http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/30mb9065.gif

This doesn't look like SSW?

Hasn't happened yet. 

---

http://modeles.meteociel.fr/modeles/gfs/runs/2014020118/gfsnh-0-324.png?18

Hints of it getting into the trop on the 18z

 

---

What is a sww?!

Embarrassed to ask but I don't know!

[sn_appr] [sn_blush] [sn_blush]

---

SSW, sudden stratospheric warming.

Simply put, in the stratosphere when a massive warming occurs this can signal blocking in about 1-3 weeks time. SSW is forecast to occur in about a weeks time.

The rough idea of how it works is this:

1) Deceleration of upper level westerlies occurs (or easterly winds develop) this causes the air to compress and heat up extremely rapidally (by 70C sometimes!)

2) I don't quite understand this fully, but so called rossby waves in the lower atmosphere tend to propagate upwards. Westerly winds propagate easily into the high atmosphere, but easteries don't.

3) Therefore easterly winds in the stratosphere prevents lower level westerly winds from propagating above that level, what this means is that the waves get stopped below the original easterly, and this one becomes easterly at a lower level.

4) The process continues with the easterly winds propagating further and further down until they reach the jet stream and weaken it, perhaps pushing it further south.

5) Southern jet allows cold air from the north to make more progress south, so in the UK that would mean cold and snow.

 

Like I say the whole process takes 1-3 weeks, and 'weakining of the jet' doesn't necessarily mean in the right place for northern blocking and cold/snow for us. But it does increase the odds. 

---

Don't be embarrassed! I asked the same question last week. Someone gave me a link to look at...quite interesting really.

---

http://modeles.meteociel.fr/modeles/gfs/runs/2014020118/gfsnh-0-300.png?18

14 days worth of low pressure after low pressure

 

---

But not in our part of the northern hemisphere....

There is no SSW forecast in the next ten days - Berlin data has no reversal of zonal winds forecast for 10hPa at 60 degrees north (technical definition of a SSW).

current and 10 days forward - not much changes in the intervening period.

http://i.imgur.com/BUuNAcR.gif 

A look at the 18Z shows the futility of looking at 10hPa temp charts in isolation - the area of warming in the strat corresponds to a huge polar upper air mass plonked over the north Atlantic and UK.

http://images.meteociel.fr/im/806/gfsnh-10-186_tdr6.png 

http://images.meteociel.fr/im/9703/gfsnh-0-186_aro7.png 

I am quite happy with my CET guess of 6C with the likes of this.

http://www.jp2webdesign.co.uk/ds/gfs.htm

---

The irony is that we didn't want the Azores high to ridge northwards so lows could go underneath the block, now the block seems to be disappearing and when we want the Azores high to ridge northwards to decrease precipitation amounts, it's nowhere to be seen!

---

plus we got to worry about the storm heading our way Wednesday looking a bit of a beast

Some changes to the severity and timing of each development is to be expected, and there has been a shift around in emphasis this morning although the system on Wednesday is still looking espescially potent both in terms of wind and rain.

The general theme prevalent for the last eight weeks remains - no HLB in our quadrant of the hemisphere at all in the forecast.

---

Good morning. Here is the report on the outputs of the NWP based on their midnight outputs on Sunday February 2nd 2014 and featured on my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

All models continue to show a very volatile and mobile setup across the UK through the coming week. With winds from between South and West through the week and Low pressure areas and trough moving across the UK tomorrow, Wednesday and again towards the weekend over the South there will continue to be spells of sometimes heavy rain coupled with strong winds which could reach severe gale force on Wednesday as a particularly deep Low speeds NE across the UK through the day. The rain will be heaviest in areas adjacent to the wind, especially the high ground of the South and West. In between the main rain bands brighter or clearer air with blustery showers will occur most likely over Tuesday and Thursday with temperatures largely near average for all but perhaps rather chilly at times over the North where some mountain snow is likely.

GFS then moves through next weekend with no changes with further windy spells with heavy rain at times as Low pressure remains close to the NW. Through the latter stages of the output the weather remains very volatile and Atlantic driven with yesterday's improvements muted today with further low pressure areas maintaining the wet and windy theme right out to the end of the run for all in average temperatures.

The GFS Ensembles today show continued very changeable conditions preferred over the period with a lot of rain possible for a good portion of the run though perhaps a trend towards less rain by the end of the run. The recent strong milder surge in uppers have been scaled back this morning with the likelihood of more average temperatures at the surface being most likely for all areas for the next two weeks with solid agreement from most members.

UKMO shows the end of the week and start to next weekend with a new depression rattling in towards Western Ireland bringing another set of troughs in from the SW to all areas by the end of Saturday with rain and strong winds followed by showers the likely sequence of events through the day for the UK.

GEM today shows deep Low pressure areas continuing to cross the UK next weekend and the start of the second week with more very heavy rain and gales all too frequently affecting all areas with the West and SW continuing to suffer the worst of the conditions with wind too newsworthy too at times.

