September 12th, 2022

Hi All,

Well just back from the Pwllheli on the beautiful Llŷn peninsular in North Wales and I couldn't but help starting off this week's blog with this picture.

I had got up early on the last morning before heading home to try and snatch one more session for Bass and Garfish on the fly after having a particularly successful session the night before. Unfortunately time and tide wait for no man (or woman for that matter) and the wind was up, the water coloured and full of weed. So I just took my camera and clicked away. I had the sun rising over Snowdonia looking one way and a full moon lighting up the beach and the sea, the other. It was quite magical and the image in my mind will stay with me for a long time. Sometimes we are blessed to be in the right place at the right time and that applies as much for scenes like this as it does to fishing. In the end I just put the camera in my pocket and took it all in. A wow moment. Then it was off to the cracking Caffi Largo in Pwllheli for a brill Flat White, a delicious slice of Bara Brith and listen to the Welsh chatting. It is a lovely language to hear but a **** to pronounce if you're not Welsh :)

Prior to heading off the forecast for Pwllheli, North Wales was pretty dire with at least 5 out of the 7 days showing rain and daily totals in the 10-20mm range, we ended up with closer to 31mm, with the worst day, 11mm and most of that falling overnight. The Llŷn peninsular is a really variable landscape with the mountains of Snowdonia to the east and the 3 highest mountains to the north that make up Yr Eifl or 'The Rivals' as they are called. For this reason, rainfall and where it falls is I think even more of a lottery than further inland and I do feel for meteorologists trying to forecast for 'The Llŷn'.

Local features impact significantly on the weather and particularly rainfall and this adds a complexity to close proximity forecasting that I don't think will ever be truly surmountable for parameters like wind, rain and cloud cover.

So last week we had more than a drop of rain for most, some really heavy rain and active thunderstorms over 2-3 days to boot. Not everyone got a lot of rain, but most did and it has kicked off the long road towards recovery from our second, hard drought in 4 years.

Later I'll look at where we are sitting in terms of rainfall and soil moisture deficit.

General Weather Situation - w/c 12th September, 2022

Now looking at the week ahead, one of the key features will be the wind and specifically the wind direction because we have the first real taste of a bit of cool weather with a pronounced northerly wind.

It forms as a result of a cool, Scandinavian low pressure (which will bring some chilly temperatures to Norway, Sweden and Denmark this week) butting up against an Atlantic high pressure trying to push in. When high pressure and low pressure meet like this, the air gets funnelled between them and usually in a northerly direction. So the week will be in two parts, warm, muggy and humid for Monday to Wednesday and then windier and cooler from then on.

Now since warmer air is coming in from the west and the cooler air is out on the continent east of the U.K, we will see somewhat of an west-east split, but Ireland, Wales, Scotland and England will all be affected by that northerly wind, just a bit less across the west. The east will have some pretty cold nights mind.

Rainfall-wise we still have that low pressure pushing rain across the U.K today and that'll continue into Tuesday but it will be on the wane. Now last week I mentioned a Bay of Biscay low pressure and sure enough it has edged up a little so we may see some rain along the south coast of England from Monday to mid-week and then as the wind turns northerly this could stream showers down the easterly coast for the second half of the week, continuing into the weekend.

Weather Outlook - w/c 19th September, 2022

Now looking at the GIF's above, we can see that next week looks pretty settled as high pressure completes its transition to sit over the U.K and the continental low pressure slinks off in a south easterly direction. So it looks like typical September weather, warm in the day, cool at night, light winds, maybe some mist around first thing and dry. This outlook looks to hold most of the week before a deep Atlantic low pressure arrives at the end of week bringing stronger westerly winds and unsettled conditions, firstly to Ireland and then the U.K.

All GFS images / output are courtesy of www.tropicaltidbits.com

Agronomic Notes

OK, first up I'll have a quick look back at August and all that heat that's already been forgotten by the masses and the lack of rainfall to boot.

I mean a week of 'on and off' rain and it's all sorted isn't it ?.....I don't think so...

