Well the first blog of September is upon us. Normally I see September as a bridging month between summer and autumn but I think this year that will be different because there’s no sign of the stabilising high pressure that tends to assert itself at this time of year and bring us an Indian Summer. Don’t get me wrong, it’s sitting out in The Atlantic but it looks like a succession of Atlantic low’s will keep it at bay for the moment 🙁
This week we will have another north – south divide in terms of the weather with low pressure affecting the north of the U.K and high pressure the south. Towards the end of the week the signs are that the low will drop south and we will experience our first Atlantic storm of the autumn.
Ok onto the weather synopsis for this week…
And it’s a quietish start to the week with Monday seeing a vestige of yesterday’s rain fronts moving away out into The Channel and The North Sea in the form of light rain over Wales, The Home Counties and the north of England. I did mention that it’ll be a north-south divide this week and already we can see rain into the west of Scotland, this will move west through the morning to bring rain to central and eastern areas as well. We also have another band of rain just approaching the west coast of Ireland and due to make landfall in Galway pretty soon. Across the south and east of the U.K, we have a muggy, misty start to the week with a low cloud base after overnight rain. It’s not all doom and gloom though as here we should see this cloud slowly thin to bring sunny intervals and probably the warmest day of the week with nice temperatures expected this afternoon. For the west of England and Wales, you’ll be the recepient of that cloud base from the west and so a dull day here with not alot of breaks in the sunshine at all. Ireland will see that rain lighten and cross country through the course of Monday and then clear from the west to leave a nice evening along the west coast of Munster. Scotland I’m afraid keeps that wet theme most of the day with the rain consolidating this afternoon to bring heavier rain to central areas. Temperature-wise, I think we may hit the low twenties later on this afternoon over The Midlands, a couple of degrees lower than that across the south and high teens for Ireland, Wales and Scotland. Winds will be southerly turning to south westerly and light initially. It will feel muggy in the south.
Onto Tuesday and here the feature of the day is a band of heavy rain that is due to cross south Munster and Leinster overnight and then push across Wales into north west England with some pretty heavy rain expected across North Wales and The Mersey area early doors, with this rain pushing east across northern England and towards The Humber by the morning rush hour. Through the morning this rain will clear the south of Ireland and push south into South Wales and The Midlands and southern England, lightening as it does so. By the afternoon this is gone and we finish here with some sunshine and warmer temperatures. After that early rain across the south and east, Ireland looks to dry up and leave a sunshine and pleasant day behind for the rest of Tuesday. Scotland looks to start dry but a band of rain affecting the west will push eastwards into Central Scotland by the afternoon bringing a wet one to this area before moving eastwards. The winds will freshen on Tuesday to moderate and be more south westerly / westerly. Temperatures will be slightly cooler with mid to high teens expected.
Wednesday and I think Thursday will be the driest days of the week south of the Pennines before low pressure comes in with a vengeance for the weekend. So make hay while the sun shines 🙂 So Wednesday still sees rain over Scotland I’m afraid, a wet week for you guys for sure sad to say with rain mainly affecting the west of Scotland through the entire day. This same rain band will also affect the north west of England, from North Wales upwards through most of Wednesday. After a dull and cloudy start for Ireland, we see the clouds break and a nice, dry day for you beckons with some sunny intervals. The same is true for the east and south of England, really anywhere east of that rain across the north west and then south across The Midlands into Central England and including Wales. Temperature-wise it’ll depend on how much the clouds break but high teens and possibly into the twenties is likely here. Mid-teens for Ireland and Scotland I’m afraid with a light to moderate westerly wind expected.
Thursday sees a similar pattern except they’ll be less rain around with just the north west of Scotland likely to be affected. Elsewhere you can expect a very pleasant day with long spells of sunshine and broken cloud across Ireland, Wales and England. Although it’ll be a drier day for Scotland, you’ll keep a thick cloud base so a dull one here. As we approach the end of Thursday we will see the first effect of that deep Atlantic depression with a heavy rain front pushing into the north west of Ireland and Scotland late afternoon / dusk. So a wet end to Thursday here. Temperature and wind-wise, similar to Wednesday so pleasant where you see the sun.
