06z model discussion - snowing now and what after?

[kold weather]

The main logic for this isn't so much based on what the models show right now but a trend I observed when we were in the strong +ve phase where everytime the model predicted a flip in the AO signal in fact it stayed +ve instead.

It's also worth noting that these sorts of things tend to stair-step there way up and down:

I haven't been paying that much attention to the upper air temps mind you (above 100mbs) so what I'm sayign here may be all well and good but there may be a new cooling which would screw us up somewhat.

There are other reasons as well why I expect that and also expect a cold plunge late Feb- early March but first i do think we will have a pretty horrible 5-7 day set-up to get through. Going to be very hard for the global pattern we are going to have at 168hrs to sustain itself, it'll go either the cold way or mild way, won't be no half-way point with this one, either very cold or very mild, GFS FI goes for very mild but that could easily change.

by the way, the jet will be no problem next winter, heading for a la nina and mightbe quite noteable as well, subsurface temps have plummeted like a stone, now average 0.43C below average already!

The last time it fell like this was 83 and that Feb turned out to be rather cold.

Edited February 8, 2007 by kold weather

[Thundery wintry showers]

The outlook out to around T+168, with continued blocking to the north and low pressure over the British Isles, looks highly likely to come off.

The Bartlett scenario, with the northern blocking receding, is far less certain as it's out in FI by any standards, but especially recent standards where models have chopped and changed constantly. Today's 12Z Model Comparison was the first to produce generally low marks for a while, and I reckon that there will be plenty more low marks over the coming week.

Put it this way, a week ago, GFS had the block retreating to Siberia by now. The Atlantic may well take over but the northern blocking is likely to, at the very least, recede at a slower rate than the models are showing, as we get into next week.

I think the most likely scenario we are facing is hinted at in the FI stages of the GFS 12Z although the cold air I'm envisaging doesn't quite make it on the 12Z. I envisage a week or so of westerly winds and a gradual retreat of the Scandinavian block, then a lull in the Atlantic followed by rising pressure to the NW- centred around or to the south of Greenland- which may then extend over to Scandinavia and bring us a spell of cool to cold (depending on the amount of cold pooling over Scandinavia) north-easterly winds. My LRF went for this initiating between 15 and 20 February; this looks less likely now but it may simply end up delayed by another week.

[smhouston]

I think that sums Sat up perfectly KW a real mess.

Seems the general pattern is the snow moving N Sat then this becoming confined to Scotland on Sun.

Next week certainly does look milder with all models agreeing to this but for some reason I have a little niggling doubt in my mind that it won't be as straight forward as the models are showing and I certainly don't agree with some of the mild outlooks in FI!.

Indeed. The models have really been struggling. This cold spell was first hinted at by the GEM (i believe?). If it wasn't the GEM it was definately one of the smaller models that people say is 99% wrong.A lot more twists and turns I believe before the end of next week

[Schnee]

By the way the AO forecasts are going too far positive at the moment IMO, expect the truth to be around neutral before a very sharp drop off towards the end of the month.

Sharp drop of towards the end of the month? Sounds like it's worth keeping an eye on. :unsure:

Hope March isn't too bad as I have a 5 day Motorbike DAS course booked for the first 3 weeks which is expensive.

[wellington boot]

Indeed. The models have really been struggling. This cold spell was first hinted at by the GEM (i believe?). If it wasn't the GEM it was definately one of the smaller models that people say is 99% wrong.A lot more twists and turns I believe before the end of next week

I believe it was the JMA. I have those runs saved somewhere. It gave us the block refusing to budge, and lows undergutting and giving us easterlies. Really not a bad effort back then. It stuck to it for a few runs as well before it got itself a tad confused

[kippure]

Is there any way of telling if the scandinavian block will increase it seems to be slowly slipping away.

[wellington boot]

Is there any way of telling if the scandinavian block will increase it seems to be slowly slipping away.

