November 1st 2021

Hi All,

Pinch, punch, first of the month and all that…..

I love autumn colours, especially in the park behind my house. This picture was taken on Saturday after the rain went through. It looked very different the next day however when this low pressure moved through !

Image courtesy of Netweather

October certainly went out with a bang with an intense low pressure system and reports of tornado’s in Northamptonshire. I was amazed to read that the U.K has the most tornados per size of land mass in the world and is in the top 5 of most tornados per year. Well yesterday’s weather was just amazing to behold. I was running Rutland’s beautiful peninsular but it wasn’t so beautiful when I was there as the wind and rain really hampered my efforts (well that’s my excuse for a slow run anyway). I just got into my car and was driving back home for a well-deserved Coffee and Rundstykker (Danish breakfast rolls toasted with poppyseed) when all hell broke loose. The heavy rain intensified and the wind gusts were so strong it was picking water up from the road. Amazing. The high wind and rainfall was contained in the cell circled in the rain radar map above which moved south to north.

A tad ironic don’t you think then that trains out of Euston Station up to the COP26 Summit were delayed due to the violence of this storm bringing down trees and flooding areas of track. Maybe someone is trying to tell them / us something ?

Continuing the bad news, Greta Thunberg made it.

The more I think about our weather and how it is changing, the more I look for data on rain rate because that’s ultimately what affects our day to day work the most. For sure 25 mm of rain is a wet day for the U.K & Ireland, but if during that wet day some of the rain falls at > 100 mm / hr, that’s the part that overwhelms the ability of the rootzone to drain, that’s the part that causes your bunkers to wash out. Even if it’s just for part of a 15 minute period. So rain rate will I think become as important as rainfall in general when it comes to managing turf surfaces and kitting our stall out accordingly with respect to drainage. I’ll be highlighting this later in the blog.

GFS output 01-11-21

General Weather Situation

As predicted last week, we will start this week with that low pressure system located over the north of the country so that’s where the majority of wind and rain will be, but not exclusively. As the low is heading north, its trailing edge will scoop showers down on a noticeably chillier west / north west wind across Ireland, North Wales and the north of England and Scotland with heavier rain for North Wales, the north of England and Scotland. Most of this rain will stay north of The Humber but some showers may make it into The Midlands this afternoon. So an unsettled, cooler day for many, dry in the south of the U.K and the same for Ireland, with a reduced risk of showers. Temperatures down into the high single figures for Scotland and just nudging into double figures for Ireland, Wales and England, with that moderate to strong, westerly / north westerly wind the culprit.

Onto Tuesday and that low pressure continues its march northwards and by Tuesday morning its centre will be just off the Swedish coast. This still means there’s some rain in the weather picture but nothing like Monday’s or the weekend’s for that matter. So Tuesday morning will see some rain across The South West of England but they’ll also be showers on the western / north western coastline of the U.K & Ireland. Some of these will push their way inland, particularly the further north you go, with some making it into Central Scotland, but on the whole, a drier day with a noticeably calmer feel to it as the wind drops away. Staying on the cool side though, well it is early November so we should expect that, with 10-11°C, the norm.

Midweek and a cold start with temperatures well down into low single figures courtesy of a wind direction change to northerly overnight. A mainly dry day again with probably more in the way of cloud. Still with the threat of showers along the north and western-facing coastline of Ireland and the U.K, with some additional rain lurking out in The North Sea close to The North East. That cool north wind will keep temperatures pegged back into high single figures and with the enhanced cloud cover, it’ll feel right chilly like with a nagging wind chill as the wind gains strength through the second part of the day.

Thursday arrives and we see a ridge of high pressure pushing in from The Atlantic but as always with the leading edge of an Atlantic high, the result is a northerly wind, so staying cool for Thursday despite this. A dry day again with just a risk of some showers down across the coast of The South West but on the whole, dry, cool and dull with that pronounced northerly wind keeping those temperatures pegged back into single figures. The step down in temperatures that we used to get in early December has most definitely arrived. As skies clear later in the day, temperatures will drop overnight so don’t be surprised to have a ground frost on Friday morning dependent on cloud cover.

Closing out the week on Friday and a much sunnier affair is on the cards, with a dry, cool and sunny day in prospect. That northerly wind will lessen in intensity and start to swing round to the north west / west, so feeling warmer despite the continuing cool start to November (less wind chill). The only fly in the ointment is right up across the north west of Scotland where an Atlantic low pressure will push in some showers to coastal areas through the course of Friday. Otherwise, cool, dry and uneventful with temperatures in the 9-10°C sort of area.

So how does the weekend look, nice and autumnal or unsettled ?

Well on Saturday that northerly low pressure system will push rain down into the north west of Scotland and then it’ll continue south down the north west of England and into northern England and Wales before frittering out. Similarly they’ll be showers across the north and west of Ireland and these will cross the country through the day, but lessen in intensity as they do so. By late evening we may see some of those showers down into The Midlands and further south but they’ll die out overnight into Sunday. So Saturday will see a slightly unsettled theme, staying on the cool side with similar temperatures to Friday though much milder overnight due to the increased cloud cover. A strong to moderate south westerly wind in situ. By Sunday this wind will be dying down and we will have a quieter day. Still with the threat of showers though across the south of England and Ireland, with these showers moving north through the day into Wales. Remaining cool with the wind swinging back into the north west for many so despite some sunnier interludes, it’ll stay around 9-10°C. Through the second part of Sunday, there’s a risk of heavier rain for a time across Connacht before this drifts off northwards.

