May 9th, 2023

Hi All,

Well it probably goes without saying, we have had a pretty wet start to May !

With accompanying milder temperatures, growth has been significant.

Walking around Rutland Water's beautiful Hambleton Peninsular over the Bank Holiday weekend, the hedgerow and verges were positively vibrant, you could almost hear them growing. Cow Parsley (Keck as we call it), Campion, Wild Garlic and Bluebells are prolific and the air is full of insects and more and more Butterflies. (More Blues this year already)

Overhead I noticed my first Swifts, (the last to arrive and the first to leave) whilst fishing into the sunset. The hedgerows are full of Warblers and I heard my first Cuckoo's calling. It was a beautiful sunset and a great fishing session as well. People ask me why I fish and a large part of the experience is being close to nature and also understanding what I am seeing and hearing.

As Morrisey once sang in that cracking Smith's tune "Ask"....."Nature is a language, can't you read ? ...I can. (most of the time :))

It was also a great way of escaping The Coronation 😉

Two short weeks with mild temperatures and rainfalls brings its pressures though in turf management although I'd always argue that having more growth than you want or can handle is a better problem than not enough. Finding weather windows to control this growth with PGR's and / or just simply getting machinery out onto the course is a current issue with some areas in Scotland and The South West receiving 25mm + of rainfall yesterday.

I'll be looking at rainfall totals and GDD / GP y.t.d for the end of April later in the blog as I review last month and of course I will look at the week ahead. There are signs that we will have another high pressure interlude at the end of the week to give us a dry weather break, but I don't think it will be a long-lasting one. Now you can bitch and moan about the rain, but believe me, we need this continual top up and the longer it extends towards the summer, the better.

What rain apps do you use ?

Talking of rain, I thought I'd do an assessment of weather apps specifically related to rain, so not forecast apps but ones that predict rain events and show how they move across the country. I get asked a lot about what is the best rain app, particularly at the moment, so if you have one that you rate, please drop me a line on markh@weatherstations.co.uk and at some point (perhaps when it is drier), I will do a review after some months of using them and observing their features and accuracy. I use netweather.tv's website (above) for my rain radar, I like the graphics, they are constantly updated and improving it and above all, they are accurate.

So how does this week and the following one look ?

General Weather Situation

So the broad schematic on this week is that we are starting off with a continuation of the unsettled theme, with some lumpy showers accompanied by thunder and lightning. This will cover the period up to and including Thursday. From Friday we see another finger of high pressure pushing up so some more sunshine, better temperatures and less rain. At this stage it looks short-lived though.

So Tuesday to Thursday follows a similar pattern, that of rain showers bubbling up during the morning across western coasts of the U.K and Ireland and then pushing across country. With temperature fuelling this rainfall, these showers will be accompanied by thunder and lightning and already Met Éireann are issuing a thunderstorm alert for Ireland. These showers will consolidate across the southern half of the U.K and Ireland through the second part of the day. Having a good rain radar app will be key this week.

So a drier start, then showers bubbling up across the west and then more heavier, consolidated rain accompanied by thunder for the second half of the day. Temperature-wise, we will be in the 14-17°C range, with westerly light to moderate winds spinning round to the east later in the week.

As we get to Friday we see a much drier picture, cloudy initially in the morning before this cloud cover breaks to give longer spells of sunshine in the afternoon and some nice temperatures, pushing up into the high teens. Saturday continues this lovely dry theme with more sunshine and pleasant temperatures. A cracking day for us all. Overnight into Sunday we see a band of rain pushing into the west coast of Ireland and by Sunday morning this is currently projected to be sitting across the east coast of Ireland before clearing into The Irish Sea during the morning and leaving showers behind. This rain front will spark off showers starting in the west across Wales and western Scotland, The North West and these will rapidly consolidate during Sunday morning. The heavier rain will reach Wales, The South West and western coasts during the afternoon on Sunday but we will also see showers across East Anglia as well. So on Sunday we will see a breakdown of that short-lived dry interlude, with a band of heavy rain crossing the U.K overnight into Monday.

(Image courtesy of www.tropicaltidbits.com)

Weather Outlook

So the above GIF amply demonstrates why I always say, May is a yo-yo month and one where we don't see day and night temperatures stabilise till later in the month. So next week we are set for a cooler interlude, with a predominantly northerly trending to north easterly wind direction and certainly for the first half of the week, plenty of rain around. The heavier portion of this rain will primarily be confined to the southern half of the U.K, pushing in off The Humber and The Wash and vectoring south and west. The east coast of Scotland and The North East will still see rain next week, particularly for the first part of the week but as we approach the end of the week, it'll turn drier. If I do a bit of (the recently-departed) Mystic Megging, I would say that this dry interlude will again be short-lived and that over the weekend (after next that is), we will see a new Atlantic low pressure push in. Temperature-wise next week I think we will see 12-14°C, with the cooler temperatures across eastern coasts because of that wind direction and of course more cloud cover and less sunshine. It probably goes without saying that the further west you are, the better.

