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  • Writer's pictureMark Hunt

August 8th - 2nd heatwave this week and then a breakdown ?



Hi All,


Out walking last week and at the weekend in a effort to rebuild my fitness after Covid, I couldn't help but notice all the signs of a prolonged drought.


Huge cracks in the clay, the crispy grassland, tinder dry, trees under stress dropping their leaves early in an attempt to reduce water consumption and the depleted flow in the brooks and streams that dot the landscape of Leicestershire and Rutland.


The image above is the duck pond at Hallaton where I used to fish for carp as a wee nipper, cycling the 8 (hilly) miles with my fishing gear strapped to the crossbar and a loaf of Mothers Pride crammed into my saddlebag, some for the carp and some for me. Not only is there very little water left in the pond but you can see the algae bloom quite clearly, both spell curtains for fish and other wildlife.

I am amazed at the amount of fields that have already been combined, winter wheat is so early this year and the berry crop likewise. That could make it very difficult for the hordes of Redwing and Fieldfares that visit our shores in the late autumn from Scandinavia to plunder our hedgerows if those berries are shrivelled and gone by the time they arrive. Nature is suffering for sure. And farmers are unable to take advantage of the early harvest because they cannot cultivate the bone dry soil and get next years seed in, now that's challenging.


Please remember this week to put a bowl of water out for your birds and night visitors because they will soon dehydrate and die, just like the Hedgehog that I found last week. Sadly he didn't make it even though Leicester Wildlife Hospital did their best. On the plus side I have 5 Hedgehogs resident and visiting my small garden so that's a lot of Ark Wildlife Hedgehog food and water required to meet their needs.


One thought though for anyone tempted to let their lawn grow into a natural foot high grassland ala Chris Packham's viewpoint. Contrary to popular media naturalists opinion, I don't think it's a great environment for birds or Hedgehogs at all, a great one for Ticks though and for cats to ambush wildlife. It makes absolutely no sense to me if the purpose is to encourage wildlife. Insects maybe, the rest, not so sure. I've watched my Hedgehogs prowl my lawn for worms and other insects. Would they be able to do the same if the grass was a foot high, the same with birds ?

As we enter this week, we are due to pick up our 2nd major heatwave of the summer as a heat plume from Africa pushes up from the south across the U.K & Ireland. The animated GIF courtesy of www.tropicaltidbits.com captures it well and shows Thursday / Friday as peak heat before it moves away to give Denmark a very hot weekend. Again this event was well forecasted and GFS picked it up two weeks ago on their output. Fair play to them.


This heatwave will be slightly different, I don't think we will hit the heady heights of July's temperatures with low to mid-thirties likely but it'll last longer. The nights though will be a little cooler and more tolerable I think because the days are shorter now. Speaking of night temperatures, we have already had some cool ones in August. I noticed at the end of last week some Davis Weather stations showing 5 - 7°C as a minimum night temperature across England and Wales. That's cool for August and also very welcome.


General Weather Situation


So as we can see this week we have high pressure dominating and that'll slowly build the heat through the week across the U.K and Ireland peaking at the end of the week and then slowly subsiding over the weekend, with the south hanging onto the high temperatures the longest.


Temperature-wise we are looking at 33-35°C for the south of England and Wales, 30-31°C for The Midlands and north of England, 26-28°C for Scotland and 24-25°C for Ireland. There will be some rain around across the north west of Scotland and Western Isles early on in the week but that's about it. As mentioned earlier, the night temperatures, though higher than normal, won't be as intolerable as July's so that means mid-teens for most and perhaps high teens for the south of England. The dominant wind direction will be easterly and winds will be light for the first part of the week, picking up as we head towards the weekend.


This last factor may mean that E.T levels aren't likely to hit what we saw in July, which is a God send.

Weather Outlook


So the million dollar question is, are we still on track for some sort of breakdown next week ?


Well I noticed the weather presenter on Countryfile was non-committal (it's the only bit I watch).


First up we do have a Bay of Biscay low pressure forming on Sunday as projected last week so that's the first part of the puzzle in place required for a change. This effectively blocks warm air streaming up from Africa and nudges the jet stream further south. We then have an Atlantic low pressure poised to fill the gap so the ingredients for change are there. Now I don't think next week will be a permanent drought-ending change, but I do think it will bring cooler temperatures and rain further south than we have seen for awhile.