Friday sees that heavy rain cross Ireland overnight to leave a much more unsettled feel to the weather for the end of the week. That rain will push into Scotland and then head south across northern England into The Midlands and finally the south of England in time for Friday morning’s rush hour. A much windier day on Friday as the low pressure exerts itself and this will be a feature for the weekend and perhaps beyond. So a sunshine and showers day for Ireland on Friday and after that initial rain pushes through we will see more rain primarily affecting the west and north west of Ireland and the U.K through Friday p.m. Once that rain has pushed through on Friday morning I see things brightening up thereafter for The Midlands and the south of England so not a wash out by any means.
So onto the weekend and if the forecast holds, it’ll be a wild one though good for boogy boarding I’d say on western coasts ! 🙂 The above shows Unisys’s projection and you can see how finely poised the weather is with warm, high pressure out in The Atlantic and a deep trough forming over the U.K, into which it is projected that this weekend’s and possibly more low pressure systems will slot.
Now I’ll add the forecasters caveat that I’ve seen this kind of forecast before and it can change with the low pressure shifting eastwards and the high following it. This time though I don’t think so, so I’m sticking to my guns in forecasting that this weekend will be windy and potentially wet as well with showers rattling in on a cool north westerly wind for Saturday. Sunday morning may see a brief respite in places with lighter winds but through the course of the afternoon, these will strengthen again and whip round to the north pushing temperatures down a little. There’s no point in adding rainfall detail on other than I think the north and west will bear the brunt of it,
So I think next week looks like starting unsettled with wet and windy conditions in place and that wind will be in the north / north west as we get squeezed between a high and low pressure. Tuesday may see a quieter, drier start but it won’t last as another low pressure is due to slip down into the trough and bring more unsettled, wetter weather for the second half of the week. With high and low pressure fighting it out, it looks like we will have northerly winds for a good part of next week so that means cooler for sure with mid-teens likely the order of the day. Any signs of hope around the corner ? Well there’s a possibility that high pressure may exert itself by the end of next week but that’s a long shot sitting at my desk here and now sipping a nice coffee and contemplating….
Ok so since this is the first blog of September, we will look back at August and what one of my regular contributors called a sh***y month and yes Pete I wouldn’t disagree with you on that one…:(
The Oxfordshire – GDD Data
So you can see in the above that August came in with a total monthly GDD of 314.5…That automatically marks it down as a cool one when you compare with last August when we hit 364.5 at the same location. We will delve down into the detail later in the blog…
Cumulatively for the year, this is how we look…
So despite having a cooler and we know wetter August, we are still on track to record the warmest year to date from a purely GDD basis. Interestingly 2014 is the current title holder and during that year we also had a wet and cool August following a very hot July because I remember Anthracnose was a real problem that year for many during August and September (the latter was very dry if I remember correctly)
UK – GDD Focus
Bit of a shortage of contributors this month but thanks for the data I did get and fortunately because I’m now able to access regional weather stations I’ve added some of my own locations of choice….
So here we can see that once again the south west of England was in the firing line for rainfall with our Devon location once again our wettest. Thereafter our London location came in 3rd highest of the rest of the U.K and that’s because the south east has a tendency to pick up continental rainfall which the rest of the U.K doesn’t always do. The west coast of Scotland, like Ireland is always going to be up there because if there’s an Atlantic low pressure system around, this area is normally in the firing line.
Ireland – GDD Focus
So Ireland paints a similar picture geographically with the westerly and north westerly locations picking up the highest rainfall. GDD-wise the results are quite similar with Dublin the highest (just) being furthest away from rainfall and closer to the warmth of Continental Europe in more ways than one I’d say 🙂
So on balance why would we describe August as a crappy month from a turf managers perspective when it hasn’t been too hot and save for the west of Ireland, Scotland and The South West, (not wishing to be dismissive here) it hasn’t been too wet with 50mm the average monthly rainfall ?
The first part of the answer is how the rainfall has fell with most locations showing that 50% of the monthly rainfall fell on just 3-4 days of the month and that provides us with a problem.
