October is the shoulder month in my mind between the end of summer and the beginning of winter and it brings with it some beautiful autumn colours. They may be the bane of greenkeepers and gardeners lives but you get some beautiful colour scapes from the changing hues of the leaves on the trees as you pass through the countryside. You also get some lovely cloudscapes as well with the lower light levels.
Yesterday I was hanging onto the coat tails of the end of the fly fishing season with a bloody cold wind coming off the water, it really chills you to the core it does. In the background you can see yet another menacing heavy shower that effectively finished the day and had me scrambling for the jetty before getting soaked. It was quite a shock to see the sun setting before we’d even got to 5 p.m now the clocks have gone back.
It is of course also a month associated with mild, muggy and humid weather particularly (for some strange reason) over Halloween and the like and so it’ll be this week / weekend as we pick up a high pressure plume of mild air that’ll send day temperatures up into the mid to high teens across the south of England and night temperatures into double figures. One to watch I think.
Of course all of this (blog) pales into insignificance when you consider the continuing effects of Covid-19 on our lives and our industry. The Republic of Ireland entered a 6-week lockdown from Friday night I think and Wales, the North of Ireland, a 4-week lockdown starting earlier this month and Wales, a 17-day lockdown. Scotland and England are operating under a multiple tier system but you wonder if it is only a matter of time before we head the same way as the rest. In some areas golf courses are closed again for essential maintenance only but you wouldn’t blame clubs from getting all their aeration done whilst they are closed so they don’t need to disrupt surfaces for the rest of the year and / or for next spring. It makes to sense to me and is one of the few positives from what is a challenging and somewhat depressing situation for us all to face. The economic impact of Covid-19 continues to be felt and will do so for many years to come. Positive vibes to you and your families.
Onto the weather.
General Weather Situation
As you can see from the GFS output above, we are sitting in a cold, deep low pressure system that’s currently pulling down chilly winds from The Arctic, so although a SW wind direction is normally associated with mild conditions, the temperatures definitely aren’t. No surprise then that Monday’s weather fits into an unsettled theme with bands of rain pushing across the U.K from west to east, with some particularly heavy showers running along the M4 as I type this. Ireland will see some showers along west and north west coasts but by and large these will fizzle out to leave a dry second half of the day. Scotland looks to be in for a wet Monday with heavy rain moving west to east through the day. Not as windy as of late today but still moderate to brisk winds on exposed sites and remaining cool with temperatures in the low double figures after a single digit night for many.
Tuesday look to continue the unsettled pattern with a band of rain into Ireland from dawn. This band of rain will push quickly eastwards across The Irish Sea into The South West and Wales by early doors and then it’ll move across the country from west to east through the course of Tuesday. It should clear the west of Ireland through Tuesday morning and probably won’t reach the east coast of Scotland / England until later in the afternoon but for central areas it will represent a wet day as it moves west to east. As the rain moves easterly, it’ll swing the wind round to southerly briefly but that won’t do anything to help the temperature which will still stay rooted in the 10-12°C range I’m afraid. By early evening that rain will have cleared most of the U.K, just in time for a new rain front to push into the west of Ireland.
Overnight into Wednesday this next band of rain will push showers into the west of Ireland, England,Wales and Scotland, aided by a strong south westerly wind. By lunchtime, these showers will consolidate to form heavier rain across the west of Ireland pushing into The Midlands and for the U.K, Wales, The South West, north west England and the west of Scotland. During the afternoon these showers will move eastwards slowly into more central areas but as they do so they’ll dissipate leaving a sunshine and showers end to the day. Similar temperatures to earlier in the week, windy with a predominantly south west wind direction.
Onto Thursday and a subtle change in the weather dynamics as you can see from the GFS output above. Rather than a cold, unsettled trough we are morphing into a warmer, high pressure peak but also you’ll notice the closely packed isobars which means pretty windy with it ! Not a a dry day unfortunately though as heavy rain will push into Ireland from first light. This rain will be spread across the whole of Ireland on Thursday and by the morning rush hour will already have reached The South West and Wales. By lunchtime the rain will be across most of the U.K except central and northern Scotland, but it’ll always be heaviest across western coasts. Clearing the south west of Ireland and England during the afternoon, it’ll continue to push north and eastwards leading to some pretty heavy downpours across the north west of England / Lake District. As we progress through the afternoon this rain clears the southern half of the U.K leaving a nice, mild evening. Milder as intimated above on Thursday with temperatures nudging into the low to mid-teens in a strong to gale force (later) south westerly wind.
Closing out the week on Friday we see this milder air push further north as a ridge of high pressure tries to exert itself. Not a totally dry picture though as Ireland will see some heavy rain across the south, south west and western coasts throughout the day. The same for the U.K with some potentially heavy rain for The South West, West Wales and up through the north west of England into the west of Scotland. At the moment it looks like this rain will stay on western coasts so the east of Ireland may just pick up showers. Across The Irish Sea and away from those showers in the west, we will see a much drier picture, though dull I am afraid. Those strong south westerly winds will moderate through the day and that’ll allow temperatures to nudge up into the mid-teens, so feeling really mild for the time of year but of course we know the end of October typically follows this pattern.
The outlook for the weekend is mild and unsettled.
