August 19th

You get an idea of what a wet August we have had when you pitch up on the River Trent and it looks like this….. The above picture may look idyllic enough but the river is at least 6 ft above normal summer level and pulling through like a train. All that energy going to waste……

So we head into the 3rd week of August with summer still on hold and an April-like weather scenario of sunshine and showers firmly established. Looking at the next 7-10 day GFS output, there’s so much uncertainty about where our weather is going that even to forecast a week away is tricky currently but I will have a go. Next weekend is MotoGP at Silverstone, last year it was cancelled because the track flooded and since they have spent a fortune resurfacing and facilitating better drainage. It may just be put to the test again 🙁

Image courtesy of tropicaltidbits.com

General Weather Forecast

The above image shows the scenario we start the week with, that of low pressure still calling the shots especially in the north / north-west of the U.K / Ireland who sit closer to the centre of the low. Very much a north-south divide this week in terms of temperature and rainfall with the north and north-west on the receiving end.

So Monday starts not bad really considering the image above with many places starting dry but we do have some showers already building along the Severn Estuary, the west coast of Ireland, The Lakes and Borders. As we move through the morning those showers will consolidate along western coasts of Ireland and the U.K by midday and then push inland through the course of the afternoon clearing the west as they do so. Between these showers it will be bright and breezy with some places staying dry all day. Temperature-wise we are looking at similar to the weekend, so high teens to just nudging 20°C. So a sunshine and showers scenario starts the week, but will it continue ?

Tuesday starts off dry for pretty much everywhere but with low pressure close by it is unlikely to stay that way. So by morning rush hour we see rain push into south-west Munster and then Connacht and this rain will head east over Ireland during the course of Tuesday morning / early afternoon. Across The Irish Sea we have a dry start for the majority of the U.K with just some rain lurking across north-west England / The Lakes. This rain will push some showers across northern England and The Borders through the course of Tuesday afternoon. Further south we look to be largely dry and set to enjoy some pleasant sunshine. By Tuesday evening that belt of rain will have largely cleared Ireland and will be pushing cloud into the north and north-west of England with some showers across North Wales. Temperature-wise 16-17°C across Ireland and Scotland pushing into the low twenties further south.

Overnight into Wednesday and that rain across Ireland will make landfall across western Scotland and north-west England so some showers across north-western coasts from the off. We may also see some showers across South Wales early doors. By the time we hit the Co. Sligo rush hour the west of Ireland will be feeling the effects of the next Atlantic low stacking up to affect our weather with rain pushing into the west of Ireland through Wednesday morning. Further east we look to be largely dry except for some patchy rain over northern England. This low pressure will be moving quite quickly so by mid-afternoon it’ll already be pushing into north-west England and western Scotland. Very much a north-south divide then because south of The Pennines will see a much nicer day, pleasantly warm with long sunny spells and temperatures in the low twenties with a lighter westerly wind as well. For Scotland and the far north of England, the boot is on the other foot with a very wet end to the day I am afraid.

Overnight into Thursday that rain clears Ireland but it’ll push rain into Wales and the north-west of England in the early hours. Some of these showers may push inland a little but they are projected to fizzle out. So first off on Monday morning we may see some cloud cover and one or two showers drifting across Wales and north west England / Scotland but it should be largely dry. Through the course of Thursday morning that low will push further rain into Connacht, Northern Ireland and western Scotland but at this stage that’s where it is projected to stay. So away from that rain front another pleasantly warm and dry day for England and Wales with moderate south-westerly winds and temperatures pushing up into the low twenties again.

Closing out the week and it’ll be 1st practice for MotoGP at Silverstone……

So when Mr Rossi & Co. venture out into the cool Northamptonshire air first thing on Friday morning, what awaits them ?

Well a very nice day is the answer with early cloud breaking to give long spells of summer (?) sunshine and temperatures pushing up to the mid-twenties. Cracking. So dry, sunny and warm across England and Wales again on Friday but across The Irish Sea we have another rain front pushing into Connacht and heading north and east across Northern Ireland and into western Scotland. South and east of this, Ireland should be dry but dull with plenty of thick cloud courtesy of that low pressure system across the west but breaking to give some sunshine as well. Temperature-wise similar to Thursday with 16°C across Ireland and Scotland but pushing up to 23°C for England and Wales. Winds will be light and from the south-west for England and Wales and strong to moderate for Ireland and Scotland.

Well onto the weather for the weekend, hmm tricky one as I’ve seen at least 4 different weather scenarios for Sunday. So here goes…

So Saturday looks like continuing that north – south divide with a line of rain stretching from Kerry across Ireland / Northern Ireland up into western and Central Scotland. West and north of this line will see plenty of cloud and rain I’m afraid. South and east across Ireland should be drier but dull I think. Across The Irish Sea we look to have a much better scenario with early cloud giving way to longer spells of sunshine and warm weather. Temperatures look to rise significantly on Saturday possibly up into the mid-twenties with light winds. The real question mark is on Sunday with a low pressure sitting north-west of the U.K and another one across The Bay of Biscay. It’s the latter that could spoil the party at Silverstone but at this stage it’s going to be so difficult to call. What we could see is the weather breaking down across the south and showers breaking out during the course of Sunday afternoon across central and northern parts of the U.K. Elsewhere looks a much better day than Saturday for Ireland and Scotland with some showers continuing to affect the west of Scotland. It could potentially be hot and humid across the south raising the prospect of thunderstorms but let us hope not.