The first components of that change should arrive during Sunday night / Monday morning with potential for a thundery breakdown across the south of England / Wales. Now there's a lot of disagreement on this one, but that's my hunch. The next component is a change in the wind direction to more north westerly through Monday / Tuesday that'll drop both day and night temperatures and feed showers in from the north and north west of the U.K. These will be more northern half of the country through Tuesday before a heavier rain pulse crosses Ireland and the U.K during Wednesday. Now again, tricky to say how far south this will come. More showers on Thursday before heavier rain arrives across Ireland and all of the U.K on Friday.


Now there's still a good number of caveats here and I can understand the reticence of the Countryfile weatherman to put his money on rain next week after watching meteorologists get lynched on Social Media last month.


It all boils down to the 'behaviour' of that BOB low pressure on Sunday but putting my meteorological neck on the block, I think it's more likely than not that next week will see a cooler, more unsettled theme take over. Now even if it does take place I don't see it as a 'drought ender', but I do think it'll shift the jet stream position further south and that'll allow more of an Atlantic theme to interject for the second half of August and therefore less risk of heat plumes. It'll also allow rain to move further south over the U.K.


It's all in the balance but we will see this time next week....


Agronomic Notes


So first up, let's look back at July 2022 from a GDD perspective.


GDD - July 2022 and Y.T.D. - Thame, Oxfordshire, U.K


So July came in at 393 total GDD for the month, which is the 3rd highest GDD total for July falling just behind 2006 and 2018. So despite the record heat, it wasn't the highest month from a GDD classification. Y.T.D, 2022 is at 1114 total GDD for the end of July, which places it 4th in the overall rankings from a GDD perspective. Now GDD probably isn't the most important parameter agronomically-speaking from a turf managers perspective when we get to the height of summer because it has no upper 'top out' temperature. What I mean by that if temperatures are extremely high then the GDD will reflect this and keep increasing, even if growth will become temperature and more likely this year, moisture-limited and go the other way.


A more accurate representation is plotting Growth Potential for July which I have done below and this shows purely from a temperature perspective, July 2022 wasn't the end of world with just a pronounced dip around the 18th / 19th when we hit those record temperatures and the grass plant shut down.


Interestingly if I project the temperatures for August onto those we have already had for this location, this is what it looks like ;


So we can see again that Growth Potential shows a projected dip for this week as the temperatures rise above those that cool season grasses can tolerate. This represents severe plant stress and should be treated as such.


Moisture-limiting growth


Of course in the midst of a drought, it isn't temperature that ultimately has the most significant effect, it is water or more precisely, a lack of it.


So I've spent a collective age today downloading Davis weather station rainfall totals from all around the U.K & Ireland. Now I know rainfall is variable, but at least it gives you a flavour of where we are. I also delved back into the Met Office's archives and downloaded the monthly data for the south east of England for 1976, so we can see how this year's drought actually compares.


It is amazingly similar.


Of course from 1976 to 2022, there's been a substantial rise in population so the Water Companies are supplying a lot more houses and industry now than they were doing back then.


So some data from around the U.K ;

Uncanny when you compare the driest location on my mini-dataset at Soham (It's in The Fens you know 😊) with the 1976 data. They're very, very similar !


Thanks to Peter Palmer for the Soham Davis weather station data....(I have to say that as he's my boss you know 😂 )


It's also interesting to see the variation across England, Wales and Scotland and to see that the east side of the U.K is much drier than the west and that this pattern extends all the way up the east coast from Kent to Fife !


At first glance it looks like the y.t.d average for the dry area locations sits somewhere between 200 - 250 mm of rainfall. That isn't a lot of water and it explains why the river and groundwater levels are so low and why we need to be concerned about this and our use of irrigation water. More on that later......


When I was compiling these figures I found it dead simple to get rainfall data from Scotland courtesy of the brilliant SEPA (Scottish Environmental Protection Agency) website (visit it here ) and I know Met Éireann's website is also excellent for historical data but I couldn't find the same for England nor Wales. Now maybe that's just down to me and lack of time but if someone could point me to a map where it shows locations and their monthly rainfall for England and Wales, that would be great !


