Hi All,

This time last year we were basking in mid-teen, day temperatures and mild nights to boot and the grass had already been growing strongly for 3 weeks. In 2017, we packed on 30GDD in this week, whereas in 2018 we will be lucky to get to a quarter of that.

Bizarre really when you consider we have just had a nice mild weekend for most but the reality is that the Sudden Stratospheric warming (SSW) that took place in the third week of February looks set to leave a cold and wet influence on March 2018.

Image courtesy of Metman James (https://twitter.com/metmanjames?lang=en)

I say that because the NAO index which is still sitting in a negative situation (i.e high pressure above us and low pressure below instead of the reverse) and as you can see from some of the weather model projections it isn’t due to cross that dotted line past the end of March. Now some models have this happening sooner (7 – 10 days off) but looking at the jet stream it is still sitting way lower than normal and it isn’t showing any signs of moving northwards till the weekend after next….

So low pressure systems are orientated south of the U.K instead of coming in from The Atlantic and this results in lots of rain. With the thaw last weekend and a wet week, last week for many, the ground is saturated and the bad news is we have more to come I am afraid until that jet stream pattern changes. It’s also likely that we aren’t done with the snow just yet and those biting easterlies (heaping on the good news…not)

Thanks….

I had a lot of feedback last week and over the weekend about the blog so to everyone that ventured an opinion, thank you very much, it is important to me.

For the time-being I am going to carry on with the present format although this week’s version will start on Tuesday from a weather perspective simply because I have had no electricity till lunchtime so no WiFi (cracking start to the week that :))

General Weather Situation

So I’ll start this week’s blog on Tuesday because by the time I’m likely to finish it, Monday’s forecast will be irrelevant. So Tuesday looks to start dry for most of us save for some wintry showers across the north-west of Scotland. By lunchtime we should start to see some gaps in the cloud base and sunshine across eastern and western areas including the east of Ireland. It won’t last for long here though as a rain band is due to push into western Munster in the early afternoon and push eastwards across Ireland and into The South West by early evening, with more rain to follow for Ireland overnight into Wednesday. Elsewhere, a dry and nice end to the day really just with the threat of an odd shower across The Midlands and Central England. Temperature-wise, 9-10°C for most areas and winds likely to be north-westerly for most places except Scotland where you are more southerly.

Onto Wednesday and that overnight rain will be set fair over most of Ireland by the morning rush hour and if anything intensifying across South Munster and Leinster during the morning, so some heavy rain forecast here. Nipping across The Irish Sea to the U.K, Wednesday doesn’t look too bad with some showers across the north-west of England / south-west of Scotland during the morning and across The South West. Elsewhere a cloudy start with hazy sunshine allowing temperatures to lift nicely into the low double figures through the day, so not bad at all really.  Ireland looks to have that rain all day on Wednesday, with heavy rain towards the south of the country for most of the day, I would expect there to be local flooding. Just after dusk we see some of that heavier rain push into The South West and into West Wales as well. Windier on Wednesday with a strong southerly / south-easterly wind.

For Thursday we see that rain over The South West push across the western half of the U.K overnight and it’ll still be there by the morning rush hour. Ireland will be drier but with another rain band following up behind the one now affecting the west side of the U.K. So by lunchtime we have two vertical bands of rain, one moving slowly across Ireland, the other sitting across a line from North Wales to the south-east of England. The picture will also be unsettled along the north-west coast of England and south-west of Scotland. The Midlands and east of the country will probably stay dry in the morning but that rain band consolidates and moves eastwards to give a wet afternoon here with some of that rain heavy over the north Midlands and north of England I’m afraid. Still unsettled for Ireland despite the bulk of the rain moving away through the day, more in the way of sunshine here though between the showers. Temperature-wise, cooler on Thursday with a strong south-easterly wind in situ so perhaps only just scraping high single figures in the wind.

Closing out the week on Friday we see that rain band now sitting from the North Midlands up to Scotland so a wet start to the day here. This rain band will push slowly northwards into Central Scotland as we progress through the day. South of this rain, a nice day on Friday with good spells of sunshine and much lighter winds. Ireland looks to have the same though still with a threat of a shower along the far south coast. These showers look set to move north through the second half of the day for Ireland, still with some sunny spells between them. For the U.K, that rain band will be slow to clear the east and north of the country with a threat of rain late on Friday across The South East and East Anglia. Late in the day there’s also a risk of a rumble of thunder or two in amongst that rain. Temperature-wise, a little up on Thursday and nudging into double figures especially where you see the sunshine across the south of England.

Ok so how is the weekend looking ? hmmmm…

There’s some disagreement among the weather models for the weekend or more precisely the exact timing of a change to an easterly airflow and plummeting temperatures. Meteoblue has this occurring on Saturday whereas most models show the wind changing from mild southerlies on Saturday to easterlies overnight into Sunday with an overnight frost and very cold temperatures during the day on Sunday. I think the weekend outlook will be reasonably dry save for some rain across Kerry and some wintry showers across Scotland and the north-east of England. Sunday looks reasonably dry at this stage but much, much colder and with the threat of snow showers across eastern areas blown in off The North Sea. It will really feel absolutely Brass Monkey’s weather when you open the door on Sunday morning.

Weather Outlook

So we have some potential good and bad news looking ahead at next week.

