February 22nd

 

Hi All,

Last week when I typed the blog and predicted conditions for the weekend just past and beyond, I said it was hard to imagine such a transition. Sure enough though it came to pass and whereas last week when I was out walking I was accompanied by multiple layers of clothing, a negative wind chill and the side of my face was numb, this week it was mild, I didn’t even need a coat. A 15°C swing or thereabouts !

Happily, the GFS looks to be fairly accurate for this week and beyond and that will be especially good news for The South West, Wales, the North West of the U.K, the west of Scotland and Ireland (though there’s still some rain to come for these areas in the first half of the week). These areas got clattered with rainfall over the last 7 days with 30 – 100 mm of rainfall typical and some local areas higher. The Severn and Wye have broke their banks again. So for all of us I think it’s agreed we need a run of dry weather. Yesterday whilst out walking, the fields were saturated with water standing in areas I’ve never seen it do so before and Leicestershire is comparatively dry compared to other sites.

It’s not just a run of dry weather we need, we also need E.T, that mystical combination of wind, air temperature, humidity and the like that allows soils to dry out more efficiently (and of course in the summer, too efficiently). Thankfully we will start to see some positive E.T kicking in this week as well.

General Weather Situation

So when I said the GFS output was reasonably accurate, above is what I meant. They correctly predicted the high pressure plume pushing up from The Med, but it’s occurring further east then they anticipated and so we will get an west-east split with our weather this week. So let’s put some detail on it.

Monday is a graphic illustration of that west-east split with a vertical band of rain moving across the U.K from west to east. As it does so it’ll fizzle out, so some places across the east of the U.K won’t even see any rain. It will be a dull day though across Ireland and Scotland though we could see some brief sunny intervals break out later in the day across England and clearer weather will follow behind the rain band. A cooler day than yesterday with 8-10°C likely with the warmer temperature reserved for the latter part of the day. Scotland looks to have a largely dry day, cloudier across the west and central areas earlier on with more in the way of brightness further east. A quiet day wind-wise with a south westerly wind veering through the day to settle back again later.

Onto Tuesday and overnight we see the winds strengthen from the south across Ireland and this will introduce rain, some of it heavy into the south of Ireland. By dawn this rain will be straddled across the whole of Ireland with Kerry and Connacht both in line for some of the heavy stuff. Across The Irish Sea that rain will already be pushing into The South West, West Wales, the north west of England and the west of Scotland. How many times have I typed that of late I wonder…..As we go through the morning the rain will push into the west of Scotland, most of Wales and The South West however it will quickly fizzle out across the latter. Further east across central and eastern areas you will see a quiet start to the day but those southerly winds will begin to strengthen through the morning reaching gale force by lunchtime. As we proceed through to Tuesday afternoon we will see that band of heavy rain lying straddled across Ireland and Scotland and it’ll be slow-moving so that means daily rainfall totals will be high in places with flooding.  That west-east split is clear to see now with Wales and the west seeing showers continuing through Tuesday but nothing like the rain of last week and then as you get east of the M5 we see more in the way of sunshine and milder temperatures, despite the strong southerly wind. So I’d say 10-13°C for Tuesday with the lower temperatures reserved for Scotland under that cloud and rain.

Onto Wednesday and overnight that rain looks to largely clear Ireland and sink south and east into the north west of England, Wales and The South West. The same for Scotland with the rain largely clearing and leaving behind some isolated showers across the north west. Ireland looks to stay largely dry save for some showers across the south west tip of Kerry. These showers will intensify as a new rain front pushes into the south of Ireland around Midday. For Wales we see rain across the west and some showers for the north and south. Further east across central and southern areas extending up the northern England , The North East and east of Scotland, we will see sunny intervals from the off and a continuation of that strong southerly wind. This will push temperatures up towards the mid-teens and it’ll be a good E.T day ! Later in the afternoon, we will see that rain front consolidate over the south / south east of Ireland, The South West, Wales and The North West with some showers pushing into the south west of Scotland. Again the dichotomy of temperatures with 10°C likely for Ireland, Scotland and the west of the U.K under that rain, but 13-16°C, for central and eastern areas. A strong southerly wind will remain on Wednesday.

