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2013 Fall Medium Range Discussion


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Hi all.

 

Just a quick post from 'the other side of the pond' as the saying goes, but after a run of shocking summers here in the UK and particular so last year, this progression towards more of a negative AAM pattern and also the current MJO phase is likely to lead to a major warm up for the UK;

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ALL_emean_phase_full.gif

 

Well and truly in phase 8 now, which using the reanalysis images for a June month leads to this - http://www.americanwx.com/raleighwx/MJO/MJO/JunePhase8500mb.gif

 

Whilst clearly not always likely to lead a distinct end result all the time, the signal there for a +ve pressure anom to develop across the UK and NW Europe in general is now being supported by the usual global and ensemble models, take the latest GFS ENS mean - http://www.wetterzentrale.de/pics/Rz500m10.gif

 

It's been long over due but that is finally a summer pattern that the UK used to see over 5 or 6 years ago with the Azores high becoming the dominant role and with a likely strong +NAO pattern as well, which in summer doesn't necessarily mean wet and windy like it would do in winter. Sill trying to get some additional information and correlation between the GWO and its importance of weather regimes/patterns within the North Atlantic area, but this could be a good example of how the two (MJO and AWW) are tallying nicely and giving an end result that is likely to lead to a major spell of summer weather for the UK within around 7 to 10 days and beyond.

 

Regards to all, Matt.

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Hi all.

 

Just a quick post from 'the other side of the pond' as the saying goes, but after a run of shocking summers here in the UK and particular so last year, this progression towards more of a negative AAM pattern and also the current MJO phase is likely to lead to a major warm up for the UK;

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ALL_emean_phase_full.gif

 

Well and truly in phase 8 now, which using the reanalysis images for a June month leads to this - http://www.americanwx.com/raleighwx/MJO/MJO/JunePhase8500mb.gif

 

Whilst clearly not always likely to lead a distinct end result all the time, the signal there for a +ve pressure anom to develop across the UK and NW Europe in general is now being supported by the usual global and ensemble models, take the latest GFS ENS mean - http://www.wetterzentrale.de/pics/Rz500m10.gif

 

It's been long over due but that is finally a summer pattern that the UK used to see over 5 or 6 years ago with the Azores high becoming the dominant role and with a likely strong +NAO pattern as well, which in summer doesn't necessarily mean wet and windy like it would do in winter. Sill trying to get some additional information and correlation between the GWO and its importance of weather regimes/patterns within the North Atlantic area, but this could be a good example of how the two (MJO and AWW) are tallying nicely and giving an end result that is likely to lead to a major spell of summer weather for the UK within around 7 to 10 days and beyond.

 

Regards to all, Matt.

 

Hi Matt,

 

I like the science here behind your forecast. I'm seeing a nice little warm up for the UK July 8-13, but the overall low-frequency pattern (interannual timescales) doesn't favor for stable warmth over the UK beyond this little warm up. I'm thinking things turn colder yet again around July 20th. I'm seeing a very strong warm signal late in July over north western Russia as the MJO pushes back over the Maritime Continent-West Pacific sector. Unfortunately for the UK, it spells cooler than average weather more likely than warmth :(

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Hi Matt,

 

I like the science here behind your forecast. I'm seeing a nice little warm up for the UK July 8-13, but the overall low-frequency pattern (interannual timescales) doesn't favor for stable warmth over the UK beyond this little warm up. I'm thinking things turn colder yet again around July 20th. I'm seeing a very strong warm signal late in July over north western Russia as the MJO pushes back over the Maritime Continent-West Pacific sector. Unfortunately for the UK, it spells cooler than average weather more likely than warmth :(

 

Hi Mike, thanks for the reply and additional information. Yeah, the MJO does look like it'll be on the move. Been looking at the full ECMWF 32 day forecast ensemble suite as part of work today (I am a meteorologist over here in the UK) and somewhat surprisingly this shows the UK and NW Europe to be dominated by a +ve pressure anom throughout the majority of July and this goes against the prediction it is making for example regarding the MJO moving around into phase 2, 3 and perhaps 4 long term. Not sure whether you can get access to that info from the ECMWF over there, but it certainly is highlighting a particularly settled and summery July for the UK, but clearly we shall see.

 

Out of interest what do you base your prediction on, the longer term prediction, regarding the MJO heading that far around into perhaps phases 5 and 6, clearly, as you state, neither of which seem favourable from the UK's point of view long term.

