Turning cooler this weekend

Turning cooler

As we head into this weekend, it will feel much colder than of late across most parts of the UK. Friday will see more in the way of cloudiness across the UK, especially in some coastal parts of Scotland and northern England. It will also feel much fresher than of late in these parts, with the occasional very light rain shower possible too. Elsewhere, will remain dry throughout Friday, and although it will be noticeably cloudier than of late, the afternoon could see some good sunny spells breaking through in places.

Saturday will also see much more in the way of cloudiness across most parts of the UK. It will also remain relatively dry across most parts of the country once again, and although there could be the occasional light rain shower in some places; these really won't amount to much at all. Saturday evening will then become increasingly chilly across many parts, with a widespread frost likely to develop under clearer conditions.

Sunday will therefore begin chilly across many parts for the time of the year. It will also remain dry across most parts of the country once again during Sunday, but with more in the way of sunshine on offer, especially across more southern parts of the UK. However, there is also the potential for some wetter and windier weather across parts of the far north, as we progress throughout Sunday and into Monday.

James Madden (UK Long Range Forecaster)

ExactaWeather.com

Content copyright © 2010-2012. Exacta Weather. All rights reserved.

Unsettled & colder weekend ahead

Unsettled & colder weekend ahead

As we progress through this evening and into tomorrow, a band of wet and windy weather will bring some heavy rain to parts of Scotland, Northern Ireland and parts of northern England, before pushing into some other parts later.

Some further rain showers will affect parts of Scotland, England and Wales during Saturday too. Sunday should remain settled across most parts after some early rain showers in places, although it will remain unsettled with some further showers possible in areas more south of the UK.

Some of the showers could turn briefly wintry in nature throughout this weekend, especially across higher ground. It will also feel much colder than of late across most parts.

James Madden (UK Long Range Forecaster)

ExactaWeather.com

Published: Thursday 15^th March 2012Content copyright © 2010-2012. Exacta Weather. All rights reserved.

UK Long Range Winter Weather Forecast 2011-2012

Duplicate from exactaweather.com (Published: 18th June 2011)

UK Long Range Winter Weather Forecast 2011-2012

My UK long range winter weather forecast in Layman's terms and the reasoning behind my basis of a severe winter weather warning for 2011-2012.

Low Solar Activity

Periods of low solar activity at present and what we have seen in recent years influence the Earth's atmosphere by allowing the stratosphere to cool. This has a somewhat more profound effect over Northern Europe and the UK in terms of colder and snowier winters, due to jet stream patterns that block warm air from reaching us and create more moisture. Although sunspot activity has increased somewhat this year and there has been an increase in solar flare activity, the activity is minuscule in comparison to what it should be like during a solar maximum and in terms of frequency. Periods of low solar activity such as this have future repercussions of low solar activity in future cycles and produce extra cloud cover that reflects sunlight with a cooling influence on Earth. The lack of major sunspots and solar flares clearly indicate a slower conveyor belt within the sun. We are now in a very weak solar maximum and my observations indicate that the next solar cycle will also be weak.

La Niña

La Niña is the cooling of the Pacific Ocean near the equator and influences changes to atmospheric pressure and wind changes. In terms of the UK this makes the jet streams in the North Atlantic stronger and therefore offers more precipitation in the form of widespread heavy snowfall during below average temperatures as cold easterlies dominate. Recent indicators from the NOAA suggest neutral conditions for the season ahead, but it is also important to consider the current Pacific Decadal Oscillation (PDO) which switched to a cold phase during 2008. The PDO is a pattern of Pacific climate variability that switches phases and lasts for 20-30 years, resulting in stronger La Niña and weaker El Niño conditions that make the likelihood of La Niña conditions returning very high. However, any return to La Niña conditions this year will not be as strong or have the same influence on the much needed respite that we received in the latter part of last winter, in terms of the milder weather conditions from the high pressure systems it produced in the North Atlantic.

Gulf Stream/North Atlantic Drift

It is visible to see from recent NOAA satellite images that the Gulf Stream/North Atlantic Drift has drastically altered within the last few years. The Gulf Stream is basically a huge volume of heated water that brings warmth to the UK in terms of a mild atmosphere. This softens the climate we experience for the latitude we lie on. For example let's take Newfoundland who lie on a similar latitude to the UK, yet they experience much harsher winters as they do not benefit from this valuable heat source.

Here is a quotation from Matthew Fontaine Maury who was nicknamed ”Father of Modern Oceanography” and "Scientist of the Seas".

"A SIMPLE calculation will show that the quantity of heat discharged over the Atlantic from the waters of the Gulf Stream in a winter's day would be sufficient to raise the whole column of atmosphere that rests upon France and the British Islands from the freezing point to summer heat" (Physical Geography of the Sea, 1855).

