March 11th, 2024

What a miserable day yesterday with cold temperatures and steady rain. It was without doubt what I call a 'garage day'. So I dutifully spent my time working on my motorbikes and watching the 1st round of MotoGP. That easterly wind ushered in a low cloud base and vectored the rain up across The South East, across East Anglia, The Midlands and into northern England. Another 10-12mm to top up levels that just didn't need any topping up. I fished the Trent on Saturday and the fields around it were still flooded and bare, crops were thin and hypoxic. Even fields with a good stand as shown below are displaying a good degree of nutrient leaching, with no opportunity to replace as the fields are too wet to take a tractor and spreader. Like our industry, agriculture is really feeling it at the moment.

Now we have a better week coming up, still unsettled but crucially we will lose that easterly wind (for now), picking up a freshening south westerly and we will have reasonable E.T. Nothing major, but it means the winds will be drying ones between the showers and that wind will push those showers through quickly, rather than the static low pressure sitting over the U.K & Ireland as we had yesterday. Temperatures will also pick up nicely. So if you are sitting there looking at a wet, drab scenario across your golf club or facility, despair not, a better week is on the way.

General Weather Situation

So we start the week with low pressure sitting off to the east of us edging away towards the continent. As it does so, it'll mark an end to the easterlies and a change in the wind to south westerly. This wind change means 3 things, milder temperatures, stronger drying winds (with some positive E.T) and a tendency for the unsettled conditions to vector more north and north westerly as the jet stream lifts northwards.

So this sets the scene for the weather this week which I will summarise rather than going through day by day as the pattern is the same. Today (Monday) is likely to be the driest day of the week along with Friday but for the north west and Scotland, you will be on the receiving end of that hike in the jet stream vectoring the rain more northwards. So Tuesday through to Thursday sees a steady stream of rain pushing across Ireland and into the north west and north of England / Scotland. Early in the week the rain will be more southerly but it will lift northwards as the week goes on, providing some respite further south. Tuesday in particular looks wet as that rain arrives across Ireland on Monday night and then heads east into Wales, England and eventually Scotland.

Wind-wise, south westerly, strong at times is the order of the day with Wednesday featuring the strongest winds.

Temperatures will gradually pick up towards the low to mid-teens, 12-14°C for Ireland, England and Wales, 9-11°C for Scotland with more in the way of low cloud and rain. They'll pick up from Tuesday onwards and stay there all week and into the weekend. With a south westerly wind and cloud cover, night temperatures will be 7-9°C, so no risk of frost.

So an unsettled week and coming weekend, but aside from the rain, a more spring-like one than last week for sure. You know in the 'old days', springtime was typified by sunshine and showers.

Thanks to tropicaltidbits.com for use of the GFS graphics

Weather Outlook

Now next week's weather looks interesting because we 'may' see a return to easterlies but for a different reason than earlier in the month. So last week we had low pressure sitting south of the U.K, funnelling in easterly winds, whereas next week we may have a northerly high (our first since October I'd say) funnelling easterly winds and next week we may see the potential formation of a blocking event or an 'Omega Blocking Event' to be more accurate.

So the outlook for next week is a continuation of the sunshine and showers theme from Monday through to Wednesday, with mild temperatures, a south west wind and rainfall more northerly and north westerly. As we proceed through into the early hours of Thursday, we lose the wind and that high pressure slips in from the north and spins the wind back easterly.

My dad used to say "Back to the wind, low on the left" which is entirely accurate but easterly winds can be associated with both low and high pressure system, with an entirely different weather outcome. I have tried to illustrate this below ;

So last week we had easterly winds courtesy of low pressure illustrated by the example top left. The weather type is unsettled, lots of cloud, dull and wet. Towards the end of week we will see the opposite potentially taking place as the easterly winds are vectored in by a northerly high pressure. The weather outcome associated with this is usually cold, dry, bright with night frosts and mist / fog. If this does take place then the projections for later in the month is the formation of an Omega blocking event shown below ;

This means low pressure systems are kept at bay and we stay settled and dry. Not particularly warm though but it will give us a chance to dry out properly. Ordinarily I wouldn't been positive on this type of weather pattern but considering what we have had, we need a break in the rain and this may (may) be it.

Agronomic Notes

Looking at the forecast we have a nice growth window coming up and in my mind it is imperative that you focus on utilising this window.

Why is it important ?

Well because 'if' we do enter into an Omega Blocking Pattern, we could see a cold nights / warmer days scenario, which we know from past experience is not a great one for generating consistent growth. Below, are 2 examples of day and night temperatures which highlight the crucial difference between the 2 types of weather we may experience.

Example 1 - Warm days, cold nights typical of a spring high pressure blocking event

Example 2 - Mild days, mild nights typical of a sunshine and showers spring scenario

(Note - I utilise 18°C in the growth potential formulae rather than 20°C)

So we can see that a high pressure blocking event weather pattern-scenario of warm days / cold nights produces 1/3rd of the Growth Potential of a mild days / mild nights, sunshine and showers type-scenario.

That is why if you have early season granular nutrition in place, it is advantageous when we get this scenario. Applying a liquid in a windy, wet weather scenario isn't a viable option, not least because of the impracticality but also the potential for leaching of the applied nutrient.

As discussed before, early season granular nutrition is more efficient and often utilises growth from a more favourable weather pattern prior to the spring.

Lots of caveats here but with confirmation last week of a Sudden Stratospheric Warming Event, (read it here) there is an increased likelihood of the development of a blocking event and wind reversal later in March, as potentially projected in the output above. So that gives us a weather-related growth window leading up to that and then a period of slow growth potential thereafter, if we do indeed see that reversal in wind direction.

On a broader note, to me this illustrates the connection and relevance (there's that word again eh 😉) between understanding weather patterns and their likely effect on agronomic processes, in this case growth. The two are inextricably-linked. Knowing more about the former allows you to make better decisions on the latter.

Have a good week and all the best.

Mark Hunt