 

Hope you (the forum) don't mind me posting a few posts now and then. Clearly don't want to clutter up the threads with UK and European info, but sometimes when you guys get talking about the MJO etc and broader scale synoptic develops, they do have some influence and importance on the UK and the North Atlantic sector, so it's always good to read those thoughts.

 

Regards. Matt.

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Probably, but not as widespread or intense like the previous heat wave. More like Very Warm/Humid. Yuck.

 

I thought this at first two, but I'm begging to see support of a developing 594 dm warm ridge pushing onshore over the mid-atlantic states... I was originally thinking mid 80s for PHL up through BOS but now I'm thinking low-to-mid 90s not out of the question, especially if most of the precipitation stays well inland. 

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I thought this at first two, but I'm begging to see support of a developing 594 dm warm ridge pushing onshore over the mid-atlantic states... I was originally thinking mid 80s for PHL up through BOS but now I'm thinking low-to-mid 90s not out of the question, especially if most of the precipitation stays well inland. 

 

Awww crud. That's even worse. That's it, I'm moving to Greenland. :P

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Hi to you all.

I often read this forum for your guys imput and knowlege and to try to gain further insight into the background to the hemisphere patterns.

I am a member of the UK Net-Weather forum and take great interest in the NWP charts and post my views over there.

 

As Mat Hugo said in a post above the UK looks set for a decent spell of warmth and sunshine-probably 10-14days minimum looking at the last CPC 8-14day forecast 500hPa anom.forecast and 00Z Euro and GFS means.

A developing Azores High building across the Uk this coming week end looking to persist for sometime.

Something we havent seen in the UK for at least 6 Summers-thanks to the path of the mean jet heading north at last.

 

Anyway just wanted to say Hi to everyone.My knowlege is pretty basic and mainly gained from chart watching over 50years but even in my senior years am always looking to learn more about the background stuff like teleconnections etc.

 

Looking forward to all your future imputs with great interest.

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I love the UK talk...only been to France and Israel in that area of the world but my mom was a long time Londoner. The NAO is clearly huge there but I also want to understand MJO in Europe.

Yeah we have a pretty lively model discussion thread over here.Winter is very busy sometimes especially when there's prospects of snow-i guess we have snow lovers here like you have over there,lol.

Anyway today the warmth promised has duley arrived with heights now building across the UK-28C around the London area today and possible 30C tomorrw.That's way above the mean max of around 18-19C for July.

MJO seems to be quiet for the coming week or so so with little organised tropical convection forecasted does this mean the NH pattern shows little change for now?

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

Looking at mean outputs and the CPC day8-14day anomalies forecasts a blocked Atlantic for thecoming period.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610day.03.gif

 

so the forecasted warm spell looking good for the UK for sometime it seems.

 

It looks like you have some real heat over there

http://www.wetterzentrale.de/pics/Rnamavn365.png

especially over the central and western states that's for sure.

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Synoptics across the UK and N Atlantic in general have produced and continue to produce one of the best spells of summer weather for the UK in many years. Gone has the more southerly track and active jet and the latest analysis shows this pattern;

 

http://virga.sfsu.edu/jetstream/jetstream_atl/big/1307/13071106_jetstream_atl_anal.gif

 

With the MJO moving into phase 1 around the 27th of June, the reanalysis shows this pattern - http://www.americanwx.com/raleighwx/MJO/MJO/JunePhase1500mb.gif - This really does match quite well and the estimated ~10-12 day impact definitely seems to have come to fruition on this one. Slight shift of the main high to the W or SW of the UK but the broader pattern re-develops by the looks once again later next week with the Azores high building back up into the UK;

 

http://raleighwx.americanwx.com/models/gfsensemble/00zENS6-10day500mbHeightAnomalyNH.gif?ts=2013071100gfsensemble-3

 

A marked region of +ve height anoms there and even by 11 to 15 day the high shifts westwards but maintains a possible ridge towards the UK;

 

http://raleighwx.americanwx.com/models/gfsensemble/00zENS11-15day500mbHeightAnomalyNH.gif?ts=2013071100gfsensemble-5

 

Support as well from the NAEFS between days 11 and 15 - http://raleighwx.americanwx.com/models/naefs/00zNAEFS11-15day500mbHeightAnomalyNH.gif

 

Could well turn into one of the most anticyclonic months for the UK now in years, given how poor the last 5 or 6 summers have been and clearly is and looks set to continue to produce some particularly impressive summer weather.

 

Regards, Matt.

 

NB: Anyone (Allan Huffman?) know why some of the forecast charts seem to take a long time to become available. The GFS ENS seems to update most frequently, but the likes of the ECM, GGEM and NAEFS seem to be particularly slow at becoming available and it is, at times, hard to know whether the 00Z run was yesterday's run or today's run for example. Thanks!

