As spring gathers apace with some lovely sunshine and warm temperatures late last week and over the weekend (for some areas), I spent two days in Scotland and Ireland driving through snow, so winter is not totally done with yet. In a topsy-turvy weather day we went from snow and 1°C at 8 a.m to warm sunshine and 11°C by midday. I also scraped frost off the car on Saturday morning. So this week we will see a week of weather contrasts with increasingly warm temperatures early on peaking on Thursday and then a sharp drop off by the end of the week before I think bouncing back again into milder temperatures next week.
So let’s put some detail on that…
General Weather Situation
Well an easy one to start the week because Monday will start dull, cool and overcast as that easterly wind pushes Haar off The North Sea. As we progress through the morning this thick cloud cover will start to break in the west and north first I think and that’ll allow temperatures to rise nicely. That cloud cover will continue to thin through the afternoon so a nice afternoon I think for most of us with temperatures rising up to 14-16°C with more warmth in the west because you’re further away from that cooler moderate easterly wind. Central and easterly locations will be last to lose that cloud cover and so here it’ll sit cooler and duller I’m afraid.
Moving onto Tuesday and overnight we see some light showers developing over Leinster and these will kind of hang around in the morning to make a dull start to the day there. Plenty of cloud cover around elsewhere on Tuesday so most areas starting off grey again. A band of rain looks set to push into The South West and South Wales through Tuesday morning and it’ll push up and across country as it does so, tracking along the south coast as well. That Irish rain will push north and west into Donegal through the latter part of the morning. As we progress into the afternoon, that rain continues to push north and east across the U.K so I expect it to be up in The Midlands and beyond by mid-afternoon. Similarly that rain across Ireland consolidates to give a wet p.m. in a line north of Dublin to beautiful Galway. By the evening rush hour that rain will have pushed up into The Borders but most of Scotland will stay dry, if a little dull through the daylight hours of Tuesday. With all that cloud and rain around it’s not surprising that temperatures are down so expect 11-13°C as the norm. Wind-wise we see a change from easterly to south westerly through the course of Tuesday and that signals the arrival of low pressure and unsettled conditions.
Mid-week already and we see that rain from Tuesday now off into The North Sea but with that wind change to south westerly we know what that means and especially for the south west of Ireland. So no suprises then that Kerry sees some Atlantic rain push in early on Wednesday morning and quickly push up country into Munster and Leinster to make it a soggy morning staring at the back of a lorry on the M50
For the U.K we see that rain into The South West at the same time and it’ll quickly push north and east up into Wales and the west coast of the U.K. So central and eastern areas look to start drier and stay drier for longer on Wednesday. By the afternoon, that rain is across Ireland, the south west, Wales, north west England and south west Scotland with some moving along the south coast as well into the south east of England later. Pushed along on a moderate, south westerly wind it’ll continue its march north and east so most areas will see rain by dusk across the U.K but as always the case with a south westerly airstream, the east will see it last and least. Temperature-wise I think we will be 13-15°C depending on whether you’re under the rain or not.
Moving swiftly onto Thursday and we start off cloudy and unsettled with rain soon arriving into Ireland, The South West and Wales I think. Elsewhere it’ll be a dull and cloudy start again to the day so a lot less sun than the previous week. At present we look to have a west-east divide on Thursday when we look at rain with Ireland, Wales and the north west of England in the firing line. South and east of this looks at this stage to remain dry with potentially some hazy sunshine breaking through as well. The same may be true for the north and east of Scotland where you have the best chance of seeing the sun along The Moray Firth, south of this it’ll be dull with that cloud thick enough for some drizzle. By close of play that rain appears to sit over most of Ireland and then track along the west coast of the U.K with significant rain into the north of England and The Borders pushing more north into Thursday night. A significantly warm day on Thursday away from that rain and expect to see temperatures pushing into the high teens, maybe 18°C in the south east of England. Under that thicker cloud and rain it’ll be more like 12-13°C for Ireland and most of Scotland.
Closing out the week (hurrah) that cool Atlantic low pressure system is projected to slowly sink south so that’ll begin to peg temperatures back somewhat for Friday, so a chillier feel to the day where you enjoyed the warmth on Thursday. Again a lot of cloud around on Friday with rain (again) into south west Ireland during the morning. They’ll also be rain for The South West, Wales and the south of England and this will push north and east through into the afternoon pushing thicker cloud cover before it. Only the east coast may see some sunshine initially on Friday but then you’ll see the cloud and by tea time the rain will arrive to cover Ireland, England and Wales with only Scotland looking to be drier. That said the thick cloud base may be thick enough here for some drizzle and light rain as well through Central Scotland during the afternoon. So most places seeing rain on Friday clearing through though as we progress through Friday night. Temperature-wise that thick cloud and rain will unsuprisingly keep temperatures pegged back to the low teens, so 11-13°C I reckon.
In last week’s forecast I promised and delivered a lovely weekend…well I’m not going to do the same this week
Saturday looks a dull day with thick cloud, some rain around for sure and a change in the wind direction to boot. Cooler as well as that low pressure sinks south right over Central England and drags cold air down with it, so a chilly and dull day for Saturday. They’ll be some rain around I think as well though some areas will just stay dry but dull. So after the heady heights of earlier in the week we stay cooler for the weekend and 11-13°C I reckon will be the order of the day. Slightly better news for Sunday though because at last we see that cloud cover breaking overnight to give most areas a sunny and dry day for the second part of the weekend. It’ll feel milder as well as that cold low slips away from the south of England, so maybe 12-14°C during the sunnier periods of Sunday, that’s nice.
So what’s the story with next week’s weather, back to winter or early to summer ?
