppa….

All the best.

Mark Hunt