January 13th, 2025
Hi All,
Well today is the 1st day I have fed the flock (?) of Blackbirds that colonise my garden during the winter months (last count was 21 Blackbirds turning up to be fed at 1st light, and it's a small garden !!!) without the ground being rock hard on the surface, though we did still have a light frost and it is still frozen below. We got down to -6.7°C during the recent cold spell with 11 consecutive frost days. Quite a novelty for us nowadays with a warming climate but typical of what we used to get in this month. Incidentally I don't think it'll be the last appearance of cold weather / snowfall this month.....
Took some lovely photographs of hoar frost whilst out for a pleasant walk with a couple of good friends. The above was a photo of a stacked log in a pile at Fineshades Wood, Corby. It almost looks alive doesn't it ?
Now whilst we on the subject of temperatures there was a lot of announcements last week about 2024 being our hottest year ever. I kept hearing this spouted by the BBC, "2024 was the warmest year ever" and it irritated me because what they weren't saying is that the announcement pertained to the global surface temperature as measured by Copernicus, the E.U's excellent climate research group. Here is the actual data announcement courtesy of Copernicus ;
Read the full report here
Now if you have attended any of my talks or read some of my earlier blogs, I have often stated that this gradual increase in temperature on a nice upward scale will not apply to the U.K because we are an island and subject to the vagaries of the jet stream. For instance in 2018 we had a really hot year, a very dry and hot summer, we saw warm summer's again in 2020 and 2022, but the last two summers have been really disappointing. So people were asking me last week, how come 2024 was the warmest year ever when we had such a dire summer ? Well as stated above, the statement circulated relates to the global surface temperature. So, I went onto The Met Office's website and downloaded their average annual U.K temperature, a series which has been running since 1886 I believe.
Above is a graph I put together on Saturday, an otherwise frustrating day for me as my Danish baking Tebirkes leaked out all of their marzipan in the oven and my Chinese Pork recipe - Siu Yuk turned out to be only half of that description, ho hum 😊
I digress.
So in 2024, the average air temperature for the U.K was 9.78°C, compared with 9.97°C in 2023 and 10.03°C in 2022. 2018 surprisingly came in at 9.45°C. So our mean temperature for 2024 showed a decrease vs. 2023. Undoubtedly we are warming up as an island (our last sub 9°C year was back in 2013) but for us it is an irregular increase with ups and downs dependent on what the jet stream serves us up throughout the year. I wonder what 2025 has to offer ?
Onto this week's weather.
General Weather Situation - w/c 13-01-2025
A big change taking place as we speak with temperatures in Scotland and Ireland already into double figures as a concerted thaw takes place today. Indeed Meteoblue is showing 13°C for Dublin as I type !
Now this is one of those tricky points in time as the surface thaws out over a frozen zone deeper in the profile as this needs management. That said it is such a quick temperature rise that this should be a rapid process hopefully and in some cases an overnight one.
For this week though, we have a mild and possibly humid high pressure taking over the weather for the U.K, Ireland and Denmark. So a thaw, some rapid air temperature changes for the west and north, slower across central areas and Scandinavia, a quick snow melt for those areas that have it and some reasonably strong winds which will help dry things down well. With the arrival of high pressure we will see an increase in disease pressure but I don't think it'll be too high at this stage (caveat).
So high pressure means mainly dry conditions this week with temperatures across Ireland in double figures all this week probably peaking today. For England and Wales, it'll be cooler, with 6-8°C typical and 7-10°C for Scotland. The clue to the rapid temperature rise is in the wind direction now, south westerly to south throughout this week, in other words a mild air stream. For that reason night temperatures should be high enough to end the run of frosts, typically 3-7°C and that'll promote a bit of disease activity but maybe not a hole bunch as the strengthening winds will negate dew formation.
We look to stay this way till the end of the week when Atlantic low pressure systems begin to stack up to the west of Ireland. Through the course of Friday morning these begin to bring some rain to the south west and north west of Ireland. This rain will vector north and east into western Scotland later on Friday. Otherwise we remain dry into the weekend I think. During Saturday / Sunday we see fronts of rain skirt the coast of Ireland and vector into Scotland, but these fronts will make progress across Ireland into the west of the U.K as well, fizzling out as they do so. So an increasingly unsettled picture over the weekend for the west, but settled, mild and cloudy across central areas, the east and I think for Denmark as well. Dry and cool but obviously milder than of late.
