February 8th

Hi All,

A bit of a change this week from last week as you can see from the pic I took of the park behind me this morning, last week, wet and mild, this week, snow and freezing temperatures with a wind chill around -8°C here currently and even lower further east. Hats off to GFS forecasting because they called it right more than 7-10 days ago. I’ll take this any day of the week in February when we are locked down market-wise and need some proper cold weather to break the seemingly endless pattern of Atlantic low pressure systems that has been in place since November.

The next question is how long will this last ?

General Weather Situation

So this week we start with cold, bitter conditions across the east of the country with widespread snow showers pushing in off The North Sea. Yesterday the east and south east got a dumping of snow as well. Through this morning the snow showers will continue to push in the length of the U.K from Kent to the tip of north east Scotland and some of these showers will push inland past The Midlands where it is currently snowing. Further west you look to avoid the snow but the bitter cold theme continues with some snow showers across North Leinster on the radar for Ireland. This pattern is set in for the day with frequent snow showers affecting the eastern half of the U.K, a strong easterly wind and a bitingly cold wind chill. Expect temperatures around freezing most of the day in the snow band and 2-3°C further west.

Overnight into Tuesday and we will see a repeat of those snow showers for the eastern half of the U.K, however they look to be more restricted to the eastern coasts rather than pushing inland. A hard frost overnight so anyone who got snow over the weekend and on Monday will see it set in for the week I think in terms of ground cover. A bitterly cold day despite plenty of sunshine for western areas with temperatures struggling to get above freezing most of the day and a negative wind chill in for the day. Under those clear skies we will see temperatures fall away quickly and another sharp frost is expected though Ireland may stay above freezing.

Onto Wednesday and more of the same with the wind taking on more of a north easterly aspect. Still some snow showers predicted to affect eastern and north eastern coastal areas but otherwise a fine, bright and again, bitingly cold winters day. Again likely to stay below freezing during the day for central and eastern areas with temperatures nudging up a little across Wales, The South West and Ireland. but we are only talking 1-2°C here. With clear skies across the snow fields expect another sharp frost across central and eastern areas.

Overnight into Thursday, the wind will strengthen from the south east across Ireland and we will see an Atlantic front try to push in early doors, whereas across The Irish Sea into Wales, England and Scotland we will see lighter winds, a hard, hard frost and another very cold winters day.  Temperatures may just pick up above freezing across south and central areas of the U.K through the day on Thursday, the same for Scotland. For Ireland, that rain will push into Kerry early on Thursday morning and will meet the cold air turning to wintry showers over higher ground. During the morning this band of rain, wintry showers and snow will push north and east, so moving up the coast into Galway and Sligo, but also inland across The Midlands and into the south and east of Ireland. As we go through the afternoon, it’ll become more wintry in nature and reach the east coast of Ireland, so wintry showers here as well. A little milder everywhere with that change in wind direction but I’m only talking a marginal gain here in temperature up to 3°C maybe across Ireland and the west and a little lower across central and eastern areas of the U.K. The wind will be stronger on Thursday and from the south east.

Closing out the week on Friday, we have that band of wintry showers running up the east coast of Ireland on Friday morning and into the north. Across The Irish Sea, there will be some showers across The South West from first thing. These wintry showers along the south and east of Ireland are likely to stay for a good part of Friday and they’ll also be some rain / wintry showers pushing in from the south west into Kerry. For the U.K, we should see those showers across The South West drop off through the morning so Friday looks to be a cold day with some winter sunshine but also plenty of cloud cover and with a strengthening south easterly wind.

The outlook for another fun-filled and challenging lockdown weekend looks like being cold, bright and bitingly cold with a continuation of night frosts, a negative wind chill and the occasional snow shower across eastern coasts. For Ireland we will see an Atlantic front push into the west of the country on Saturday bringing rain and milder temperatures. This will push inland but is expected to be confined to the west side of the country with some heavy rain continuing into and through Sunday. During the 2nd half of Sunday the rain will push eastwards across Ireland. Across The Irish Sea to the U.K and Sunday looks bright, cold and sunny after another hard frost. The wind will strengthen as we go through Sunday across the southern half of the U.K with a strong south easterly in situ.

Weather Outlook

So quite a complicated picture for next week as you can see from the GFS output above with an Atlantic low pressure trying to push in from the west and a cold high pressure over the continent. As is usually the case when we get stuck between a low and a high, the wind funnels up between them and increases in intensity. So you can see for the start of next week, we have some tightly-packed isobars with strong southerly winds for Ireland and south easterly winds for the U.K. Now up until this point this winter, I’d be saying that the Atlantic low pressure will push in bringing milder air and rain for Ireland initially and then the rest of the U.K, but maybe not this time. That high pressure over the continent will serve to keep this low pretty much at bay so we won’t see a return to mild, wet conditions next week though the west is likely to see some of this rain. So Monday will indeed start wet for the west with rain and wintry showers for Ireland and these will push into The South West of England, Wales but maybe not a lot further east. This pattern of rain, wintry showers for the west and dry, cold for central, northern and eastern U.K will continue through Tuesday but as we go through Wednesday we see high pressure exert itself and push that moisture away from the U.K and Ireland and back into The Atlantic. For Thursday and Friday next week that Atlantic low pressure pushes bands of moisture across Ireland and the southern half of the U.K and I’m thinking that this will mainly fall as snow as it comes eastwards and the wind swings more easterly. By the weekend (21st Feb) we could be back to an easterly wind direction, cold and snow showers !