GFS Output 08-11-21

Weather Outlook

Ok, so this is how we are due to start next week on my birthday actually. Happy birthday to err…me 🙂

So we have that troublesome North Atlantic low pressure off to the north west and high pressure pushed further south. Which one will dominate I wonder ?

Well at this stage, it looks like low pressure, with Monday promising to start off wet and very windy across Scotland and through the course of the day that rain will push across Ireland, Wales and England. Less rain reaching the far south though but windy certainly. Onto Tuesday and overnight, a more southerly low pressure is pushing in from The Atlantic bringing rain for Ireland and by dawn, the southern half of the U.K. So Tuesday looks a bit intense, wet and very windy like, with the wind from the south west. That windy and unsettled theme continues through to Wednesday with another front of rain crossing the U.K overnight. Continuing windy and wet then through mid-week but as we approach Thursday things calm down a little with lighter winds and drier for a time. Drier for a time because in the second half of the day we will see more rain into Ireland and Scotland and pushing eastwards on a cooler wind I think. We should finish the week, quieter and drier hopefully.

Doing a bit of Mystic Megging, there is a warm high pressure showing on the long range output due for the middle of November (16th, 17th onwards). If this comes to pass and it might easily not, it may represent some significant disease pressure. One to keep an eye on for sure.

Agronomic Notes

I intend to do a full GDD / G.P / Rainfall review of October next week but for now here’s a snapshot looking at our standard location in Thame, Oxfordshire.

So here October 2021 checked out with a total GDD figure of 186, that’s towards the top end of the pile but by now means as mild as we have seen of late, with 2017 being our warmest. The devil is in the detail as usual though because we picked up some pretty mild night temperatures during the month which fueled some disease pressure but maybe not as much as expected thankfully.

Cumulative for the year though, at 1743 total GDD, we still lag behind some the warmest years, a good way behind actually courtesy of the cool spring (April in particular) and a cooler August as well. We are going to be going some to reach the magic 2,000 mark of total GDD for the year and we will likely be cooler than 2020. Not quite what the rhetoric is saying on increasingly warmer years is it ? Of course we know the reason why and it is because of our geographical location and the important part the jet stream plays in our climate.

We won’t follow the trend for sure but we will have more extremes, of that there is no doubt in my mind.

Storm cell 31-10-21

Bunker wash from a summer downpour

Talking of which I promised earlier to highlight the subject of rain rate (in mm per hour) and how it really tells more of a story from a turf management perspective. So yesterday we had a heavy rain day, nothing too surprising about that in October but as mentioned above we had an intense ‘storm cell’  (highlighted above after it had passed through my location) and it brought a short period of intense rainfall.

Here’s some stats from a Davis Vantage Pro weather station situated south of Birmingham and it highlights the point I’m making about rain rate rather than rain total being the key to some of our maintenance dilemmas (do you know I always thought that was spelt with a ‘mn’ and not an ‘mm’)

So first up here’s the rainfall totals falling in a 15 minute interval across the day leading to a total of 22.8 mm for the day

Rainfall in mm per 15 minute interval – 31-10-21 – Birmingham

You can see how the main rain event took place from 06:15 am through to 10:00 am with a peak rainfall total of 5 mm falling between 09:30 and 10:00. It doesn’t really look that dramatic does it and there’s certainly nothing to suggest it would cause an issue on a golf course or sports pitch / race course from a flooding perspective ?

Now let’s look at the rain rate in mm per hour for the same location and the same time period using data from the Davis VP2.

Rain rate in mm per hour per 15 minute interval – 31-10-21 – Birmingham

Aha, a bit of a different story now then with a peak rainfall rate of 106.6 mm per hour taking place between 09:30 and 09:45. So even if only 2.4 mm of rain fell in that quarter of an hour period, it was this part of the rainfall event that would have overwhelmed drainage rates on most surfaces and for sure contributed to localised flooding of turf surfaces and bunkers alike.

Looking at the rain rate data for this location, you can see how it pans out across the month when 136 mm of rain fell at this location ;

Rain rate in mm per hour per 15 minute interval – October 2021 – Birmingham

So 4, arguably 5 high rain rate events for the month, with 2 occurring in the last two days of October and at the weekend as well 🙁

Tightly-compressed surface organic matter is the enemy regardless of %

I’m sure some wag will comment that their particular rootzone drains at a far better rate than that or was designed to anyway, but hypothetically I might counter-comment that that was before you plonked organic matter on the top of it.

Obviously it’s that top 25 – 50 mm that is the initial impediment to rainfall / water movement and here then the ‘nature’ of the organic matter has a key part to play. I know we measure % organic matter as part of benchmarking our surfaces but critically it is the ‘nature’ of that fibre that really points the way in the above respect and many others. For example we may measure 4.5% organic matter in the top 0-25 mm but if that represents the top 12 mm being tightly packed organic matter with next to no topdressing through it to create porosity and allow air and crucially water movement, it isn’t particularly useful information. The % figure may seem right, but the performance of the surface may not reflect this.

Time for a ponder on this one….

Ok that’s it for this week, enjoy the cooler weather 🙂

All the best.

Mark Hunt