Love it or hate there’s simply nothing you can do about it. That glorious conversation piece has recently become even more topical. Here Graeme Pullen gives an insight in trying to understand
“The wonders of the British weather”…
It does not matter what you think about it, I can honestly confirm to you that the patterns of the British weather are not what they used to be.No,come on, they weren’t always as bad,cold,wet,windy,drizzly and pernickety as they are now. We must have had some days over the last forty years that were good. The problem with British weather is that it is changeable, and forecasting just when those good and bad systems are coming through is getting more demanding, even with all the technology the met office has at its disposal. With fishing you need to know pretty much what is going to happen out on the water, and small boaters are especially vulnerable to the whims and fancies of wind strength and direction. While many just consider themselves as amateur meteorologists (I’m one of them), watching out for some of the old timers tips can still “hold water”, though many will soon be forgotten with the age of the Internet. I would guess as the wind drops away on a summer evening and you get a spectacular sunset we all feel uplifted, with enthusiasm for the next day to arrive. Yet for me, even modern amateur forecasting is a bit of a struggle. And its not just fishing and boating in general that needs to watch the weather patterns. It affects a wide range of industries, Agriculture, for crop sowing and harvesting. Building contractors need to know when they can begin certain projects in order to plan their material orders well in advance. Ships need to arrive in port for goods unloading under the best conditions possible. Lost time unloading is lost money, and the main profit on shipping can often come on loading for a return journey.
It was back in the early sixties that there began a rise in serious forecasting, and this was brought about by the rocket inventions during the Second World War, when Germany would fire the “doodlebug” bombs over to our cities. That same rocket propulsion was used in peacetime to send instruments into the upper layers of our atmosphere, and it was then that the true worth of global atmospheric conditions started to take shape. This atmosphere can extend outwards from the earth’s surface as high as 200 miles to the two layers known as the Stratosphere and the Troposphere. The Stratosphere is the higher, and clouds rarely exist higher than 7 miles high. Above that level there is little in the way of weather, and this makes it an ideal place for air travel. Running between the Stratosphere and Troposphere are the high velocity winds known as “jetstreams”, and while they have been recorded as travelling at speeds up to 300 miles an hour, they are the main instigator of manipulating the direction of weather systems. I recall a plane trip back from a fishing trip to Florida. We were hit from behind with a tube of air in the jet stream travelling at 200mph,which coupled to the 550 of the aircraft hurtled us home at 770mph.But get hit head on, or from the side, and the jetstream tosses even a jumbo jet around like a paper toy. I know, I’ve seen many used sick bags on some trips!
It was in early 1976 that I believe I started to notice the change in global weather patterns, though I wasn’t aware of the term back then. All I know is that we used to catch nearly all our summer Tench on the floatfishing method. Still, quiet dawns, mesmeric evenings and lots of fish. Over the next few years it became more difficult to get the perfect floatfishing conditions. Winds would constantly ruffle the surface, dragging the float out of position from the baited area. Today it is rare to get a breezeless day, and the heating up of those high levels of atmosphere are definitely causing more wind. On the boat fishing front it was possible to get lucky several times during a week and go out day after day in perfect conditions. Today those perfect conditions rarely last more than a single day, as another weather system starts barrelling in.
Our prevailing wind direction has altered as well, due to the fluctuating paths taken by the jetstream, as it feeds the Atlantic low pressure systems towards us from America. Now the jetstream can push the lows vertically up to the north and Iceland, where it clips the top of western Scotland leaving wind and rain, while the south and East of the country can remain bone dry. In more recent times not only has that west to east direction slowed, but it has actually gone back the other way! Now that cannot be right. This can allow a blocking high to drop over us from Scandinavia, which feeds an easterly airflow across the country, carrying no moisture. In the winter the high pressure brings cold Arctic conditions, in the summer it produces a dry wind, with no moisture. Traditionally our weather patterns would form around what was known as the “Azores High”. It would move up from the south and bring us good weather, as a high pressure system in the northern hemisphere spins in a clockwise direction. The winds would be warm southerlies or westerlies.But now the Azores High is a rarity, and the high is just as likely to be blown northwards by a wayward jetstream and give us a “set” of winds from the East. Colder winters, wetter, more unsettled summers.
The high and low pressure systems are marked in rings on the weather charts, with lighter winds on the outer edge, and the strongest wind closest to the centre. The rings are measured in barometric pressure contour lines, much like the circular contour lines on a land map that shows you how high a mountain rises. Equate the isobars of the pressure system to a weather map, and you can see that the worst of wind and rain on a low pressure system is inverted at the centre, while a high pressure is like a big dome in the centre, rising high where there are few clouds. A low is like a cup, the high is like a dome. So if you have an interest in at least trying to guage if the forecasters are right, why not look to some of the traditional old school ways of checking what may, or may not happen. All those on a boat will have heard from the shipping forecast the terms “veering” and “backing “The old time saying was that a veering wind brings good weather with its clockwise blowing high pressure system, and the backing winds bring bad,i.e. anti-clockwise low pressure systems. Here’s an interesting tip. If you stand with your back to the wind, the low pressure, or bad weather area will be to your left, and the high pressure or good weather will be to your right.
