March 15th

Hi All,

Last week I forecast a much nicer week this week with some warm temperatures and a drier aspect to the weather as high pressure was projected to build. I ended with the caveat of a fly in the ointment scenario being the ECMWF projection that had the high pressure building further west than the GFS one. Well the ECMWF forecast was more accurate than the GFS on this occasion. So that’s what we will see this week. Much drier and milder for the first half of the week but with the high pressure building further west it means we pick up the leading edge rather than the trailing edge and that means northerly rather than southerly winds later in the week. So drier with a milder 1st half of the week and a cooler 2nd half is the synopsis.

Had my AZ jab on Saturday. What an efficient process, in / out and 10 minutes later I was sipping a Flat White, munching on a Pain Aux Raisin and looking for the Peregrine Falcons in our Church Steeple. I read all the fuss (European of course) about the risk of blood clots but figured the odds are very low even if there is a link or it could be totally unrelated. A bit like 10 people have the AZ jab and then have an RTA, are the two linked or is that just the normal incidence of RTA’s per 100,000 people ?

It reminded me of when I first started in this industry. In the early 90’s, lots of soil samples were conducted on golf greens and the results found that they had high levels of phosphorus. The greens were also populated by Poa annua. So the conclusion was drawn that the two were linked. People then spent a lot of time trying to prove this link and failed. I mean it wasn’t a great surprise because if you look at the fertiliser recommendations in the 70’s and 80’s, they were practically all NPK, with a high phosphorus input in the autumn (3-12-12 for example). We know the grass plant utilises very small amounts of P (from tissue analysis), so if you’re applying 3 x the annual rate of P every year, it is hardly surprising that it accumulates. 🙂

I think we all know the drivers for Poa annua domination lie elsewhere.

Onto the weather…

General Weather Situation

So the schematic above shows from left to right where the high pressure was projected to be, the middle image shows where it’s now likely to track and by the end of the week you can see in the image on the right how it is pulling down cooler, north easterly winds.

Now it depends on whether you’re a glass half full  or a glass half empty sort of person, but I think it’s still a positive. We will have high pressure so for everyone that is trying to dry out, that’s got to be a big plus.

For Ireland and Scotland, you’re closer to the centre of the high pressure, so you’ll pick up some half-decent temperatures without them being accompanied by rainfall….what’s not to like ?

It’s actually the southern and eastern half of the U.K that comes off the worst because here we will be further away from the centre of the high, so we will be cooler and with a north east wind in situ, there’s always a possibility of picking up some showers and Haar from The North Sea.

So let’s put some detail on it.

So we start Monday with a north west wind and a mainly dry picture across the U.K & Ireland. Mainly dry because there’s a line of showers pushing down from Leeds towards Hastings and also across Kerry, Galway and Connacht. These showers will move south and east through the course of the morning. Not bad temperature-wise with double figures for most areas and western locations will nudge the low teens as we go through the day. Those bands of showers will be few and far between but will continue through the day across areas of Ireland and the U.K. Most places will be dry with eastern counties enjoying some sunshine for the 2nd half of the day. After dusk we will see some heavier rain push into The Western Isles and western Scotland. So not a bad start to the week I’d say.

Overnight into Tuesday and that rain over Scotland pushes south and east across northern England into North Wales before tracking into The Midlands and East Anglia in time for the morning rush hour. We see the same pattern across Ireland as rain tracks down from Connacht south and east into The Midlands and eastern counties in the early hours before clearing through the morning. So the rain over the south east / east of the U.K will move off during the morning to leave a dry, dull picture. Further north across Scotland we will see some brightness and temperatures picking up nicely into the early teens with lots of sunshine. Further south it is an all together duller affair with more in the way of cloud cover but across the southern half of Ireland we will see some sunny intervals and the same for southern England and Wales later in the day. Milder feeling on Tuesday with the best temperatures of the week pushing up into mid-teens for Wales and low to mid-teens for Ireland and Scotland. Across the south and east where we hang onto cloud cover for longer, expect low double figures, maybe just nudging the teens. The wind will be a moderate north westerly veering more northerly through the day.

