February 1st

 

Hi All,

First up, sorry for the blog not arriving yesterday. Our hosting site went down repeatedly through the day to the point where it was better for me to do something else and come back to this today 🙂

Well that’s goodbye to January and when I look at the combination of lockdown and weather, you’re welcome to it as a month. The first day of February today and to me the last month of winter proper so not long to go now before spring and hopefully some better news on many fronts. The good news potentially on the weather side is that the pattern for February looks potentially drier, still cold with easterlies but crucially drier and by heck we need some dry down time.

Normally at this time of year I can look out of my loft office window and see a few puddles in the park. These come and go usually at the wettest part of the winter. This winter, like last winter is different. The puddles have now formed into a small lake, the children’s play area has a semi-permanent water feature and it has been this way for weeks now. Market Harborough isn’t anywhere close to being a wet part of the country, we are in the middle of England so the rain has to travel a long way overland before it reaches us. Nevertheless, our fields are sodden, our rivers are at the top of their banks and this winter I’ve seen water where I’ve never seen it before and I’ve lived here since 1969. It is easy to pull out the old ‘climate change’ discussion from the top drawer and of course some wag will point to a time when it flooded in the past, but like this ?

Winter months are now seemingly characterised by their lack of dry-down days and near continual rainfall as low after Atlantic low pushes into the shores of the U.K & Ireland. Point of fact if we didn’t have a lockdown, most golf courses and sports facilities would be closed anyway due to either snowfall or waterlogging.

I’ll be looking at the stats on dry-down days or the lack of later in the blog because it’s pertinent to what we do.

For now though onto the weather and what looks like a change in the jet stream pattern and the potential for some of those very rare creatures…..dry days !

General Weather Situation

So as we can see from the GFS output today we have another Atlantic low queuing up to bring a wet, windy and mild start to the week for the southern half of the U.K & Ireland, but further north this will be characterised by colder temperatures and snowfall. So Monday looks to start already wet for Ireland but the first tranch of rainfall looks to head slowly north and east across Ireland and not make it across The Irish Sea. So it looks like being mild, dull and drizzly at times for the southern half of the U.K before brightening up and cold, bright and frosty for the northern half. Ireland sees that rain move north and east, clearing the south and west of the country through the afternoon but later we see the main body of rainfall from that low pressure push into Kerry at around dusk. Not a great deal to shout about temperature-wise, 3-5°C for the U.K, but milder under those south west winds and rainfall across Ireland with 6-8°C likely. South east winds for the U.K.

Overnight that band of rain pushes some heavy pulses across the south west / west of Ireland and also makes landfall across Devon & Cornwall before pushing north and east across the U.K. Where this band of rain butts up against the colder air across northern England, it’ll readily turn to snow. By dawn on Tuesday, this band of rain will cover the southern half of the U.K but also extend up the north west coast of England into Scotland. It’ll have cleared the south and west of Ireland as well. As we go through Tuesday morning, this band of rain and wintry showers will clear the south and south west of England, Wales and push north and east falling more readily as wintry showers. Ireland will see more rain push into the south and west by lunchtime unfortunately. By mid-afternoon, Ireland will be pretty much covered by this rain front and it’ll also have moved across The Irish Sea into The South West, Wales and the western half of the U.K, joining up with the wintry front sitting over northern England and southern Scotland. During Tuesday night, this rain, wintry showers mix pushes eastwards but may clear the south and south east of England as it does so. As this rain front pushes in the wind will switch from south east to south west and that’ll pick up the temperatures markedly with double figures likely across the southern half of the U.K and Ireland. Across the north and Scotland, that colder air mass will stay in place and so here we will see more like 2-4°C and snow.

Mid-week and that low pressure is still sitting west of Ireland but it joined by a Bay of Biscay one that will pull rain into the south coast of England from dawn, some of this rain may be heavy. Ireland looks to start dry on Wednesday save for some showers across the west. Scotland hangs onto that band of wintry showers and snow for the third day running which means significant accumulations are likely. During Wednesday morning, we see rain push more into central / western areas of Ireland and that front across the south of England will move eastwards leaving a dry gap from London up to The Humber I’d say. Through the afternoon, we should see some sunny intervals develop across central England, Wales  but North Wales, the north west of England and Ireland and Scotland looks to hang onto that wet weather, be it rain, wintry showers or further north, more snow. So not a bad day for some in the south and Midlands of the U.K and Ireland, 8-9°C with sunny intervals can’t be sniffed at for February, but more like 2-4°C for Scotland. Winds will be predominantly westerly.