Thursday sees that rain move away from the U.K overnight leaving behind some showers across The South West and the south coast of England. They’ll also be some showers, some of them wintry for the north west of Scotland. Through the course of the morning we will see those showers across the south coast move north and east into central areas but otherwise we look to be dry across England, Wales and Ireland. Scotland looks to hang onto that rain / wintry shower mix across the north west. Ireland will see a much-improved day with the sun pushing through however it’ll be cooler as well. We close out the day with showers still affecting the south and south east of England, sunny intervals elsewhere and a pretty dry picture. The wind will change from southerly to westerly on Thursday and that means cooler temperatures with 9-11°C typical.

We close out the week on Friday with high pressure building to the south east of the U.K and only a continuation of those wintry showers across the north west of Scotland to blot the copy book. As we go through the day we will see rain edge towards the west of Ireland but high pressure will be keeping it from making too much ingression eastwards. So a settled dry day with the best chance of the sun across the east of the U.K, with Ireland, Scotland and the west having more of a dull affair. Later in the afternoon, that rain front pushes into the west of Ireland but makes slow progress from there as it butts up against the high. Remaining on the cool side with 9-11°C despite the longer spells of sunshine across England with the south westerly / westerly wind pegging back temperatures.

The outlook for the weekend is good with high pressure in situ for most of the U.K and Ireland. It looks to be a duller affair on Saturday with a cool westerly wind and the risk of the odd shower across Wales, but otherwise dry, cloudy and dull. Sunday sees much more likelihood of sunshine but I still think we are talking about 9-11°C temperature-wise. Not bad for the end of February and dry everywhere will be a welcome consolation.

GFS prediction – March 1st, 2021

Weather Outlook

So above is the projected GFS output for next Monday which will be the 1st of March….ta-da !!!

As you can see we have high pressure in charge and it’ll be feeding in a mixture of wind directions and hence temperatures dependent on your location. (remembering that high pressure systems rotate clockwise)

Through the course of next week we see cooler air push in as that high pressure sinks south and east but from mid-week we see a new high pressure build from The Atlantic. So we look to have a pretty dry week, next week with only a weak front pushing through on Tuesday across Ireland, the north west and maybe central areas of the U.K for awhile, the only blot on the landscape. Otherwise dry, maybe towards the dull side but nothing too great temperature-wise, I think a continuation of the end of this week / weekend’s sort of stats, i.e. 8-10°C. Probably at the moment, the most important part is the dry part 🙂

Grass Agronomics

So it looks like we have finally thrown off the seemingly perpetual succession of Atlantic low pressure systems and after the west taking a battering recently, that can only be a good thing in my books.

Mid-week this week we will have some pretty good G.P, but otherwise I think we will just tick along. So let’s start off by looking at the prospects for growth over the next 10-14 days.

Below is how it looks from a daily G.P perspective for the next 14 days working on a projected forecast for 4 locations ;

Daily Growth Potential – England, Ireland, Scotland, Wales

So you can clearly see that we get a strong growth nudge mid-week, this week in all locations with the highest projected daily G.P for England at 0.55 and the lowest for Central Scotland at 0.26. This rise in growth is pretty short-lived because we lose day and night temperature with a change in the wind direction (explained above) and so we then settle down to a pretty low growth rate on all locations with the west edging the daily growth over the north or the south for that matter. Typically the range is between 0.1 and 0.2 once we get to the end of the week and if next week’s forecast is accurate, this won’t change much going into the first week of March. Now I also expect us to be pretty dry so that means if you’re applying a quick release granular anytime soon and you aren’t based in Ireland or the western half of the U.K, quite ironically you won’t get much rain to wash it in.