Agronomic Notes

April 2023 review - GDD Total - The Oxfordshire

April 2023 came in with a total GDD of 82.3, which is sort of mid-pack when we look at totals stretching back to 2005. Not a bad growing month, not great but predominantly the biggest plus point during April was not related to temperature but to moisture.

We had a good supply of April showers, some heavier than we would have wished for but I'd have them any day compared to a dry, cool April with no growth and golfers complaining about surfaces (yeah I know they do that anyway)

The yearly total of 220.6 is towards the top end of y.t.d. GDD totals at the end of April and that is primarily because of the milder start to the year in January and February before we experienced the SSW event in early March that brought snowfall and penetrating frosts. When you look back at other years when we have experienced SSW events, (2009, 2010, 2013, 2018) we are quite away ahead and that is because in 2023, the SSW occurred in late February and so affected March and April (warmer months) rather than occurring in December or January. So a late SSW event isn't all bad news really.

I was asked recently if the occurrence of such an event had a correlation with a dry summer. The basis of this question is that our last SSW year was 2018 and of course it marked an exceptionally hot and dry summer. So being the weather-geek, nerd, delete where applicable I am, I looked at the data from our default location at The Oxfordshire.

Here is how the rainfall totals look ;

So no clear pattern between a SSW-event year (marked in blue) and summer drought as you can see from the Jun-Aug rainfall totals vs. year. Interestingly I plotted out the Jan-Apr rainfall totals year-on-year to the end of April and this year we are on 212mm vs. 165mm at the same point last year, so that's +28% vs. prior year, with the trend continuing into May. 212mm to the end of April is the 4th wettest spring since 2005 for this location and whilst this amount is a fraction of what south westerly and northern locations receive, it still presents issues.

Growth Potential & Rainfall Summary - U.K Round Up

Looking at the collective G.P from across the U.K, we can see significant variation in not just the G.P for April but also the total G.P for the year-to-date. Okehampton and Guildford stand out as head and shoulders above the rest from a total growth perspective and they're also some of the wettest locations at times, especially Okehampton. The average G.P was 7.36 across April out of a possible 30 (30 days of optimum G.P = 30 X 1.0), so not an earth shattering month growth-wise, which is what we have come to expect of April, however this year it was made better by the presence of moisture.

From a rainfall perspective we again had significant variability with some of the heaviest totals coming across the southern half of the U.K. This is because of the fact that most of April's rainfall was associated with BOB's - Bay of Biscay low pressure systems. These tend to affect the south and sometimes south west of the country and so we can see high totals for Bristol, Brands Hatch, Sevenoaks and further north, Dumbarton.

Lifting a report off Prodata Reports for a course near Sevenoaks, Kent, we can see that down south it was particularly challenging in the middle part of the month with not only a significant amount of rain but also some very high rainfall intensity as well.

In terms of rainfall intensity, heavy rain is classified as falling between 7.6 - 50mm per hour with violent rainfall > 50mm per hour. You can see how those events exceeded the highest level of this classification and that would have meant flooded paths, bunkers and it will probably have exceeded the ability of the course to move that water away. On the plus side, it would have filled any irrigation reservoirs pretty rapidly as well !

Growth Potential & Rainfall Summary - Irish Round Up

These Irish G.P stats make very interesting reading because they come in a good way higher than most of our readings for the U.K and that makes sense to me. During April we had a good amount of easterly winds courtesy of the SSW event (I think) and that means that the U.K would have been more affected by those than locations further south and west. So it is logical to see higher monthly G.P stats for the Irish locations. The U.K average G.P was 7.36 vs. the Irish average of 9.2, that is 25% more growth !

You can also see the y.t.d total is significantly higher for Irish locations than for the U.K, another consequence of the SSW event me thinks. At a guess, the Emerald Isle is currently doing a very good impression of such at the moment !

Significantly more rain as well y.t.d for the Irish locations though interestingly not in April. Again I think some of this is due to the fact that a lot of April's rainfall events were BOB-related and these don't tend to affect Ireland as much as they do the south of the U.K. A drier April was good news for Ireland though after those March rainfall totals !

Disease Pressure

In last week's short blog I hinted that the arrival of milder air temperatures, moisture and therefore humidity might spark off some disease issues and that definitely was the case over the weekend with the Smith Kerns showing a clear upward progression across Scottish, Irish and English locations (don't have Welsh data sorry). You can see this in the Prodata Reports pdf for a golf club near Bracknell.

I think this will continue through this week and weekend until we get a wind change to more easterly airstream when it should decline.

OK, that is it for this week, my head is scrambled with figures, charts and graphs so I need to get some fresh air before the rain arrives.

All the best.

Mark Hunt