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  • Writer's pictureMark Hunt

April 9th, 2024

Hi All,


Apologies for being a day late with my blog but the truth is yesterday was such a nice day and today such a crap one, (cold and wet) that I decided to do a swapsy. Last week I showed how a low-lying jet stream is responsible for our constant run of wet weather, though the weekend did provide some significant drying with ET levels climbing to over 4mm a day on Sunday in that strong wind and decent temperatures.


Well this week we are going to see that jet stream snick up higher as a high pressure system builds to the south of us. Below left is last weeks image and below right is the GFS projection courtesy of tropicaltidbits.com for Thursday, 11th April. You can see the jet stream position is now projected to sit across the north of Scotland and this means a break from the consistent rainfall that has challenged our ground conditions and our mental wellbeing !



It can't of escaped anyone's notice that current groundwater levels are the highest they have been in living memory I would say. Just a small amount of rain now puts rivers at the tops of their banks. Reading the governments own survey data on the water situation (find it here) reveals even in one of the traditional driest areas of the U.K (East Anglia), levels are high to exceptionally high with a projection that they will remain that way till the autumn. Certainly if you have travelled on the A14 around Newmarket lately, you'll have noted the high groundwater level causing flooding from below. Even today there are reports of severe flooding in Sussex as the River Arun broke its banks. Storm Kathleen is blamed but when I have looked at the rainfall stats for that area, I can't find anything particularly excessive local to the flooding. Looking into this further, high tides and strong onshore winds are also implicated (neither of which was mentioned in the articles I read by the way....)


The shift in the jet stream position is the first sign that the light at the end of the tunnel may have just been turned on because it does mean a lower probability of trough systems and a higher probability of warm, dry, high pressure peaks. 100% we aren't out of the woods yet, we will still get rain, (start of next week) but I think this is a welcome shift in the weather patterns that will provide some respite. As I commented last week, with daily ET levels building, 2-3 days of dry weather will give us significant dry down. So we are potentially turning a corner, not a completely dry outlook, but a better one.


Nature has turned a corner as well. Last week I saw my first Swallows and House Martins, that's 10 days earlier than normal. The Bluebells are a fortnight early and I also think that the wet winter has been great news for spring flowering plants like Bluebells, but also Celandines, Anemones and Primulas.



Reproduced courtesy of https://climate.copernicus.eu


Of bigger concern is that the global warming trend, now 10 months of consecutive record temperatures as reported by Copernicus.eu, with no reference to previous weather records. Just look at the chart above, ( find it here) it is one that has global meteorologists / climate scientists extremely worried as the world climate is behaving in a way that they haven't projected. 2023 and now 2024 so far are recording temperatures way higher than expected, El Niño or no El Niño.


Sometimes data like this seems remote and not really pertinent to our situation in the U.K & Ireland, but it is. Remember that the jet stream is ultimately powered by the temperature differential between the North Pole and the equator. If the North Pole is warming faster than projected, that means less temperature differential, which means a slower moving jet stream and more potential for those peak and troughs and extreme weather events. That said, it isn't what we have seen this winter, quite the opposite in some ways, so I am still looking for a viable explanation as to why the jet stream position sat so far south for so long.


General Weather Situation - w/c 09-04-24


So this week we see high pressure build to the south and that will usher up warming south westerly winds and push rainfall further north. Before we get to this transition, we have a current low pressure system pushing rain across Ireland and the U.K.


Today we have wet weather currently over the west of the country and this band of rain will track east and south through the day. Ireland will have a dry day after yesterday's rain but a new rain front will push into the south west of Ireland early on Wednesday morning. This front will track across the U.K, tracking north and east clearing the south in the afternoon. The shift in the jet stream will vector more rain to the north west of the U.K so the west of Scotland will be in the firing line. Temperature-wise, expect 10-12°C for Tuesday / Wednesday. Winds will be strong to moderate and westerly, shifting south westerly. The exception temperature-wise is across Ireland where that temperature hike will take place on Wednesday, pushing up to 19°C !