Growth Degree Day (GDD) Total - August 2022 - The Oxfordshire

So above is the GDD total for August, 2022. As a reminder what we are measuring here is the average of the maximum and minimum air temperature and subtracting a base temperature to give an estimate for grass growth. I use 6°C as the base temperature. This gives us a figure for potential growth but as I have pointed out on endless occasions, GDD lacks meaning in this respect (but not others) in the middle of summer because we often exceed the optimum temperature for cool season grass growth (and we did this summer for sure). It is however a useful measure of temperature and the higher the average temperature, the higher the GDD.

So August's figure for our default location of Thame, Oxfordshire comes in at 396 GDD, just surpassing July's 393 GDD. The record is still held by July 2018, at 434, when we had our last hot summer, drought event and uncannily, July and August's GDD total from 2018 (796) is very close to 2022. (789)

The two summer's have very similar blueprints in more ways than one...

When we look at the cumulative GDD total for 2022, we sit at 1510 at the end of August, which is second only to 2017, the last year we had a decent spring and nice summer (rather than a heatwave) to boot. Again looking at 2018, we are very close and to 2020 as well.

In fact, 4 of the last 6 years have exceeded 1500 total GDD by the end of August, whereas no year before that (going back to 2005) has done that before.

An indicator to a warming planet or just a short-term blip ?

Soil moisture deficit

As discussed before, summer rainfall is a fickle friend and although our weather picture has changed for the better, we aren't back to 'normal' yet, whatever that is. In fact, looking at Facebook and Twitter turf sites, images of stressed grass and dried up lakes have been replaced with pictures of disease, Crane Fly and bird or badger damage :(

C'est la vie Mes amis....

Depending on whether you got heavy rainfall or not so far this month, you'll either be in a moisture deficit or surplus situation for September to date.

Here's some snapshots using data from Davis weather stations across the U.K showing September data up until and including yesterday ;

Location Rainfall E.T Difference

Thame 46.2mm 23.3mm +22.9mm

Northampton 22.4mm 20.1mm +2.3mm

Luton 40.4mm 19.3mm +21.1mm

Northolt 60.8mm 25.8mm +35mm

Braintree 19.8mm 31.4mm -11.6mm

Brands Hatch 41.6mm 22.5mm +19.1mm

Dartford 38.8mm 18.4mm +20.8mm

Sevenoaks 46.2mm 22.0mm +24.2mm

Guildford 72.4mm 17.9mm +54.5mm

Dumbarton 75.4mm 17.6mm +57.8mm

So typically we are about 20mm up for the month, but some locations are much better placed and the odd one is still in deficit because they have had high E.T and low rainfall so far this month.

Looking at how 2022 compares to 2020 and 2018 using data from a Northampton location (thanks Rob), we can see we have only just blunted the end of the soil moisture deficit graph and are no way close to getting back to where we need to be.

Now things are heading in our favour, shorter autumnal days means less E.T, lower temperatures and an increasing chance of rainfall, so I'd like to think we are over the worst from that respect but two severe droughts in the last 4 years does make you think or should do. Particularly when you look across Europe and the fact that our last drought before that was in 1976.

Here's a comparison of rainfall vs. E.T using data from 2018, 2020 and 2022

You can see how similar 2018 and 2022 are in terms of the actual soil moisture deficit figure and the way this deficit has come about.

Rainfall patterns across the U.K & Ireland

As I did last month, I have compiled some rainfall data from across the U.K and Ireland and as usual I have some loyal contributors to thank for this, cheers one and all 👍

Here's how we look for the U.K and Ireland ;

Our driest location in The Fens, Soham is actually sitting below the mean rainfall figure for the South East of England back in 1976. So having 20, 40 or 60 mm of rain since the end of August isn't really going to change us back to where we need to be.

For your information, the dry summer of 1976 was followed by a very wet autumn with 135.7mm in September and 165.4mm in October of that year.

It'll be interesting to repeat this at the beginning of October !

And now for Ireland....

The two driest locations, Killiney and Bray are on the east coast, close to Dublin, although I have to point out Killiney is in Dún Laoghaire–Rathdown and Bray is in Wicklow else I'll get in so so much trouble 😊

Given that Ireland's rain tends to come from the west or south west, it isn't surprising that the east coast is drier. The same tends to follow for England and Scotland for that matter.

