140707_gfs_pres_500p_loop_eur

Hi All,

Well after a packed weekend sport-wise that saw my favourite team: Costa Rica, knocked out of the World Cup (now England that’s what you call passion, committment and discipline), the Tour De France done in quirky Yorkshire style (and didn’t they do it well!) and Lewis Hamilton breezing to a well-earned win at Silverstone (even though his trophy looked like it came from Poundshop and fell apart on the rostrum), it’s back to the more down-to earth task of weathWeather070714er watching 🙁

Most of you will have got some rain on Friday night and maybe on Sunday evening as there were some very localised downpours floating around.

This week’s weather is all about that battle between a warm Atlantic high and a wet, humid, continental low (see above right). Depending on where the dividing line is drawn between the two at the back end of this week will determine where and how much of that fickle continental rainfall will occur. The rain, if it comes, will form into a vertical line up the U.K. stuck between the two competing weather systems. The question is where does that line form and when?

General Weather Situation

Ok, so starting the week we have a dry start over much of the U.K. and Ireland, but during the morning a rain front pushes in from the West over Ireland and Scotland, but also reaching Wales and the south-west of England by early afternoon. East and South of this, it’s a lovely settled day after a cool night, so temperatures are set to climb to the high teens / low twenties with a moderate south-westerly wind. Through the afternoon and evening, that rise in temperature will kick off some rain inland, so you could catch a shower anywhere really, but they appear to be concentrated in a line drawn from the south-west to The Humber.

Onto Tuesday and we follow a similar pattern though maybe the rain front that pushes into Ireland in the morning may feature heavier rainfall. This will form a diagonal line firstly affecting west Munster / Connacht, but then it’ll drift across Ireland reaching Leinster by late morning. Across the Irish Sea, that rain front will push into westerly coasts of the U.K. by rush hour and progress across country through the morning. By early afternoon the west of Ireland should be pretty much clear of the rain and by then it will have reached the eastern coastline of the U.K. lightening as it does so. Temperatures on Tuesday will be similar to Monday, however as the two weather systems begin to butt up against each other, the wind will swing round to the north.

Wed090714

Image courtesy of Meteoblue

By mid-week, that battle starts in earnest and though there is still rain out to the west of Ireland, you can see from this Meteoblue graphic of projected rainfall bullding up over the continent for Wednesday, that the threat comes from the east now.

So this is where things start to get a bit shaky from a weather forecast perspective because we’re talking continental rainfall. At present it appears that the rain will stay just off the eastern coastline of the U.K. on Wednesday, so a dry day for most places though there may be some rain flirting into the western coast of Ireland during Wednesday morning, but it’ll be light in nature. Temperatures will be up on Wednesday for the west into the low twenties, as that warm Atlantic high pushes in, though it’ll stay similar to the early part of the week elsewhere, the wind will strengthen though from the north as the weather systems push up against each other in earnest.

By Thursday, that rain has pushed into the eastern coastline of the U.K. during the night making landfall in a line done from the Forth estuary to The Wash. As we go through Thursday the rain consolidates and drifts westwards and south affecting northern England down to the Midlands and further south during the late morning. Now all this has a high potential for change, so update your weather forecast during the week to see how it progresses. By lunchtime we have a true East / West divide with the East under heavy rain and the west, bright sunshine and low twenties temperatures.

Quite where the dividing line is remains to be seen, presently it’s projected to be east of Birmingham for the rain and progressing right down the U.K. to the South Coast later on Thursday. Rainfall amounts could be heavy as this rain is likely to stay static and dump over one location area. As we go into Friday that rain eases and drifts into the west of the U.K. overnight, but it’ll take most of the day to clear the east coast of the U.K. So again, another west / east divide, dry and warm for Ireland on Friday and for most of the west side of the U.K. until late in the day when that weakened rain may eventually push across, but all the time it’s fizzling out, so the south-west should stay dry all day hopefully. So still a northerly wind, though a little lighter on Friday and maybe high teens under the cloud.

So how is the weekend looking ?

