Model Output Discussion

[Glacier Point]

may i ask , is it possible to get a heatwave here without all these composites falling into place? or is our weather inextricably linked to tropical convection etc in the indian/pacific oceans?

Inextricably linked both to what happens over the tropics (MJO) and how the extra-tropics (atmospheric processes revolving around torques and eddies) react (GWO).

Key phases for heat hunters: look for the MJO and GWO heading towards phases 5,6,7 and 8

http://www.bom.gov.au/bmrc/clfor/cfstaff/m...Last40days.html

http://www.cdc.noaa.gov/map/images/gcm/gwo_40d.gif

Current MJO forecasts are spread but do indicate some westward motion in the atmosphere which is crucial in helping to lift angular momentum out of the La Nina mire.

http://www.cpc.ncep.noaa.gov/products/peop..._CFSOP_GEFS.gif

http://www.cdc.noaa.gov/map/images/reanaly...m.sig.90day.gif

From the looks of, the opertional GFS is starting to shift convection eastwards and increase angular momentum.

[mushymanrob]

Inextricably linked both to what happens over the tropics (MJO) and how the extra-tropics (atmospheric processes revolving around torques and eddies) react (GWO).

Key phases for heat hunters: look for the MJO and GWO heading towards phases 5,6,7 and 8

http://www.bom.gov.au/bmrc/clfor/cfstaff/m...Last40days.html

http://www.cdc.noaa.gov/map/images/gcm/gwo_40d.gif

Current MJO forecasts are spread but do indicate some westward motion in the atmosphere which is crucial in helping to lift angular momentum out of the La Nina mire.

http://www.cpc.ncep.noaa.gov/products/peop..._CFSOP_GEFS.gif

http://www.cdc.noaa.gov/map/images/reanaly...m.sig.90day.gif

From the looks of, the opertional GFS is starting to shift convection eastwards and increase angular momentum.

thanks

[BLAST FROM THE PAST]

Damn GP away from the east coast which general means the other side of the Pennines. Interesting that the atmosphere is behaving like La Nina. Is this a lag effect or due to the lack of solar activity????

I'd suggest the low solar activity is part of it. However, point of interest last year or two duing certain discussions I took a look at El Ninos, their strength and how they affected NH winters and particular us and W Europe. Over the 20th century as a whole there was a 50 50 split as to it giving us mild winter and cold winter. However, before 2007 from early 70s every mod to strong El Nino gave a mild to v mild winter. Now was that because of the perturbation cycle and/or PDO state? They were in warm phase during that period. Something to look at as I think external drivers are at play here......cool perturbation cycle, -ve PDO, low solar activity, low solar mag field, lunar cycle driving jetstream southwards [3 summers now where it is keeping further south than one would expect...GWO theory?].

Does anyone know if ENSO has a lag or should it pretty much have fairly instant affect? Slightly off topic sorry so back to models and pretty southerly jet in place with Scandi Torough waiting in the wings. I still think that late July will see HP fron GH extend and build pressure to our NE [pretty much like last month]

BFTP

Edited July 12, 2009 by BLAST FROM THE PAST

[Koppite]

Inextricably linked both to what happens over the tropics (MJO) and how the extra-tropics (atmospheric processes revolving around torques and eddies) react (GWO).

Key phases for heat hunters: look for the MJO and GWO heading towards phases 5,6,7 and 8

http://www.bom.gov.au/bmrc/clfor/cfstaff/m...Last40days.html

http://www.cdc.noaa.gov/map/images/gcm/gwo_40d.gif

Current MJO forecasts are spread but do indicate some westward motion in the atmosphere which is crucial in helping to lift angular momentum out of the La Nina mire.

http://www.cpc.ncep.noaa.gov/products/peop..._CFSOP_GEFS.gif

http://www.cdc.noaa.gov/map/images/reanaly...m.sig.90day.gif

From the looks of, the opertional GFS is starting to shift convection eastwards and increase angular momentum.

Hi GP, does this mean better weather could be on the way?

