October 30th, 2023

Hi All,

As we reach the end of October, we can reflect on what has been an extremely wet month. Here in The Midlands, a wet month means anything over 100mm, currently we are sitting at 131.8mm for the month, with a big chunk of that courtesy of Storm Babet.

The bad news on the rainfall front is that we have something equally significant and potentially worse heading our way in the form of Storm Ciarán and perhaps as importantly (but currently ignored by the media) another low pressure system that will follow almost immediately after it. The combination of the two will I feel cause some really bad flooding events I am afraid.

Recently I wrote an article for Pitchcare magazine about how to spot a potentially damaging, low pressure system. I called it "Spotting a Wrong Un".....well this week we have one, arguably two 'wrong uns' heading our way and we must prepare for this event.

Although we will see rainfall totals change on a daily basis on the run up to Storm Ciarán I am going to devote this blog to detailing what we have coming and where it is likely to affect worse as it stands early on a Monday morning.

All images courtesy of tropicaltidbits.com unless otherwise stated

As we start this week, the scene is set for the arrival of Storm Ciarán, with a low-lying jet stream (dark green band) allowing Atlantic low pressure systems to slot in and form the characteristic trough pattern in the jet stream that we now associate with slow-moving weather systems and very high daily rainfall totals. So the start of the week is the most settled we are likely to see the weather this week in terms of both wind and rainfall although showers of rain will be with us from the off this week.

By 18:00 on Wednesday, you can see how the situation is developing. So from Tuesday onwards across Ireland, we will see winds begin to crank up from the south west and rain, some of it heavy pushing into the south west of Ireland and England and then moving north east across both respective countries in the second part of the day. The wind direction will ensure it'll be mild as these weather systems push in. The presence of 2 low pressure systems is key as you will see shortly.

By Thursday 03:00, the two low pressure systems have merged to a formidably strong storm system which is Storm Ciarán. Look at how tightly packed the isobars are. This indicates extremely high wind speed from the south / south west initially on its leading edge and northerly on its trailing edge. The estimates are wind speeds up to 90mph as this storm tracks along the south of Ireland and south of the U.K on Thursday.

Together with this wind, there will be some very heavy localised rainfall, with high rain rates (measured in mm per hour). The graph above courtesy of Meteoblue.com shows a projection of 03:00 Thursday, with the main areas affected across Ireland being Cork, Wexford and Wicklow, possibly pushing up to affect Dublin (remember the exact track may change between now and then). Wales, The South West, the south coast / south east of England are also in the initial firing line.

During the course of Thursday, the storm tracks along the Irish and English coast and then moves northwards across East Anglia and the east coast of England, which means the heavy rain will move through The Midlands and north of England.

It is clear to me that Storm Ciarán is currently projected to follow a similar path to Storm Babet and so we are very likely to see bad flooding. Not least because slow-moving means high rainfall totals and because the rain will now be falling on saturated ground with river levels still tracking higher than normal after some rain last week. Saturated ground means there will be less ability to soak up the rainfall and it'll flow much faster into ditches, streams and rivers. As the storm moves north on Friday, it'll affect the north east of England and east of Scotland, the latter an area seriously affected just a short while ago.

A concern.....

The biggest concern to me is that very shortly after Storm Ciarán has moved across the U.K, a new low pressure system will follow it, impacting a very similar area across the south of Ireland and England during the course of Saturday. The only saving grace is this one will move a little faster and so hopefully rainfall totals will not be as high but it will falling on saturated ground with river levels already at a maximum.

This Prodata report snippet taken from a golf club in Central England shows the issue with slow-moving low pressure systems such as Storm Babet and I think Storm Ciarán.

It isn't just the rainfall total per day that is high but also the rain rate which would be classified as violent rain on 2 out of the 3 days (> 50mm per hour rain rate)

Weather Outlook - w/c 06-11-23

As you can see from the GIF above, next week is projected to continue the run of windy, wet and cool weather with a strong westerly wind and still a low-lying jet stream position. The synopsis is therefore, for the unsettled and cooler conditions to continue next week until next Thursday / Friday, when a weak ridge of high pressure looks to build and provide a very welcome drier and more settled period, with mist / fog and perhaps some frost.

Agronomic Notes

Agronomically, sitting here on a Monday morning, there is very little I would advise to do now other than communicating what is potentially down the line this week and coming weekend.

The agronomic reality is pretty much in line with what I talked about last week.

Put simply, this is what we do aeration and topdressing for.

To move water effectively through the profile to facilitate a dry and firm surface. The problem of course is the sphere of influence of this process with the bulk of the aeration and topdressing targeted at greens, tees and approaches in a golf course scenario, with fairways and roughs largely down to the native soil type combined with vertidraining and the hopefully some lateral drainage. Very few facilities have the budget to topdress fairways and so it is often this area, along with the semi rough and rough that prevents the course from being playable, long after a storm event such as the one I have described. It is also causes issues with Buggies and their ability to be utilised on a golf course.

High Rainfall - Low E.T - a bad combination....

The other part of this weather dynamic is that with shortening days and longer nights we have a steadily decreasing E.T process. So drying down of the surface, drying down of worm casts for example, so they can be more easily brushed into the surface is a much slower process.

Below is a summary for October from the same club using a soil moisture deficit / surplus report from Prodata Reports ;

You can see quite clearly how far the balance is tipped in favour of rainfall and wetter ground conditions and away from dry down with the soil moisture deficit / surplus equation.

So far this month this particular location is sitting at 116.2mm of rainfall with only 24.94mm of E.T.

That is the reality of shorter days, less E.T, less dry down and sometimes, more intense rainfall.

It is this that has to be communicated effectively to management and membership alike when the familiar "Why is the course so wet?" scenario raises its ugly head.

It is tempting in a quieter moment maybe, to think the utterer lives in a hermetically-sealed container with no ability to understand anything outside of what must be a very narrow frame of reference (and I am being very kind here).

"What do you mean the greens are flooded ?"

I heard this scenario recently, spoken to a golf course superintendent standing right in front of me, when the course had just received 21mm in the past couple of hours and the said person had just driven through the same rainfall, the same puddles, the same flooded roads that I had, to get to the golf course !

It is no wonder that sometimes golf course superintendents and groundsman alike follow a thought process that leans heavily towards an alternative career pathway :(

Dealing with weather scenarios like I have detailed above for this week, making the course or facility as resilient as possible when they occur and trying to future proof the same for repeat scenarios in the future is all in a days work for a modern greenkeeper or groundsman.

Without a doubt 'some management' and 'some members' need to consider this fact more before they find themselves in a scenario when no one wants to do the job that they berate.

All the best most sincerely for the coming week.

Mark Hunt