So next week, starting wet and milder in the west but staying cold (though maybe not as cold as this week) across central, northern and eastern parts of the U.K. As we progress through the week, colder air pushes back in along with easterly winds and an increased risk of snow showers. So we don’t seem to be letting go of winters grip anytime soon with the long-long term prognosis suggesting the possibility of colder air staying around up until the end of February. (long-long range forecast caveat included)

Agronomic Notes

Monthly Summary – January 2021 – U.K Locations – Rainfall and Growth Potential

So for 2021, I have decided to summarise total monthly Growth Potential instead of GDD, because it gives me and hopefully you a better handle in terms of how this compares with optimum over the course of a month.

As I discussed in January, the major issue with using GDD is that there is no ‘top out’ facility for potential growth, whereas the Growth Potential formulae has an optimum temperature for growth and a finite scale from 0.0 -1.0, where 1.0 = optimum growth potential. We know that if we see a G.P = 0.0, there is no growth, 0.2 means from a temperature perspective, the plant can grow at 20% of optimum (0.2/1.0) and so on. If we extrapolate across a month we know the optimum total G.P in any one month will be between 28 and 31. So for example in January, we have 31 days and theoretically the optimum growth for the month would be 31 (31 days x 1.0). A 30 day month would have an optimum growth potential of 30 and a 28 day month, 28. I’m sure you get the picture.

So when I show you the graph above, you should be able to quickly see that as a growth month, January 2021 was pretty poor. The highest total monthly G.P figure we got was from Matt down in Jersey at 4.7, but even this is nothing to shout about because when we work out the % of optimum across a whole month (4.7 / 31 = 0.15), it is only 15%. If we look at the lowest total from Fife, at 0.6 for the entire month, that comes in as 0.019, in other words 1.9% of optimum (0.6/31) . So we know that the grass plant in Fife was pretty much dormant in January 2021. We can make these assumptions using Growth Potential but can’t across a whole year with GDD because we know that in the summer, GDD will keep on increasing, whereas G.P will reflect periods of the year when it is too hot for grass growth.

January 2021 – Daily Growth Potential and Rainfall – Norwich

If you look at the graph above which is showing daily rainfall and Growth Potential from Norwich, in the east of England, you can see how the stats panned out for January 2021 on a daily basis.

Indeed if we use a daily G.P = 0.4 to reflect a good growth day in the spring (40% of optimum is what I’d call a good growth day from a G.P perspective in spring), we can see that the daily G.P only got close to this on one day, the 20th of January, when that location recorded a lowest day temperature of 9.21°C and a highest day temperature of 11.58°C. So that was it, one good growth day in January 2021 for this location.

Even for Matt down in barmy Jersey, he only recorded 6 days when the G.P was > 0.30 and no days when > 0.4. Not great when you’re still open, getting lots of daily play and you also have 118 mm of rain for the month !

Monthly Summary – January 2021 – Irish Locations – Rainfall and Growth Potential

So looking at the Irish data we can see that January 2021 was broadly similar to conditions across The Irish Sea with the lowest total monthly G.P figure for Cavan at 1.7 vs. the highest for sunny Valentia (not) at 4.85. A pretty similar situation I think you’d agree to the U.K locations listed above both in terms of low growth and high rainfall.

If I pick one location, Wexford, we can see a similar growth or lack of growth graph.

January 2021 – Daily Growth Potential and Rainfall – Wexford

So you can see that there were no days during January 2021 at the Wexford location when the daily Growth Potential exceeded 0.4, so no good growth days and only the 19th of January came close at 0.31. Like other locations we also see a bunch of rainfall with 144.5 mm recorded for the month falling over 24 wet days. That translates to 77% of the month.

Recovery from disease scars and January aeration work 

Quite a lot of clubs / facilities have undertaken aeration during January to take advantage of the absence of golfers and lockdown period. Quite understandable. Obviously putting the stats up above isn’t the greatest reassurance to you that things will be ticking along from a recovery perspective but as with all things I think we have to be realistic. Most clubs are working with restricted staff numbers, rotating crews, etc. and so even if we had weather windows to sand topdress and fertilise to speed recovery on, it wouldn’t easily be achievable, especially when you think about other jobs that need doing as well. (reinstating bunkers and drainage to name but two)

January can be a reasonably good growth month, last year for example, we had a total monthly Growth Potential in the range 5-7.0, with 6-7 good growth days, better than 2021 true, but not outstanding. The year before that (2019) was similar to 2021. February to me is usually the coldest month of the year and the month most likely to represent winter. The fact that last year we already started to see air temperatures in the teens by the middle of the month was unusual. This year will likely be true to type, i.e. a bloody cold month.

So I guess what I am saying is that I still would have done the work in January even if I knew what was coming weather-wise because the work is done, some degree of recovery is on the way and you are set for the spring. The chances are we will waltz from winter to spring to summer in a blink and I’ll soon be talking about E.T, lack of rain and slow recovery due to drought 🙂 Difficult to believe I know as I look out of the window at the snow coming down but it wouldn’t surprise me 🙂

2021 GDD Spreadsheet

Hands up time from me I’m afraid and time to wear a hat with a ‘D’ on it and sit in the corner of the room.

I made a couple of mistakes when I published the 2021 GDD spreadsheet in January 🙁

First up, one of the calculations was wrong (cumulative G.P) and the column for this was missing off the summary page. There was also no monthly G.P chart present in the charts tab of the spreadsheet because the Smith Kerns one had over-written it. All ‘my bad’ as they say, humble apologies, less haste, more speed from me I guess and maybe this year I’ll start work on it in November rather than early January !

You can cut and paste the data straight from your existing spreadsheet into the new version which is available here

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OK that’s me for another Monday, wrap up well, keep safe and healthy…

All the best.

Mark Hunt