Hi All,

A belated Happy New Year to you all and my apologies for the delayed start to the year with this blog, unavoidable I’m afraid.

After a pretty interesting Christmas period we now start the reasonably short plod to spring with the evenings beginning to stretch out just a little every day (or is it my imagination I wonder..) and gathering real pace as we close out January.

Here in The Midlands of England, we got clattered with some pretty heavy snow and ice storms between Christmas and The New Year and whilst they made getting about tricky, the winter scenes were beautiful. Sadly the snow didn’t come in time to save my Paddy Power bets (missed by less than half a day in some locations but c’est le vie 🙁 ) for a White Christmas so I am now down on my luck with the score standing at Paddy Power 5 MH 2. Proof indeed that gambling doesn’t pay….:)

General Weather Situation

By the time you read this it’ll be Wednesday so I’ll start my forecast there and thus lessen my workload.

So Wednesday sees a band of rain that crossed Ireland late on Tuesday move eastwards across the western coastline of the U.K and inland, weakening as it does so.  By dawn this rain will be in a vertical band straddling an area from London right up the central spine of the U.K and may be falling as wintry showers across central and eastern areas of Scotland. As we progress through the morning this band of rain will slowly move north and eastwards towards the east coast of the U.K. For Ireland, they’ll be some breaks in the cloud for Connacht possibly, but that’s about it in terms of seeing the sun with some rain pushing into Kerry and Cork from the off, slowly moving northwards. The wind will shift around to the west for the U.K and away from the east and that’ll lift temperatures at night and during the day, nothing great like, but maybe we will hit a heady 8°C across the south of England. Now I know that doesn’t sound great shakes but because we’ve been cold for a good while now, any slight lift in the air temperature is I think more noticeable. Through Wednesday afternoon we may see a rain front push into The South West of England but it should be pretty short-lived before it moves out into The Bristol Channel. By dusk we should have a pretty much dry picture everywhere, cloudy though, as has been the norm now for awhile.

Overnight into Thursday we keep a large part of that cloud cover, possibly clearing though across the west of Ireland leading to a sunny, but cold start to the day. It should be a frost-free one for most because of the inherent cloud cover but it’ll be close if you go into Thursday clear overnight. It will feel cooler on Thursday due to another flip in the wind direction, this time to northerly but it will bring the bonus of pushing that cloud cover away, clearing from the north first. By lunchtime there’s a good chance the top half of the  U.K and most of Ireland will be feeling those nice sunny rays (but without much in the way of heat mind) before central and southern England clears during the afternoon. Clear skies mean a colder night on Thursday and likely I think to see a touch of frost in places.

Closing out a short week meteorologically and Friday sees that cloud building again overnight for most areas of the U.K and Ireland, with perhaps The North East and eastern Scotland seeing a sunny start. That cloud will thicken over Ireland ahead of a pretty consolidated rain front which will move into the west around lunchtime bringing heavy rain to south west Ireland. For the U.K we look to be dry and dull I’m afraid with maybe some breaks in the cloud across the north west initially. During late Friday afternoon that band of heavy rain moves east across country reaching The South West of England and West Wales just after midnight. Wind-wise we start off with a north westerly, cool wind on Friday but switch round during the middle of the day to a south easterly. A cool day for the U.K with temperatures barely hitting mid-single figures (if that), milder over Ireland under that rain and strong, southerly airstream.

That rain front is slow to move and by Saturday morning it won’t have cleared Ireland completely sitting over the eastern side of the country and stretching across The Irish Sea into Wales and The South West where it’ll be butting up against a cold front and so may easily fall as sleet and snow, especially over elevation. It’s a bit of a guessing game quite how far inland it’ll reach across England but with a cold, south easterly wind there’s a change of some wintry showers inland across North Wales, Scotland, the north west / east of England and possibly extending into the West Midlands. A raw sort of day with a prevailing south easterly wind pushing cloud in from The North Sea, so dull with it as well. For Sunday we that rain front push west again across into eastern Ireland, Wales and The South West before fizzling out during Sunday morning. Dull as dull can be I’m afraid on Sunday with some wintry showers persisting across central Scotland. Later on Sunday afternoon we see another band of heavy rain push into the west of Ireland and move eastwards bringing rain to the western side of the U.K overnight into Monday. Temperature-wise nothing to shout about on Sunday with 3-5°C across England and slightly higher across Ireland where the wind will take on a south / south westerly direction.

Weather Outlook

So after a pretty drab and unsettled week how are we looking next week ?