Thursday sees a reasonable chance of a dry start across Wales, England and Ireland whereas the north west of England and west of Scotland hangs onto that band of wintry showers for yet another day. Through the course of Thursday morning we will see rain showers into the south west of Ireland and England and these will push north and east slowly and a continuation of those wintry showers across Central Scotland though these may fall more readily as rain. Through into the afternoon that rain across The South West pushes into Wales and the rain across Kerry pushes up into Clare and Connacht, falling as a mix of wintry shower, snow and rain. Again central England and the east gets off lightly with another dry start but as we go through the day the wind swings round to the north east and that’ll knock off the milder air for the time-being. So showers across the south and west of Ireland turning more wintry through the afternoon, the same for Wales and the south west of England and finally the rain, wintry showers, snow band pushes into the north east of Scotland on its way out. Temperature-wise, a bit cooler for England, Wales and Ireland as that wind shifts round to the north east with 7-9°C likely, but still 2-4°C across Scotland.

Closing out a pretty mixed up week on Friday sees a day of sunshine, cloud and wintry showers with a bracing north easterly wind for all areas with plenty of wintry showers running across both the southern half of the country and up the east coast. The same for Ireland. Probably fair to say the most showers across The South West and Wales and the North East of Scotland. A much colder day down south on Friday as that chilly north east wind pushes cold air down from Scotland, dropping temperatures markedly. Plenty of winter sunshine between the showers, particularly from The Midlands north and across Ireland.

So what’s the outlook for another lockdown weekend ?

Well in a sentence it’ll be right parky wherever you are with a really strong north easterly / easterly wind associated with low pressure sitting below us. This low pressure will rattle in some wintry showers to the east of Scotland / north east of England through the course of Saturday but otherwise a cold, wintry day with some sunshine, a strong wind / wind chill factor and the risk of wintry showers on eastern coasts in particularly. Through to Sunday this risk increases with likely accumulations of snow across The North East, East Anglia, the south east of England and The Midlands. The same is true for Ireland with Leinster in for some wintry showers and a likely Christmas Pudding photograph opportunity for The Sugar Loaf ! Scotland looks to have plenty of wintry showers across the east on Saturday but the risk will decrease as we go through to Sunday. Temperatures will struggle into the positive for the weekend, so 1-3°C tops but the wind chill will be definitely make it feel more like -3-5°C I’d say. Well Parky.

Weather Outlook

If you look at the output above you can see why the start of next week is going to continue the theme from the weekend and that is very cold winds, a biting wind chill and a continuation of wintry showers, especially for North Sea coastal areas. The development I am interested in sits above Scotland, over Iceland and is a potential blocking high pressure. Haven’t used that term, High pressure since sometime last year !

During the course of Tuesday, this northern high pressure is projected to sink southwards and as it does so it’ll turn the winds more northerly and drop their strength down a notch. By mid-week, next week we will have high pressure in place (hopefully) and as you can see from the GFS projected output above, this will serve to push any Atlantic low pressure systems north of us. So this means potentially a period of dry, cold and settled weather with night frosts likely and fog at times I’d say as well. So next week in summary looks to start biting cold with strong easterly winds, snow showers for eastern coasts and working inland on Monday, decreasing in frequency on Tuesday as the winds drop and turn more northerly. From mid-week onwards we should be quieter on the wind-front (so to speak), dry, cold and settled, which if it comes to pass will be good news for everyone !

Not that I would get too excited about it just yet but the GFS outlook beyond that suggests this high pressure will stay in place for a good chunk of time which means February may turn out to be a cold, dry month which is pretty much what we need after the near continuous rainfall that has characterised this winter.

Agronomic Notes

So how wet was January ?

Well I decided to pick out 3 locations in England, one from the south west, one central and one from the north west.

Now these locations could easily have come from Ireland such is the similarity between where the areas receive the rainfall, volumes and frequencies !

(i.e. The south west of Ireland tends to be the wettest along with the north and north / west with the eastern side usually the driest)

So here’s how it looked in January 2021….

Rainfall stats for Okehampton

Rainfall stats for Thame, Oxfordshire

 

If you look closely at the Okehampton and Thame locations, you can see they are pretty similar in terms of the days when it rained and in fact identical in terms of number of dry days (7 out of 31) and wet days (24 out of 31). The only difference is that Okehampton had one more frost day.

So the timing and frequency is the same and that makes sense because Atlantic fronts tend to hit The South West first and then either push north and east into central areas (represented here by Thame) or stay concentrated along the west and north west of the U.K. So the rain comes into the south west of the U.K first and therefore Okehampton receives a much higher rainfall total than Thame (183.9 mm vs. 95.4 mm).

