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  • Writer's pictureMark Hunt

June 12th, 13th 2023

Hi All,



So on Sunday I got up early to do some bank fishing at Rutland Water before the heat built and then headed home when it got hot at midday. I could see the first Cumulus clouds forming in the distance out east.

The first storms were just starting to show on the radar around 4.30pm. when I set out on my newly-restored, 1989 Honda Hawk 650 for a suspension test. I thought I'd have an hour before they reached home.....I got about 8 miles when I heard the first clap of thunder. I immediately did a U turn and within 0.5 mile went from bone dry and hot to absolutely torrential rain, bloody hard hail bouncing off my visor and aquaplaning round every corner. Needless to say I was a tad soggy when I got home and my Honda Hawk is no longer immaculate !!



That hail was powerful enough to knock holes straight through the leaves of plants in my garden. This is the Mrs's treasured Hydrangea afterwards....a bit trashed.....


As I type this the following day, the skies have darkened and we are in for round two....Thanks to John for this pic of a storm building over the town of concrete cows.


We had 16.2mm with a rain rate of 133mm an hour at the storm's peak !


Over the last 24 hours, there have been 35,375 lightning strikes recorded, that's impressive ! (Image courtesy of netweather.tv)



I apologise to everyone reading this that hasn't had rain but although this week's showers are hit and miss, there is a suggestion of more on the way next week. Now I am away on hols for a week from Friday and of course we have Glastonbury starting up next week as well. Those two events on their own are sure fire indicators of a breakdown in the weather and for rain. 😀


Over the last 2-3 weeks, the long-term GFS (7-10 days) has been all over the place teetering from an African hot air plume forming a temporary peak in the jet stream to an Atlantic low pressure system causing a trough to develop. Over the last few days the signal for the latter has strengthened and so we look odds on for a period of cooler and unsettled weather next week although this could clear in time for Glastonbury.



General Weather Situation - w/c 12th June. 2023


So this week starts off with a repeat of those heavy storms across the U.K and rain across the east and north of Ireland. The storms seem to start over the M1 sort of region (no surprise there then...) as heat is probably vectoring up into an updraft from all the stationary traffic. Unfortunately for the parched east, very few storms have formed off-shore of East Anglia. If you're in the heat then you're looking at 26-28°C, if you're under the rain, you can take 10°C off that. Those storms will move north and west across into north west England and Wales before heading across The Irish Sea into the east overnight into Tuesday morning. Tuesday should see an end to these showers for the U.K, though for Ireland they'll push into the north west and then consolidate later in the day across Connacht to give it a nice drop or two. Tuesday will see long spells of sunshine and temperatures again pushing up into the high twenties across all of the U.K with Scotland topping 27-28°C. You may have seen recently how dry Scotland is with wild fires south of Inverness and Loch Ness itself the lowest level it has been for over 30 years.


Mercifully we have lost those goddam awful north easterly winds for the time-being but by Tuesday / Wednesday the wind will pick up again from the east this time pushing up the E.T again....Weather-wise we look set for the rest of the week, warm, dry and sunny, a bit more cloud around on Thursday a.m. and rain for the north, west and north west of Ireland on Tuesday and Wednesday p.m. with temperatures in the low twenties across Ireland. Temperatures will remain in the high twenties across England and Wales this week and mid-twenties for Scotland. This run of weather will continue into the weekend with high humidity and high temperature.


The first sign of a change comes for Ireland late on Friday evening as an Atlantic low pressure as a weak rain front pushes rain into the west and south west. During Saturday this rain isn't projected to make much progress from the west and north west of Ireland before petering out but think of it as a first foray with more to come. For the U.K, the weekend looks nicely set across the U.K with long spells of sunshine but maybe more in the way of cloud cover for the west. Ireland should see the rain fade away from the west and north later on Saturday to give a fine day on Sunday.


Weather Outlook - w/c 12th June. 2023


If we look at the projected GFS output for next Monday morning courtesy of tropicaltidbits.com, we have a weather pattern we haven't seen for awhile with a low pressure system out west of the U.K & Ireland. If this all goes to plan and there is some variability attached to this because you can see a high pressure peak trying to form and block this low from moving eastwards. It could still do this so we will see.


If we go with the projections, we will see this low pressure push across Ireland and the west of the U.K from Monday onwards introducing a cooler more unsettled theme with rainfall for Ireland, The South West and Wales before this moves eastwards and northwards on Tuesday. How far east is tricky to say but it may not reach the eastern half of the U.K which is desperate for rain. This unsettled theme continues through Wednesday into Thursday before high pressure looks to settle us down again. Now currently the projections are for a heat plume to develop which could bring some very high temperatures across the U.K for the end of next week, just in time for Glastonbury. We shall see. Temperature-wise I think we will drop down to low twenties next week with more in the way of cloud cover.


Agronomic Notes


MAY 2023 - U.K Rainfall & Growth Potential Comparison


So first off as promised last week, I take a look back at May, 2023 and the reason why many of us are in need of some rain. Now when you look at the rainfall totals, bear in mind most locations saw the last rain anywhere from May 9th to May12th. So 2/3 of the month was dry as a bone and that has continued into June with the E.T ramping up with some areas now over a month without rainfall. For once both Okehampton and Dumbarton are pretty similar to most other locations from a rainfall perspective.



Monthly rainfall totals are deceptive because as I mentioned the above graph doesn't show that since the 12th of May, rainfall has been in short supply and E.T has been in abundance with the constant north easterly winds. It is June though that has really ramped up the imbalance between the two.


A hard start to June....