Well the projections is for another deep, low pressure system to push in from the North Atlantic and that’ll bring strong, south westerly winds to all areas overnight into Monday quickly turning north westerly. This is a pretty deep low and if the projections are right it’ll sink south through the course of next week forming a pronounced trough in the jet stream (see below image from Unisys for the end of next week)

You’ll note that the low pressure has pushed the winds round to the north west so that’ll be another feature of next week, cool, strong winds pushing rain and possibly wintry showers in from the north west through the week starting with a dollop of rain for us all on Monday. I think the depth of the low will mean it is categorised as a storm system and if so this one with be called Fionn (F-yunn) and yes the ‘f’ will be particularly appropriate :). Later on in the week it may be that we see more in the way of sunshine between those blustery wintry showers but that’s about all the positive spin I can put on it at present.

Agromonic Notes

Since it’s my first blog of 2018 it seems pertinent to look back at 2017 and see how the year shaped up for us all.

First off we have the GDD stats from our normal Thame, Oxfordshire location….

So we can see that December 2017 went down in the weather logs as a cool month, cooler than 2016 and pretty typical as December’s go over the last 8 years of recording. The two anomalies being the extremely cold December of 2010 and the very mild, wet December of 2015.

From a cumulative GDD perspective, 2017 checked out as the warmest year we have recorded since we started in 2010 coming in nearly 13% warmer than 2016 and close to 6% warmer than the previous record holder, 2014.

Now 13% warmer from a GDD perspective may not sound earth-shattering but if that relates directly to grass growth, that’s a lot more grass growth generated than any previous year and as we know from last autumn and disease management, it isn’t just grass that responds to warmer air temperatures…

Total GDD – U.K & Ireland 2017


So there we have it, 6 different geographical locations across the U.K and a close on 35% difference between a Scottish location and one just south of London. Fife would be a reasonably mild Scottish location in my books and further north and east in Scotland, I’d expect the differential to be closer to 50%. Many years ago when I was a mere slip of a lad I worked in agriculture and called on farmers in the Midlands of England right up to north of The Black Isle in Scotland. During my time many English farmers sold up a small farm in England and brought a large farm in Scotland. I remember talking to them about their sillage yields and how much lower they were in Scotland compared to Central England. If I’d known about GDD then I could have shown them why….

For Ireland we see the difference between the mildest location (Valentia) and the coolest, Claremorris (in beautiful Co. Mayo though before the slagging starts) is around 25% from a GDD perspective, quite significant when you take into account that the distance between the two is only 138 miles as The Crow flies….There’s a similar difference of 20% in total GDD between Claremorris in the west and Killiney in the east.

A diary of a year in GDD….UK – Location Thame

To do this meaningfully I decided to split the year up into the seasons we manage from a grass perspective so that’s January – May  / June – August /  September – December and I’ve picked a location from the U.K and one from Ireland as well.

So first up we can see that spring actually started with a very mild 2nd half of February that really kicked off on the 20th of the month with 15°C air temperature. That’s only 5 weeks away if it repeated again in 2018 (the power of positive thinking 🙂 ). When you look at the comparison with 2016, you can see how poor a spring it was back then with barely more GDD in April 2016 than we recorded in February 2017.

March continued motoring forward in 2017 , hitting mid-teens through most of the month and peaking with 20°C on the 30th, you can only dream about those sort of temps at the moment. On paper April looked to continue the warm trend but GDD doesn’t tell the whole story because April 2017 was a really dry month and at this location we only recorded 6mm of rain all month. When you take into account that the total moisture loss by E.T was 69.8mm, then the moisture deficit was 63.8mm. That means a drying surface and drought stress way back in April. Throw in 5 frosts right up until the end of the month and we can see that April 2017 continued the pattern of this month being one of the hardest months of the year to achieve consistent growth. Food for thought if you are planning aeration this spring. Seedheads were earlier in 2017 and at one stage looked set for a flush in early April but the dry weather held that back, once the rain arrived tin late April, they were off.

May 2016 I remember as being a grass factory of a month with growth going from zero to flat out in three days (and seedheads likewise) and this pattern was repeated again in May 2017 and then some, with another 22% more GDD and air temperatures > 25°C in the last week of the month triggering early Anthracnose spore germination.

Onto summer and a scorcher of a June with some really high temperatures in the third week of the month with 4 consecutive days of air temperature > 30°C. I remember at the time that the local temperatures in London were much higher and that the baseline temperature at Wimbledon exceeded 40°C during this period, not fun for ryegrass that.

The high temperatures continued into July with air temperature > 30°C recorded at the end of the first week and temperatures continuing in the high twenties through the first half of the month. It was dry too with barely a mm of rainfall over the same period, in short, a stressy period of weather. All change in the second part of July with a fortnight of continuous rain rounding a month roughly similar to 2016, GDD-wise.