Onto mid-week and Wednesday brings a dry picture everywhere with a west-east  / north-south split in terms of sunshine and temperatures. The north and west will pick up more in the way of sunshine, with Ireland, Wales and Scotland having more than the fair share :). They’ll be a line drawn vertically dissecting the U.K, with the western half enjoying sunshine and mild temperatures up into the low teens and the eastern half sitting under thicker cloud, a cold northerly wind and ‘enjoying’ temperatures just into the double figures. They’ll be a north east wind in place, light to moderate and this will weaken as we go through to the evening.

Thursday sees a very similar picture with a duller start for everyone but Ireland, Wales, the west and Scotland will see some sunny intervals, maybe less than Wednesday. The east and south will pick up more cloud cover again and a strengthening north easterly wind which will push in more cloud from The North Sea and introduce a chillier feel to proceedings. It may also introduce some showers in off The Humber and The Wash estuaries through the second half of the day. So dry just about everywhere save for a risk of showers pushing in from the The North Sea.

Overnight into Friday and we may see some showers push in from the continent across the south east of England but these should have cleared by morning. A different day on Friday because the cloud cover is swopped around with the west and north (Scotland) picking up the bulk of the cloud cover and the south seeing some sunshine. So a much brighter day for the southern half of the U.K, with plenty of sunshine, whereas the north and west will pick up more in the way of cloud and consequently cooler temperatures. Still there’s a risk of showers coming in off The North Sea estuaries through the mid-part of the day and pushing across into The Midlands but generally the dry picture continues. Scotland will see a sunnier second half of the day with sunny intervals breaking through across central regions. That north east wind will be lighter on Friday but it’ll feel noticeably cooler, especially in the areas that enjoyed better temperatures earlier in the week. Scotland looks like being the warmest places with low teen temperatures, whilst Ireland will sit in the low double figures and Wales, England will just break into double figures. Eastern coasts will be coolest again, continuing a theme for the week.

So how does the weekend look ?

Well not too bad I’d say with a change in the wind direction from north east to north west bringing in some slightly milder air for the U.K, but of course more in the way of cloud cover for the west and north. So this time the east may pick up some sunshine through Saturday and particularly the afternoon. Otherwise, slightly milder on Saturday with light to moderate north westerly winds and temperatures in the low double figures. Duller across the west and north and consequently a little cooler. Sunday looks a much duller affair for the west in particular as a strengthening north westerly wind nips the temperatures back into high single and low double figures. Again the best chance of seeing the sunshine will be across Central Scotland and the north east / east but it’ll feel cooler everywhere.

Weather Outlook

So here’s how we look at the start of next week and this time GFS and ECMWF are in broad agreement for the start of next week though their projections diverge as we move through next week.

So the high pressure is still with us but it’s tipped on its side which means we will maintain those north westerly winds from the weekend. With low pressure sitting north of us we will see some rain pushing into Scotland on Monday / Tuesday but other than that we look like remaining dry for the week as high pressure resists both westerly and easterly low pressure systems. Temperature-wise I think we will sit in the low double figures and maintain reasonable night temperatures because of cloud cover. We look to lose the wind next week so that means quieter days and depending on cloud cover, the risk of dew becoming an issue.

Now towards the end of next week the GFS and ECMWF models begin to disagree with the former showing high pressure still sitting over us whereas the ECMWF model suggests that low pressure will begin to push in from The Atlantic at the end of next week so that means a change in the wind direction to south westerlies and a more unsettled picture emerging as we come into the weekend at the end of March. Either way I think we will check out of March with a pretty low GDD / G.P figure and that’s what I want to talk about next. My hunch is that we will see out March unsettled but with a milder airstream.