And clouds in particular, are a great guide to getting a handle on what may be coming. Most of our weather systems should approach from the west, though this is certainly changing. If you get a red flush at sunset (the west) that reaches well up into the sky it may look pretty, but it doesn’t mean good weather. The sunset with a low glow in the west means more settled and fine weather. The highest layer of the cloud family is the Cirrus, consisting of frozen vapour particles, and which are often stretched out by upper atmosphere winds into what we know as “Mare’s Tails”, another sign of winds on the way. If the tail end of the cloud pattern is flicked up at an angle it means a clashing of wind direction, with strong winds and probably rain on the way. Exactly when that arrives is difficult to predict, but it will surely arrive. The most familiar is the Cumulous, derived from the Greek “accumulate”, and these bubble up slowly in fine weather, or quickly if they tower up to over a mile as they gather intensity from the base. The lowest is the Stratus cloud, which scuds across the sky at low level, and when they cover hills and mountain peaks are almost a guarantee of rain. The atmosphere below these clouds is very clear and ships can be seen clearly on the horizon. The same can be said over land. If the visibility is pin sharp and crystal clear then rain is surely on within the next 24 hours. The same goes for definition of the cloud edges against the blue background. If the cloud edge merges gradually into the blue expect fine weather the next day, but if it is sharply edged against the blue then stormy weather is on the way. The “mackerel” sky is that of Cirro Cumulous and looks like ripples on a sandy beach. They are measure that a change for the worse is coming, but it may be short lived. The term “Mackerel sky” must surely come from the early fishing boats under sail that knew they should retire to port while they could, rather than get caught out during a sudden change.
While all of us generally rely the TV weather, met office or independent weather stations it can often be difficult to dispel some of the old weather lore, and it has stood the test of time as some sayings go back to the bible.”Red sky at night, Shepherd’s delight: Red sky in morning, Shepherd’s warning”. The same goes for a pale, watery sunset, that signals incoming rain, or when it is dark and the moon rises it has a pale, watery halo around it. The further away from the moon the halo is, the faster the rain will come in. This ring is formed by the refraction of moonlight through ice crystals in the high levels of Cirrus clouds. I have also seen a halo around the sun in daytime, but don’t look straight at, block the sun out with your hand and you’ll see the halo if rain is on the way.
As for pots of gold at the end of the rainbow, it depends when you see it. You can only see a rainbow with the sun behind you and the rain cloud droplets creating the shafts of light, from the opposite direction. As the sun rises in the East and you see a rainbow in the West it will mean the rain is coming towards you.Diversely, in late afternoon the sun sinks to the West, and the rainbow, or rain will be behind you, in the East. One sure pointer I have learned is that if the barometer carries on falling for 3 days after fine weather the bad spell, when it comes, will last longer. I always reckon if you get 4 straight days of good weather, you’ll get at least 6 or more of the opposite. Although the last three years it has been quite difficult to actually string three good days together in a row. It seems as if there is one good day, or weather “window”, and if you can take time at short notice it’s to your advantage, as it fades into poor weather, and certainly wind, within 48 hours. There is little doubt from my own observations that there is more wind now than there was say, twenty years ago.
Another pointer is to watch out for the term “Ridges” and “Troughs”. A ridge is like a long, narrow mountain range, either side of which are low pressure systems, so if you can get out while the ridge is over you, there is a chance of fine weather, but be aware it is not going to last with two bad weather areas jostling either side of it. The Trough is exactly the reverse, a long, narrow upside-down mountain range shape, but while it may have some short lived bad weather in it, there are good weather highs on either side of it which might just move in your direction.
The data obtained by various land or sea based weather stations, coupled to information beamed down from various satellites would make you think we have everything covered. But data can also be found a long way back from man’s recordings. Shaved down tree rings, when viewed under a powerful microscope show cycles of rainfall in thick rings where tree growth was fast, and dry years, when droughts held back all growth. With Britain lying in a maritime position between the vast Atlantic Ocean and the huge land areas of Europe has proved difficult for even modern forecasters to predict. We can all see the radar images of rain coming in, but you still cannot predict the exact speed of these systems, or the final directions, due to the recently altering direction of the jetstream. There isn’t a day goes by that I don’t tap the Aneroid barometer in my office to see which direction it is heading. Slow movement of the needle in either direction means low winds and good fishing. Sharp movements mean high winds. Low pressure means rain, high pressure means drier. If you take an interest in the older weather lore, and couple it to the TV weather, you will get fairly adept at mowing the lawn at the right time, or picking the best boating or fishing day. Let’s face it. Without the vagaries of the British weather, whatever would we have to talk about!!.
COPYRIGHT: Graeme Pullen. All rights reserved.