August we can see shows a significant reduction in GDD in 2017 vs. 2016 with a 14% decrease year-on-year. Anyone that took a summer holiday in the U.K in August 2017 will probably remember it wasn’t a warm month and in fact we recorded 9 nights when the temperature dropped into single figures culminating with a near grass frost on the last day of the month. Plenty of rain as well in August pushed humidities up to the max and made an early start to the Microdochium nivale season, not to mention Anthracnose and Dollar Spot 🙁

The story of the autumn at this location was definitely October 2017 with nearly double the GDD of October 2016 (which was uncommonly cool actually). The high daily GDD caused not only high growth rates / clipping yield but also severely aggressive Microdochium nivale activity. With constant cutting and new growth emerging on an accelerated basis, the longevity of fungicide applications was significantly reduced with systemic applications lasting 7-10 days less than the year before, typically 14-17 days was your lot.  November 2017 continued a high GDD compared to the previous year with significant, short-lived peaks of mild day and night temperature. This tended to encourage re-activity around existing scars rather than new infection. December 2017 rounded off the year cooler than the previous year with the first proper December snowfall since 2010. Again numbers can be deceptive because even though the month was cool, we still had two periods of Microdochium nivale activity, the last of which ran right up to Christmas Day and did result in new infection on some sites, mainly because of periods of snow cover I think. So 2017 finished off 13% higher from a GDD perspective than 2016 for this location.

A full schematic of the autumn last year showing the periods of recorded Microdochium nivale activity is shown below for the same location…

A diary of a year in GDD….Ireland – Location – Johnstown Castle, Co. Wexford

The picture in Co. Wexford was slightly different with a milder and wetter January than its English counterpart and strikingly similar to the previous January from a GDD perspective. February 2017 showed itself to be much milder than the previous year with mild air temperatures feeding through from The Atlantic in the 3rd week of the month to get growth off to an early start. March 2017 showed a similar pattern to the U.K location, with a much milder month and a 3x higher GDD than the previous year. Rather than high day time air temperatures, the month was characterised by many days of low to mid-teens maximum temperature and consistent rainfall, in other words, a pretty good growing month.

April 2017 in Wexford was a mild but dry month with 17mm of rain across the whole month and a GDD figure 2x the previous year. Most of the high GDD days were in the first two weeks of the month however when it was dry and towards the end of the month growth dropped off a cliff as we picked up some night frosts. (in common with the U.K location). So for Ireland as well as England, April proved a tricky month to produce consistent growth / recovery.

May 2017 turned that around with good day and night temperatures but growth didn’t really get going until the rain arrived mid-month. The 25th of May was the first day that the air temperature exceeded 20°C, nearly 7 weeks later than the Thame location in the U.K.

Once again GDD doesn’t tell the whole story of a similar level of growth in June 2017 compared to 2016. June 2017 was an extremely wet month for Ireland and at this location, 125mm of rain was recorded for the month with 30mm falling on just one day (5th June). The 2nd and 3rd weeks of June showed good air temperatures and with a saturated soil, growth bordered on being out of control for a while.  July 2017 continued a positive Irish weather story for the summer with a warmer July than the previous year with plenty of consistently warm days and half the rainfall of the previous month. Like the U.K, if July was above-average, August was anything but, with no days when the air temperature exceeded 20°C and 4 single-digit nights. Throw in 75mm across the month and you have a recipe for soggy sand castles and scenes of Craggy Ireland 🙂 In common with the U.K location it also meant an early start to the Microdochium season.

A very different story in Ireland during the autumn with a practically identical October 2017 vs. the previous year from a GDD-perspective, however September showed the same pattern as the U.K with a cooler, more humid month and like there, this continued Microdochium nivale activity that had started in August. We also saw more Dollar Spot in Ireland during August and September (in particular), a disease that was practically unheard of there 10 years ago. Prolonged leaf wetness and high humidity are the key drivers for this disease.  October 2017 didn’t log the same record high GDD as the U.K location coming in 30% lower but a period mid-month when night temperatures ran in the consistent low to mid-teens resulted in extremely aggressive Microdochim nivale activity that was hard to control. November continued the pattern displayed in the U.K as a warmer month than the previous year from a GDD perspective with 3 distinct, short-lived disease peaks caused by high day and night time temperatures and high humidity. Again we tended to see re-infection around existing scars rather than new infection sites. Finally December 2017 came in cooler than the previous year but again in common with the U.K location, it also saw peaks of disease activity, the longest running through to Christmas Day, a wholely unwelcome Christmas pressie. Comparing total GDD 2017 vs. 2016 showed that this location came in 4.5% higher, so a similar pattern to the U.K, but not as high a difference.

This is I think to be expected because Ireland picks up more Atlantic weather systems than a Central England location and doesn’t tend to pick up the full benefit of continental high pressure systems in the summer nor the full extent of the cold from Scandinavia and Russia during the winter.

So there we have it, a look at two locations through 2017 from a GDD perspective, I hope you found it interesting and maybe it struck some chords with your own experiences ?

All the best for 2018

Mark Hunt