October 21st

Hi All,

At this time of year I get a lot of questions about what winter has in store and whether we are likely to experience a hard winter ?

Now if you follow all the climate data it would seem less and less likely that we will a hard winter but because of our position on the jet stream and its ability to throw in some peaks and troughs over the winter months I don’t think you can rule it out.

If I look to signs from nature I saw / heard my first Redwings and Fieldfares nearly a month ago which is very early for them to be making the trip west from their summer nesting grounds in Scandinavia and Russia. I also think the Martins and Swallows shipped out earlier than usual this year for warmer southern climes. So maybe nature is forecasting a harder winter ?

I wouldn’t even bother looking at a forecast beyond 7 days for a longer-term meteorological perspective because its accuracy would be about as likely as a bunch of politicians making a collective, progressive, logical decision.

I place a lot of store in nature so we will see.

On the home weather front, at last some respite from the succession of Atlantic low pressure systems that have been feeding in for the last 3 1/2 weeks now pretty much unhindered. This has led to saturated surfaces, a good deal of worm activity but as explained last week, lower than normal disease pressure for October. The risk in terms of the latter doesn’t come from Atlantic low pressures but from continental high pressure particularly those that push their winds up from The Med / Africa.

If you are a weather watcher this is the weather pattern we don’t want to see any time from October to February. As you may be able to read from the image, this occurred on the 26th December, 2018. The high pressure sat just off Ireland and pulled up warm air accompanied by high humidity and light winds and gave us rampant disease pressure. A great day for walking off Christmas dinner but not much else 🙁

So as we go into more avariable weather pattern with low pressures pushing through and then a period of high pressure, we have to be especially on our guard from a Microdochium perspective.

General Weather Situation

So looking back at last week’s blog, I predicted a calm, dry start to the week with a low pressure moving through from Tuesday for the west and that’s pretty much how it will play out this week.

So Monday starts off dry for most of the U.K & Ireland save for a slow-moving rain front that’s affecting The South Coast and South East bringing consistent rain this morning I’m afraid. Elsewhere we have a few scattered showers pushing in off The North Sea on a north-easterly wind so expect some sharp showers across East Anglia and Lincolnshire. As is usually the case with a NE wind, the west / Ireland ends up being drier and that’s the way we look at the moment with a cold bright start for Ireland and Scotland (more in the way of cloud over the latter). Through the course of the morning we will see that rain over the south-east of the U.K remain stubbornly in place and only slowly move off into The Channel this afternoon. Elsewhere we look to remain dry if a little dull with the odd shower pushing in off The North Sea. As normal with a NE wind, it’ll feel cool with 8-10°C for Ireland in that bright sunshine, and 11-13°C for the U.K with more in the way of cloud cover.

Onto Tuesday and overnight we see rain push into the north-west of Scotland. This is associated with a new low pressure system but unlike my projection last week it isn’t now due to push in till overnight Tuesday so we have another reasonably dry day for the U.K and Ireland as a bonus 🙂 It’ll feel a little milder as well because the wind will swing round from north-east to south-west and it’ll pick up in strength for the north and west as that low makes its presence felt. So 11-13°C  again I’d say for Tuesday, plenty of cloud cover so a little on the dull side with the occasional sunny interval. With skies clearing later it looks like being a cold night with some mist / fog patches and light winds.

Overnight into Wednesday we see that rain nudge into the west of Ireland and push eastwards into The Midlands by lunchtime. It then looks to stall which is bad news for the west of Ireland as that means the associated rainfall totals will be high I’m afraid. Further east we look to stay dry  and largely dull though the north and north-east of England may see more in the way of the sun during the day. During the late afternoon that rain front makes a 2nd push and moves eastwards into the east of Ireland and north-west of Scotland. At the same time an associated front looks to push into the south of England, South Wales and the Midlands during Wednesday evening so a wet end to the day there. Overnight some of this rain will be heavy for these areas but either side of that rain will remain dry. Similar temperatures to Tuesday with 11-13°C. Winds will be light to moderate and southerly.

Onto Thursday and that rain will be straddled in vertical bands across the U.K first thing in the morning and these bands will move slowly eastwards through the course of the morning. Ireland, Scotland and The Border counties though should start off reasonably dry as that rain stays east and south of these areas. As we progress towards lunchtime the rain begins to dissipate but they’ll still be plenty of showers for across the U.K and we will also see a new front push into the west of Ireland and north-west of Scotland. This rain moves eastwards across Ireland during Thursday afternoon and we will also see that rain over the bottom half of the U.K consolidate to central areas leaving showers for the west / Wales. As we approach dusk that rain clears Ireland to leave coastal showers behind with more showers across the east of the U.K through Thursday evening. The rain over the north-west of Scotland doesn’t look to move into central and eastern areas through Thursday so a reasonably dry picture here, some showers around until later into the evening when the rain pushes eastwards. Winds will be moderate to strong westerlies for the north and west with lighter winds further south.

