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Model Output Discussion - Into Autumn 2020.


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Good evening! 😀 1st ever post! 1st of many I hope. Love this forum.   ECM: Tonight Matthew, I’m going to be... The GFS from yesterday!     A real tease, shame the OP only

Fitting macro scale ENSO patterns, (or any other macro scale drivers) to idealistic synoptic patterns is inevitably set to lead to departure in reality from such expectations.   The macro scale wind-f

ECM indicating a return to some settled weather end of next week however a few showers & the flow becoming Northerly so the potential for some frost developing- Nice & seasonal.

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10 minutes ago, northwestsnow said:

You are referencing winter on the back of one operational in mid November?

Really?

To be fair,  he's basis, is on the fact that percentage wise the most likely out come for Winter from a starting point like this,  is a mild one. Not saying that's how it's going to pan out, but there's a high chance.

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42 minutes ago, northwestsnow said:

You are referencing winter on the back of one operational in mid November?

Really?

 Have you not seen the de-amplification trend of all models when they get to crucial 144-192h? Its already apparent.There is a presumption here that GFS has a strong vortex bias past 240h I dont think so,its the oposite,NAO and AO very positive + this 10hPa zonal wind profile going forward with mutual model agreement.Anything else then zonality would be a miracle in next 4 to 6 weeks.

u10serie_cfsRawCorrGefs.png

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1 minute ago, jules216 said:

 Have you not seen the de-amplification trend of all models when they get to crucial 144-192h? Its already apparent.There is a presumption here that GFS has a strong vortex bias past 240h I dont think so,its the oposite,NAO and AO very positive + this 10hPa zonal wind profile going forward with mutual model agreement.Anything else then zonality would be a miracle in next 4 to 6 weeks.

u10serie_cfsRawCorrGefs.png

4-6 weeks miracle? That’s a long time when it comes to weather. It maybe but to call zonality for upto the next 6 weeks? 

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14 minutes ago, jules216 said:

 Have you not seen the de-amplification trend of all models when they get to crucial 144-192h? Its already apparent.There is a presumption here that GFS has a strong vortex bias past 240h I dont think so,its the oposite,NAO and AO very positive + this 10hPa zonal wind profile going forward with mutual model agreement.Anything else then zonality would be a miracle in next 4 to 6 weeks.

u10serie_cfsRawCorrGefs.png

Doesn't always play out like that though. In 2009/10 there was a very strong PV from mid December going into mid January....we all know what happened. Very cold second half of December, snow & white xmas.....coldest January since 1987 followed. A strong PV doesn't prevent cold. I'm sure when these chart appeared in the first week that people weren't expecting what followed soon after!

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10 minutes ago, mb018538 said:

Doesn't always play out like that though. In 2009/10 there was a very strong PV from mid December going into mid January....we all know what happened. Very cold second half of December, snow & white xmas.....coldest January since 1987 followed. A strong PV doesn't prevent cold. I'm sure when these chart appeared in the first week that people weren't expecting what followed soon after!

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something has changed since 2013/14 I think.I hope to be wrong as much as anyone of course

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Some great models today, i think i know what part of Europe we all want to be in for christmas. However cold air is slowly making it's way down south. Looking like a cold christmas, any chance for snow on christmas is now relying on that push down. But perhaps a beast from the east is still possible in March time best charts since i've entered this forum that i've found myself. 

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GFS ensembles have definitely started to take a more unsettled turn - the mean is now down to 1020mb, with a growing number of more unsettled members pulling the average down. For comparison, the ensembles from the 12z run on the 9th had a mean of around 1034mb for the 19th. Quite a turnaround in a day and a half!

The ECM is closer to 1025mb, but there is a 30mb spread from 1010mb to 1040mb at day 9. A big tussle between deepening Atlantic low pressure and building Azores high pressure the culprit here.

Clusters showing a few different outcomes:

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1 hour ago, jules216 said:

 Have you not seen the de-amplification trend of all models when they get to crucial 144-192h? Its already apparent.There is a presumption here that GFS has a strong vortex bias past 240h I dont think so,its the oposite,NAO and AO very positive + this 10hPa zonal wind profile going forward with mutual model agreement.Anything else then zonality would be a miracle in next 4 to 6 weeks.

u10serie_cfsRawCorrGefs.png

You could well be right.

However, as alluded to by other posters, there are multiple solutions to getting cold weather here even in the face of what seems an unfavourable circumstance. Even the heavily sought after greenland blocks, Scandi highs, and SSWs are no guarantee of cold, though of course they greatly increase our chances. 

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