Hi All,

Well as forecast we endured a pretty torrid Easter with incessant torrential rain in the south, west and east and snow further north. Truly I can’t remember a time when I’ve seen so much water lying on the landscape locally with rivers bursting their banks, reservoirs being pumped out to reduce dam pressure and the like. Image right is the usually tranquil River Welland that flows through Market Harborough. The reason for this weather as we know dates back to mid-February and that Sudden Stratospheric Warming (SSW) event which has pushed the position of the jet stream south and allowed low pressure to dominate proceeedings, bringing cold, snow or rain. The rub is when is our weather going to get back to normal because the economic and agronomic impact of this latest SSW is significant and goes way further than a low GDD calculation.

Looking at the jet stream position, the questions on everyone’s lips are when are we going to get some warmth and now more significantly, when is it going to stop raining ?

Image courtesy of NetWeather

As you can see from the graphic above which shows the current position of the jet stream (yellow / orange pattern), it is still lying well below the U.K and Ireland and while it does so we can still expect more rain and an unsettled outlook, particularly for the south of the U.K because the low pressure systems are sitting south rather than west of us. There is some positive news however and that concerns temperatures because this southerly air stream is projected to give us some decent day and night temperatures over the next week or so. So that will start some growth plus warmer days will also initiate some surface drying by raising E.T, however if it keeps raining, the latter’s effect will be minimal.

The problem for our industry is that it is saturated soils and not a tardy GDD figure that closes venues and restricts income and that’s what we are facing at present.

Sorry not to be the bearer of positive news with an anticipated end to our current run of crap weather but the truth is we aren’t out of the woods yet and although we will pick up some welcome warmth, it may well be transitory.

Image courtesy of Unisys Weather

General Weather Situation

Wednesday sees a raft of moisture over Ireland falling as wintry showers, sleet and rain and extending across Scotland. A belt of heavier rain is also projected to extend across North Wales into northern England first thing and this will drift south and east into The Midlands, central and southern regions through the course of tomorrow morning. By late morning Ireland should have lost that colder moisture and it’ll be replaced by sunny intervals but much cooler on Wednesday due to a northerly wind across Ireland.  At this stage it looks like the heaviest rain will be across northern England, North Wales and the south coast of England as well falling as wintry showers at elevation but there will be rain for pretty much everyone through the day. As we go through the evening that rain will clear most areas but any remaining will turn to more of a wintry shower mix as the wind takes on a north-westerly slant. A little cooler feeling on Wednesday with still mid-single figures for Scotland due to a northerly wind aspect and low double figures for Ireland, Wales and England.

Thursday looks to be a much better day from a lack of rainfall perspective with a cool, bright start to the day for most areas save for a block of wintry showers across the north-west of Scotland. So a bright, but cool day on Thursday with a north-west wind keeping the lid on temperatures across the U.K (southerly across Ireland). A bit of cloud cover moves into Ireland in the afternoon, pushed ahead of another rain front coming in off The Atlantic but that’s about it. A little milder feeling for Scotland with 6-7°C likely here in a north-west wind and 9-10°C further south and across Ireland and Wales.

Friday sees a new band of rain push in off The Irish Sea into Kerry and Connacht and here it may be heavy I’m afraid. This band of moisture may fall as snow for the north-west of Scotland as it meets the cold air pushing south and east through the morning. Elsewhere a dull and cloudy start to the day but with a south-easterly / southerly wind in situ it’ll feel much milder with temperatures pushing up into the teens through the course of the day despite the lack of sunshine. Through the afternoon that rain will cross over Ireland and push into The South West, Wales and the west coast of the U.K and through the course of Friday night become heavy over Scotland. Different ends of a low pressure means Scotland’s temperatures look to remain on the cool side between 6-8°C, whereas a southerly wind aspect for England, Wales and Ireland will mean milder temperatures pushing up to 11-13°C  depending on rainfall / cloud cover.

So how does the weekend look ?

