In Depth Model Discussion, Analysis and Summaries

[Isolated Frost]

An indeed v good GWO plot moving from 8-1 rather soon. Retrogression still a good bet.

As you say GLAAM has taken a sharp dip and a final blow to the vortex with a reversal of mean zonal winds and a warm strat have shown in recent days, good posts from LS and Lorenzo.

[Glacier Point]

Both frictional torques and mountain torques are showing strong negative tendency, consistent with a large scale removal of westerly winds:

Tendency in relative angular momentum showing a substantive drop and the scrubbing of westerlies / addition of easterlies across the Northern Hemisphere.

With overal relative angular momentum still dropping back as a result of a lack of tropical activity in the last few weeks, and dare I say it the sun slumbering, we see the GWO displaying a trend towards phase 8 with scope for continued reduction in westerlies / negative frictional and mountain torques. Note how the GWO was in a similar position at the end of January.

This brings it into line with the current phase space for the MJO component (see post above). With forecasts for the MJO and the environment in the Indian Ocean looking favourable for the development of deep convection, a strong MJO / GWO coupling for phase 1-2-3 type orbit looks good (GWO possibly being held back into phase 3-2-1), this is a good signal for anomalous mid or mid to high latitude ridges to develop with the low point in westerly flow associated with these phases.

That would suggest NCEP ensemble means and CPC output tonight is solid. Now will the ridges over Siberia and the mid Atlantic meet up ? Taking a punt, I would suggest the position of the ridge shown by the CPC is a little too far south so I would nudge it further north.

Edited February 15, 2012 by Glacier Point

[Swave Snow]

Your punt could lead to a severe easterly.

Taking a punt, I would suggest the position of the ridge shown by the CPC is a little too far south so I would nudge it further north.

[bluearmy]

Your punt could lead to a severe easterly.

Taking a punt, I would suggest the position of the ridge shown by the CPC is a little too far south so I would nudge it further north.

for the time being, the nwp is not really getting any closer to positioning the atlantic block far enough north to introduce any serious CAA towards us. if anything, it is heading the other way. however, if GP is right about the telecon stuff he has posted above, the ncep models may well begin to play catch up a bit and head back towards the colder solution they were showing a day or so ago in deep fi. i note that the 14 day ecm ens for london are going a bit chillier with each run.

[karyo]

Thank you for the update GP. I love the comment about the slumbering sun!

Karyo

[Continental Climate]

Thank you for the update GP. I love the comment about the slumbering sun!

Karyo

I agree Karyo, is there any links or evidence that points to the sun being very quiet at the moment? I thought the sun was getting more active and we were in a solar maximum at moment? Help please too much conflicting evidence!!!

[cj114]

G.P, please elaborate please?.

[ZONE 51]

G.P, please elaborate please?.

You only have to ask and they would explain, it is confusing when you view those charts and not understand what they are showing, but when you learn them it makes them more exciting to view! Edited February 16, 2012 by ElectricSnowStorm

[BLAST FROM THE PAST]

Talk fo slumbering sun, I'd be very surprised if 'favourable' blocking occurred in Feb now, prob more like into March...but I agree it is probably 'ironically' coming.

BFTP

[La Bise]

Feel free to explain why you think so Fred, maybe a few charts from your special method alongside a few explanations might help since you seem to want to contradict GP at every turn and offers not much more than some tantalising clues about drivers behind drivers and energy peaks.

You never know, it might make you as popular as GP...

[BLAST FROM THE PAST]

Feel free to explain why you think so Fred, maybe a few charts from your special method alongside a few explanations might help since you seem to want to contradict GP at every turn and offers not much more than some tantalising clues about drivers behind drivers and energy peaks.

You never know, it might make you as popular as GP...

Its not my method my friend its current hemispheric pattern. Ain't saying it won't develop just that it has to develop within a week....29 days in Feb remember.....next 5-7 days pattern looks pretty much set....so a week then for it to develop...and nothing happens overnight so I'd say simple maths suggests that even if it developed in last week it probably won't be in place until say last couple of days of Feb...at best. And the stubborness of the AZH and PV havce made it very difficult this winter.

Now by Sunday -15c with easterly gales and blizzards....am I as popular now?

BFTP

[johnholmes]

oh how I wish BFTP that you would favour us with posts that showed your plain English simple fully constructed sentences rather than the journalise we so often have to wade thought

Please?

[cooling climate]

Feel free to explain why you think so Fred, maybe a few charts from your special method alongside a few explanations might help since you seem to want to contradict GP at every turn and offers not much more than some tantalising clues about drivers behind drivers and energy peaks.

You never know, it might make you as popular as GP...