Not to exclude Ireland, I've been wondering to myself how dry it is over on The Emerald Isle (or maybe not so Emerald in places if you look at the July data !???), so here's a mini data set from Ireland. Thanks to Aine for sticking with it and supplying me this data rather than swanning off in the campervan, boogy board in tow 😂


Just like the U.K data, we see wide variation north to south and east to west in the Irish rainfall data, particularly when you look at coastal locations on the east coast. Bray and Killiney are the two driest locations close to Dublin whereas not that many miles away in Casement they have had 2x the rainfall vs. these two locations. That dry July rainfall pattern extends down the east and south east of Ireland to include Cork at just 21 mm and Johnstown Castle (Co. Wexford) at 24.4 mm. July 2022 was indeed a very dry and hot month for Ireland.


It isn't just about rainfall.....


The frustrating thing for me as I've commented on more than once (I know, I know) is that I can't plot E.T data for all the locations nor do I have access to historical E.T data. My hunch is that we run higher daily E.T levels than we used to but as we saw with last week's blog data, July 2018 was a slightly higher E.T month than July 2022 for our Thame location.


Looking at the soil moisture deficit and comparing rainfall with E.T on a daily basis, we can see that in some locations (in this case using data from Rob Hay at Northampton County Golf Club, ta Rob) that 2022 although dry, isn't yet surpassing 2018 in terms of this parameter.

It is just a snapshot of one location though because when I look at our driest location in the above stats at Soham, Cambridgeshire, they have had 141.8 mm of rain but 569.9 mm of E.T putting their moisture deficit at - 428.1 mm !!!


What's to be done ?


Well we know what happened last time when it came to water restrictions, the leisure industry (apart from Premier League clubs of course because money talks) were hampered severely in terms of what could and could not be irrigated. Of course water usage is now front and centre because it is in short supply and if we get rain, it will soon be forgotten but the fact is we are running out of time (and water) to correct the situation.


Someone I think is very well versed on this specific subject area is Tony Hanson of Environmental Solutions International.

I have been reading his posts regularly on LinkedIn and I found this article particularly interesting and a tad concerning....

You can read it here

In the article it mentions The Leisure Operator Water Charter and how it can help your facility to prepare for similar shortages in the future. You can download the form to join the charter here


When you think about it, if we are using mains water to irrigate our facilities, that's drinking water being applied to turf and public opinion will go against us pretty soon when it becomes scarce.


You only have to look at the public's and regulators mis-informed viewpoint of golf courses and the like when it comes to fertiliser and pesticide usage to understand this.


They don't appreciate or understand how small the % of a golf course land footprint (for example) is intensively managed.


They don't understand how having grass cover all year round is such an effective capture mechanism when it comes to pesticide and nutrient leaching vs. agriculture (for example)


They don't understand how forward-thinking course managers are actively encouraging insect, mammal and particularly bird species biodiversity on the less intensively managed areas of their facility.


Education is required and we are a long, long way back as an industry in this respect. I believe it is because we are so fragmented across the leisure industry and as such are perceived in that light. As it stands now we are a sitting duck.


I'd also make the point that across the majority of the U.K, mains water is hard, alkaline and full of calcium and bicarbonate, which isn't exactly ideal for grass in the first place. You only have to look at the difference between the effect of rainfall and irrigation on turf to know this. (OK, there are other factors at play here as well I freely admit). Investment in water capture is expensive and a major investment for any club, but it is a necessary one in order to future-proof your facility. And ironically so is drainage but it's what we do with that drainage water that we also need to think about


So we have to think smarter, we have capture this water when it is in surplus to help us through the dry times. We also have to utilise more drought-resistant varieties of grass, soil moisture monitoring, PGR's, pigments, biostimulants and soil surfactants. All of these play a part I think and in this respect we have made some great in roads.


I also believe we need data to support what we are doing, and how and why we are doing what we are doing from a management perspective. Without data your arguments are subjective and we know how members and the general public alike, love subjective, data-devoid arguments !


Now you can take this as a plug for getting a weather station and OK, in part it is, but how can you irrigate effectively, if you don't know your E.T and rainfall stats ?


OK, time to hop off the soapbox because I'm mentally cream-crackered and need to have an hour or two's physical exercise :)


All the best for the coming week and let us hope our BOB low pressure systems play ball and this time next week I'm considerably cooler and the grass outside is considerably wetter 😊


Mark Hunt

markh@weatherstations.co.uk

Prodata Weather Systems


Unit 7, Espace North Building, 181 Wisbech Road

Littleport, ELY, Cambs. CB6 1RA, UK


Tel: 03336 664175



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