Saturday looks like being wet from The Pennines south after a dry start to the day across the U.K, with Ireland looking to have a nice and largely dry Saturday after some morning showers. By Sunday the boot is firmly on the other foot because a new Atlantic low pressure will push rain and strong winds into Ireland overnight and this rain looks pretty heavy. During Sunday morning that rain will push into Wales, the north west of England and west of Scotland and it looks pretty heavy with it. Through the course of Sunday that rain will move south and east into Wales, The Midlands and Central England, but the heaviest rain will sit across The Lakes where I expect some significant flooding to occur as the ground is already saturated. The only consolation to a very unsettled weekend for the U.K & Ireland is the fact that it’ll remain really mild with temperatures still holding between 14-16°C across many areas. A windy weekend as well, especially on Sunday with that mild south westerly airstream continuing.
So above we can see the projection for next Monday when we will be into the start of November. How time flies.
An interesting weather week next week potentially because we look to start the week as we will finish this one, mild, breezy and unsettled particularly for Ireland, the north west and for Scotland. As we progress through Tuesday, that rain pushes southwards on a more north westerly wind so that means cooler on Tuesday. From Wednesday, we see an Atlantic high pressure begin to push in from the west and this will settle down the weather rainfall-wise and bring some cooler, northerly winds into the U.K from Thursday onwards. By the weekend that high pressure will have moved eastwards and that means some potentially cool, easterly winds from the weekend possibly for the southern half of the U.K. Some possibly cooler and drier from mid-week, next week after a mild, windy and unsettled start to the week.
Last week’s high disease pressure across the south of England did indeed show itself on untreated areas but so far I haven’t heard too many horror stories from a Microdochium perspective. We are as an industry adapting our IPM programs to deal with the ever-present threat of this disease. Next week we nudge into November so that’s one of the worst potential months for this disease done and dusted. That said the mild weather forecast from the end of the week may prove an issue and I’ve definitely got my eye on early next week when we could possibly transition from a low to a high pressure system.
The wind is your friend…
Now you may be slightly at odds with that statement if you manage a facility where you have lots of deciduous trees and are currently chasing around and cleaning up piles of leaves only for the process to repeat itself as another load is dumped overnight. You may also be trying to get a spray down and mindful that there aren’t many spray windows this week with the combination of wind and rain, but windy weather is a double-sided coin.
Sure enough we have the negatives that I’ve mentioned above, but wind also creates evapotranspiration which dries down leaf surfaces and reduces disease. High wind speed also prevents dew forming on the leaf and fungal mycelium growing, so having a blowy day is actually a god-send from a disease management perspective. That is why if you are able to create more airflow on sheltered locations, you will create a highly significant effect on disease development, not just from Microdochium but also some of the other prominent foliar diseases like Dollar Spot and Anthracnose Foliar Blight.
The chart below shows the effect of a breezy day on leaf wetness after a small amount of overnight rain…
So you can see a brief rain shower at 03:00 quickly saturates the plant leaf and in a normal, calm day that would probably then translate to a heavy dew and high disease pressure as a consequence. On this particular day the wind gets up from 05:00 and you can see the leaf wetness level drops from 15 (maximum) down to around the 5 mark, which translates to barely damp. As the sun comes up and the wind strength increases, we start to build E.T, and dry down the leaf completely by 09:00. On this particular day we only had 1.0mm E.T for the whole day, typical of the autumn with its shorter daylight hours and lower temperatures, but it is enough to dry down the leaf and surfaces as a consequence. True the amount of rain was low on this particular day but you can see the potential benefits (hopefully) of a breezy day.
Disease Pressure Outlook
Last week I projected some pretty high disease pressure on sheltered sites across the south of England and I did get feedback to this effect. Of course if your surfaces are protected you shouldn’t see this manifest itself as actual disease but may do so on untreated areas like aprons, surrounds, tees, etc. This coming week and again it’s all the about the role that wind will play in drying down our surfaces and limiting fungal mycelium growth. So although we are set for some pretty challenging temperatures from an encouragement of Microdochium nivale perspective, the high winds projected should decrease the impact of those double digit night time temperatures somewhat, except on sheltered locations (heavily wooded sites for example)
Just like last week, the highest pressure is across the south of England because it’ll be nearest to the high pressure system pushing those mild temperatures in at the end of the week. It is also furthest away from the low pressure creating the higher wind speeds and unsettled conditions that we will see across Ireland, the north west of the U.K and Scotland.
The projected disease intensity for 3 sites is shown below ;
So you can see the south of England again is very much in the firing line. (again)
With the combination of mild temperatures and rainfall, we will see an increases in grass growth from the end of the week onwards and likely (unfortunately), an increase in worm activity as well.
So this makes it a great time to get a granular fertiliser down on areas that need a bit of help after a dry September maybe or if you’re doing some renovation and want to speed recovery up potentially ?
Hitting high moss population areas with an approved, high-Fe Mosskiller is also ideal from a timing perspective because the moss will be fully wetted up and the nutrition will also help to tip the balance in favour of grass growth and away from moss growth. This is particularly important as we go through the winter months when low light levels and wet surfaces tend to tip the balance in favour of moss.You can see the growth flush in these Meteoturf snippets taken from different locations around the U.K and Ireland ;
So maybe a welcome increase in growth for some but it will of course mean that any applied treatments will grow out faster, so that means dew control, non-pesticidal and pesticidal treatments 🙁
OK, that’s me for this week, got some Davis weather stations to upgrade / improve 🙂
All the best