As most of us sit here and contemplate another very cold weekend with heavy, drifting snow in places and severe windchill, it’s quite difficult to appreciate that tomorrow is the Spring Equinox, the date when day length and night length are practically the same.
Out cycling on Friday evening in shorts it was so beautiful and spring-like and also so difficult to believe that less than 12 hours later we would be facing an Arctic blast but that’s exactly what we got. The temperature drop as those easterlies pushed in was dramatic as output from my Netatmo shows. Yesterday the ‘high’ temperature was -0.3 °C and the windchill coming off the snow facing into the easterly wind whilst walking was eye-watering.
Looking back at 2013 when we also had a late Sudden Stratospheric Warming event, there were days (at the end of March that year) when the temperature barely rose above freezing so it’s what we should expect especially when the NAO (North Atlantic Oscillation) is so negative.
Last week, someone asked me to explain the NAO and it did make me smile as I am not and have never pretended to be a trained meteorologist, though maybe that’s my next vocation 🙂 Put simply it’s the pressure difference between the polar low pressure system and the Azores high, but you can find a much better explanation here
In simple terms I like to think of it as dictating the position of the jet stream by and large because when we have a negative NAO, invariably the position of the jet stream sinks south, allowing cold air to influence our weather. If we have a positive NAO, then the jet stream is placed higher and we tend to have high pressure dominating the weather.
You can see the predicted NAO index’s here. Just to highlight the relationship, here’s the current graphic showing the dip at the end of Feb and over the last weekend when we experienced our cold weather and snow events.
You can see from the projections that the most of the models are putting us back into a weak positive NAO towards the end of this month (though not all are, see below ), such are the vagaries of weather forecasting. On a short-term (10-day) basis there are signs that the jet stream is beginning to move more northerly and therefore back to a position where colder air from the east can’t influence our weather . It is not there yet and probably won’t be in 10 days time. Here is Unisys’s output, I’ve marked the position of the jet stream in red so you can see the progression northwards, however the cold air, trough pattern is still present.
Short-term then we are returning to more normal temperatures, medium-term there still exists the potential for cooler and crucially wetter weather to dominate I’m afraid. Just as I finished typing this, Metman James tweeted the latest NAO predictions and unfortunately it bears out my note of caution above with a return to a negative NAO in early April. I hope they’re wrong because that would mean a very cold Easter.
2018 is starting to feel to me very much like 2013, when we had a late SSW event. Looking back at our temperatures then we didn’t go into a positive NAO and westerly airstream until mid-April. That said, we all know the inaccuracy that comes with long-range weather forecasting so let’s all hope they’re wrong this time.
On a positive note, my Netatmo Weather Station has just pinged my Garmin watch to say it is recording rainfall which means the dollop of snow sitting on top of my Netatmo rain gauge is beginning to melt. The thaw has started !
General Weather Situation
Ok so enough of the ‘Mystic Megging’, when are we likely to see the back of the current snow and ice ?
Well not on Monday because it’s the last of the very cold days although it will be a much brighter day with only the far south catching some more wintry showers and snow I am afraid during this morning. So a bright, cold day on the whole with for a change some good news for Scotland in that you’ll be warmest of all areas and that’ll set a thaw on its way. As we move further west we will also see temperatures creep up into mid-single figures, nothing to shout about I know but a lot better than Saturday and Sunday and enough to start a thaw here as well in the sunshine. Currently I’m sitting at 4.2°C here so already an improvement over yesterday when we didn’t get above freezing at all. All areas will still have that strong, gusty, bitingly cold easterly wind for Monday I’m afraid, maybe less so for Scotland and that’s why the temperatures will be a little higher.
Overnight into Tuesday and with clear skies we see another frost although not as intense as the last few days, so that means temperatures will recover into positive mode quicker. So another dry day on Tuesday but with the wind swinging round more to the north-east, we will face a risk of wintry showers blowing in off The North Sea through tomorrow morning I am afraid. So cloudier and therefore duller for the east side of the U.K, but for Ireland, Scotland and the west side of the U.K, a bright and dry day with lots of spring sunshine. Scotland and Ireland again look to top out the temperatures pushing up to 8-9°C for the latter with a much lighter wind over these areas. Further south I think it’ll be more likely to be 6-7°C, cooler across the east with that cloud cover.
