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  • Writer's pictureMark Hunt

August 1st - our drought continues, but just maybe the first suggestion of a change mid-August ?

Hi All,


No sooner had I typed last week's blog which focussed heavily on our continued drought than the BEEB dashed out the driest year since 1976 feature, you can read it here


Well, I am old enough to remember that drought, I watched the rivers dry up into individual pools and the reservoirs run down to next to nothing. The local canal just held water in the boat track and it was gin clear as there were no boats able to navigate it due to the lack of water. The harbingers of doom explained that it would take months of rainfall to correct the situation and we even appointed a drought minister. 3 days later at the end of August it started raining and the rivers began to flow again. We had a very wet autumn and pretty much soon, the drought was forgotten.


When I look at some of the monthly stats coming in with respect to rainfall (or lack of it) and the super high E.T, I wonder how much water there is still kicking around and how soon it will be before the hosepipe ban in Hampshire and The Isle of Wight is extended ? In the last restrictions, golf courses in particular didn't come off well in terms of how they were treated by the water companies and legislators. This led to a flurry of reservoirs and bore hole applications once it had broke. With our seemingly never ending desire to build more and more houses and of course supply them with water, this time around will be even worse I think.


It does make me wonder why we aren't building more reservoirs (I mean of the likes of Rutland and Grafham) to store the water when it's plentiful in the winter (well sometimes) ? I often watch our local river Welland flooding over the winter months and think of all that energy (in the flow) and water just running out into The Wash to be lost. It seems crazy to me.


Onto our current weather and of course the all-important outlook. Is there any rain on the horizon for the south of England, Wales and the like ?


Well we need to see a northerly tracking BOB, a Bay of Biscay low pressure, because this can bring rain to the southern half of the U.K and it can punch a hole under a jet stream peak that allows cooler, wetter weather to extend south.


General Weather Situation


So we start the week, mainly dry and settled with heat building in the south. A heavy rain front is due to push into the west and south west of Ireland on Monday morning and this will move eastwards across Ireland on Monday and into the western / no half of the U.K. This rain will mainly be from mid-Wales up and across to a line drawn north of The Wash on Monday, crossing Scotland on Monday night as well. South of this rain, it'll be a dry, warm and settled day with temperatures in the mid-twenties. Ireland will be muggy and humid as temperatures remain in the low twenties.


Overnight into the first part of Tuesday, this rain 'could' dip down into The Midlands, East Anglia and sort of north of the M25. It could, it might not and we will see. So Tuesday sees rain move away from the east coast of Ireland and push across the middle of the U.K, missing Scotland, South Wales and the south of England. So continuing dry and warm for the south, some rain for the middle of the country and a better day for Ireland once the rain clears the east. Showers and sunshine for Scotland with mid-twenties expected in the south of the U.K, low twenties for Scotland and still warm and muggy in Ireland.


Wednesday sees overnight rain move in a narrow band from The Severn Estuary to The Wash. A frustratingly narrow band. Some showers are likely overnight across the west of Scotland but these will clear through the morning. The same for Ireland, some showers for the north and north west, clearing through the morning. A dry settled day thereafter with temperatures remaining in the mid-twenties for England and Wales, high teens for Scotland and a cooler one for Ireland with 17-18°C likely.


Winds will continue the westerly theme from the start of the week.


Thursday sees a change in that theme though because the winds will swing round to the north west and so that means a cooler feel to the weather and this will last through to the end of Saturday. This wind change is courtesy of an Atlantic high pressure building so really Thursday to Sunday should be seen as a separate block of weather. Slightly cooler, dry and settled for nearly all areas. There will be some coastal rain and showers for Scotland and the north west of Ireland on Thursday and the chance of some rain for The North West but that's about it. The further we get into the week, the drier the outlook, as that high pressure builds. By Sunday we see the wind drop, swing round to the east and that'll allow temperatures to increase into the mid-twenties for Wales and England, with Scotland in the high teens and Ireland nudging up into the twenties again.


Weather Outlook


Now before I go onto this part, let's consider what we need to see in the weather outlook order for the drought to break in the southern half of the U.K and that includes South Wales by the way which is equally dry. (there is a media preoccupation that the drought is an England-only issue).


So first up, is there any rain in the outlook for next week ?


Well no, most of the week looks dry and settled with a building peak system in the jet stream (see the graphic below for 10-08-22 from Netweather.tv) which will allow heat to build across the U.K & Ireland.

The focus is on the weekend after though, the mid-part of August, because until recently, the GFS output had high temperatures building under that peak and a possible heatwave again. Today, the output changed to suggest a BOB may form and build through this period and if it does continue to project this, that means rain for the southern half of the U.K could occur mid-month.