NAVGEM shows a vicious little Low crossing Southern England next weekend with very heavy and prolonged rainfall moving East over the day and followed by more unsettled and windy Westerly breezes with further rain and showers in very average temperatures.

ECM today has removed the hint of somewhat drier conditions late in the run and replaced it with a continuation of wind and rain at times, sometimes heavy and prolonged at times as the run continues to show areas of Low pressure and fronts running in from a very active Atlantic Ocean.

The ECM 9 and 10 Day Mean Charts have deepened the trough still more over the UK in 9 and 10 Days time with undoubtedly no chane in the wet and windy wether under Low pressure to the North and West late in its run so no improvent from this model.

http://www.wetterzentrale.de/pics/Reem2161.gif
http://www.wetterzentrale.de/pics/Reem2401.gif

The Jet Stream continues to pump Eastwards over the Atlantic and across Southern Britain and Northern France and apart from temporary and slight migrations away from this pattern as Low pressure areas wax and wane over the UK little overall change is shown that would in any way release the UK from the current wet and windy theme.

In Summary the weather remains locked in this pattern of wet and windy weather which is rapidly heading towards the wettest winter of all time if we continue down this never ending tunnel of Low pressure through the periods covered by this morning's output. The amounts of rain and wind remain rediculously high again this morning with absolutely no chance of the very short drier interludes between the rain areas being long enough for any alleviation in conditions to flooded areas before any improvements are removed by the next storm but unfortunately that's how it looks again this morning. Winds too feature strongly at times with severe gales likely at times giving rise to their own disruptive recipe almost anywhere. The one consolation that while these conditions prevail there will be little or no risk from snow with ice, frost and fog no more than a local issue on the rare occasions when clearing skies between systems overnight allow patchy ground frost to be possible.

---

The key question is when will the wind and rain abate?

The most skilled view of what the models are showing is METO.To sum up the months outlook I can do no better than quote from the latest forecast for days 16-30."Current indications point towards early Februaries changeable conditions persisting for the rest of the month"

There is some amelioration possible for the  south in that north western parts of the country  are likely to have the most frequent spellsof wet and windy weather.

Cuurently all the models have nothing but zonal flow throughout  their op runs. 

It si not unreasonable to seek if the ensembles throw up any hints at all of an end to zonal.The only crumb of comfort is right out at the end of FI where anticyclonic flow ,largely around HP to the south or south east of the UK,appears  in around half the ENS at 384H. 

 

I never thought I would say this but I would very much welcome a Bartlett dominated February with quiet mild mostly dry weather.

Come on Uncle Barty where the hell are you.

Andy

---

Rather than a Winter is Over post, I'd like to make a W. D. O.  Winter Didn't Occur post.

Its been mild, windy, very wet, pretty much frost free, its been quite dark, and other than the light and the calendar, meteorolgically speaking it has not been winter.  Barely seen a snowflake.  These "winters" do happen from time to time.

My thoughts now turn to spring and I hope very strongly that we are not punished with another cold one.  Mild winters are not always followed by cold springs.

---

There obviously has been but It can't remember such an Atlantic dominated perid as we are having

http://modeles.meteociel.fr/modeles/gfs/runs/2014020200/gfsnh-0-78.png?0

http://modeles.meteociel.fr/modeles/gfs/runs/2014020200/gfsnh-0-150.png?0

GFS

http://www.meteociel.fr/modeles/ecmwf/runs/2014020200/ECH1-168.GIF?02-12

ECM

Whichever model we pic, the outlook is woeful

 

 

 

---

I wouldn't be too unhappy with a cold snowy March make up for the crap we have seen over the last few months

---

Like it or not it is far to early to say with any certainty that "winter is over" unless forecasting accuracy has improved rapidly, since yesterday. However it is safe to say that the coming days look very unsettled once again with very windy and wet weather, and yes like or not, quite a lot more snow on the already buried Scottish mountains.

The main talking points however will most likely be Wednesday's and then Saturday's storms. Both these features look potentially problematic with the former impacting many areas already badly affected by this winter's weather.

http://www.wetterzentrale.de/pics/Rtavn781.png 

In any other winter this feature would be a major talking point at this range, but this year it is just another Low in a series that is gracing our shores.

In terms of temperatures it looks mild enough not to be cold but cold enough to be unpleasant and wintry at times, although this will be largely limited to northern hills.

I guess I could have saved time and just said:

"For the next week, more of the same".

---

http://www.wetterzentrale.de/pics/Rtavn781.png  In any other winter this feature would be a major talking point at this range, but this year it is just another Low in a series that is gracing our shores. In terms of temperatures it looks mild enough not to be cold but cold enough to be unpleasant and wintry at times, although this will be largely limited to northern hills. I guess I could have saved time and just said: "For the next week, more of the same".