Well tricky to forecast for one with more in the way of wintry showers turning to rain for Scotland starting off Saturday but with a southerly wind in situ this should clear off into The North Sea through the morning to leave a dull mild Saturday for you with much-improved temperatures. Ireland and Wales look to have a dull, mild day with a low threat of some light showers but it’s the south of England that’s the tricky one to call. There’s a risk of a band of showers pushing into the south coast and extending northwards across to The Wash through the day. My call on Saturday for The Midlands and south of England is mild, dull and unsettled with a risk of rain through the mid-part of the day and a mild south-westerly wind. All change on Sunday with the wind doing a 180° and swinging round from to the north-east to bring a more unsettled feel back to the weather and for Scotland a drop in temperatures compared to Saturday. Still mild though for Ireland, Wales and England with temperatures peaking at mid-teens for the south of England, a couple of degrees down on that for Ireland, Wales and The Midlands and then only high single figures for Scotland with the risk of some snow showers still remaining for the north east of England. Again I don’t think it’ll be entirely dry across England with a risk of rain across East Anglia and The South East through the day. Dull again for most but maybe Scotland seeing the Lion’s share of the sunshine once those wintry showers depart.

Weather Outlook

Well taking into account that the greatest issue currently is saturated ground conditions then the fact that we may have a continental high pressure system building next week could be the kind of breather we need to help things dry out. It looks like we will still remain unsettled through Monday with a small low pressure bringing rain but after that it looks like high pressure is going to build over Scandinavia from the early part of next week and that will work to block Atlantic low pressure systems. So I reckon we will be drier next week but not necessarily warm because a continental high pressure is likely  to funnel over easterly winds through the week and probably cloud cover coming off The North Sea. So I’d say 8-10°C would be my guess during the day and hopefully with cloud cover, frost-free.  So a cool, dry and largely settled week, probably on the dull side as well with fog / mist and if I really Mystic Meg it, I reckon we may see the wind change back to south-westerlies at the end of the week / weekend to push in more milder air, but more unsettled as well.

Agronomic Notes

Crumbs, where do I start to write this weeks notes when I know the state we are in presently and would like to put some positive spin on it ?

Well first up let’s do a thorough review on March and I’m going to burn some midnight oil on this one to give as wide a perspective as possible geographically.

We will start with our default, Thame location.

GDD Review March 2018 – The Oxfordshire, Thame, England

Well I guessed that March would finish off with a total GDD of 15 ish halfway through the month and I wasn’t that far off with a GDD total of 21 at this location. That’s the second lowest on record since 2010, with 2013 the lowest at 12.5. Now we know both 2013 and 2018 have in common, a late SSW event so it’s interesting that their effects on air temperature and therefore grass growth have been broadly similar.

If we compare with last year, we have had only 17.7% of the GDD of March 2017, so it cannot be a surprise to anyone (but of course it will be) that we are behind growth-wise.

Now that’s only one part of the equation that is making life difficult at present, the other and more significant one is rainfall and saturated ground conditions, but of course a lack of heat means less evapotranspiration and therefore less drying so there’s a link between the two.

From a cumulative perspective, a GDD total of 57 by the end of March is again second only to 2010 though it has to be said that other SSW-event years have similarly low cumulative GDD figures.

Comparing this site with 2017, we hit a total cumulative GDD of 57 on the 23rd of February so we are 36 days behind last year in terms of reaching the same growth point.The graph below illustrates how 2013, 2017 and 2018 pan out from a cumulative GDD perspective, you can download it here.

If I look back at 2013 we are 4 days ahead of that year so in other words we are tracking pretty much bang on 2013 when we had a late SSW event.. uncanny eh ? It is worth remembering that in 2013 we carried that cooler theme for the spring till the mid-part of April and so that’s why I’m not convinced we are totally out of the woods yet.

Data usage from this blog

Just a quick note on data from this blog in terms of usage – It’s come to my attention that my various competitors are using information from this blog for their own commercial ends so please be advised that all the information in this blog is protected by personal copyright, it is not permissible to download, duplicate, tweet or share this information without the express wish of the author and that’s me. This blog is designed to provide information to greenkeepers, superintendents, course managers, groundsman, lawncare operators and the like working in the turf maintenance industry and not to further the ends of a commercial business and especially one that competes with the one I work for. Go off and do your own hard work.