You can clearly see the peaks in rainfall above which represented 15mm + of daily rainfall occurring on a low number of days. If we drilled down further it is also likely that during these high daily rainfall events, the actual rainfall rate in mm per hour probably exceeded 100mm per hour at some points in the day. This type of rainfall rate in mm / hour will quickly saturate a push up green, soil-based sportspitch, fairway, semi-rough, delete where applicable.
When it was wet it was also growing at close to maximum…
The reason why I produce these ‘stacked’ graphs with one parameter on top of another (you should try it sometime, it’s a real head scratcher to do…) is so you can see the relationship between the two across a set time interval.
So if you look above for both the Okehampton and Cork locations, you can clearly see periods of the month when the Growth Potential was close to 1.0, (most of it in the case of Okehampton) i.e optimum conditions for cool season grass growth and you should also be able to see that these periods coincided with rainfall.
So we have saturated or potentially saturated surfaces growing really quickly and needing cutting even more regularly than normal. Just getting the job done is hard enough resource-wise but maintaining good presentation as well without loads of clippings lying around is tricky to say the least. So that’s one of the reasons August was a bit of a pain from a growth management perspective, the other is unquestionably disease activity…
Temperature + moisture = high humidity = plant leaf wetness = disease
I know I have talked about this before so forgive the scratched record scenario but the reality is that leaf wetness promotes disease and the higher the humidity, the wetter the leaf surface. Just typing this now it’s really muggy outside and my weather station is saying we have been tracking at > 90% Relative Humdity since 10.12 p.m last night and currently we are still > 90% so that means 14 hours of high humidity coupled with an air temperature that hasn’t gone under 12ºC over the same period.
In other words ideal disease development weather.
Picking the Swansea location (about time I included South Wales in the weather stats), here is the data for August, 2017 and remember we are looking for > 90% humidity as a driver for disease…
So we can see that for 19 days out of the 31 days in August the maximum humidity exceeded 90% and for 7 days it exceeded 95%.
These will have been the real driver days for disease development and that’s why you will have seen more Dollar Spot, Red Thread, Microdochium nivale and Leaf Spot (on sports pitches mainly but also some high ryegrass content rough) during this August compared to other years.
What is to be done going forward ?
The immediate problem for me is Microdochium nivale because if we look at the fact that we are carrying disease now in our swards into September and that the next 7-10 days (depending on your location) looks unsettled with further rainfall and high humidity, then it’s likely that this will continue into the middle of September at least.
The problem with this is that as daylight hours shorten, then grass growth levels will begin to drop back as temperature and particularly night temperatures drop.
If you look at the GDD information at the beginning of this part of the blog you can see the difference in monthly GDD totals between September and October. In a mild October we can lose 25-30% of our growth potential vs. September, in a cold October this can increase to 50%-60%. (look at 2016 as an example)
So the dynamic between growing out the disease as fast as it develops begins to change and we see a higher potential for the disease developing down into the crown of the grass plant and ultimately causing scarring. So that’s why I am a fan of trying to minimise the population of the disease before we reach October.
Easy to say, harder to do, with less effective, systemic fungicides as the future option and the loss (at some point in time) of Iprodione, the job is and will get harder for sure. That’s why we have to work on all of the contributing factors to disease development wherever and whenever resources allow us to do this including dew removal, surface organic matter control and maximising plant health through this period.
Again easy for me to sit here and type this, but I appreciate with resources and specifically staff numbers difficult to keep at a constant (particularly through the holiday period) it’s no wonder we drop the ball on occasions. It sure is a big challenge as is maintaining surfaces with casting worms and increasing insect populations with the demise of control options – answers on a postcard on that one…:(
Sorry to be a bit doom and gloomy but it is a fact that the weather can make or break this game we are in and when it works against us, life can be tough for sure. During these periods it is essential to communicate to your team and management of the challenges we face and are facing and hopefully the data in this blog goes some way to help this process.
Ok I have a bitch of a week ahead (mostly of my own making) so it’s time to face up to it and get my own house in order.
All the best for the coming week….