Edited July 12, 2009 by Koppite

[TEITS]

Very nice GFS 00Z run for early next week, a shame its a massive hot outlier and as likely as england winning the ashes

ECM sticking to a cool northerly.

http://www.wetterzentrale.de/pics/Recm1441.gif

This chart keeps popping up though despite being an outlier.

http://www.wetterzentrale.de/pics/Rtavn2041.png

Remember if the GFS Ops continue to be outliers then the chances are the Ops are actually correct. Seen this many times especially during the winter months and the reason could be down to the resolution.

Still at the moment the GFS suggests this will be a very shortlived warm plume. However its worth watching to see if the GFS Ops continue with this and if the Ops are too progressive in moving this LP E. Who knows we could be seeing the first signs of a heatwave coming!

[PB22]

I'm with Dave here, I'm getting the feeling that something is developing, and we could be looking at a rather different outlook fairly soon.

GFS keeps throwing up a plume scenario, and although its an outlier at the moment, I'd watch it carefully. In addition, the ECM ensembles suggest the ECM 00z operational was one of the colder runs, and the ECM control run went much warmer.

[Guest North Sea Snow Convection]

I think there is a chance that the models may all start to latch onto a brief plume event in a week or so time - much as the GFS suggested earlier. But there is nothing to suggest anything other than a continuing unsettled outlook with a lot of heavy showes and more organised bands of rain, most especially but not exclusively in western and north western areas.

As long as pressure stays low over Scandinavia then nothing more than a 'southerly toppler' is likely. So heat fans will be watching these much as cold weather fans take the converse as 'crumbs' in winter.

Best chance imo, perhaps, for things settling down a bit more remains towards months end

[PB22]

Not bad for Thursday on the 06z GFS, as we pull up warm air from the southeast:

http://www.wzkarten.de/pics/Rtavn1081.html

http://www.wzkarten.de/pics/Rtavn1082.html

http://www.wzkarten.de/pics/Rtavn10817.html

However, it turns very wet from the southwest later in the day:

http://www.wzkarten.de/pics/Rtavn1084.html

[bluearmy]

I'm with Dave here, I'm getting the feeling that something is developing, and we could be looking at a rather different outlook fairly soon.

GFS keeps throwing up a plume scenario, and although its an outlier at the moment, I'd watch it carefully. In addition, the ECM ensembles suggest the ECM 00z operational was one of the colder runs, and the ECM control run went much warmer.

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

and the far off fi warm runs are all dropping out which is odd for late july where automatic pilot would dictate a fair proportion of runs above 25c for holland.

maybe the scandi trough is the ticket for the rest of the month ??

[MR EXTREMES]

Damn GP away from the east coast which general means the other side of the Pennines. Interesting that the atmosphere is behaving like La Nina. Is this a lag effect or due to the lack of solar activity????

indeed my thoughts aswell.

but overall this summer has not been to bad but so far apart from the heatwave not terrible but not total bbq summer.

will the regular 30c be reached like the met office indicated

but over all its a cert at some time things will settle down before summers end,

but anything in the 20s is good,

just right for growing and this looks like the picture for awhile,

so overall still not as bad as last summer.

good chance of some storms this week with southeast looking the best and perhapes the driest.

great post by GP.

[Snowyowl9]

We`ll have to wait 1 whole week before many changes come,as it looks as we`re stuck between a rock and a hard place yet.

http://91.121.93.17/pics/Recm1441.gif

http://91.121.93.17/pics/Rtavn1321.png

3rd summer in a row with a jet where we don`t want it.

http://91.121.93.17/pics/Rtavn13214.png

[Terminal Moraine]

Tentative signs from GFS that Friday could be an interesting day for those of us who are pluvially minded.

This model showed a small area of low pressure bringing heavy rain to the south east and east a few days ago only to abandon it; it has now re-appeared but further west.

ECM has the same area of low pressure much further south at the same time and, due to the time jump between frames, it's almost impossible to see the detail of what they do with it after that.

[valiant]

The speed and extent to which westerly winds were removed from the circulatory system is an important sub-seasonal issue. Far from above average angular momentum, we find ourselves mired in a low angular momentum base state despite the equatorial Pacific SSTAs being well above average.

Tropical convection is centred in the western / central Indian Ocean (MJO phase 2/3). The movement of this eastward looks to be painfully slow and ties in with forecasts for the MJO into phase 3/4 at low amplitude:

SST departures in the eastern Indian Ocean are +1C. I'm expecting at least some rebound of total angular momentum which should see the MJO show a little higher amplitude into phase 3/4, allied to the SSTAs.