Ok that’s the rubbish out-of-the-way, let’s get down to business.

GDD Comparison – U.K

So I wanted to split this up into GDD and rainfall comparisons vs. last year and include as many geographical locations as I could. The problem is I don’t get GDD / Rainfall data from a lot of locations so I’ve burned the midnight oil on Weather Underground, accessing weather stations data from around the U.K and calculating GDD and rainfall totals. If I tell you it took me 8 hours to put together the chart below, you may understand why the blog is late this week 🙁

This data is available for end-users to download as a pdf here

So the above chart shows the cumulative GDD figure at the end of March 2018 vs. the end of March 2017. The next column shows the variance between the two, so if for example the figure from Uppingham shows a variance of -70%, it means the figure from 2018 is 70% less than the figure from 2017. The next column shows how many days in front or behind 2017 we are at the end of March.

So if I look at the data from Norwich I have a figure at the end of March 2018 of 59.8 cumulative GDD. In 2017 we hit this same GDD total 34 days before so that would be something like the 26th of February.  This gives a good indication of how far behind we are this spring vs. last spring in terms of growth.

The chart shows that the variance vs. 2017 ranges from -55% in Kent to -93% up in The Highlands of Scotland at Charlestown of Aberlour or Aberlour as it’s commonly known.It serves to illustrate just what a hard winter Scotland has had and is still enduring.

If you’re wondering where Aberlour is, it’s a simply beautiful spot on the River Spey where I used to deal with a rough and ready Farmer many years ago, who shall remain nameless, it’s also the home of Walkers Shortbread. After the usual tense and terse negotiations contracting Spring Barley seed acreage (not helped by my nationality I might add) , I would sit on the bridge and watch the Salmon jump and munch on a packet of said Shortbread biscuits by way of compensation for having to call on a miserable chappy, 8 hours drive from home in my 4-speed Volvo 340DL that I eventually wrote off out of sympathy.

A slow spring isn’t all bad news…

I digress, so rather than just look at figures let’s talk through the implications practically of being behind in the spring season and note that it isn’t all bad news.

Firstly, of course if we are looking for recovery from disease scarring or aeration then for sure having a spring where we have only had 30% of the growth of the previous year will present an issue, the process will be slower. If however you have come through the winter with a good sward cover on say greens than that’s great, they’ll be just ticking along nicely with no growth flushes.

Now when we come to outfield turf and look at areas receiving wear day in / day out so that means winter season pitches, wear pathways from green to tee and the like, then these areas will have received wear but not had the recovery growth and so will be looking pretty tired and thin. Trying to get new grass cover, a result from overseeding and / or divot recovery on tees (and fairways if you do it) will be slower because until recently we haven’t had the soil temperature to promote germination and establishment.

As an example, I put some Fescue / Rye seed out in the middle of February (before the SSW event I hasten to add), hoping to catch some early mild weather and get ahead and to this date it hasn’t germinated, so that’s going on 7 weeks now.

The lack of growth is in some cases an advantage though because it means less cutting and no growth flushes over the Bank Holiday so no piles of clippings lying around. On the flip side it does make it difficult to get presentation between fairways, semi-rough and rough if growth rates have been slow but you can always use iron for this purpose. Similarly converting from winter sports to cricket requires consistent growth to take down the cutting height on cricket squares and outfield, again until recently this hasn’t been forthcoming.

I think one of the major benefits (which isn’t readily apparent) is root development, specifically because the plant won’t have been putting its efforts into top growth. When I’ve been out and about, taking cores, I’ve been encouraged to see really good root development and that should stand us in good stead if we get our usual dry, cold period towards the end of April.

Rainfall Comparison – U.K

This data is downloadable as a pdf here

The above is more straight-forward I think and reflects a comparison of rainfall totals for the period January 1st to 31st March, 2018 vs. the same period in 2017. Now there’s several caveats to these type of figures that should be made clear from the outset.