The good news is that it should be a lot drier than this week, the bad news is that we will see a return to some pretty un-typical March temperatures with Sunday and Monday in particular looking well parky. I’ve already seen the t****y headlines proclaiming a return of “The beast from the east”, ho-hum and all that, but yes we will have a period of northerly and then easterly winds commencing some time between Saturday and Sunday and kicking off into next week. The easterly wind is coming from a slightly different direction to previous so I can’t see it being like before in terms of snowfall and temperature extremes, but it will be cold and we will see some snow on easterly coasts. So expect overnight frosts probably from Friday night onwards and lasting till at least next Wednesday night, perhaps longer. I think we will be dry and cold though on the whole. That said with northerlies and then easterlies, there’s always a chance of moisture pushing in from The North Sea in the way of snow showers. Towards the end of next week there’s a suggestion that the jet stream will kind of ‘reset’ and assume its traditional place across Ireland and the U.K, thus returning us to a milder, westerly airstream and more normal temperatures. If this comes to pass it will mean a cold spell of around 5 weeks since the occurrence of the SSW.

Agronomic Notes

So with some slightly milder weather last week (albeit wet weather), we have seen signs of growth out there in some areas of the U.K and Ireland. I am also very aware that some northerly locations still have standing snow due to the magnitude of the drifts the previous week.

Soil temperature taken at 10 a.m. on Friday 9th March, 2018. Last year on the same day it was 8 degrees C

So where are we versus last year growth-wise ?

We are way behind last year as the graphs below of daily and cumulative Growth Potential show….

As you see from the above year-on-year graph showing cumulative Growth Potential we will have reached the same total on the 22nd March, 2018 (calculated by using forecasted temperatures as I haven’t quite mastered time travel as of yet..) as we did on the 25th February, 2017. That puts us about 25 days behind last year from a growth perspective.

SSW’s aren’t good news for business or growth….

If I compare it with 2013, when we also had a late SSW event, you can clearly see the similarity between 2013 and 2018 in terms of low growth levels through March..

So my advice is plan for a low temperature run through March in terms of nutrition….

Stop – Start Growth Signs..

Yes I know we talk about this every year and in fact I tweeted this image on Friday because I thought I’d drag myself into this century and use Twitter more….I had a lot of reaction so thanks for that…

The above shows some biotypes of (in this case) Poa annua displaying the typical purple colouration that we associate with a run of warm days and cold nights. During the day (and in particular on turf areas that are more out in the open) the grass plant produces sugars by photosynthesis but with rapidly falling temperatures at night, these sugars are not translocated from the leaf. They therefore accumulate and in so doing bind to a purple pigment called anthocyanin. The upper layer of the plant leaf then takes on a purple colouration, as opposed to the more usual green that we associate with the pigment chlorophyll. The biotypes that are growing better during the day display a purple pigmentation vs. other biotypes that are slower growing which remain green. If you look closely at the purple areas with a hand-glass and turn the leaf over, you’ll see it is only the upper leaf surface that is purple, the underneath is still green. This is because the upper leaf of the grass plant is exposed to the greatest temperature variation.

Now I’ve seen this pigmentation on Poa annua and Bentgrass, but not on Ryegrass so I’m interested to know if anyone has noted it on the latter ?

Normally the purple pigmentation grows out once temperatures become more stable, in particular night temperatures, so that won’t be anytime soon then eh ?

Disease activity

Last week I included this image of new activity around existing scars and sure enough we saw quite a bit of disease activity of this type through the week, courtesy of some pretty rapid increases in air temperature accompanied by high humidity. This mix as we know is very conducive to Microdochium nivale development.

Downloading my faithful little Netatmo Weather Station’s readings for last Monday highlighted the above conditions clearly…

The columns marked in red show when conditions were in favour of disease development. We can see this was from 10.42 a.m. right through till 4.42 p.m. on the 5th March, that’s 6 hours and more than enough time for this pathogen to develop mycelium. The humidity was flat-lining at 100% for pretty much the entire day with only a short period (2 hours gosh golly) when it dipped down to 96% ! In other words the plant leaf surface was pretty much saturated with moisture, another reason why fungal mycelium could develop.

Not the only pathogen problem at present…

As many Corvids (Crow species) currently have young in the nest, they are on the hunt for food and so pecking damage is very much in evidence on turf surfaces be it golf, cricket or race courses. I saw Magpies doing this damage on the approach to a golf green and expected to find Leatherjackets as the intended target but was surprised to see Bibionid sp. larvae (shown below)

These are larvae of species like Fever Fly or the most-aptly named, St Mark’s Fly (nice to have a fly named after you 🙂 ) and are found in clusters just below the turf surface in the upper layer of thatch. I say surprised because I’ve seen these larvae at the same stage of development in December so they’re obviously like grass, a bit behind the curve….Nothing really we can do right now for this species or the other types of insect larvae present at this time of year.

Behind the curve on shoots but maybe not roots…

The other interesting point that I would make before signing off this blog in the middle of a damp and dank Monday evening relates to the image above. I’ve noted lots of white roots in evidence on cores I’ve taken recently even though as our GDD / G.P information shows we are a long way behind the curve growth wise in terms of top growth. It’s a fact that when the plant isn’t putting its efforts into top growth (leaf shoot growth), more resource (biomass) is available for root development and although the temperature cut-off for leaf shoot development is around 6°C air temperature, root development in grasses appears to continue right down to 1-2°C . Part of the reason for this is that the soil provides some insulation to the effects of colder air of course, but part is due to a partitioning effect in terms of growth between leaf and root biomass production. When conditions are conducive to growth (light, temperature and moisture) and particularly when there’s surplus nitrogen around, the grass plant will divert its energies into shoot development at the cost of root development. This clearly isn’t the scenario now and so that’s why you are more likely to see some pretty positive root development at present, particularly if you’ve carried out some early season aeration (that old chestnut again you sigh…)

Ok that’s it for this week, sorry for the delay in posting this blog.

All the best for the coming week and wrap up well if out and about at the weekend 🙂

Mark Hunt