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Yeah we have a pretty lively model discussion thread over here.Winter is very busy sometimes especially when there's prospects of snow-i guess we have snow lovers here like you have over there,lol.

Anyway today the warmth promised has duley arrived with heights now building across the UK-28C around the London area today and possible 30C tomorrw.That's way above the mean max of around 18-19C for July.

MJO seems to be quiet for the coming week or so so with little organised tropical convection forecasted does this mean the NH pattern shows little change for now?

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

Looking at mean outputs and the CPC day8-14day anomalies forecasts a blocked Atlantic for thecoming period.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610day.03.gif

 

so the forecasted warm spell looking good for the UK for sometime it seems.

 

It looks like you have some real heat over there

http://www.wetterzentrale.de/pics/Rnamavn365.png

especially over the central and western states that's for sure.

 

I've am quite amazed at how well the MJO composites have lined up for you...seeing as this was purely a circulation dominated circuit of the RMM index. In fact, all amplitude in the RMM index over the past week has been dominated but other tropical waves projecting onto the index.  The MJO band convection has been suppressed over the IO for the entirely month of July/June and (http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdet/7.5S_7.5N/2013.png). You can see nicely how the OLR index has only peaked recently, due entirely to the presence of an ERW and Kelvin wave, exciting the RMM index, when the MJO was actually suppressed in the region. This is a really nice example of how when the conditions are right, the RMM index fails at tracking the MJO.

 

rmm_variable.40.png

 

The circulation associated with a remnant MJO from the first week of June has finally circumnavigated the globe, and as it emerges over the IO, coupled with an active kelvin wave, a new MJO is likely to develop. (http://www.atmos.albany.edu/student/macritch/showhovs.php?bknum=3&lat=75S75N). Perhaps a strong enough WWB will bring warmer SSTs back to the E.Pac...

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  • 4 weeks later...

 

 

NB: Anyone (Allan Huffman?) know why some of the forecast charts seem to take a long time to become available. The GFS ENS seems to update most frequently, but the likes of the ECM, GGEM and NAEFS seem to be particularly slow at becoming available and it is, at times, hard to know whether the 00Z run was yesterday's run or today's run for example. Thanks!

 

I've been working for the past couple of weeks on updating our model center site. One of the improvements will be better information on the maps.  Rather than relying on the timestamp at the bottom of the maps, I've made it so the initialization date/time, valid date/time, and even the valid time for your own timezone will display at the top.

 

Now regarding the speed of the output, that would be on Allan's end who generates the maps with his own equipment (though we are talking of perhaps getting it up on the cloud soon.)  I haven't seen any evidence of slow output other than brief interruption while moving his equipment to another location.

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  • 1 month later...

The guidance continues to advertise a rather complex and complicated pattern unfolding later this week across the Western 2/3rds of the North America. A potent cold core upper low and a deep trough will drop S into Southern California and the Desert SW and slowly eject across the Rockies into the Plains lending to lower elevations rains and higher elevation snow fall, potentially heavy. A Pacific front will approach Texas and pull up stationary across Central Texas as a short wave/low pressure disturbance drops S toward the base of the Western trough. Add to the mix a developing EPAC tropical system that appears to be pulled N toward the Baja Peninsula and then turn NE spreading abundant tropical moisture across Mexico and Texas and the Southern Plains. Such patterns in past events have led to potential heavy rainfall events in October across Texas/Louisiana/Arkansas and tend to raise an eyebrow. It will be interesting to see if such a pattern continues to develop as the guidance is suggesting. As we near the weekend time frame rain chances do increase and may well continue into mid next week before a much stronger front clears the Region associated with the remnants of the WPAC typhoons and a power Pacific jet pushes E.

 

 

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The overnight guidance continues to advertise a very wet and stormy pattern for portions of the Southern Plains and locations E into the Ozarks and mid Mississippi Valley. Locations in Mexico, Texas, Oklahoma, Arkansas and Northern Louisiana may see rainfall totals exceeding 3-5 inches with higher isolated totals where training storms may develop. The European suite is suggesting a potential multi day significant heavy rainfall event beginning Saturday and extending into mid next week as a complex pattern develops with a deep Western trough, a potent shortwave disturbance and 94E currently developing offshore of Acapulco moves NW and turns ENE across the Baja Peninsula and spreads deep tropical moisture across the Region where PW's above 2 inches will be in place across Texas ahead of the advancing trough.



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  • 2 weeks later...

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