How do you go about explaining a guess. His posts are made to look like he knows what he's talking about but

but its just waffle (WAG's). Sometimes if you guess often enough you will get it right. Best to ignore.

[Isolated Frost]

How do you go about explaining a guess. His posts are made to look like he knows what he's talking about but

but its just waffle (WAG's). Sometimes if you guess often enough you will get it right. Best to ignore.

wrong end of the stick sorry

Edited February 17, 2012 by Isolated Frost

[Cheese Rice]

Seriously? Are you talking about GP here? Get a grip.

No its BFTP.

I think this post and the other ones should be deleted to stop thread exploding into an argument ....

[Isolated Frost]

Oh right woops sorry mods for the confusion- yeah should probably delete all of these.

[Cloud 10]

With the NAO (north atlantic oscillation) looking like returning positive values for all three months this winter,thought i

would check back through the archives for other winters with +ve NAO.

www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

This is the February composite for those winter's. Looks familiar!

Rolled forward a month to March after those same winter's,things change radically,with blocking to the north

and low pressure to the south (-ve NAO)

Which continues into April

And May

Some very interesting weather to come if Spring 2012 follows a similar trend!

[coldwinter]

Yeah i have been thinking that we could be in for a colder spring, certainly, if GP is correct it will probabally be quite chilly at times!

Ryan.

[lorenzo]

Had a look over at the AMWx site and much debate going on around NAO and ENSO, this link and paragrpah from provide interesting reading.. place your bets..!

Based on current atmosphere-ocean conditions, I believe the odds for this La Niña event to continue right through early summer (June-July 2012) are just about 50%. Beyond that, it is worth noting that four of the ten two-year La Niña events between 1900 and 2009 ended up as a three-year event, so I would put the odds for this to occur in 2012-13 at 40% right now. The remaining six cases all switched to El Niño, leaving not a single ENSO-neutral case.

http://www.esrl.noaa.gov/psd/enso/mei/#discussion

[johnholmes]

Interesting link-thanks

the official IRI page, see below, suggest about equal chances for La Nina or El Nono by early/mid summer.

I think they quoted somewhere around the 20% risk for each, one a touch higher than the other and neutral conditions about 50%

http://iri.columbia..../technical.html

Edited February 24, 2012 by johnholmes

[Glacier Point]

This brings it into line with the current phase space for the MJO component (see post above). With forecasts for the MJO and the environment in the Indian Ocean looking favourable for the development of deep convection, a strong MJO / GWO coupling for phase 1-2-3 type orbit looks good (GWO possibly being held back into phase 3-2-1), this is a good signal for anomalous mid or mid to high latitude ridges to develop with the low point in westerly flow associated with these phases.

That would suggest NCEP ensemble means and CPC output tonight is solid. Now will the ridges over Siberia and the mid Atlantic meet up ? Taking a punt, I would suggest the position of the ridge shown by the CPC is a little too far south so I would nudge it further north.

For the last 7 days:

The mean anomalous ridge position there very consistent with previous analysis.

Over the last few days we have seen a significant removal of westerlies / addition of easterlies with a strongly negative mountain torque episode.

Tendency in relative angular momentum is now well down and the GWO has developed a very low AAM / Nina type profile.

Total angular momentum has reached depths not seen this winter, and, looking at where westerlies are fading and easterlies persisting, it looks like we'll be in this base state for a while yet.

This would suggest a type 1-2-3 orbit in the GWO continuing. Composites for these phases:

>>

These summarise low pressure in the Atlantic and higher pressure to our NE, becoming more like a -NAO signature in time and probably cooling off a little as we enter second week of March. Interestingly the NAO looks to be neutral negative whilst the AO remains positive, quite an unusual combo (basically all examples I can find of this teleconnect to higher pressure over Scandinavia for March).

This is backed up by GFS NAO ensembles heading neutral and ECM and GFS ensemble means.

So not much hope for substantive rain there. More blocked weather pattern starting off mild but becoming cooler with winds probably becoming more easterly in time.

[johnholmes]

the 500mb anomaly charts are in fairly close agreement of that Stewart for the start of March, beyond that is not my scene so I'll leave that to you.

[chionomaniac]

It is good to have signs that we have stratospheric support for the NE pressure rise scenario from day 7+.

March can still deliver some quite potent cold spells and it wouldn't take too much change in todays ECM to demonstrate this.

[johnholmes]

after post 1430 the ECMWF and GFS output this morning has thrown a spanner in the works it seems, marked troughing into the Uk and little sign of any ridge Best to wait 2-3 days to see how things develop in them.

[Glacier Point]

models being thrown by this..

huge loss of westerlies in the last few days, big negative mountain torque.

Modelling very much reflecting the phase 1 composites for GWO, however, increased chances in my book for phase 2 (composites as above).