Onto Wednesday and again a likelihood of frost overnight but not a severe one and with a change in wind direction to north-westerly, we will see temperatures pushing up again much quicker. A change to north-westerly invariably means moisture and sure enough north-west Scotland will pick up some rain, sleet and snow over elevation from early doors, Wednesday morning. This band of moisture will push down the east side of the U.K through the course of the day and turn to snow as it hits the colder air from the continent so a risk of snow for a time before it turns to rain along the east coast possibly (it all depends on temperatures at the time) through the evening. Scotland will be the cooler area under that cloud cover and rain / wintry mix but further south and west we should get up to 8-9°C hopefully and a dry if duller day. For Ireland I think a duller day on Wednesday with some of that rain catching you across the northern counties from mid-morning onwards and then heading into Northern Ireland through the afternoon. A much duller day on Wednesday but mild like.
Thursday sees that rain push southwards overnight introducing plenty of cloud cover and some rain to the south-east but the positive flip side to this is no frost. 🙂 Scotland sees a dry but dull start as does Ireland but for the latter we will see a band of rain push in from The Atlantic mid-morning moving westwards across the country through the course of the day. This rain will reach the west coast of Scotland during the evening on Thursday. Further south and east of this band of rain, Wales and England look to miss it on Thursday through the day but overnight into Friday it’ll reach the west coast of the U.K and push eastwards. Temperature-wise with the wind swinging round to more westerly, the day temperatures will hover around high, single figures and critically the night temperatures will stay positive also, so that’s encouraging 🙂
So Friday will start dull with that overnight rain sitting across the U.K as we start the morning rush hour. It should have cleared Ireland by this time as well perhaps lingering over the northern counties, but although you’ll be mainly dry first thing, a new band of rain is projected to push in from the west, mid-morning. So a wet start to Friday for many but with a strong to moderate south-westerly wind in situ, that rain will soon move off into The North Sea to leave sunshine and showers behind. It won’t be dry everywhere though because that rain over Ireland will push into north-west England during the afternoon. So a potentially wet end to Friday I think for the west of the U.K, Scotland and Ireland. Some of that moisture may turn to sleet and snow at elevation on Friday over Scotland. Temperature-wise, still staying high single figures possibly nudging into double figures for the west and south as that milder airstream from the south-west pushes temperatures a little upwards.
So how does the outlook for next weekend look ? Will I be losing the feeling in my fingers again whilst fishing or are things on the up ?
Well tricky to say at this point (as always) but I think not a bad weekend for most places, still with the threat of some showers pushing through particularly for the south-east of England on Saturday forming into heavier bands of rain here possibly. Elsewhere I think a nice day, quite spring-like with temperatures up in the high single / low double figures and with plenty of sunshine. Still a chance of the odd shower across Ireland and Scotland but with a light to moderate south-westerly wind in situ, it’s more likely to be dry than wet, except across The South East on Saturday. A drier picture on Sunday here and just about everywhere save for some showers across the north-west of Ireland, England and Scotland. Temperature-wise, 9-11°C gets my vote.
So I think next week looks like a quiet start to the week as high pressure from The Atlantic extends its influence across Ireland and the U.K. I expect it to be similar temperature-wise to the weekend because we will have light northerly winds in place, but at least it’ll be dry. So a dry start to the week and a cool one perhaps with overnight frost but as we move into the 2nd part of Tuesday we will begin to come under the influence of a North Atlantic low pressure system. This will switch the wind round to westerly / north-westerly and introduce more cloud cover and rain into the north-west of Ireland initially before reaching most areas on Wednesday, along with stronger, westerly winds. So turning windy and unsettled from Wednesday with that low pressure set to sit over us for the 2nd part of next week and drawing in colder, northern air as we approach the end of the week. Remaining windy and unsettled I think over the Easter weekend with a cool, northerly airstream if this projection stays on track but plenty of time to change yet.
Ok so with all eyes on our slow start to the spring I thought I’d throw in a couple of comparison graphs which I will update on a regular basis.
2018 vs. 2017 vs. 2013
The first is a year-on-year comparison featuring 2018, 2017 and the last really slow spring, 2013, using data from The Oxfordshire, my default location.
So looking at data from this site, we are sitting 11 days behind 2017 currently but the gap will extend as we go through the week because you can see this time last year we were piling on some good growth. By next Monday it wouldn’t surprise me if we were 17-18 days behind growth potential-wise, year-on-year. You can download the above graph here.
Let’s just think what this means in practical terms with respect to aeration.
