That's an odd south-westerly

Originally Posted by: Tractor Boy 

To add to my point, Bracknell is listing these features as troughs.

Do not rely on them, they are among the hardest features to predict, and they often give extremely heavy, but also extremely localised precipitation. Ignore this if you live in N ireland or W Scotland (perhaps N england?), you have the lake effect; for you snow is all but guaranteed, a trough will just make things more interesting.  

Originally Posted by: Quantum 

I would add this area to that for the same reasons. The Severn estuary can generate a classic streamed in the right conditions. Incredibly rare though

Originally Posted by: Matty H 

This should really be in the media thread, but it may get overlooked. An interesting video

http://www.metoffice.gov.uk/news/releases/archive/2015/volatile-weather?utm_source=twitterfeed&utm_medium=twitter

Originally Posted by: Matty H 

Yeah, little in the way of progress toward a consensus 4-6 day outlook this evening.

Divergence point posted below (ECM on the left, GFSP right):

The focus region is the eastern third of the U.S/Canada and the westernmost N. Atlantic.

Look at the ridge/trough combination and the differences become clear; ECM makes less of the ridge and doesn't dig the trough as far south as GFSP.

GFS is close to GFSP (having increased the ridge strength since this morning) and UKMO close to ECM.

A stronger ridge leads to earlier phasing while also 'holding up' the progression of lows from the U.S. to the Atlantic.

So, who's got the better handle on the U.S. pattern at 4 days range, the American models or the European ones? I would be amazed if this wasn't sorted out by tomorrow evening. Each new set of runs will be edge-of-seat stuff.

The MJO update today shows that it has amplified beyond even the most vigorous of yesterday's model outlooks (GEFS still the only one even close. It's been miles ahead of ECMF with the accuracy) - as suspected given the GFS/GFSP trend. Yet the lack of response from ECM/UKMO places the idea of influence at such short range under question.

The ECM 12z op shows how that version of events can still set up a sliding lows/Scandi High situation in the longer term (by keeping the Azores High well to the west), with cold air still being drawn into the mix while we wait - but it's generally marginal for snow and trough development to the NW remains an issue, though weaker than we are seeing in the short term:

So concludes looking ahead for the time being. Focus is now shifting to short-term rain, wind and possibly snow.

Originally Posted by: Stormchaser 

Wow that has snow across my area, what model is showing that? 

Originally Posted by: Quantum 

Yeah, little in the way of progress toward a consensus 4-6 day outlook this evening.

Divergence point posted below (ECM on the left, GFSP right):

The focus region is the eastern third of the U.S/Canada and the westernmost N. Atlantic.

Look at the ridge/trough combination and the differences become clear; ECM makes less of the ridge and doesn't dig the trough as far south as GFSP.

GFS is close to GFSP (having increased the ridge strength since this morning) and UKMO close to ECM.

A stronger ridge leads to earlier phasing while also 'holding up' the progression of lows from the U.S. to the Atlantic.

So, who's got the better handle on the U.S. pattern at 4 days range, the American models or the European ones? I would be amazed if this wasn't sorted out by tomorrow evening. Each new set of runs will be edge-of-seat stuff.

The MJO update today shows that it has amplified beyond even the most vigorous of yesterday's model outlooks (GEFS still the only one even close. It's been miles ahead of ECMF with the accuracy) - as suspected given the GFS/GFSP trend. Yet the lack of response from ECM/UKMO places the idea of influence at such short range under question.

The ECM 12z op shows how that version of events can still set up a sliding lows/Scandi High situation in the longer term (by keeping the Azores High well to the west), with cold air still being drawn into the mix while we wait - but it's generally marginal for snow and trough development to the NW remains an issue, though weaker than we are seeing in the short term:

O

So concludes looking ahead for the time being. Focus is now shifting to short-term rain, wind and possibly snow.

Originally Posted by: Stormchaser 

The snow accumulation chart he keeps referring to shouldn't be treated literally I guess. It shows 10-20cm right here

Originally Posted by: Matty H 

I can believe it for one or two spots. I remember the odd happy occasion when a trough would suddenly appear (completely contrary to predictions) as a dark bank of cloud that would deposit a quick 10cm in less than an hour before buggering off. 

Originally Posted by: Quantum 

 The snow accumulation chart he keeps referring to shouldn't be treated literally I guess. It shows 10-20cm right here

Originally Posted by: Matty H 

Yeah, little in the way of progress toward a consensus 4-6 day outlook this evening.

Divergence point posted below (ECM on the left, GFSP right):

The focus region is the eastern third of the U.S/Canada and the westernmost N. Atlantic.

Look at the ridge/trough combination and the differences become clear; ECM makes less of the ridge and doesn't dig the trough as far south as GFSP.

GFS is close to GFSP (having increased the ridge strength since this morning) and UKMO close to ECM.

A stronger ridge leads to earlier phasing while also 'holding up' the progression of lows from the U.S. to the Atlantic.

So, who's got the better handle on the U.S. pattern at 4 days range, the American models or the European ones? I would be amazed if this wasn't sorted out by tomorrow evening. Each new set of runs will be edge-of-seat stuff.

The MJO update today shows that it has amplified beyond even the most vigorous of yesterday's model outlooks (GEFS still the only one even close. It's been miles ahead of ECMF with the accuracy) - as suspected given the GFS/GFSP trend. Yet the lack of response from ECM/UKMO places the idea of influence at such short range under question.

The ECM 12z op shows how that version of events can still set up a sliding lows/Scandi High situation in the longer term (by keeping the Azores High well to the west), with cold air still being drawn into the mix while we wait - but it's generally marginal for snow and trough development to the NW remains an issue, though weaker than we are seeing in the short term:

So concludes looking ahead for the time being. Focus is now shifting to short-term rain, wind and possibly snow.

Originally Posted by: Stormchaser 

I noticed that on this video from the Met Office they have a rather good looking snow map or snow accumulation map

https://www.youtube.com/watch?v=wza569RpKMw

Anybody have any links to it directly ? 

Originally Posted by: Cumbrian Snowman