Moving into Thursday and we begin to see the change as temperatures pick up markedly, the wind shifts round to the south west and much drier conditions will prevail. They'll still be some showers kicking around across the south of Ireland moving across The Irish Sea into the north west of the U.K / western Scotland later in the day. Temperature-wise, expect 19-20°C in some areas across Ireland and the south of England. A similar outlook for Friday, good temperatures, a drying wind but still some showers pushing across the south of Ireland and into The North West. The same outlook continues into the 1st part of the weekend but across the north it'll turn chillier as the wind swings round to the north west for a time. Cooler for everyone on Sunday as cooler air pushes further south and this will continue to push showers into The North West and west of Scotland. So mid-teens for Ireland and the south of the U.K and 9-10°C for Scotland, with more in the way of showers here. Late in the day we will see showers pushing further south.




Weather Outlook - 09-04-24


So next week we start with cooler air sitting over the U.K and north westerly winds pushing rain down across the U.K on brisk winds. It'll be a wet start to the week on Monday and a cool one. That low pressure will quickly push south across the U.K on Monday and leave behind a showery outlook extending through Tuesday into Wednesday, still with that cooler northerly / north westerly wind. As we move past Wednesday, we see another ridge of high pressure building out in The Atlantic to the west of Ireland. This is why I think we have turned a corner, yes they'll still be rain but now it'll become interspersed with better weather and a drying window. Now there will still be showers across Scotland later in the week, but further south and west we will have a drier picture, not particularly warm but towards the end of the week, the winds will turn westerly and that'll pick the temperatures up.


As I write this blog, that high pressure looks to continue building through into the weekend after next, so that's good news potentially. 👍



Agronomic Notes


So I thought I'd start this week's notes with a snippet from Prodata Reports taken from a location in East Anglia. I have included it to illustrate the point that typically at this time of year, ET levels rise to a point where they have a significant impact on rainfall levels. In this report you can see that so far this April the location has had 22.8mm of rain but also 22.3mm of E.T. One has effectively balanced out the other. Now ok we are coming from a long way back, we have very high soil moisture levels and as previously mentioned, a very high water table, so it'll take time to have an impact. As soil levels do dry out, high clay content soils will be prone to cracking or hardening off with a surface crust. Both issues will need cultivating before overseeding / reinstating.


I have seen lots of comments on Twitter regarding the continual impact of wet conditions and of course, there's been a bottom line impact on revenue. Wet weather, course closures, buggy and trolley bans all have a cumulative effect on revenue. Hopefully we are turning a corner in this respect but on heavy soils, it'll take time.


One of the continual issues associated with the continual moisture and warmth is maintaining higher-height-of-cut areas that are on heavy soils. If you look at the report above, you can see during recent days we have had very high Growth Potential figures, topping 0.91 on the 6th April, so that's 91% of optimum growth. With moisture and heat, grass has been growing much faster, for longer this spring than last.



Above is a comparison of Cumulative Growth Potential comparing 2024 with 2023 for the same location.


Reviewing the graph above, the cumulative Growth Potential (Jan 1st - April 9th) has hit 23.15. Comparing to last year on the same date, it was at 15.9. That's 46% more growth.


In 2024 we hit a cumulative growth potential of 15.9 on the 20th of March, so effectively we are 20 days ahead of last year growth-wise. Ordinarily that would be great news, but the problem is in the majority of situations and particularly on heavy soils, we can't get machinery out to cut those areas. Hopefully in the next few weeks, the situation will ease somewhat, but the damage to revenue will take longer to repair I think.


Looking at other locations further afield, Scotland is showing very little difference year-on-year from a Cumulative Growth Potential perspective, with figures of 12.39 and 11.77 for 2023 / 24 respectively. For Bath, the figures are 14.36 and 18.84 for 2023 / 24 respectively, so it looks like the eastern part of the U.K is ahead of the west by some margin.



The uplift in temperatures this week will create quite a growth flush but thankfully it will be short-lived as the wind direction switches around from the temperate south west to the cooler north west. Ireland and Wales will see a similar picture although for the former it'll start a day earlier. Scotland's growth flush will be limited to Thursday and Friday before cooling off significantly thereafter.


Poor ground and strong wind conditions have negated for many the ability to apply a PGR to outfield areas but again, with a drier outlook for the second half of April, let's hope we can get on top of things and focus on preparing for the summer.


OK, that's all for me this week.


All the best.


Mark Hunt







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