Just a week away from the shortest day and winter has yet to really show its teeth. This is normal though because south of the Scottish border and across to Ireland, winter doesn’t really seem to start till after Christmas. Meanwhile we have the rain and a succession of dull days to keep us company 🙁 Yesterday was one such day, dull, drizzling and cold with the night warmer than the day ! Thoughts are already turning to the Christmas Break and whether we will see any change in the mild airflow and for some areas I think we will, especially over Scotland. For the south it is delicately balanced for Christmas Day. My Snufflepigs are still happily consuming a very expensive packet of mealworms a week and only Mum and Dad have curled up and hibernated for the winter, the 4 offspring are making hay while the sun shines, or doesn’t to be precise 🙂
Ok onto the all-important weather and for many the last chance to get a pre-Christmas tonic on.
General Weather Situation
So we start the week with a mix of rain, sleet and wintry showers sitting over Scotland, primarily looking to affect a line from Stirling / Perth sort of way and northwards. At the same time we have a band of rain / heavy rain making landfall in West Kerry. This will push up across Ireland during the morning and will likely give some heavy bursts along the east coast of Wexford and up to Dublin. For England and Wales it looks to be a dull start to the week and by mid-morning we’ll see some rain pushing into the south west and Wales, slowly moving inland through the day to affect western areas. They’ll also be a risk of some rain over The Midlands through the later morning. The sun will be taking yet another day off so expect high single figure temperatures and light southerly winds for most areas, maybe stronger over Ireland and along the west.
Overnight into Tuesday we have that rain still affecting the south and west of Ireland by dawn and also a lighter band of rain over northern eastern England and Scotland. Dull and dreary everywhere else I’m afraid with little sight of the sun. By mid to late morning we see more rain pushing into the south west of Ireland and England and some of this will be heavy in nature. Through the afternoon this rain sweeps north and east across Ireland and England so by the evening only the north and east of England will have been spared. Winds will remain light to moderate and the temperatures similar to Monday, high single figures so nothing to write home about. Through Tuesday night that rain carries on moving north into The Borders and north east of Scotland so a wet end to the day pretty much everywhere, but it’ll be noticeably milder through the night.
Moving onto Wednesday we still have that rain sitting over the U.K and Ireland by the morning rush hour, though it’ll be more fragmented and lighter in places. We will see a change in the wind direction to the south west and this will pull in milder air for mid-week, so milder and windier at the same time. Through Wednesday morning / early afternoon that rain becomes more localised along the west coast, but across the east coast we may even see a yellow round object previously known as The Sun gracing our presence 🙂 These breaks in the cloud cover look to be primarily along the north east coast of England and Scotland, so a mild, sunny end to the day there. Elsewhere we should see that rain gradually fizzle out to leave a mild might going into Thursday with temperatures not likely to drop below double figures.
For Thursday we have rain pushing overnight into and across Ireland so by dawn it’s affecting all areas though perhaps heaviest over Leinster. That same band of rain will also be into the west coast of the U.K in time for the morning rush hour and as it moves inland during the morning it’s likely to become localised and heavy over Wales. By lunchtime that rain is still affecting the west coastline of the U.K from Cornwall all the way up to The Highlands but it will have cleared the east of Ireland to leave some sunny spells would you believe. As we approach dusk more rain moves across Ireland and inland across the U.K to give another mild, wet night concluding with heavy rain for the south east of England. Winds will be moderate to strong especially over western coasts and it’ll feel very mild with temperatures in the low teens.
Closing off the week for Friday and we have light rain affecting the west and north west coast of the U.K and some showers over Ireland. Elsewhere it looks like a dull and slightly cooler start to affairs on Friday as that mild air moves through. By lunchtime we still have some rain across the west coast of Ireland, the north of England and Scotland, but they’ll also be some short breaks in the cloud as well as we move through to Friday afternoon, principally in the south of the U.K. By Friday night that rain over Scotland and the north of England looks to slowly drift down into The Midlands for the start of the weekend. Cooler on Friday with temperatures just making it into the low double figures with a strong to moderate westerly wind.
How are we looking for the last shopping weekend before Christmas ?
Well Saturday looks like being wet as another band of heavy rain pushes in from The Atlantic across Ireland during Saturday morning and into the western coastline of the U.K. The main path of this rain is north and east so it’s possibly that central, eastern and southern areas may miss the bulk of it. The flip side is that Wales, the north west and Scotland won’t. This rain looks to clear Ireland by late afternoon but there’s still a risk of some rain hanging on over west Munster. This western theme extends to the U.K because as we move into Saturday evening the rain will mainly be confined to western coastlines (again) It’ll be feeling mild again in a strong to moderate south westerly wind so temperatures up into the teens again. Overnight into Sunday looks to show more rain moving in a belt up from the south west of England over The Midlands into East Anglia with other areas drier and for Ireland brighter 🙂 It looks to go cooler and windier for Sunday with some cold air pushing down into Scotland and the north of England so any moisture here will fall as wintry showers.
