May 2nd

170502_gfs_pres_500p_loop_eur

Hi All,

Well after a not so bad Bank Holiday weekend and a welcome drop of rain (6mm) on Sunday night (our first for a month) we are all set fair to start May. Unfortunately the high pressure and warm southerly airstream projected last week has gone off kilter and it’s now projected to tilt on its side and pull in easterly winds instead for England. Our loss is a Celtic gain though and particularly Scotland’s because the warmer part of the high will be further west and north so you’ll see a cracking week temperature-wise up north and better temperatures the further west you are. Even for the south of the U.K, it won’t be the end of the world because at least we’ll keep half-decent night temperatures and that’ll help growth along a bit, however easterlies rarely bring rain, (though some may drift off the continent this week) and that means we’ll continue dry for the foreseeable. So not the best news I know, not the worst either, but you can put that factor 30 on hold for the foreseeable 🙂

General Weather Situation

Ok so we kick off Tuesday with a dry day and plenty of spring sunshne out there on offer. That breezy east / north easterly wind will be in from the off so that will pull some cloud cover off The North Sea through the day and that’ll peg back temperatures on the east coastline of the U.K particularly. Later on in the day there’s a risk of rain pushing over from France into the south east and south coast of England so a chance of a drop of welcome rain tonight in those areas. Temperature-wise, expect 12-13°C on the east coast but across the west coast, Wales and Ireland, it’ll be 3-4°C warmer so a much nicer day here. Scotland will also be 2-3°C warmer so here as well a lovely day. The only plus side for the south of England is that with the ever-present cloud cover departs the risk of frost.

Northsouthdivide

Quickly onto Wednesday and the theme for the week is kind of set as this graphic (courtesy of Meteoblue) shows with cloud cover coming in off The North Sea and pegging back temperatures for south and particularly east England whereas further north and west, you’ll have lovely sunshine. So after some rain overnight for the south east of England, Wednesday promises to be a lovely day for Ireland, most of Wales, the north of England and Scotland with lots of sunshine. For England though certainly from The Humber estuary down we’ll have thick cloud cover off The North Sea so a dull and bloody cold day for sure with a pronounced north easterly wind. Bah Humbug. Temperature-wise expect 14 -17°C for Wales, the north west of England, Scotland and Ireland and then lop a good chunk off that for Central England with 11-13°C likely under that cloud, some of which may be heavy enough for some mizzly drizzle.

Thursday sees a continuation of the above weather pattern with cloud again for the south of England but this time it stretches over to Wales. Less cloud about north of this though so The Midlands will see some sunshine as will Scotland and the north of England. That band of cloud will push over the Irish Sea into the south of Leinster and Munster so more cloud cover as well for Ireland but it’ll still feel pleasantly warm. That wind will still be brisk to moderate and perhaps more easterly than north easterly on Thursday and that’s why the cloud cover and temperatures are a wee bit better. A mild night again with temperatures not set to drop below 7-8°C and that’ll help growth somewhat.

Closing out a short week on Friday we see that cloud cover thicken late on Thursday across the south east of England, dense enough for some drizzle in places I’m guessing. Through the course of Friday morning that cloud cover sinks south and departs into The Channel so Friday looks to be a much better end of the week for everyone with lots of sunshine and some reasonable temperatures. Still though we will have that ever-present, easterly wind in situ and that’ll make things feel cooler across the east, but nice out of the wind mind. Temperature-wise expect 14 -17°C for Wales, England, Scotland and Ireland.

The upcoming weekend doesn’t look half bad but they’ll be a subtle shift in the wind direction from easterly to northerly through the course of Saturday night so you’d expect this to mean it’ll be cooler for Scotland. Not a bit of it and a cracking weekend in prospect as I sit and type this with temperatures likely to hit 20°C up there. It’ll be a real case of east / west divide though because it’s likely that we will still see some thicker cloud cover particularly across the north east of England on Saturday and this will make it a dull, cool day there. This cloud cover will drift down along the east coast during Saturday and push into central areas overnight into Sunday so more in the way of cloud and slightly cooler on Sunday for England with a light to moderate northerly wind in situ. For Ireland, Wales the west / north west of England and Scotland, no such worries here as Sunday looks to be a beautiful sunny day with pleasant temperatures pushing up in the high teens.

So the bottom line is if you’re thinking about nipping off for the weekend and you live in England, point the car, motorcycle, bike, camper (delete where applicable) westwards !

jetstream020517

Image courtesy of Netweather Extra

Weather Outlook

When you have a jet stream that is so fragmented, (see above) it’s little wonder that long term, 10-day weather forecasts can change, so trying to predict next week’s weather is going to be tricky. That said the first part of the week is easy because it looks like high pressure will still be dominant so I think next Monday looks warm and dry and that’s the way we should stay with a change in the wind direction to more southerly as we get to mid-week.

Now low pressure systems are stacking up east, west and north of the resident high so you’d think they’d be a good chance that at some point one of these is set to dominate and that’s the way it looks for the end of next week with an Atlantic low pressure (our first for yonks) set to push in from Friday next week and over the weekend so south westerly winds and rain for most parts of the U.K and Ireland could be on the cards. That’s what all 3 long-term models are indicating so there’s a good chance it may well happen 🙂

Agronomic Notes

Ok first up it’s a look at April 2017, a month I’m sure that will be looked back on as not particularly easy from a managing surfaces perspective whether that be fine turf or the conversion of winter sports pitches to cricket outfields in a schools scenario.

GDD Comparison

First off with the April comparison, we will look at our set location of Thame.

