With temperatures into double figures at the weekend in some locations and probably into them today in most, you could be forgiven for thinking that spring is on the way and we have turned the corner from winter. Last weekend I was walking in horizontal sleet and snow with all my layers on, this weekend gone I could have walked in a T-Shirt. Next weekend hmmm more about that below….
Unfortunately the arrival of an early spring is unlikely to be the case in 2018 because of an event taking place way above our heads in the upper atmosphere known as Sudden Stratospheric Warming (SSW). I am indebted to Mick over the Irish Sea for bringing this to my attention at the back end of last week. A Sudden Stratospheric Warming event is not uncommon at this time of year but its effects on our weather can be profound and prolonged, you can read a full explanation of what constitutes an SSW here.
In a nutshell the occurrence of an SSW can fundamentally disrupt the flow of the jet stream to a point where it stops and even flows back in the opposite direction to its normal west – east flow. This then allows cold air to flow in from the Arctic east / Siberia and we have a prolonged period of cold until it kick starts again. Now the other point that should be said is that there’s no real way of predicting what’s going to happen beyond the 5-day mark forecasting-wise because an SSW doesn’t always result in prolonged cold weather but all the indications are in my view that it will do. The last time this occurred was in March 2016 and before that, January 2013, and you’ll remember how cold those springs were with snow still in the hedgerows at Easter in 2013.
Another feature of an SSW event is that we also see a shift in the position of the jet stream far to the south of the U.K and looking at the output from Netweather for this coming weekend we can see the main body of the jetstream is flowing over North Africa instead of mainland Europe. I for one have never seen it this far south.
You’ll note the deep meandering split from the jet stream over the U.K which will allow a blocking high pressure to establish over us and set in place an easterly airstream that has its origins across northern Scandinavia and Russia. Now eventually the speed and position of the jet stream re-establishes and we come back into a milder westerly airstream and currently the prediction is for this to occur in early March so we are likely to pick up 10-14 days of cold weather as a result of this SSW. I say ‘likely’ but there is great disagreement and uncertainty when an SSW occurs in forecasting beyond 5 days so I must add the caveat of watch this space and your forecasts from the weekend onwards, if you see temperatures diving and the wind direction in the east then the SSW is having its predicted effect.
One last point and it is a positive one for our industry I believe, SSW’s in my experience tend to bring in cold weather from the east but seldom wet weather so if you’re looking for a dry spell to finish off winter projects or just to dry your golf course out then you may well get it.
If you take a look at the Unisys graphic at the top of this blog you’ll see the unusual phenomenon of weather systems moving east to west towards the end of the run, that’s the SSW effect they’re projecting.
General Weather Situation
So Monday starts off mild but overcast for most of us with a band of dissipating rain sitting across central and eastern regions of the U.K in a vertical line all the way from the south coast up to Scotland. Through the morning this will drift eastwards and depart into The North Sea to leave a dull but very mild day for all of us. Ireland the same, dull, cloudy but mild with I think South Wales picking up the mildest temperatures just shy of 15°C, treasure them because you won’t be seeing the thermometer anywhere close again for awhile me thinks. Come the back end of the afternoon we see a new rain front push into west Munster / Connacht and move eastwards across Ireland and also the west coast of Scotland later on Monday evening. Winds will be light and more north westerly I think.
Tuesday sees another mild night / start to the day with temperatures unlikely to dip below 6 – 8°C in most places overnight and almost a re-run of Monday with some light rain sitting across the north east of the country and moving off into The North Sea through Tuesday morning and leaving us with another pretty dull day with the exception of Scotland which will see some brighter weather over central parts through the 2nd half of the day. We may also see the sun across the west of Ireland and along The Bristol Channel. A slightly cooler feel to the day as an arriving high pressure (cue the first piece in the SSW puzzle moving into place) brings a more northerly airstream into play, so 7-10°C is likely in a moderate to strong northerly wind with again Wales likely to be warmest.
Wednesday sees that wind swing round to the north east and so we see temperatures take another dip down from the previous day, this time towards the 5-6°C region and that’ll begin to set the stall out for what may well transpire if the SSW plays out as predicted by some weather models. With any easterly airflow it’s usually the west of the country and Ireland that sees more of the sun because of the propensity for ‘Haar’ and low cloud to push in from The North Sea and that is likely to be the case on Wednesday with brighter spells across Ireland and the west and here we will see the highest temperatures and cloud cover for the east. Dry though.
Thursday sees the wind turn full on easterly and perhaps in the direction we shall be accustomed to for a little while and so a mix of cloud and sunny intervals on Thursday, a light to moderate easterly wind and dry. Not really the end of the world though is it ? We will probably get our first night frost on Thursday night and this will then kick in a succession of night frosts I think dependent on cloud cover. It has to be said that because we have easterlies in situ, then the west will have the best of the temperatures with Ireland perhaps sitting in the 6-8°C range vs. 2-4°C for the east of the U.K.