My 10-day projections take me right up to Christmas Eve now so we nearly have a handle on the Christmas period. Here’s how it looks…
Monday looks to start extremely windy with some very closely-packed isobars, particularly for Scotland and the north. Initially this will pull cool air down but it’ll be a north-south divide with cold air over Scotland and milder air over the southern half of the U.K. As the wind will be westerly in nature it’s no surprise that this combination will push rain across Ireland and the U.K on Monday with some of this moisture falling as snow over The Highlands. The windy, mild (for the south) and unsettled theme continues into Tuesday with more strong, westerly winds and rain rattling across the U.K and Ireland. For Wednesday those winds, still strong, swing round to a more north-westerly aspect and that pulls cooler air down into the north of England and The Midlands. They’ll still be showers around, some of them wintry in the north for a time before turning back to rain as the wind shifts round to the south west and pushes milder air in (Blast, bugger and damn for my Paddy Power bets :() Christmas Eve looks to be dry and mild across the south with decreasing winds, but Scotland could pick up a dollop of snow potentially over The Highlands. For Christmas Day I think we could see a sneaky southern low push southerly and therefore mild winds across the U.K and with it some rain, potentially heavy for the south. This pattern of strong westerlies and unsettled milder weather looks to continue through the Christmas period so a potentially mild end to the year in store. That said it’s no different to most years now with mild, wet weather for the close of December courtesy of a strong jet stream that shows no potential to dip south and allow colder weather to prevail.
2015 Rainfall Stats and GDD / G.P Excel Spreadsheet
As we approach the end of 2015, I’ll make my customary appeal for end of year rainfall stats once we have kissed the year goodbye. If you could kindly send them to firstname.lastname@example.org Paul will do his usual excellent job of trying to cram them all onto a U.K and Irish chart so we can see how we’ll all compare. We will also have a new 2016 GDD / G.P Spreadsheet available on next week’s short blog (I’m trying to finish early for Christmas ahahahaha)
This year has really demonstrated to me the benefit of having GDD and G.P information available, especially in the spring to highlight what a difficult start to the season it was with very slow growth up until May. To be able to show when things were growing and when they weren’t and to be able to compare year on year data was invaluable. Growth Potential data also proved its worth in highlighting summer stress levels in early July and pinpointing uptake windows for fertilisers, PGR’s and fungicides. I freely admit I’m learning as I go along here how best to use both models but what can’t be denied is that they are both useful.
To highlight the above I have charted out the growth potential from the beginning of October till the 14th December for this year and last year using data from Sean at The Oxfordshire. (Cheers me dears)
It dramatically illustrates how this autumn / winter has been so much milder than last year (which wasn’t particularly cold anyway) with growth continuing strongly into mid-December (and beyond I’d bet)
You can clearly see that the only real cold snap we’ve had occurred in the third weekend of November…
Rainfastness and Sprays….
Speaking of uptake windows and spray days it looks tricky this week for some of you with strong winds but rainfall the main issue.
I often get asked how rainfast formulations are, particularly fungicides and there’s actually very little credible information kicking around. I am aware that data has been generated for Iprodione (we generated it :)) and the following has been found. (Please note this will vary according to manufacturer / formulation for this active)
Amount of Iprodione lost with 10mm of rainfall following application ;
10mm rainfall 1 hr after application = 45% lost / 55% retained
10mm rainfall 2 hrs after application = 40% lost / 60% retained
10mm rainfall 4 hrs after application = 28% lost / 72% retained
The above represents a pretty rainfast formulation that I do know.
Now 10mm of rain is pretty heavy rain following application but you can see that in essence you need a minimum of 4 hours between application and heavy rain in order to retain nearly 75% of what you’ve applied on the leaf. I think that’s a pretty good benchmark for most sprays whether they are fungicidal or not, so that’s what I work to. Of course once it’s washed off the leaf then it depends upon how well the active binds to organic matter (and thereby resists leaching) and indeed whether the plant can take it up through the root system to determine plant uptake. Either way it’s likely to be a lot slower at this time of year with a definite lag between foliar and soil applications in favour of the former being the quickest uptake option.
So how are we looking this week for spray windows to put on that Christmas tonic ?
For The Midlands and south of England I think the best spray day is likely to be Wednesday after the overnight rain has moved through because you aren’t due more rain until late on Thursday so that’ll give a window of nearly 18 hours. Add in to that the arrival of milder air mid-week means your uptake will be pretty efficient too. Failing that then Friday looks like being half-decent with little or no rain on the horizon though it will be cooler.
For the north of England, Wales and Scotland this one will be tricky because you have stronger winds and more persistent rainfall in your forecast. Your window is likely to be shorter because of this but again I’d plump for Wednesday morning (wind-allowing) once the overnight rain has moved through. Friday also looks better with light rain forecast though the wind will still be a likely issue.
For Ireland it’s a pretty similar picture to Scotland, Wales and the north of England with the bulk of the rainfall passing through up to mid-week and therefore the best opportunity either on Wednesday or Friday. The west of Ireland is a much harder call because you guys get Atlantic rain first and so your windows are short and sweet. Again Friday looks the best window in your week with the heavier rain not arriving till overnight Saturday.
In terms of composition of any spray you’re likely to want to apply, we certainly don’t need much N because as you can see from the above we still have good G.P and therefore growth rates in December so I’d be looking for a small amount of N, a good hit of iron for sure and a little potassium to round it out.
Ok that’s it for now, next week will be an abridged version of my blog all things considered.
All the best.