Well it looks like we will start next week with a deep low pressure system sitting off the north west of Scotland and this will drag down some cooler and unsettled conditions for Monday, initially to the north, north west and Ireland so I think a wet start to the week there. Overnight into Tuesday I think we will see that rain move eastwards across most of the U.K and it’ll feel cool as the wind temporarily swings round to the north. Fear not though because if it pans out as projected, that shift in the wind to northerly heralds the arrival of high pressure and that will begin to build from mid week, next week. So staying unsettled across Scotland I think for Wednesday and perhaps Thursday but all the time that high is pushing in and pushing warmer air further north. So by the end of next week we look warm, settled and dry with potentially some very warm conditions / temperatures for the end of next week / weekend.
Now as always there’s a caviat with a weather scenario when you have a low and a high pressure battling it out. The money’s on the high winning the day but that could change and in which case we will stay cooler and unsettled. Three of the long-term weather models agree so I’m sticking to my guns and willing that high pressure in.
Ok as promised last week I intend to keep a weekly log on how the spring is progressing GDD-wise and isn’t it flying ? (well in some places anyway !).
Next week we will have our usual start of month round up so then I’ll be able to compare a growing number of locations across Ireland and the U.K so don’t moan that I’m just using one location this week
So I have used the projected figures for our location (in this case The Oxfordshire at Thame) to finish off the month. If this week’s temperatures pan out as planned we will hit a total y.t.d GDD figure of 174 at the end of March 2017, which is significant and I’ll explain why a bit later. Before I do so (yes you’ll just have to be patient) let’s compare 2017 with the same period 2016 GDD-wise.
So you can see the way spring tracked (or rather didn’t track) in 2016 in red vs. where spring 2017 is tracking in green.
Some difference I’d say and the above graph typifies to me why understanding and applying growth models to year-on-year data is so useful.
So comparing for this location (not necessarily yours though) I can see that on March 31st, 2016 we finished the month at a total yearly GDD to date of 75.
We passed the same cumulative GDD figure this year on March 8th !
That means for the Thame location we are 23 days ahead of 2016 from a GDD standpoint.
Poa annua Seedheads
So in my studies marrying up Poa annua as a flowering spring plant (because that’s how we must think of it) , I have seen the annual biotype (Poa annua var. annua) flower from 100GDD measured from January 1st using a base temperature of 6°C.
I have also noted the perennial biotype (Poa annua var. reptans) begin to start its seedhead flush from around 180GDD measured from January 1st using a base temperature of 6°C. So for this location by the end of March we will be knocking on the door of the commencement of the seedhead flush in earnest.
Now a couple of things to take on board here…
Firstly, you have a mix of biotypes on your surfaces in most cases though on sports pitches which are aggressively maintained annually I think you’ll have more of the annual biotype.
Established golf greens usually have a mix of bunch-type, fine perennial Poa annua (see below left and right core) or more elongated, coarser annual biotype (middle core)
So you’ll see some seedheads early which will be mainly annual biotypes and then the main seedhead flush will be from the perennial biotype in most golf green situations (unless of course you’re pure Fescue or pure Bent and in which case this blog and my ramblings are meaningless to you)
Secondly, is that your Poa biotype will be specific to your situation because it’s an adaptative species. For that reason your Poa may seed at 160GDD or 200GDD and that’s where you need to marry up your own GDD data and your visual observations. It won’t be the same for every location, in fact I have a feeling that Poa annua seeds earlier across the sea in Ireland (especially in the west of Ireland) than it does here but that’s just a feeling…
Looking ahead…Poa seedhead formation…
Looking at the way the weather is panning out I think we will see a start to the main seedhead flush later this week though with temperatures dropping it may be a slow start, however with some warm temperatures on Thursday that may do the trick in some locations…
Looking at the Meteoturf prediction we can see a pronounced spike this week before the temperatures drop away…This will be particularly pronounced in Central and Southern England and Wales as well.
For Ireland and Scotland it won’t be as marked a spike (see below) and so I think the seedhead flush will be slower, possibly later and will have a less pronounced start…
So for me I’d be starting my Cultural Poa seedhead work this week in the warmer locations and in the cooler ones I think you’ll be 10 days or so behind. Certainly if the weather for next week pans out then a warm high pressure will really tip the cards towards a Poa seedhead flush.
Looking ahead….Microdochium nivale activity
Now this week will be interesting because if we do get a very warm day on Thursday and indeed we carry that temperature into Thursday night / Friday morning then coupled with high humidity (from the rain earlier in the week) you may see a sudden flush of new M.nivale across turf surfaces and even some of the more temperature / humidity-liking fungal diseases like Superficial Fairy Ring and Red Thread.
The key will be the strength of the wind and its ability to dry down the leaf surface. If the wind dries down the plant leaf fast enough then you won’t see that disease spike, if it doesn’t, you will…Feedback welcome please either way…
Looking ahead….Weed Growth
It’s interesting to see how suddenly weeds have sprung into flower particularly Daisies and Dandelions and how two weeks ago you could hardly see any and now they are everywhere. The spike shown in this week’s growth forecast would normally provide a great uptake opportunity for applying a selective herbicide but I’m afraid that might be difficult with the strength of wind and the risk of rainfall. Next week’s high pressure (if it does come to pass) will provide good spray conditions and a great opportunity to get good uptake.
Looking ahead….Outfield PGR Usage
The same rationale in my mind applies to a PGR on outfield height-of-cut turf, it may be advantageous to sneak one on this week but if it’s not practically feasible then I’d apply next week if the high pressure arrives so you have your labour-intensive areas of turf buttoned down before Easter because it’ll be with us before you know it.
Ok that’s it for this week, lots to chat about and again I’d appreciate any feedback you’d care to leave regarding the points I have outlined.
I guess I should stress this blog constitutes my thoughts and observations and not the company I work for or represent just so we’re clear on that front.
All the best..