Hmmm tricky to say as the line tilts a little and that allows rain into the west of Ireland, but also there’s a risk it will build through the day and produce showers and heavier spells of rain in a line from The Wash right across to The Western Isles, south and west of this, it should be a pleasant day with lighter winds allowing the temperature to increase through the day and there’ll be some sunshine as well. Sunday looks to continue that unsettled theme with rain for Ireland, particularly the west and the risk of further showers over the U.K. merging into heavier rain. Here the threat is for the south-west up the west coast of the U.K. initially but later in the day that rain spreads eastwards and northwards, so maybe only the South-East may miss it. Temperatures will stay up in the high teens / low twenties though as the wind swings round to a more south-westerly orientation from Saturday lunchtime.

Weather Outlook

I think the outlook is continuing unsettled with similar temperatures to this week, but particularly for the first part of next week, plenty of showers around in the south-west of the U.K. and Ireland. So high teens / low twenties, south westerly / westerly winds but not bad really. Later on next week there’s a threat of a new low pushing in and that’ll bring a risk of more sunshine and rain for the end of the week / weekend.

Agronomic Notes

ETS (Etiolated Tiller Syndrome) and TE

Had some really interesting feedback so thanks to everyone that contributed. The general impression is kind of mixed, certainly no one is saying that TE causes ETS with many people commenting that their greens suffered from ETS long before they started using TE. That said the question relates to whether the symptoms of ETS are exacerbated by the use of TE and one piece of feedback from a Sports Pitch showed an overlap with TE and etiolated growth more pronounced in that area compared to non-overlapped, clear as day, in a line. So the jury’s out in my mind on this one, let’s see how some of the trials I’m doing pan out through the summer and autumn and I’ll let you know.

Growth Potential and Growth-Degree-Days  – June

Looking back at June, we can see we had a good growth month in general though it was characterised by some pronounced flushes through the month as this chart of GP through June shows.

GPJune14

If you look at the period from the 6th-7th June, the growth potential went from 0.2 (low) to 0.96 (nearly a theoretical maximum) in the space of a day, so a real struggle here to keep good greens speeds and on top of growth on outfield areas. I remember seeing my local council cutting verges at the time and you could have bailed the grass there was so much of it!

Using GP Data

The GP data also shows that for 16 days of the month of June, grass growth was at 70% or higher of its potential maximum, so that means a lot of cutting and therefore a high diesel / fuel cost for June because of this. You can also see from the GDD data below that June as a month represented the highest cumulative growth for the last 4 years.

Growth-Degree Day Data

Although I’m using Growth Potential through the summer (because it takes allowance of when temperatures get too high for growth and GDD doesn’t) it’s worth looking at the GDD information to see how the year is stacking up, particularly since temperatures didn’t actually get high enough to actually shut the grass plant down from a stress perspective. Since temperature is only one part of the growth equation however, we have to qualify that statement because moisture levels were variable across the U.K. depending on whether you got that continental rainfall or not. So on outfield areas although the GP was high, you would not have seen that growth because moisture became a limiting factor in some, but not all of the U.K. In fact I think the east side of the U.K. e.g. Norfolk and Suffolk were probably the driest. There was also a period from the 18th to the 28th June when no rain was recorded at The Oxfordshire, so GDD and GP doesn’t tell the whole story, but it does help I think.

GDDmonthlycomparisonJantoDec2010to2014image

GDDmonthlycumulativeJantoDec2010to2014image

In general then, I think we are having a ‘normal year’ growth-wise, no extremes of temperature yet and although June was a dry month, for most, just enough rain to keep things ticking over. Why are we having this type of weather? Well it’s that fragmented jet stream that’s still in-situ, it hasn’t allowed one type of weather to dominate as of yet.

Disease Activity

The combination of warm temperatures, rainfall and humidity has mantained a pretty high disease pressure for most areas with ‘Summer Fusarium’ (ok Kate, Summer Microdochium :)), Fairy Rings, Superficial and Thatch Fungus doing the rounds of late. I covered this a few weeks ago so I won’t repeat the information other than to say that it’s key at this time of year to maintain low levels of plant stress and where we’ve been dry, keep up with your wetting agent / biostimulant mixes because they do help. Low levels of plant stress now will carry over to low levels of Anthracnose next month, but if you have a stressy plant, you might as well print a calling card now.

That’s all for this week, have a good one and key your eye on that rain from the continent, it may well change its position and intensity as we get closer to the end of the week, so don’t throw your toys out of the pram if it says no rain today and you get hammered on Thursday or vice-versa.

Mark Hunt