Weather Outlook

With all the uncertainty around current GFS forecasts, I’m a bit reticent about this one but saying that last week’s outlook for this week is pretty accurate. So next week looks like carrying over some of the unsettled weather associated with that northerly low pressure so potentially continuing wet and windy and on the cool side for the west and north. Thereafter though a much better picture images with an Atlantic high pressure system projected to push in through the course of next Tuesday bringing more stable dry and fine weather for the U.K and Ireland. So fine, dry and warm particularly through the second part of next week before a new low pressure arrives to potentially bring unsettled weather to the north and west next weekend. Now it is the first time for quite a while that I’ve seen a high pressure push in from the west so this could mean a fine and dry start to September. Fingers crossed.

Agronomic Notes

It’s all in the rain you know…

Image courtesy of NetWeather’s lightning archive

Since we have got quite a bit of summer rainfall (at least it is warm rain) I thought I’d kick off with a chat about that. So in early August we had a big thunderstorm here with some pretty close lightning activity close by. Yours truly was out positioning a sterilised container and funnel to get the most of the rain whilst staring up into the heavens wondering when the next strike was due. We had one strike that was instantaneous lightning and then thunder, a wham, bang, thank you Ma’am kind of moment 🙂

So Wendy kindly forwarded me the chemical analysis results of the afore-mentioned rainfall this morning and they made interesting reading.

The pH of the rain from that storm was down at 6.0, so moderately acidic. It contained the equivalent of 0.55 kg per ha of N per inch of rain (How’s that for a mix of metric and imperial units) which by most standards isn’t much really for a lightning storm.

It also had a significant dollop of sulphur (12mg/l)  (which is unusual nowadays since we closed our coal-firing power stations and the equivalent to 3kg per ha of sulphur per inch of rain) and a smidge of sodium and chloride suggesting that it picked this up from the sea on its way over I guess. The pH of the next storm I measured came in at 6.3 so we’ve been getting some nice acidity in the rain this summer if these samples are anything to go by.

Soil Moisture Status – 2019 vs. 2018

Continuing my rainfall theme, I graphed out the theoretical soil moisture status comparing 2019 with 2018 starting at June 1st to the present day at The Oxfordshire location. Now this is one of the drier locations in summer 2019 and I am sure if I had access to daily rainfall and E.T totals from a more northern / western site, the results would be very different.

So in 2018, in the period from June 1st to August 18th, we had 41 mm of rain and 303 mm of moisture lost by E.T making us -262 mm soil moisture status.

In 2019, over the same period  we had 119.2mm of rain and 249.7 mm of moisture loss by E.T, making a soil moisture deficit of 130.5 mm.

It is interesting to me to think that we have still experienced a relatively high E.T summer with only 18% less total E.T than last summer for the same period. So the desiccation pressure on the grass plant has been significant. The difference has been in the rainfall totals with another 78.2mm of rain this summer vs. last and that has made all the difference. That rain hasn’t all fell in one great dump either, it has been spread out across the period so rather than 80 odd days without rain, the longest period for this site has been around 17 days, strangely at the start of July and again at the start of August, weird ?

As mentioned above this location at Thame, Oxford is notoriously on the dry side but it just goes to show the E.T stress on the plant has been significant this year especially on un-irrigated outfield sites but the saviour has been the summer rainfall.

Disease Activity

Following on from a wet week with extended periods of both soil and leaf wetness it is no surprise that we have plenty of disease activity out there.

Summer 2019 is definitely the summer of Fairy Rings with them cropping up everywhere from greens to fairways to outfield and cricket squares. I was listening to the cricket commentary the other day trying to avoid some monotonous current music or ineffective politicians and I heard one of the commentators mention the presence of Fairy Rings and their likely effect on ball bounce. 

Treatment of Fairy Rings is a tricky affair because the depth that they are active varies from right in the surface (Superficial Fairy Rings usually) to deep down the profile. Strobilurin chemistry will have an effect but you have to get the chemical into the active zone of the fungus and so combining it with a soil surfactant is very important. I always suggest doing a droplet test on a core taken from the active area to determine where the fungus is active in the soil profile. The image above shows surface activity of Basidiomycetes causing the rootzone to become hydrophobic but on well-established Fairy Rings, it is present much deeper and so requires spiking / tining period to treatment to get the best result. Often the issue is purely aesthetic as we see the characteristic green rings resulting from the conversion of organic nitrogen to mineral N. For many they aren’t as great concern until the telly cameras get hold of them that is 🙂

With high pressure looking to make a potential appearance at the end of August / beginning of September we should get a quieter period from a disease perspective. Amen to that.

OK short and sweet today as the T.T.D (Things-to-do) list beckons……

All the best.

Mark Hunt

 

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