In terms of the GWO, frictional torques are helping to oppose the easterly winds coming out of the tropics. This is usually a precursor to increase in momentum transport across 30N and we should see the tendency in angular momentum increase driving the GWO towards phase 4:

Taking the likely MJO and GWO positions - heading towards phases 3/4 in harness - the composites for MJO phase 3 and GWO phase 4 are realistic forecasts of where we might be come month's end:

So about average for the time of year.

[Jezzer]

As a newby on here, can I just ask a quick question. When talking about long range forecasts, I often see FI mentioned, can I just ask what it stands for?

Thanks

Jez

[snowingman]

what a downward spiral on the models.... the charts look more autumnal now.. LP after LP to our west moving and becoming centred more or less slap bang over us...

also dragging in cool if not cold weather... which is being fed by a long stretch from the far north..

as for the weather

- showers or longer spells of rain.. expect some very large totals over the coming 2 weeks

- temperatures: subdued and never quite achieving normal in the NW, as ever the SE will experience the odd warmer interludes

- winds, depending on where those LPs are... general breezy from SW

- sun... early morning then forget it as the clouds and showers get going..

quite depressing especially after our early summer which is now a distant memory

welcome to Britain in the global warming period... tis a joke really

[johnholmes]

As a newby on here, can I just ask a quick question. When talking about long range forecasts, I often see FI mentioned, can I just ask what it stands for?

Thanks

Jez

hi Jez

welcome to NW

the term refers to when the models are looked upon as less reliable the time frame is quite elastic really. In a very uncertain/changeable situation it can be a s little as T+96 just 4 days ahead. Its more often meaning T+168 and beyond.

The GFS model as well can sometimes show quite different ideas between runs once its on its 'course' mesh data set, someone will give the actual T+time, I can never remember, around T+168-180 anyway.

hope that helps.

Edited July 12, 2009 by johnholmes

[MR EXTREMES]

i cant really see it being all that bad i dont think it will be as cool as predicted and its certain summer is not over.

i wonder wether the neg PDO will continue into winter because as it stands maybe another 08/09 winter lol sorry of topic.

[Nick L]

As a newby on here, can I just ask a quick question. When talking about long range forecasts, I often see FI mentioned, can I just ask what it stands for?

Thanks

Jez

It be Fantasy Island, a time period where models can throw up very favourable scenarios, but being so far away the chances are they will never come to fruition.

[Iceni]

As a newby on here, can I just ask a quick question. When talking about long range forecasts, I often see FI mentioned, can I just ask what it stands for?

Thanks

Jez

Fantasy Island - anything after 180 hrs.

[Moisty]

Having a very basic understanding of the models they dont look great for the week ahead but in this part of the country summer so far has been better than the last 2 years.

For me as long as there is some sun its ok, at this time of the year no matter where the wind comes from it feels warm in the sun, yesterday was grim but today is shorts and patio windows open again, I cannot remember that happening much in 2007 and 2008.

[Iceni]

Are the charts archived anywhere from a couple of weeks ago (i.e. during the good weather)? I want to compare what the jet stream was doing then compared with now, so I can educate myself.

[Thundery wintry showers]

Try "Archiv" here:

http://www.wetterzentrale.de/topkarten/fsavneur.html

[Jezzer]

Thanks for your help guys

Now hoping for some warm, sunny conditions in the next couple of weeks, will be on a canal trip near Leighton Buzzard from the 24th July!

Edited July 12, 2009 by Jezzer

[Methuselah]

Thanks for your help guys

Now hoping for some warm, sunny conditions in the next couple of weeks, will be on a canal trip near Leighton Buzzard from the 24th July!

There is (or was, heaven knows what it's called now!) a nice pub called the Three Locks, on the Grand Union just up the way from Leighton Buzzard...Have a great day!

[Jezzer]

There is (or was, heaven knows what it's called now!) a nice pub called the Three Locks, on the Grand Union just up the way from Leighton Buzzard...Have a great day!

Cheers Pete, thinking along the right lines there, I'll get that in the log book! Any idea if this possible warm spell may materialise in the south east over the 24th, 25th and 26th July? Still a way off I know