Rainfall is extremely localised, so for example Uppingham has had 15mm more rain than the same period last year but I happen to know a golf club barely 8 miles up the road that had another 30mm in March alone. Secondly it’s often not the total amount of rain that has fallen but how it fell and in particular, the number of dry days that allow turf surfaces to dry out that matters to us.

Lack of dry days

March 2018 has been one of those months where we have had more rain than previous years yes, but it has fell consistently so we have had very few drying days in-between that allows turf to recover and surfaces to dry down. Trawling through the data I would say on average we have had only 20% of the month with dry days and no rainfall for a typical U.K location.

Now I know for some places that figure is lower, but there’s not many that are higher. The last caveat relates to snowfall in that snow doesn’t contain the same amount of moisture as rain, typically it’s 10%, sometimes 15% for dry powder snow. I think that’s why some weather stations and particularly those in the north and Scotland are showing less rain vs. 2017 because it fell as snow and contained less moisture. It’s still disruptive though.

GDD & Rainfall Comparison – Ireland

Thanks to Aine for her consistent data summaries, the Irish comparison was considerably less work 🙂

This data is downloadable as a pdf here

Looking at the Irish GDD data we see a similar pattern in terms of variation vs. 2017 with a range of -51% from Valentia Co. Kerry to -77% from Ballyhaise, Co. Cavan. As we would expect there’s a north – south and east-west bias here in terms of growth and that is reflected in the GDD totals. All things considered we vary from 37 – 65 days behind 2017 in terms of GDD across the 7 Irish locations.

The rainfall stats also show an east-west bias with Dublin, the driest location, and Valentia not surprisingly, the wettest. Aside from those two locations, there’s some significant year-on-year variation when it comes to rainfall with the location in Co. Wexford receiving 58% more rain in the first 3 months vs. 2017, just short of 5″ and similar for Co. Cavan with 74% and 136mm extra rainfall.

So for both U.K and Irish locations we see that the trend is for significantly less growth and more rainfall in the first 3 months of 2018 vs. 2017 and that’s a fact.

GDD Spreadsheet

Just a quick note that the GDD spreadsheet is available here to download if you fancy filling in your max and min temperatures and rainfall. I’m working on an upgrade for 2019, which will provide you with a lot more features and information from the GDD spreadsheet, more on that when it’s finished :). You can download the current spreadsheet here

Pathogen Activity

I expect with some milder nights (for some) this week, you’ll see some Microdochium activity out there but hopefully with milder nights comes growth so we should be back to the balancing act between generating growth and growing out disease.

I’d also expect to see more in the way of grub activity as the soil temperature warms up including Bibionids which will be set to hatch into adults over the next 3-4 weeks. Also keep an eye out on any core holes for that familiar countersunk appearance as larvae like Leatherjackets emerge at night to graze around the edge of a tine or vertidrain hole. This can seriously slow down recover from aeration.

Augusta Comparison

So this week marks that lovely tournament that sends predictable ripples through our industry every year and raises many a collective hackle.

I’ve updated the comparison with our default UK, location and here’s how it looks…

So at the end of March, Augusta were running 62 days ahead of our U.K location, that’s a whole 2 months and highlights the somewhat ludicrous nature of the comparison.

Now looking at their GP figure of 45.2 (yes I know I swop around between GDD and G.P), last year in what was a good spring, The Oxfordshire didn’t hit that cumulative figure till May 26th.

So what we are saying is that the air temperature / Growth Potential that Augusta receives by the end of March this year was equivalent to what The Oxfordshire receives by the end of May, so there’s the two months difference again.

If you want to know where Augusta were from a GDD perspective at the end of March, the figure was 570.35 !

Compare that with the charts above for the Irish and U.K locations…

Ok that’s it for this week, my head is swimming with numbers, sorry it’s taken longer than normal but there was a lot of data to collate.

All the best…

Mark Hunt