Signs now seem to lead us to a fairly sure conclusion that it will slip away rather than strengthening

[kippure]

Signs now seem to lead us to a fairly sure conclusion that it will slip away rather than strengthening

Thanks :unsure:

[snowingtequila]

Signs now seem to lead us to a fairly sure conclusion that it will slip away rather than strengthening

I am not so sure that you should be so fairly sure. Which signs are these? I think things are very much open at the moment

[mcweather]

The models seem agreed but do they have the right solution! It looks like the atlantic will win out next week but NOAA have basically slated all the models and again especially the gfs with low confidence in this. Heres the link.

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

Theres basically low confidence in any of the model solutions at present.

Those NOAA discussions are very interesting Nick. With todays news release from the METO about further snow risks over the weekend and early next week. I have a feeling that the Meto have half an eye on the block not really breaking at all. ( perhaps retreating slightly then beefing up with a vengeance) Their spokesman on on my bbc local radio station this morning when questioned about the rest of the month mentioned that the second half of feb could prove to be even more wintery. The second half of Feb starts next Thursday that doesnt leave time for much of a milder interlude. Meto aside the big models have performed exceptionally poorly over the last few days. So I,m pretty much ignoring them until they throw up something a bit more sensible.

[Matt Jones]

It really is looking like a milder spell of weather for most of the UK once we get through the weekend, the fronts from the south will shift the cold air northward to leave the really cold stuff just north of shetland, northern areas cool and southern areas back to double figures. I don't believe the block to our north and east to be strong enough to prevent this. Any snow on saturday will be reserved for inland areas, especially high ground.

Hopefully though there is the chance that the cold air will return once more from the north and the sooner the better.

[KTtom]

Personally I think this chart emphasises just how close we came to something really special...a few more Mb's to the high to the north and its there...

http://www.wetterzentrale.de/pics/brack1.gif

KTtom

Edited February 8, 2007 by KTtom

[snowingtequila]

Personally I think this chart emphasises just how close we came to something really special...a few more Mb's to the high to the north and its there...

http://www.wetterzentrale.de/pics/brack1.gif

KTtom

but this hasn't happened yet!

[North-Easterly Blast]

Further on with the models ECM tonight while not very inspiring is not totally awful either. It does not build the Bartlett properly and keeps the jet mainly close to the UK rather than through the GIN corridor and shows average to mild conditions close to the UK up to 240 rather than very mild. ECM also maintains heights further to our north up to 240. If a Bartlett does come off it will highly likely nail the coffin for the rest of winter, and a few of the ensemble members at 240+ suggest a rerun of mid Feb 1998 is a possibility. A Bartlett still looks a high possibility to me for later in the month going by the fact that all GFS runs these last three days have repeatedly shown this scenario, and even a mid Feb 1998 rerun does look an outside possibility, and it would take rather a major turnaround / backtrack in the GFS in particular for the Bartlett not to be the case. Despite this, I think myself that it is highly unlikely we will return to the pattern of early to mid January after the middle of Feb, as Feb is rarely as unsettled as Dec and Jan and often is quieter with fewer gales and less stormy weather; February often brings less mobile and more blocked weather to the UK, the key is where the block sits, sometimes it can be in a favourable place for cold in the UK, sometimes not, and once established, February's weather patterns can often be very repetitive.

It makes you wonder why February is not almost always the coldest month of the winter.

[carnoustie]

http://www.meteociel.com/modeles/ukmo2.php...&carte=1021

Nice looking chart for my location, but with North Sea temps being to warm I'm afraid that it'll just be cool and wet, rather than cold and snowy.

Should be good for the mountains though.

[BLAST FROM THE PAST]

The main logic for this isn't so much based on what the models show right now but a trend I observed when we were in the strong +ve phase where everytime the model predicted a flip in the AO signal in fact it stayed +ve instead.

It's also worth noting that these sorts of things tend to stair-step there way up and down:

I haven't been paying that much attention to the upper air temps mind you (above 100mbs) so what I'm sayign here may be all well and good but there may be a new cooling which would screw us up somewhat.