Now here's a massive caveat. We are right at the extremes of forecasting here, it could easily change back and high pressure dominates. Nothing is as variable to forecast as summer rainfall and particularly for the south of the U.K, so let's not get too excited just yet. If that GFS projection is still there this time next week, then that's more certain. As we stand now, it's just a suggestion and I would work on the basis of no appreciable rain for the southern half of the U.K for the first half of August other than what I've already suggested may occur this week and that is more northerly and westerly orientated in the main.


Agronomic Notes


Well of course the theme continues to be water-focussed or more precisely a lack of it.


That said, we did pick up rain at the end of July in some locations that hadn't seen rain for a most of the month. Here in Leciestershire, we picked up 5 mm over the weekend and it was so so welcome. OK, that's a day or two's E.T but it helped for sure. Last night there were some heavy storms over South Kent. It is so frustrating though, when you're dry, you can see rain close but it never comes your way.


July was a bruiser of a month as we know for many locations, firstly because we were dry, secondly because of the high temperatures and lastly, we had some really high E.T days. The frustrating thing for me is I can't give you a countrywide E.T chart because I don't have Davis stations that I utilise for data in Ireland, South Wales or the north of England. So you'll have to bear with me when I put up data relating to other locations.


We know all about the temperatures in July, but here's some rainfall vs. E.T figures from around the U.K.


Location July Rainfall July ET Difference


Thame 16.8 mm 123.67 mm -106.87 mm

Dunstable 18.4 mm 115.49 mm -97.09 mm

Milton Keynes 18.4 mm 119.36 mm -100.96 mm

Brands Hatch 8.2 mm 125.86 mm -117.66 mm

Sevenoaks 8.2 mm 116.05 mm -107.85 mm

Guildford 8.6 mm 112.65 mm -104.05 mm

Northampton 16.4 mm 97.51 mm -81.1 mm

Dumbarton 123.2 mm 90.94 mm +31.26 mm

*Maybe Scotland can export some water south ?? :)


Aside from Dumbarton, most sites are looking at around - 100 mm moisture deficit vs. rainfall.


Now if we look back to the summer of 2018 for example and July 2018 specifically we are actually looking at very similar statistics I think.


For the Thame location, this is how it compares ;


Location July Rainfall July ET Difference


Thame (2022) 16.8 mm 123.67 mm -106.87 mm

Thame (2018) 16.4 mm 132.70 mm -115.67 mm


So we have been here before and not that long ago in terms of lack of rainfall in July and high E.T. The difference in 2018 was that we had a wetter winter and spring before the dry summer.


Let's just consider what this means...


If we were looking to keep grass healthy, we would normally replace 60% of E.T by irrigation. Now some of you I know run it much lower, down to 40% and on fairways / outfield it is fair to say that by this stage of the year, a lot of clubs have taken the decision not to irrigate fairways in order to preserve water reserves.


You can understand why...


If for the sake of argument we replaced 40% of the moisture deficit by irrigation that means applying 40 mm of water over the month. 40 mm of water equates to roughly 400,000L per hectare and so for a club with 15 hectares of fairway, that would mean 6,000,000 L of water or 6,000 m3. Now that's a lot of water to apply and unless you have a very good storage reservoir, running a greens, tees and fairway cycle to keep up with the moisture deficit we are seeing would be beyond the capabilities of most systems. Taking that amount off the mains would be a significant financial commitment. And remember, that's the bare minimum of % replacement.


What it also means is that 100mm of moisture was lost by evaporation from storage reservoirs, that's about a million litres per hectare. Walking around Rutland Water last week, it was noticeable how much the water level had dropped in the past month.


So aside from some rain a little further south possibly this week, we look to continue dry and that means this summer's dry weather will extend beyond the time in 2020 and 2018 that it broke. In other words, this run of dry weather is a long one.

Agronomic consequences


Well we have to water a lot at the moment on the surfaces we have decided to prioritise and with the heat and in some cases (Ireland, Scotland) and humidity, we will be seeing some of our usual summer suspect diseases because of this. So I've picked quite a few Anthracnose reports, plenty of Waitea Patch, Take All and Superficial Fairy Rings.


Aside from the Anthracnose and Take-all, which can take grass cover completely, the other diseases are more aesthetically disruptive. I have attached an early paper on Waitea (pronounced 'Wait here') or Brown Ring Patch as it's also known below.

Waitea
.pdf
Download PDF • 3.35MB

More of the same then, balanced nutrition, PGR usage and focussing on plant health. If we get to a doomsday scenario of restricted water supplies, then that's when PGR's and perhaps pigments will come into their own.


Let's hope that the GFS signature for mid-August continues to build, that said, if you're heading away on your hols...maybe not :)


All the best.


Mark Hunt

Prodata Weather Systems

03336 664175

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