We close out the week with a much colder day on Friday with again easterly winds in situ. A mix of cloud and sunshine though and dry so really a repeat of Thursday except we are starting each day from a progressively colder base as the degree of overnight frosts ramps up. This will especially be the case for the coming weekend where I think we will pick up some pretty keen night frosts. So dry again and with sunshine and patchy cloud, not a bad day but a pretty cold easterly wind. Temperature-wise I think Ireland will be warmest at 5-8°C and the east coast of the U.K, the coldest, at 2-4°C.
The outlook for the weekend is pretty similar to the end of the week I think but for the fact that we will have some pretty severe night frosts across the U.K, I’d say -3 / -4°C territory with Ireland just staying the positive side of a frost. The other feature of the weekend will be a strengthening easterly wind which will push in more cloud cover and ramp up the windchill so lower day time temperatures and less in the way of sunshine for central and eastern areas with the best chance of seeing the sun across the west. Truly bitter weather for sure so wrap up well with a negative windchill likely.
As mentioned right at the start of this blog there is a great deal of uncertainty surrounding where the weather is likely to go after the weekend with broad disagreement between models but I’ll pin my flag on Unisys’s interpretation and we will see how we get on. So I’d say next week looks to be a bitterly cold one with biting easterly and north easterly winds pushing cloud cover in off The North Sea, ‘Baltic’ would sum it up. There may be a risk of wintry showers from eastern and central areas as a nearby low pressure feeds moisture into the airstream but currently this doesn’t amount to much (but we will see). There’s a sneaky low pressure passing very close to the south coast later on next week and this will be one to watch if it nudges northwards but at this stage it is set to miss us. Later in the week the wind edges round to the north east to rachet down the temperatures even more. The only saving grace is that it’ll be mainly dry but I think we will have a run of successive night frosts starting at the end of this week and continuing for at least 10 days. Now that’s one interpretation, there are others but time will tell who has the correct handle on predicting our weather under the influence of an SSW. If they are right it won’t be till around the 5th of March before the job rights itself again.
Following on from last weeks blog on spring aeration and whether March and April are the best months for us to do this I just to wanted to clarify my viewpoint.
The gist of what I was trying to say was that we have to cut our cloth to suit and so if the weather outlook / GDD looks grim for the next 7-10 days in March / April, then I don’t see the point in double hollow coring, Gradening and the like if your expectation is for poor recovery. Fine to do that in January if ground conditions and O.M levels dictate that this is feasible / necessary but not for early March if we are stuck in an easterly airstream as indeed we may well be. So I’d rachet off my spring aeration if conditions aren’t conducive to recovery but on the understanding with your club that it still needs to be done at another point in the season.
This point is typically August because with summer holidays and the like, it is often quieter from a play perspective, we have optimum growing conditions normally and provided you have the resources and an irrigation system that works, I see no reason why you can’t gain recovery in 7-10 days from aggressive aeration. The greens are then set fair for the autumn and what is now one of the most popular revenue months of the year, September.
There’s a flipside to this coin and that’s if the weather outlook / GDD looks optimum for recovery and here you could up your game in terms of organic matter removal because you know the conditions for recovery are likely to be good.
Let’s look at the last 7 years from a GDD prespective and see how an early and late spring pan out in relation to an SSW event.
We can see from the above that over the last 8 Springs we have had 3 SSW-related cold snaps and this has really affected the amount of growth as determined by GDD.
So in essence what I was saying last week is summed up in the graph below, i.e if we are looking likely to have a cold spring think about if you are going to aerate and perhaps as importantly, how you are going to aerate….
So the graph below shows a comparison of two springs, one in 2016 when we had an SSW event and subsequent cool March and April, the other 2017 when we didn’t. It assumes we aerated on March 1st in both years and that soil moisture and nutrition were in place to gain recovery. It also assumes a total Growth Potential of 4.0 is the magic figure to gain recovery from 12mm hollow coring at 2″ spacing (mixture of units there, sorry it’s just habit)
So there you have it, 15 days in a good spring and 35 days in a poor one…
Plenty of pecking out there…
Well it’s clear the Corvid species (Rooks, Crows, etc) haven’t been watching the long-term forecast because these guys were laying eggs in January and now have some hungry mouths to feed. That has resulted in alot of reports of pecking activity around greens, tees and the like. One club I visited last week had put up some rotating Crow scarers which were having some effect (if you kept moving them) and also a model of a dead crow which looked very life-like. (or dead-like I guess ?). The culprit in the above case was immature Chafer Grubs, clearly recognisable with their defined head vs. Leatherjackets. And of course we have nothing to treat either so it’s a case of trying alternative methods as described above or grinning and bearing it for the time-being I’m afraid.
Ok that’s it for this week, let’s hope all the projections are wrong and the SSW doesn’t have its predicted effect on the weather and spring arrives on time 🙂
All the best.