August 2022 was a dry, warm month for Ireland as well and continued the pattern from July, so even being further west and closer to The Atlantic didn't mean that Ireland escaped the reach of 2022's Europe-wide drought. That surprised me. The Emerald Isle wasn't an apt description for July and August but I'm sure it's getting there now !

Practical agronomics of where we are now....

What this means from a practical perspective is that the arrival of moisture is allowing the grass plant time to recover and grow without being temperature and / or moisture-limited. Newly overseeded areas are taking really quickly because the soil temperature is still up, the E.T is lower, so the soil isn't drying down as quickly and of course we have had rain. In other words, we have excellent conditions for recovery and the internet is full of lots of pictures of great seed takes. Yep for sure, but dependent on the rest of this autumn and your surface organic matter levels, it's not necessarily going to still be there in the spring.

As discussed before and this is as pertinent to outfield overseeding as it is to greens, you need soil contact for that seed to establish beyond two-leaf stage. If you seed into surplus organic matter, yep it'll take, but the roots won't penetrate that compressed layer of fibre and so the newly established grass plant will either check out over winter due to waterlogging / hypoxia (lack of oxygen) or fade away next spring when we run into our usual dry April and we dry down from the surface. Outfield scenario's do have the advantage of Lolium perenne (sometimes) and its ability to push deep roots through fibre layers quickly but it isn't always used or preferred for a myriad of reasons and perspectives that I'm not going to discuss now.

I do wonder how much of autumn 2018's overseeding work stood up to the extreme's of 2022's summer ?

I appreciate it isn't a discussion for outfields and the like but when you overseed after hollow coring you tend (IMHO) to get much better establishment and I think a better chance of seedling survival over the short-medium-long-term. I'd argue / respectfully suggest that this is because the seed is sitting below the cutting height and it roots into fresh medium with no organic matter impediment. It's just my personal perspective.

I am sure opinions are divided on this but I remember seeing some really great Fescue establishment on a beautiful west coast of Ireland links course after hollow coring a specific area. It really opened my eyes because Fescue isn't the easiest species to establish but grand when it does.

Of course the other images gracing social media are hordes of Crane Fly emerging from greens and the like now that the rains have arrived and it is September. I was feverishly tying Daddy Long Leg dry fly patterns last week on my hols (I live the high life eh 😂 ) in readiness because they are a favourite autumn fly fishing pattern. The above image is courtesy of Iain Richardson (cheers chap)

Back to the turf side of things and clicking onto Syngenta's Turf Pest Tracker is in my view time well spent in terms of reporting pest activity and understanding the options available. You can find their site by clicking here

Gently does it on the nutrition front....

September is a tricky time in terms of turf nutrition I've always found. On one hand you want to push recovery but on the other you don't want to generate a lush grass plant with thin cell walls that is an easy target for Microdochium nivale and the like. We also know that with a warm soil and newly-arrived moisture, we get a natural growth flush irrespective of applying any fertiliser and this can easily carry on into next month. Gentle, 'tickler', low nitrogen granular applications have always worked well for me, particularly with a composted organic component, with the additional bonus that they tend to be more resistant to leaching. Dove-tail that in with light, 'turf hardening' liquid applications during the high pressure periods (as in high pressure weather systems rather than high disease pressure !) and it should work well.

I ran some Smith Kerns numbers this afternoon and we are well up in the mid to high forties currently in most parts of the U.K & Ireland because of the high humidity and air temperature and that'll continue through to mid-week, dropping away when we get that change to northerly winds and lower humidity.

As I type this at 8 pm, it is still 20°C and the humidity is sitting at 89% on my weather station. That's good disease weather I am afraid so I expect to see plenty of Microdochium and the like doing the rounds on Twitter and Facebook tomorrow morning.

Ok, enjoy the late summer / early autumn weather. Out of respect to the day in question and the passing of our Queen, I won't be doing a blog next Monday.

All the best.

Mark Hunt