There are other reasons as well why I expect that and also expect a cold plunge late Feb- early March but first i do think we will have a pretty horrible 5-7 day set-up to get through. Going to be very hard for the global pattern we are going to have at 168hrs to sustain itself, it'll go either the cold way or mild way, won't be no half-way point with this one, either very cold or very mild, GFS FI goes for very mild but that could easily change.

by the way, the jet will be no problem next winter, heading for a la nina and mightbe quite noteable as well, subsurface temps have plummeted like a stone, now average 0.43C below average already!

The last time it fell like this was 83 and that Feb turned out to be rather cold.

Kold

I am with you on this one big style. We do have to weather the next week to 10 days out and I mean weather as it will be stormy but average. However, a big switch is looking on and I think a very cold last week to 10 days is on and a prolonged set up lasting well into march. I don't think it will be a too late scenario either as there will be an awful lot of cold air to tap into. Also the 12z is showing a change that will be enhanced on further models down the line as the signals get picked up. Much messiness to come but I think mild bartlet or zoneality will not be the outcome.

BFTP

Edited February 8, 2007 by BLAST FROM THE PAST

[Snowly does it]

Hmmmm T144-T150, Scandi regathering?

Now where's the cut off low to flood the cold in?

[BLAST FROM THE PAST]

Hmmmm T144-T150, Scandi regathering?

Now where's the cut off low to flood the cold in?

Yes SM

Scandi block forming....what is post T168

BFTP

[Shiny_Bottom_1]

Also perhaps slightly interesting. The 18z, although still not brilliant for the midlands south on Saturday, does paint a better picture than the 12z (I think anyhows).

Fingers crossed for an improved picture tomorrow

[lesta_snow]

Yes SM

Scandi block forming....what is post T168

BFTP

so are we expecting another cold blast shortly after this one

[Snowly does it]

Yes SM

Scandi block forming....what is post T168

BFTP

Giant and impressive Scandi High against an Atlantic that seems intractable. The 18z has mild winning out despite some intense cold attmepting to push West. Can't see the Atlantic in a weak jet phase standing up to that sort of presure build frankly. Even has a Azores to Bartlett Ridge AND a mighty Scandi going on simultaneously. Changes afoot for better or worse post 14th I think.

[TEITS]

so are we expecting another cold blast shortly after this one

Not really expecting anything at the moment TBH.

The theme is one of becoming less cold but personally I wouldn't go beyond +168 at the moment which makes it 15th Feb. My hunch is a less cold week next week before the cold returns once again the following week.

[Snowly does it]

Entertaining teaser in the outer reaches from the GFS with a blast from the north and some very cold air ansking down over Iceland with the country under -5s again.

[BLAST FROM THE PAST]

so are we expecting another cold blast shortly after this one

No, not yet. what the models are beginning to show is that Northern blocking won't go away and is going to be pretty strong for the last 3rd of this month. We will see milder but stormier weather next week, interesting on its own because there will be some storminess. however, what some of us are looking for and what is progged by 'alternative' method is that HP will be strong to our NE and North and that a sustained coldspell will dominate from say 17-21 onwards for a 2 week period 'at least' with an Atlantic that falls asleep.

I am very happy with sudden progression of models. By mid next week we will see more and more of this as the dust settles...but a very interesting month this will be. Just to say that with what the 18z has progged no way will that Scandi HP come off second best...no way.

BFTP

Edited February 8, 2007 by BLAST FROM THE PAST

[davehsug]

No, not yet. what the models are beginning to show is that Northern blocking won't go away and is going to be pretty strong for the last 3rd of this month. We will see milder but stormier weather next week, interesting on its own because there will be some storminess. however, what some of us are looking for and what is progged by 'alternative' method is that HP will be strong to our NE and North and that a sustained coldspell will dominate from say 17-21 onwards for a 2 week period 'at least' with an Atlantic that falls asleep.

BFTP

Several people have kept repeating this in the last few days, but would you not expect at least a few of the ensembles to be picking up on this by now? I don't recall seeing anything in the past few days, apart from the odd glimpse in extreme FI.

I'm not saying it won't happen & there is definitely a logic to it with which I agree, I'm just puzzled that no ensemble member that I have seen has gone for it.

Dave