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The watcher

The Watchers Winter Forecast 10/11

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Winter Forecast 2010-2011

(The Watcher)

This forecast I have constructed using sound knowledge of Global and Hemispheric values and their effects in long term patterns. I have also factored in SST anomalies, amplification of the jet stream and its counterpart in upstream patterns (using an evolving logic) and a small dose of Solar influence.

A La Nina (Strong) dominated winter coupled with a moderate – strong and a high tendency of upstream amplification in the jet stream suggests HP will be dominant in certain areas this winter. Favourable areas are the North Atlantic, Northwest Europe and the UK (in particular). However, at certain junctions I suspect (using an evolution of jet stream patterns) we will see 2 significant periods of a more mobile pattern within the early and late winter periods. Solar influence will be less of an influence this year as we see a slightly stronger period than the minimum of last, although as we head towards a max in 2013 of a somewhat weaker cycle we do have a small helping hand in bringing the colder aspects of winter to light. Let us move on to a little bit of forecasting now shall we.

DECEMBER:

First week of December will begin on a cold-very cold note with High Pressure in situ to the Northwest of the UK with Low Pressure to or on the SE of the UK. Significant snowfall could occur to areas of the NE/E/SE of the UK in the first half of this period, although the SE will tend to be more liable for rain/sleet. Other areas will likely see wintry showers (mainly of snow), most frequent on coastal areas. Frost will be widespread at night, especially to the North and West. Temperatures will be bitterly cold and struggling to get above freezing for most areas.

During the mid – latter half of the first week winds will back WNW-W as a West based -NAO sets in, allowing High Pressure to develop to the SW of the UK whilst Low pressure to the NW pushes SE. An unsettled period for the bulk of the UK will last for around 10 days with the Jet stream pushing North over the UK, bringing wet and windy weather at times and temperatures 3/4c above average by day, with mild nights where cloud cover persists. Although the SW will favour drier weather at times as the High Pressure gets close to the UK. Overnight frosts will be rare during this period.

Into the 3rd week of December we still start to see High Pressure ridging towards Greenland again from the Mid Atlantic. Winds will veer Northwest bringing an initial cold showery spell for Northern and Western areas while the East and Southeast remain drier. As the week progresses it will quickly become colder as an area of Arctic Northerly air heads South over the UK with showers quickly turning to Snow for areas in the North of Scotland and then progressing South to most areas partial to the strong Northerly airflow. The South and Southwest will remain driest overall, but will still see the chance of wintry precipitation at times.

The Christmas period will see a settled spell begin to push over the UK from the SW, winds will become slack allowing frost to become hard and severe at times for many areas, especially central UK. High pressure will likely dominate this period with a possibility of only the far North and SW seeing the possibility of any precipitation at times. Fog and cloud will be extensive in SE areas of the UK.

DECEMBER CET: 3.8c

RAINFALL: 85%

JANUARY:

Beginning on a dry note, especially for Central and Eastern areas, but only a few days in and a breakdown from the SW will occur pushing High Pressure to the North East of the UK and bringing a very brief period of very mild temperatures, wet weather and possibly some strong winds, especially to the S and SE of the UK. This unsettled spell will push into the near continent leaving the North and East to become drier whilst the South and West will see Low Pressure close to the SW at times pushing Eastwards and bringing some wet weather. Winds will be from a general ESE/E/ENE direction during this period and things will cool down from the North and East, bringing colder weather as we approach the mid month period. By mid month the whole of the UK will see colder air sourced from the East and High Pressure situ close to NE Scotland will mean Northern areas will remain driest while the South will be most likely to see precipitation (of a wintry nature) at times.

After mid month we are likely to see this colder spell break down from the West once again with the chance of some significant snowfall in the North and East of the UK as it comes up against the colder air mass in these regions. We are then likely to see a period of Low pressures pushing through the UK, bringing a real mix of weather for all areas, with milder air on the leading edge followed by brief Northerly airflows behind we can expect to see some Wintry showers following any spells of rain, especially for Northern and Western areas. I expect temperatures in this period to be average. As we approach the end of January things will generally settle again for the SW of the UK as the Azores ridges towards us, leaving the Northeast in the brunt of a colder and unsettled period for the remainder.