GDDmonthlycomparisonJantoDec2010to2017image

GDDmonthlycumulativeJantoDec2010to2017image

So looking at our GDD figure for April 2017, we see we hit 98.25 for the month compared to 119 for March, so the first thing we can ascertain is that March 2017 was a warmer month than April 2017, surely some mistake ?,

No that’s the way it played out and re-affirms my assertion that the calendar and turfgrass management don’t sleep in the same bed together 🙂

Cumulatively of course we are racing ahead because of the warm 2nd half of February and March with close on the highest cumulative GDD figure (280.8 y.t.d) since we have been recording the data (just pipped by 2011 though I can’t remember that being a good growth)

U.K Site Comparison

Thanks to everyone for sending their data in, this week we can look at GDD and rainfall the length of the U.K.

GDDRainfallApril2017

The first thing that’s apparent here is the lack of rainfall and that’s part of the reason April 2017 has been a tough month in most areas to get consistent grass growth. Those GDD weren’t spread evenly across the month either as you’ll see later in the blog when we dig into the month proper to see the pattern of growth.

Irish Site Comparison

GDDRainfallApril2017Ireland

Now there’s not many times that I’d put this data together and then look enviously at Valentia’s rainfall total for the month because usually it’s rather high (as a comparison it was 104mm in April 2016 ). So Ireland is dry as well, joining the U.K in having a very dry start to the year.

Pattern of growth and rainfall….It’s all about the direction of the wind….

You may or may not have noticed that it seems like it has been a long while since we had a continuous south westerly wind ushering in an Atlantic low pressure system ?

So this month I decided to do some delving into wind direction to see if there’s anything in this….

Below is a cute little graphic (well I like it but then I am sad…) called a wind rose and I’ve used it to show the number of days that the wind blew from different directions. I’ve used data from Sean at The Oxfordshire because he always includes wind direction 🙂

WindroseApril2017 WinddirectionApril2017_2

So the first thing you should notice is that we had plenty of days when the wind wasn’t in the direction that is normally associated with good day and more critically, good night temperatures. This would normally be S, SSW, SW, WSW, W.

Actually the chart shows that for nigh on 2/3 of the month it wasn’t in the right direction to provide good day and night temperatures for growth. This was because rather than having low pressure systems from the west or south west, we had high pressure systems from the north or east.

Just as a refresher if night time temperatures are low it really impacts on the potential of the grass plant to grow…This graphic which I’ve put up before shows two different scenario’s, one with good night time temperatures and one without and you can see the effect on Growth Potential.

SpringDayGP

So temperature was growth-limiting in April 2017 because of the high frequency of days when night time temperatures were low.

But that wasn’t the only growth-limiting factor, we were also dry….very dry in fact..

Growth Potential and Rainfall – April 2017

So let’s drill down into April 2017 and see where and when the growth occurred and the same for rainfall….

GPRainfallApril2017Thame GPRainfallApril2017Fife GPRainfallApril2017Dublin

You don’t have to be a resident rocket scientist to figure out that the non-existent top graph denotes a) Low daily rainfall events and b) High dry day frequency.

High Moisture Deficit

If you look at rainfall vs. evapotranspiration through the month of April for our Thame location, the stats indicate that they received 6.2mm of rainfall and 69.8mm of E.T, so they had a moisture deficit of 63.6mm.

That means if they were working to replace 80% of the E.T loss / moisture deficit, they’d have had to supply 50.88mm of rain through irrigation, now that’s a lot of water to be applying.

Just to add a further negative note, many facilities reservoirs used for irrigation water are extremely low because of the dry winter and this points to a tough time coming in the summer unless Mother Nature decides to balance the rainfall books.

Growth-wise we can see that we had temperatures consistent enough to generate good spring growth for ;

Thame – 9 out of 30 days = 30% of the month

Fife –       6 out of 30 days = 20% of the month

Dublin – 3 out of 30 days = 10% of the month

Remember what I said about wind direction and growth and here we can see the relationship is confirmed using the Thame location data. So for 39.9% of the month the wind was in the right direction to provide good day and night temperatures and that tallies closely with the % of days when the G.P figure required for good spring growth. was 0.4 or above.

I think this shows quite clearly that April 2017 was a bruising month for growing grass because it was either limited by temperature or moisture or both !

Looking ahead…

As my outlook suggests I think we have a pretty dry picture for the next 7-10 days with the exception of some continental rainfall creeping across The Channel. We will also be cool in the areas of the U.K affected by the cloud cover pushed in off The North Sea so don’t expect bundles of growth too quickly in those areas. Happily one location’s pain is another’s gain because the west and north will have better day and night temperatures this week and that means some good growth prospects (provided you have irrigation 🙂 )

Here you can see the projections for the next week across different locations….

GPMay2017

Accepting the fact that we are dry we should be able to get a good response from a foliar application this week, especially if it is applied towards the end of the week as temperatures look to rise (even in England) but of course you’ll need a grass plant that is irrigated or that benefitted from last weekend’s rain else you won’t get a growth response.

Manage soil moisture and plant stress

So management of soil moisture levels going forward over the next 7-10 days will be hyper-critical to ensuring a consistent surface and generating consistent growth. I’d suggest being careful when looking to carry out any operations that could add to plant stress including heavy lateral aeration and even something as straight-forward as applying a selective herbicide to outfields areas.

I’d also expect a continuation of the increase in Poa seedhead development as forecast last week because with better temperatures and drier rootzones, Poa will look to seed to survive.

Beyond the next week we can hope that we will see some consistent rainfall at the end of next week and that heralds a more stable, westerly airstream and in turn consistent growth.

Ok that’s all for this week, I think I’m charted out mentally 🙂

All the best..

Mark Hunt

 

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