Now we look at the stats for Bolton (above) and first thanks to Steve for sending these, it’s great to have some good stats from the north west of England :). So up the north west of England and we see ‘only’ 13 wet days, that’s the good news but you can see the characteristic of the rainfall in January 2021 at this location is different to the other 2 locations. Less rain days but more rain in total with 233 mm for the month and 5 days when the daily total exceeded 25 mm (1″). Here the rainfall is caused by Atlantic fronts again but instead of moving into central areas, they tend to confine themselves to the western side of the U.K, that is Wales (especially North Wales), the north west of England, Lake District and west of Scotland.

So we had 2 main rain dynamics going on in January, Atlantic fronts that pushed across the country into central areas and Atlantic fronts that stayed confined mainly to the western coasts. The latter is the reason why the daily rainfall totals tend to be higher in that the rain sits over an area (in this case the north west) without pushing through. Slow-moving or static rain fronts are as we know typical of a trough pattern in the jet stream and we had a number of those during January.

So we have 3 different locations, 3 very different rainfall totals, but the truth is all the sites will be saturated because even on the lowest rainfall location (Thame, Oxfordshire), there have been so few dry-down days in-between the rain events during and leading up to January 2021.

Lack of dry down days isn’t a new phenomenon but the reality is that during recent autumn winter periods, the % of wet days can easily top 70-80% of the months total number of days.

If we look at the Okehampton and Thame locations, you can see this pattern clearly leading up to the end of 2020, so even before we started the new year, we were extremely wet.

This amount of rainfall has a number of consequences for turf management and most (but not all) are negative.

Saturated rootzones during the winter are low in oxygen because water contains a fraction of the oxygen dissolved in it than air. (Air typically contains 21% oxygen and water less than 1%) So the grass plant which requires oxygen to breath has low oxygen availability and this can make some grass species extremely vulnerable to damage from hypoxic stress. Hypoxia is a lack of oxygen and the grass species most affected is Poa annua var. annua. In northern climates for example, where turf surfaces can spend long periods under snow and ice cover, it is well known that Poa annua tends to check out within 14-21 days due to a lack of oxygen whereas bentgrass species can withstand months of low oxygen levels before emerging healthy in the spring. Over here what we tend to see is Poa annua becomes more sensitive to stress, be that physical wear and tear (not an issue currently). applications of products that affect the ability of the plant to respire potentially or change the growth rate (some surfactants, PGR’s and fungicides though the latter is much less of an issue now than it was with some older chemistries). Even fertiliser applications can exacerbate hypoxic stress because the plant receives a growth stimulus in the form of nutrition and so increases its respiration rate but oxygen is the limiting factor and often turf injury follows. Hypoxic stress is a bit of a sneaky one because often the plant doesn’t show symptoms till a secondary factor is introduced.

Root development is also affected during periods of saturated rootzone in the winter because this is normally the time that the plant is developing good roots. Optimum rooting takes place when air temperatures are low and limit shoot growth but soil temperatures are still high enough for root growth. You can see this in practice when you turf an area in the winter. How many times have you put down turf during cold weather to see the roots develop rapidly despite the low temperatures ?

In this instance, the grass plant is able to divert energy towards rooting as a consequence. When soils are saturated with low oxygen availability, this potential to produce and develop roots is curtailed. Of course when ground conditions are like this we are not able to help the grass plant achieve better rooting in terms of deep aeration because often we cannot move machinery out on site and also the actual benefit of aeration during wet conditions is limited due to smearing of the tine profile, capping the surface and achieving less fracturing of the rootzone profile. For this reason, I am hoping that the forward forecast for a stable, high pressure February stays on track which will then allow rootzones to dry out and beneficial aeration to take place.

There is a potential benefit from saturated rootzone conditions and that comes in the form of reduced Microdochium pressure. We know that the spores of Microdochium nivale do not survive well when they are exposed to prolonged periods of cool and wet conditions. So we tend to see less active Microdochium in the spring if it follows a wet, cool winter and more active Microdochium after a cold dry winter . This happens whatever the level of frost because as we know Microdochium nivale can survive temperatures down to -20°C, so frost doesn’t kill Microdochium nivale. In fact I have a suspicion that we tend to see more aggressive disease activity coming out of a frosty period sometimes. The reduced viability of the spore of  Microdochium nivale is often seen during the winter when we look at the severity of disease attacks on push up greens vs. free-draining ones. In the early part of the autumn I think you tend to see more aggressive disease on the typical microclimate greens (shady, damp surfaces), but as we go through into the winter, this tends to change if we experience cool, wet conditions with the drier greens seeing more aggressive disease later into the winter and the early part of the spring. It goes against everything we do in a way as an industry in terms of producing drier surfaces for increased playability but unfortunately I think it is true.

Food for thought.

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All the best for the coming week, wrap up well at the weekend because that wind chill will be bitter.

Mark Hunt