Weather Outlook - w/c 20-01-2025
Ok, onto next week and critically the forecast for Harrogate and BTME 2025. Well I think the first part of the week looks ok forecast-wise for BTME but it may get a little hairy on the last day as exhibitors are packing up. Just a little reminder whilst we are on the subject of BTME, I am giving a seminar on the 1st day, you don't have to book, it is a first come, first served basis. it doesn't cost you anything and you never know, you may just learn something. 😊
I will primarily be speaking about Davis weather stations as they are the ones I have experience with but a lot of my talks applies to considerations you should give to any weather station.
Well now.....if you look at the animated GIF above you can see we have some pretty serious low pressure systems stacking up. Next week I think we will see high pressure hold off these strong Atlantic low pressure systems until mid-week, next week when winds will strengthen across Ireland and the west and that deep low pressure (possibly named Storm Éowyn) will push into Ireland and The South West early on Thursday next week with very strong winds and heavy rain. This rain will push northwards from the south of England up towards The Midlands, north of England and Scotland during the course of Thursday pushed on by very strong southerly winds. It'll move quickly across the U.K and out into The North Sea introducing some rain and wintry showers to Denmark I think. Friday starts wet but dries up and is a bit of a hiatus before hot on the heels of this low pressure, another, deeper, more southerly-biased low pressure arrives across Ireland and the southern half of the U.K on Saturday. This one may be named Storm Floris apparently.
Now this is nearly 2 weeks off, the timings and tracking of these low pressure systems may indeed change but it looks like the end of January could finish off wet and very windy as the GFS projection stands now. I think the 2nd storm is more problematic potentially.
Agronomic Notes
Ok, a couple of pertinent subject areas for this week, one of which (thawing) may already have happened across the west and north to a point where it is irrelevant but I always think it is worth stressing this one.
After 10 days or so of consecutive frosts, we now have a situation where the air temperature is rising, in some places rapidly. The surface can then appear completely clear and playable, but just below the surface, it may be still frozen. This can cause issues where the upper, thawed layer becomes 'plastic', moving across the frozen lower layer and causing root shearing and at the same time, presenting a health & safety issue as throw in a contour or two and people are very likely to lose their footing / balance and potentially break a bone or two. It is a transient scenario with the thawing taking place from the surface down. Once enough depth has thawed out to provide integrity with foot traffic, you are all well and good, it is that initial part of the process where the risk is highest. Club management have to buy into this because if they don't it becomes a very stressful situation for the greenkeeper / groundsman and maybe your public liability
.
If the thaw takes place with snow melt and / or rainfall, the water will be perched on top of the frozen layer below until thawing allows its progress down through the rootzone. I have written a short pdf about this process which you can download here ;
The other thing to point out is that this spell of concerted frost will have played a nice part in opening up the soil structure with the repeated freeze and thaw cycles expanding or decreasing water molecules within the soil profile. I call it Nature's vertidrain.
Disease Pressure
I was doing some disease modelling work first thing this morning after I noted the very rapid rise in air temperature across Ireland and Scotland and I wondered if the sudden change in climatic parameters would be enough to potentially trigger some disease pressure issues. Above is my graph for a Central Scotland location and you can see from the 12th onwards the pressure has picked up to a point where it is nudging over the activity threshold I have created from correlating end-user observations with disease scores. As was the case in December, I think this will primarily manifest itself as activity around existing scars rather than new inoculation activity. I also think that as the wind strength picks up it'll be mild and strong enough to dry off dew formation and lower the risk accordingly. At present though in the areas where you have seen a rapid increase in air temperature overnight, it is an issue. So for me that is across Ireland and Scotland primarily.
As discussed above, Wales, England and Denmark won't see as quick a transition because the air temperature is only currently 5-7°C and so the threat from Microdochium will be lower. One to keep an eye on though around existing scars.
Ok, that's me for this week, I hope to see you in Harrogate next week, come along to stand 634 in Hall 6 and speak to myself and / or Peter Palmer about our weather station options, our Prodata Reports software (that you can add to an existing Davis weather station) and disease modelling work.
All the best.
Mark Hunt
Commenti