Volcanoes

The Icelandic volcanic eruptions Eyjaffjallajokull 2010 and Grimsvotn 2011 are important in terms of sunlight reflection over the Northern Hemisphere. The dust and ash particles can remain within the atmosphere for one to two years and reflect heat away from an already quiet sun. Converted sulfur dioxide emissions from volcanic eruptions can also cause sunlight reflection in the atmosphere. It is also important to consider the currently erupting Chaiten volcano in Chile as this may have the potential to cause long-term climatic effects globally.

Conclusion

I therefore expect the 2011-2012 winter to follow a similar pattern in terms of how November and December was in 2010 for the vast majority of this winter. It will be exceptionally cold and snowy with well below average temperatures. I fully expect to see records broken with the highlands of Scotland being once again particularly hard hit. It is therefore vital to start preparing now in terms of high energy bills and raising awareness amongst the most vulnerable and elderly people of society.

James Madden (UK Long Range Forecaster)

http://www.exactaweather.com/

Published: 18th June 2011 (21:29) BST

Content copyright © 2010-2011. Exacta Weather. All rights reserved.

UK Winter Forecast 2011/2012 - Update

Duplicate from exactaweather.com (Published: 30th May 2011)

UK Winter Weather Forecast 2011-2012

The importance of the Gulf Stream and thermohaline circulation (THC) are vital in regards to the upcoming 2011-2012 winter. I firstly issued my original warning on Exacta Weather over four months back in regards to the upcoming winter. I also clearly stated at the time “that the UK will begin to see the dire lag effects of the Gulf Stream, especially if nothing improves soon”. I first issued my concerns in regards to the gulf loop current and the functioning of the thermohaline circulation over 12 months back, along with the consequences of what might happen in regards to the Gulf Stream since 2008.

In terms of sea surface temperature in regards to the gulf stream, the diagram (FIG.1) below should be more comparable to the left hand side, than the right hand side at present.  Unfortunately the NOAA only allow you to run reports for a short time period now, hence this being the example I have used.

FIG.1 NOAA, (2011)

In terms of the surface horizontal current in regards to the gulf stream, the diagram (FIG.2) below should also be more comparable to the left hand side in 2009, than the right hand side at present.

FIG.2 NOAA, (2009 and 2011)

The gulf loop current is a key part of the thermohaline circulation that regulates world temperature. This has drastically altered the Gulf Stream and this is not the sort of system that can re-establish as rapidly as it declined. So, unless I am mistaken and the textbooks are wrong, the UK will without a doubt see progressively worsening winters due to its latitude, as will other European countries that benefit from this valuable heat source.

There are some recent suggestions that a neglected current known as the Agulhas Current may compensate for this valuable loss of heat, in the form of leakage. Unfortunately, there is very little or no evidence to confirm this, with no immediate signs of compensation in terms of the Gulf Stream. It is difficult to assume that this is the answer to our problems, especially with something that has been rarely studied and is very difficult to measure.

There are also suggestions that the Gulf Stream acts as a major steering mechanism for the jet stream. Although I do believe that it has some influence, a primary driver of the jet stream within my calculations is also solar activity.

We must also consider other major natural factors such as La Niña, and how this can influence the jet stream in terms of the UK and Europe. Recent NOAA predictions give a 50% chance that La Niña will have completely disappeared by June 2011. However, I am not convinced that it will completely disappear. Recent indicators may suggest neutral conditions for the season ahead, but it is also important to take forecast accuracy into consideration for this time of year and the current phase of PDO. The possibility of La Niña redeveloping will become clearer over the next few months.

Periods of low solar activity at present and what we have experienced in recent years, influence the Earth’s atmosphere by allowing it to cool, with a somewhat more profound effect over Northern Europe and the UK. Low solar activity also enhances cloud formation and therefore influences lower temperatures, with future repercussions of low solar activity in future cycles. This also has a major influence on the geomagnetic index, solar flux, and the behaviour of the jet stream.

In terms of sunspot activity, the diagram (FIG.3) below should be more comparable to the left hand side during a solar maximum in 2001, than the right hand side at present.

FIG.3 SOHO/NASA (2001 and 2011)

Although sunspot activity has increased and there are some visible sunspots, they really are minuscule in comparison to what they should be like during a solar maximum.

It is also important to consider the Icelandic volcanic eruptions Eyjafjallajökull and Grimsvotn, in terms of sunlight reflection over the Northern Hemisphere from an already quiet sun.

Based on the natural factors that I have covered and in terms of how I calculate solar activity into my forecasts, it would be adequate to suggest prolonged periods of well below average temperatures and widespread heavy snowfall throughout this winter. This will result in the fourth bad winter in succession for the UK, and will prove to be the worst of them all. I now fully expect records to be broken, with the Highlands of Scotland being once again particularly hard hit. It is therefore vital to start preparing now in terms of high energy bills, and raised awareness amongst the elderly and most vulnerable people.

Content copyright © 2010-2011. Exacta Weather. All rights reserved.