JANUARY CET: 3.4c

RAINFALL: 110%

FEBRUARY:

Beginning settled in the South and West with the North and East colder and more unsettled with some snowfall for Scotland and NE England. To end the first week High pressure will begin to develop to our Northwest introducing a colder Northeasterly flow for all areas of the UK with some further significant accumulations likely in Northeastern areas as the cold air pools to our NE and spills down over the UK. I expect this colder period to last for 8-12 days with the winds veering between North and Easterly directions during the period, bringing snowfall to most areas of the UK with only the far SW liable to remain the driest. During the second half we will see a breakdown of the colder weather to be replaced with LP to the South and West of the UK, possibility of a snowy breakdown most likely in Central and Northern areas. Once again I expect the jet stream to appear over head or slightly North of the UK meaning a Westerly dominant regime for us all. Temperatures will be generally be average-slightly mild in the latter half and rainfall could be exceptional for Southwestern areas, especially Wales and Ireland. So an unsettled end to February seems most likely with the far North and Hills having the likelihood of seeing any wintry precipitation.

FEBRUARY CET: 4.2c

RAINFALL: 150%

Into March and there is a good possibility we will see a return of some wintry weather into the Second week with a potent Northerly bringing snow to Scotland and some Central areas of the UK, however settling snow is not likely at Low Levels.

I have also created a wind direction percentage chart, showing over the 3 month period what wind directions we are most likely to see.

It is attached below.

post-7838-0-77791800-1290439876_thumb.gi

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Well laid out forcast and easy to follow, Lets see what happens, good luck with your forecast Watcher.

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Thanks guys, a brief summary would be overall a slightly below - below average winter with a few milder interludes. Rainfall to be sparse in the first half, becoming more widespread in the second.

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Yes good detail , i like the wind chart thats a new idea! Many would be pleased to see alot of snow chances, which your lrf shows.

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Interesting read suggesting a real topsy turvy winter with some bitter cold spells interspersed with average and at times milder than average weather, but on the whole a settled winter.

If we are to see high pressure dominating christmas period it will be no less than the fourth time in five years such a synoptic has developed alebit in various disguises -

2006 - heights directly overhead but no real cold pooling so average temps

2008 - cold heights over near continent - cold dry

2009 - cold heights very frosty

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Interesting read suggesting a real topsy turvy winter with some bitter cold spells interspersed with average and at times milder than average weather, but on the whole a settled winter.

If we are to see high pressure dominating christmas period it will be no less than the fourth time in five years such a synoptic has developed alebit in various disguises -

2006 - heights directly overhead but no real cold pooling so average temps

2008 - cold heights over near continent - cold dry

2009 - cold heights very frosty

Yes, seems alot of christmas to new year periods have had HP dominance around the UK lately.

Topsy turvy would be the best description to provide. I believe since the UK's weather is greatly influenced by the Jet streams strength, location and upstream patterns that it is a great way to define periods of stronger zonal/atlantic dominated weather using a patterness evolution to it's position in relevance to the beginning of winter. For instance right now it is amplified and strong and to our South allowing the WAA and GHP to develop, but 10 days from now, it will de-amplify again upstream but remain strong for a week or two before it invigorates again but this time it'll be moderate in strength allowing HP to develop further East and over the UK rather than in the Mid atlantic.

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Signals are good for the cold to recede again for a few days with a NWsterly/Westerly, then a renewed push from the Mid Atlantic high North pushing a Northerly overly the UK again before HP moves SE over the UK again for Christmas, I've good confidence in this with what Teleconnections are showing and the general pattern of the Jetstream.

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The rollercoaster continues....I could well be short of the mark (too high) for this years December CET value judging by the trends, but I'm certainly VERY happy with what I have suggested in my forecast simply because my forecast was alot more detailed than many others....apart from Crewecolds....his was very detailed too.

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December turned out well for me apart from the CET Value, something I will have to consider more thought process into when I forecast a month like that. January upto first few days was okay, then instead of a NE/E Blast we had the Northerly, which is looking like breaking down just before mid month. I'm still expecting a few Northerly flirts during the atlantic runin, but I don't see another potent blast of cold air until last minute January, start of February.

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