Agronomic Notes

So we have some drier weather this week with better temperatures before cooling off. Just what the doctor ordered if you’re looking to dry down your site in order to get work done before opening (England). Of course in Wales, facilities got all of 18 hours notice at the end of last week before they opened. Some I know where in the middle of aeration, others were far too wet to open anyway, Covid restrictions or no Covid restrictions. A bit of a farce that one. In England we know the clock is ticking down to the end of the month.

So let’s look at growth prospects from now to then in a few different locations across the U.K & Ireland summarising data so far and using projected data up to and including 28th March, 2021.

Now I’ve picked a number of locations at random and of course you have to allow for inaccuracy projecting forward but since we are talking a predominantly stable weather pattern, I don’t think these values will be a million miles away….

Here’s how it looks ;

So you can see the short-lived peak in daily G.P that we enjoy this week in some locations but even at the warmest projected location (Mallow, Ireland), we still are only just hitting 0.4 daily G.P, which I would rate as good daily growth. Then we you look at the total projected G.P up until and including the 28th of March, you can see that there isn’t a lot of difference between the locations with the highest coming in at 4.91 (Thame) and the lowest, 3.06, for Bolton. When you consider that the maximum total G.P for 28 days = 28 (optimum daily G.P = 1.0), then we are looking at 11 – 17.5% of optimum growth for March, so in other words, March 2021 looks to be heading the way of March, 2020 in being a cool month. All things point towards a late spring this year.

Strategies for optimum growth

Bearing in mind the first half of this month has featured alternating low and high pressure and plenty of rainfall, then we have to assume that granular fertilisation is more efficient than trying to make liquid applications when wind speed levels have been high and in some places it’s very difficult to move application equipment around the golf course / sports facility because of ground conditions. In general, granular fertilisers are more resistant to leaching and more persistent in terms of offering consistent nutrient availability to the grass plant, though a lot depends on the N source.  So let’s assume you have a low N, cool-temperature available, granular fertiliser on already. I’d expect to see a nice growth increase for the first half of this week but thereafter this response will drop back as temperatures decrease for the 2nd half of the week.

We have to be realistic then that trying to promote more growth (for disease and / or aeration recovery) is going to be pretty limited when we have a daily projected G.P level hovering around 0.2 per day till the end of the month.

During spring high pressure periods, the air temperature will often rise more than the ground temperature, especially on heavier soils which hold more water and are slower to warm up. We can take advantage of this phenomenon by applying a low N foliar to the grass plant to ensure optimum nutrient availability on a ‘little, but often’ basis. Combining this with a liquid iron provides a nice cosmetic effect, especially as some clubs approach opening their doors at the end of the month and some are already open. Low rates of foliar N, 5-6kg / N/ ha based on cool-temperature available nitrogen forms like ammonium sulphate and potassium nitrate are perfect for the type of weather pattern we look to have for the second part of March. That said, don’t expect lots of clippings / recovery because growth will be temperature-limited.

Disease activity

I had a number of reports last week of Microdochium disease activity due to some lighter winds, dew accumulation and milder temperatures overnight on the 10th and 11th March. I would expect to see a little more in the first half of this week in those locations that are set to enjoy the milder temperatures but as the temperatures drop and winds pick up towards the end of the week, this should back off as well.

A bit of patience will be required

It is going to be one of those springs that requires patience, last March was the same. For the Thame location in 2020, we hit 4.74 total G.P for the month, so I expect March 2020 and March 2021 to be pretty similar in a lot of locations. That said, April 2020 started off with temperatures hitting 20°C in the first week and we ended up with a total monthly G.P of > 14, so a much better growing month.

That’s an indication of how fast things can change. Till then I think it’s ‘slowly, slowly, catchee Monkey’ (Old English proverb), so I don’t think I’d be embarking on anything too radical in terms of shaving down cutting height, lateral aeration and the like, until we see some discernible improvement in growth prospects.

All the best.

Mark Hunt