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Hi All,

I did say in my last blog that if I got a chance for a mini-update and / or saw a significant change in the weather on the horizon, I’d try and snatch a few minutes to publish a shortened blog.

It was only 8 days ago that I put up a graph showing what happened in November 2010 and reminding us all that it was possible to go from extremely mild to extremely cold on the flip of a coin. At the time there was nothing to suggest that this could happen, now there is……..

There’s a change coming…

Take a look at the two weather graphs below, you can see the cold air (in blue), the yellow air marking the line of demarcation that is the jet stream and the warmer air sitting below it. The projection for this coming weekend is that we are entering into a ‘Trough’ pattern in the jet stream which will allow cold air to stream in from Siberia and winter will start both early and with a vengeance…

Nov20152010comp

Uncanny how they’re so similar isn’t it ?

And just remember 8 days ago there was no suggestion that this was in the offing, so yet again I state my utter conviction that 8-10 days is the limit of our forecasting ability in terms of weather, regardless of what the tabloids and some weather gurus believe…

General Weather Situation (Abridged)

For the rain-ravaged north west, where we have seen more than 10″ of rain fall in a short space of time and currently where we have heavy rain sitting over north west Scotland, I hope this will be the last of the extremely heavy downpours for this week. They’ll still be rain around for sure today and Thursday, but with the cold, it’ll decrease in intensity and of course it’s likely to change to sleet and snow at the weekend.

For all of us the change day is Friday, where we see the wind swing round from the west to the north west and then the north by early doors on Friday for Scotland and the north of England. Those isobars will be packed tight so it’ll be a strong northerly wind to boot and by close of play Friday we will all feel the difference..It looks like Friday will be pretty dry for all of us and bright with it, but that sun won’t be warming anywhere, anytime soon. Close of play Friday I expect the first of the wintry showers to be pushing into the north east of Scotland and across Donegal and north Connacht.

Overnight into Saturday it looks like we will see wintry showers, a mix of rain, sleet and snow depending on altitude push across Ireland and down the west coast of the U.K into Wales / the south west of England. By dawn, central and eastern areas of the U.K should start bright and cold with a penetrating hard frost. For Ireland it looks the same, dry on the east, but wet down the west coast of Connacht and Munster. During the morning those wintry showers will push down from The Highlands into Central Scotland and the north of England by lunchtime with some significant snow I think for The Pennines. As we approach dusk those showers spread more east and south to The Midlands and south of England. Again a mix of rain, sleet and snow expected. Temperatures will barely break freezing and with that strong north wind I expect the windchill to be around -9 to -10°C !!!!! In other words, absolutely Baltic !!!!

Sunday sees a day of sunshine and wintry showers after another overnight frost with a likelihood of more rain, sleet and snow over Scotland and a tendency for most of the wintry showers to be along the east coast this time. Again another day of biting northerly wind accompanied by a significant windchill.

Winter

Weather Outlook

So is this just a blip or a portent of things to come for the winter of 2015 ?

This fast transition from an extended mild autumn to a hard winters day doesn’t look to be a permanent one from what I can see with a change to milder air on the cards next week, though we won’t be going back to the teens anytime soon I think. Even though the Arctic blast is likely to be a short one, I think winter has shown a glimpse of its hand and I expect they’ll be more to come. Hopefully this will be around Christmas and I can retire to Costa Rica on my Paddy Power winnings 🙂

So next week looks like starting cold, dry and settled for all of us after another frost, though likely not as hard as the weekend’s. Already on Monday we’ll see milder air coming into Ireland and the west of the U.K so here you may escape a frost completely. Through late Monday into Tuesday sees the wind decrease and swing round to the north west and eventually the west bringing those temperatures up as we see more in the way of cloud cover and the risk of light rain for Tuesday, particularly in the west and north later on in the day.

By Wednesday we start to see another change as the wind swings back to the north west and  the isobars begin to tighten so a markedly windier day on Wednesday and that will start to drive rain associated with a north west low pressure across Ireland and the U.K. That sets the tone for the end of next week, extremely windy with heavy rain likely, particularly across Scotland and the north west I’m afraid to say. Further south and east it’ll remain unsettled, very windy and cool with temperatures likely to remain mid-single figures for the time-being.  The end of the week will see temperatures start to tumble again, first across Scotland and the north with some of that rain likely to turn to wintry showers through Friday and into the weekend. By Saturday I think only the west and far south will still be sitting in mild air. It wouldn’t surprise me if we finish off November with another cold, northerly blast.

Agronomic Notes

So life for us and the grass plant is going to feel very different in just a few days, the difference is we know its coming and can plan….

Preparing for cold….

For the north and west, the heavy rainfall will make most of the suggestions in this blog irrelevant so please excuse me on this one. To prepare for cold weather my advice is very simple, leave some leaf on the grass plant and if conditions make it practically feasible just put a light roll on the greens to keep some pace. I would try to avoid a cut on Friday and roll instead to leave the plant protected for what will be an icy wind blast over the weekend.

You have to think of it from the grass plants perspective. Up until this Thursday it has been growing super-fast for the time of year with many end-users feeding back to me that clipping yields have been like ‘cutting in the summer’. That means it’ll have a high nitrogen content in the leaf, a high water content and the leaf epidermis is likely to be thin. (due to a fast growth rate) In other words it’s totally unprepared for extreme cold and we may see some grass loss in areas where the rootzone is saturated and this is followed by sudden, heavy frost.

Our experience of 2010 showed that leaving a slightly higher cutting height benefited the plant during periods of cold weather and that would be my advice for this week.

I’d also stop short of applying anything to the plant leaf on the run up to this weekend because although it’s unlikely with the high winds and rain that you have a spray window, I’m not sure you’ll see a benefit from doing this, it may even count against you.

So let the plant go through this period as protected as possible and by next week it’ll start to get the message that the days of growth are finished for the time-being..You can clearly see this on Meteo Turf with the decrease in daily GDD / G.P…

MeteoTurf181115

Disease Activity

I expect with this severe transition into cold weather that disease activity will come to a pronounced halt as will re-growth in scarred areas. It certainly doesn’t mean that the Microdochium nivale will be ‘killed’ by exposure to hard frost, I don’t believe this old wives tale, but for sure one of the key drivers of disease, that of air temperature, will be exiting stage west for the time-being. With the loss of temperature and grass growth, we will also see a drop-off in uptake efficacy of fungicide A.I’s because the grass plant will effectively ‘shut down’ for the foreseeable. So my only exception to keeping applications to a minimum this week would be if you still have active, aggressive disease and want to get a fungicide application in. I would though keep tank-mixing to a minimum in terms of putting other non-fungicidal materials in the tank. Remember with that cold and severe windchill the plant will easily become desiccated, particularly if the ground is frozen, so you don’t want to be plastering lots of iron onto the leaf just prior to this in my humble opinion, as that may (depending on the type of iron) add to this desiccation effect.

Ok that’s all for now, sorry it’s not the usual full-on blog, but time and tide wait for no man…

Remember to dig out your thermals, buffs and winter hats for the weekend, because boy are you going to need them. That said I expect we will still see the comical sight of some teenagers, oblivious to the weather forecast until they step out of the house, walking around in shorts and a T-shirt in a negative windchill 🙂

Have fun..

Mark Hunt