As it looks right now depending on where you are located we may (I said may) enjoy a phased return to golf from the end of March in England. Obviously Ireland and the devolved nations are on a different road map but let’s imagine for the sake of logic we all work to similar (ish) guidelines. This means we have the whole of March to prep our respective surfaces and maybe for the Schools and Colleges side of things, a more relaxed transition from winter season to cricket given the lack of winter play and recovery required compared to ‘normal’ (whatever that is). Now I know that Ireland looks to be on a more gradual relaxation of lockdown but really I’m just looking at from now to the end of March as a period of time so please bear with me.

If you want to move things on right now and are in the west part of the west-east meteorological divide then this week is a time to get a granular on when there’s still plenty of rain around and you’ll also take advantage of the mid-week growth spike. If you’re on the east side, then I think a different approach is required. Here we will have less chance of rain, some nice spray windows (though the warm weather peak this week will coincide with strong winds so that can’t be utilised I am afraid) and dry conditions. So I think it’s going to be foliar nutrition using low temperature-available N forms including sulphate of ammonia, potassium nitrate and the like to facilitate a response. Remember though that this response will create a significant growth flush, more a gradual green up and ticking along sort of growth. Obviously applying a form of iron within the mix would be great to keep them looking good but probably the next thing your surfaces will benefit from doesn’t come out of a bottle.

Textbook version of root development across a season….

As surfaces dry out it gives us the opportunity to get some deeper aeration done in the form of vertidraining, Air 2G2 and the like. This I think will be critical because if you look at the typical temperatures and projected growth, we aren’t going to see the grass plant leaping out of the ground with lots of new shoot growth. Instead what we will see as the soil drains down and water is replaced by air within the profile is an increased soil oxygen potential which will allow the grass plant in turn to grow roots.

The textbook schematic above sort of describes how things should work with a stable set of seasons, predictably warm springs, hot summers, you get the picture…Nah…it ain’t happening 🙂

This model assumes stable seasons, nice spring’s and high temperature heat stress consistently through the summer, whereas as we know our weather doesn’t often work in such a predictable fashion.

Sometimes I think rooting in our climate looks more like this ;

Now of course the above is a generalised schematic for a generalised grass species. For instance if this was Poa annua, you’d anticipate a loss of rooting from the end of April onwards as the plant diverts the majority of its energy towards seed production at the expense of shoots and roots. Typically April can be one of our hardest growing months with frequently either cold / dry or hot / dry. Either way it isn’t great for the plant in terms of building or maintaining a root system. When this dry spell breaks we typically jump straight into growth or seedhead development, neither of which is likely to be good for rooting (hence the flat line through May into June. The above scenario assumes a wet, warm summer with a period of heat during August before the plant recovers. Typically we lose our high E.T and high night temperature days at the end of August and so from hereon I think we start to build roots again. Now the next part really depends upon your type of rootzone but if you hold water you are likely to lose roots in the winter as soil oxygen levels get depleted. Remember, low oxygen means low growth potential whatever the temperature.

So once your rootzone dries down nicely (and I accept this won’t be for a good while in the west), I think you can achieve a good benefit by opening up the rootzone at deeper depths, allowing some gaseous exchange (venting if you like :)) and thereby increase soil oxygen levels. Compact vertidrains are a great weapon for such a job.

Disease Activity

A little bit of activity last week as predicted with the rapid thaw and increase in soil and air temperature.

Boy was that a rapid transition. In our Great Dunmow location, the soil temperature rose from 1.3°C to 7.3°C in a little over 6 hours, aided of course by mild rainfall.

The schematic for air and soil temperature during February 2021 is quite something….Spot the cold spell 🙂

Air temperature and soil temperature (@ 25mm depth) – Great Dunmow, Essex

So it’s not surprise where you already have a high disease population (around the periphery of an existing scar) that you may have seen some activity.

Looking ahead this week I don’t expect any repeat with the mid-week growth blip because although we will have warm, humid air, we will also have a drying wind.

As the wind drops at the end of the week and we pick up lighter winds and a return to some dew formation, we may see some reactivity again around existing scars.

OK, that’s me for another week folks, next Monday we are into March would you believe 🙂

Stay safe and healthy.

Mark Hunt