Closing out the week on Friday we will see a drier picture initially but we have a sneaky Bay of Biscay low zipping up into the south-west of Ireland in time for the Sneem morning rush hour (:)) bringing rain some of it heavy. This rain will quickly push north and east across Ireland on Friday morning. Further east and north we have a dry start to Friday with moderate south-westerly winds but by lunchtime that rain has crossed The Irish Sea and will be pushing into The South West, Wales and west / north-west of England / Scotland. The rain consolidates over Ireland and looks to be extremely heavy with flooding possible through Friday afternoon into Friday evening. Not pleasant for you guys. The path of this rain looks to affect Ireland, mid-Wales northwards and the north-west of England / south-west of Scotland later on Friday night with some of that rain turning to wintry showers over elevation. South of this rain front probably from The Peak District south should have a mainly dry and dull day with a moderate to strong south-westerly wind. Similar temperatures to the rest of the week on Friday, 11-13°C .

Not surprising then that Saturday look some heavy rain overnight for the north-west of England and Scotland with Saturday morning looking to start with a band of showers across Ireland and England and heavier rain for Scotland combined with a freshening wind that swings northerly through the day. Saturday afternoon could see those showers move through to give a brighter picture over England and Wales but still the threat of showers across the south and west of Ireland with heavier rain over Scotland. Some of the rain over Scotland will again fall as wintry showers over elevation. Sunday looks a much better day as we pick up lighter winds and that rain pushes away so not a bad 2nd part of the weekend for the U.K & Ireland with maybe some showers Sunday p.m. across The South West. Remaining in that 11-13°C temperature range though.

Weather Outlook

That drier end to the weekend is courtesy of the high pressure system that I predicted last week should settle our weather down from next weekend onwards but the question is will it last ?

Well at this stage the high pressure doesn’t look like it’ll keep the rain away from Ireland and the west, but it should give the south east and east of the U.K some respite. So we will have a west-east split next week I think, well at least for the 1st part of the week with warmer air for the south and south east of England pushed up against a more unsettled picture for Ireland, the north-west of England and Scotland with rain pushing through here on Monday, Tuesday and to a lesser degree on Wednesday. By Thursday those Atlantic fronts are lining up again and the high is projected to get pushed out of the way allowing the unsettled weather to encroach further east across the U.K. So by the end of next week I think we will be back into the western air stream with strong westerly winds and frequent rain. Ho hum it will be a wet October for many of us.

Agronomic Notes

Microdochium nivale disease pressure

As you can see from the graphs below we are predicting a high spike in activity this week for some areas of the U.K and Ireland with mild air, light winds and high leaf wetness probability for some.

For the north and west this probably won’t be a problem because you’ll already have higher wind speed and rainfall as a new low pushes in but for The Midlands south I think we will see some heavier pressure this week if we get lighter winds at night and mild temperatures.

This is pretty much on par with last year.

You can see the milder nights on Wednesday, Thursday and Friday that could present an issue in the Meteoturf graphic for the Bracknell area below ;

Contrast this with Meteoturf output taken from Dunbarton, Glasgow and you can see how the scenario’s are quite different with the milder nights early in the week for the north (and Ireland) and then a pronounced drop off in temperature at the end of the week as that cold low pressure moves through. Unlike the southerly locations though, those milder nights will be accompanied by higher wind speeds and rainfall and that should lower the Microdochium pressure.

One size hat certainly doesn’t fit all when it comes to disease pressure….

Fungicide Longevity

Now I’ve used some weather data from Northampton (cheers Rob) to plot likely fungicide longevity this month assuming an application was made at the beginning of the month (which is normal) . I work on a cumulative G.P of 10 for fungicide longevity but of course that number comes with a few caveats. Firstly, a fungicide won’t just suddenly stop working nor will it work from day 1 of the application unless it is a contact curative fungicide and we don’t have those anymore. That said you could apply that definition to a protectant chemistry like Fludioxonil (Medallion and a component of Instrata Elite) because it sits on the plant leaf rather than enters into it and so is effective as soon as it is applied as a protectant. (Not as a curative note)

So that figure allows for a ‘cross over’ between one product dipping out and another one being taken up by the grass plant.

The graph above is obviously using predicted max and min temperature data from 21st October – 31st October. The initial application is projected to have lasted around 19 days from 1st October, with the 2nd application likely to last a good deal longer because of the cooler 2nd part of the month that is forecast.

This follows a very similar pattern to October 2018 with the 1st application lasting 14 days and then the 2nd one extending into well November.

Spray Windows…

Now obviously with the variable weather dynamic across the U.K your local forecast is key.

The Weathercheck output above indicates that finding a spray window is a tricky proposition this week especially in the north and west with the growing chance of rain as we go through the week and the cooler outlook meaning slower uptake of products.

Further south it isn’t a whole bunch better with Monday and Tuesday good spray days and then a decreasing probability thereafter. If the disease probability projections are right you’ll need to be covered this week going into next for sure…

OK,  that’s all for today, the in-tray beckons…

All the best.

Mark Hunt

 

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.