Imagine that we aerated our greens on 1st March in both 2017 and 2018 and we were working on the basis of requiring 10 days of good growth (Good growth = average daily G.P = 0.4) for full recovery. In other words when we reached a total G.P of 4.0 from 1st March, I’d expect us to be pretty much recovered from a standard spring hollow coring (10mm tines at 62.5mm spacings) provided adequate nutrition was in place.
In 2017, in a good spring, we would have had recovery in 18 days
(Total G.P from 1st March, 2017 to March 18th, 2017 = 4.2)
In 2018, in a slow spring, we would still only be halfway there by today and I reckon we will need pretty much the whole month to hit that total, but we will see.
(Total G.P from 1st March, 2018 to March 18th, 2018 = 2.1)
That tournament….The Masters
As we near the date of The Masters in Augusta, I’ve been asked if I might update one of my talk slides with a 2018 comparison between the location for the Augusta National in Georgia, U.S.A and my default location, The Oxfordshire, Thame, Oxfordshire, U.K.
As luck would have it the Weather Underground Network shows 2 weather stations just across the road from The Augusta National location highlighted in the above image in yellow. You can see their current temperature is a very nice 15.8°C, but they had a wet start to the day with 8mm odd of rain. So I’ve lifted data from the weather station above to compare.
Now we know that Augusta has some very specific agronomic issues relating to shade so this won’t be representative of these areas, but it will reflect a green in an open-aspect vs. the same at The Oxfordshire.
I’m also pretty sure that Sean at The Oxfordshire doesn’t (to be best of my knowledge of course :)) call upon lighting rigs, undersoil heating and fans, etc to produce his surfaces and nor do I suspect that the budgets are similar either, but lets look at the two purely from a growth comparison perspective.
So below is a Cumulative Growth Potential comparison of the 2 sites from yesterday’s date…
So we are currently tracking 48 days behind Augusta National at The Oxfordshire from a Growth Potential perspective. Indeed if I look to 2017, The Oxfordshire didn’t hit a cumulative Growth Potential of 36.1 till the 26th of May.
A comparison between the two is therefore pretty meaningless, but of course that won’t stop it happening. You can download the above here though I intend to update this every Monday on the run up to the event.
There are two sides to every coin…
Now it should also be said that although they have much better conditions for growth at Augusta, looking at their weather statistics the job sure can’t be easy from a turf management perspective.
They have a lot of days of frost in the morning and mid-twenties by the afternoon and their last frost was only 4 days ago. They hit 28.8°C on the 16th February and were into the 30’s shortly afterwards accompanied by > 90% relative humidity, so one can only imagine the pressures on the resident grass species from a disease perspective.
Working on my usual stats for Anthracnose spore germination, I reckon they passed the trigger point on the 19th of February and so could expect disease activity 4 weeks later potentially and what’s more they encountered acute plant stress (as denoted by a dip in Growth Potential) just a week later. They also look to have had a pretty cold first half of March with frequent frost before temperatures recovered over the last few days.
Sure they don’t have pressures to produce grass growth like we may have currently, but they have plenty of others that go with the territory. I know they have a pretty unlimited budget compared to this side of the pond and a number of features to improve growth that I have already highlighted, but as a turf manager I cannot presume to imagine the pressure that this weather, location and that tournament brings.
We of course have plenty of pressure this year whichever side of the fence you’re standing whether you’re trying to produce consistent turf or supply products to the same, life ain’t easy, but just like 2013, we will prevail starting with some slightly better growing weather this week.
Transition from Winter Sports to Cricket…
One area that the slow start to spring is likely to impact on is the conversion of playing areas from winter sports to cricket that is set to take place at schools over the next month or so. Thankfully it looks like at least we have some potential for growth on the horizon however areas of turf that have been in play over the winter will be further behind than previous years, not just because of the slow start to the spring, but also because of a lower growth rate during November and December. So these areas may need more of a helping hand nutritionally compared to previous years because of low growth rates pre and post-Christmas. All the best to the groundsmen and groundswomen on this one.
The same is also true of areas in play on the golf course, particularly tees, wear pathways from greens to tee and other traffic routes.
Regardless of which weather projection is correct on the run up to the end of this month, low temperature-available forms of nitrogen including ammonium nitrate, sulphate and potassium nitrate will help in this respect to produce growth even at low soil temperatures. This is because of the lack of microbial conversion required to make these nutrient forms available to the grass plant. Now if you’ve come out of the winter healthy and with a good sward then you’re ahead of the game but I think for many that won’t be the case.
Ok a late blog again, must get up earlier in the morning, my apologies…
All the best.