To demonstrate this, I picked a location across the east of England which traditionally would be one of the driest areas of the U.K, a golf club near Bury St Edmunds. I plotted out the daily rainfall and E.T from the 1st of May to today and then the cumulative effect of the two in terms of cumulative soil moisture surplus / deficit. Now even this level of data provides a somewhat skewed picture because at this particular location, it has a sandy soil that drains and won't hold any surplus of rainfall. In the winter this is a bonus, in the summer it is not...


Here is the daily rainfall and E.T graph, this pattern is repeated across the U.K and Ireland currently.

You can see how the rainfall is confined to the beginning of May with just a touch of moisture from Haar at the end of the month.


Here is how it looks if you take into account the cumulative effect of rainfall and subtract moisture lost by E.T with the blue columns showing a moisture surplus and the red, a deficit.

I would say that is pretty clear cut when it comes to summarising the relationship between moisture applied (through rainfall) vs. moisture lost (through E.T).


Over the last 7 days, this location has lost 29.66mm through E.T.


Interestingly, the course manager started to irrigate on the 22nd May from a plant health and low soil moisture perspective. That is within a day of the graph going into soil moisture deficit zone.


So we have a plant that is under stress currently unless of course you have been lucky enough to receive some of those thundery outbreaks as we have here in Market Harborough. Plant stress and disease sleep in the same bed together, so I'll look at that relationship later in the blog.



Looking at the Growth Potential stats from around the U.K, it is a pretty similar picture to last May with around 60% of optimum growth for the month. The reality with May 2023 is that growth was not limited by temperature but in the latter parts of the month by rainfall. This meant early on in the month, growth levels on higher-height-of-cut areas were excessive after the wet start to the month. The warmest locations for growth are across the western and south western side of the U.K and the coolest across the east and north. The reason for such a sharp contrast in May 2023 was the north easterly wind direction and more cloud cover (and lower temperatures across the east. As a local Norfolk Bass fisherman remarked to me on the phone yesterday evening, "today is the first time we have seen the sun for a month in North Norfolk".......


MAY 2023 - Ireland - Rainfall & Growth Potential Comparison



Ireland mirrors the pattern across the U.K, in that eastern locations are sitting drier than western locations from a rainfall perspective. Across the west it has been an unusually dry and hot start to the year. Hopefully this week and next week's low pressure will ease the situation somewhat. Growth-wise, we see very similar levels of growth, approximately 10-15% higher than the U.K locations, with again growth becoming limited by moisture rather than temperature. For some Irish locations, the last rainfall in May was a week earlier than in the U.K, so their dry spell started earlier.


Anthracnose trigger ?

The graph above highlights air temperature, humidity and leaf wetness stats taken from the Davis Vantage Pro weather station at The Oxfordshire (thanks Sean). This location has received rainfall but regardless most locations are watering at night and so the plant leaf would be sitting wet.


The air temperature threshold of 25°C was comfortably exceeded and this is applicable for just about anywhere in the U.K and Ireland, including the west. We can also see some long periods of plant leaf wetness overnight which would have allowed the fungal mycelium to develop into the biotrophic state (if you want to read about the various life cycles of Anthracnose in turgrass, click on this link).


Effectively in the biotrophic state, the fungus enters into the leaf without triggering the plant's defence mechanism and then sits there waiting for a trigger that will transform it into the necrotrophic state. This trigger tends to be associated with plant stress so if we don't get the stress than we don't tend to see the Anthrancose. Similarly if we have 25°C air temperature but no plant leaf wetness / elevated humidity, we don't tend to see the disease.


As it stands now, we are I would say 'primed' for Anthracnose and if I was sitting on a course with a past history of this pathogen then I would be applying a preventative fungicide in the next 7-10 days. If I was sitting on a course with no recent Anthracnose, I would probably just make sure I ticked the well-established BMP's from Rutgers University during this period and obviously I would try to alleviate plant stress using research-proven biostimulants and possibly, plant pigments during periods of high U.V stress. (I say possibly because I never got round to researching them in my previous employment so I don't consider myself qualified to comment). That said the research work is out there.


The trick with Anthracnose is breaking the chain


If you have recurring Anthracnose, you will have built up a spore loading in your turf and because this disease primarily (but not always) takes out Poa annua, you will have developed bare areas after the disease which will tend to be occupied by the annual biotype of Poa. You know the one, the seedy, pale and coarse clumping plant that you can see from Google Earth. It just so happens the annual biotype of Poa is the most susceptible to this disease and so the cycle tends to repeat - susceptible plant affected by disease - bare areas - bare areas colonised by susceptible plant - susceptible plant affected by disease.


So you have to break the spore producing cycle of this disease, which then reduces the spore loading in your turf and allows you to overseed with plant species that are less-affected by this disease (primarily bentgrass). Amongst these species, there are cultivars that have better Anthracnose resistance than others, so ask your seed company about this specific area rather than just overseeding with the latest 'faddy' cultivar.


The other trick is adopting those BMP's that Rutgers spent 10 years of research establishing, it's not like we need to wait for new research to help us here, the work has already been done. Click the link below to read about their work.

anthracnoseRutgers2018
.pdf
Download PDF • 1.74MB

Of the BMP's, I think maintaining healthy plant leaf tissue levels of N and K, rolling instead of cutting during periods of stress and maintaining a sensible cutting height are the key ones in my mind.


Ok, that's me done. Next week I am on my hols so I may just do a mini-blog looking at the weather before heading down to The Two Magpies in Wells Next The Sea for a Flat White and Kanelsnegle (Cinnamon Danish) and then watch the world go by 😀


All the best.


Mark Hunt











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