johnholmes

Found this about weather balloons; certainly in my time world-wide ascents main times were 00 and 12Z for all data including balloons. Currently, the global radiosonde network includes about 900 upper-air stations, and about two-thirds make observations twice daily (at 0000 and 1200 UTC). The network is predominantly land-based and favours the Northern Hemisphere.

Max balloon data is 00Z and 12Z

Is it me, perhaps I'm seeing something that is not correct? Most avid followers seem in despair after each 00z GFS run, fairly elated then after almost each 06Z and 12Z runs?

A snap answer would be possibly! Like my post mentioned I need a couple more outputs to make a definite prog

Not got time to post charts etc but 10-14 day NOAA shows a westerly into the UK, still a bit below 500 MB temperatures for UK, 6-10 shows pattern I posted yesterday. ECMWF also v slightly downgraded in its time frame, shows very slack COL situation by end of its period which is a similar time frame to 6-10 NOAA. I prefer to see 2-3 charts being consistent before making any forecasts.

dry with mainly large amounts of CuSc after 1 or 2 light rain showers; 0.4 mm since midnight; current low is 2.3 C

no ppn forecast of snow is accurate even at short times scales. Not that different to the summer forecasts of rain if you look back. How often even at T+24 or less was the ppn not in the right place/not the correct intensity etc. With snow there are further 7 or 8 parameters to consider! Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5003580

no ppn forecast of snow is accurate even at short times scales. Not that different to the summer forecasts of rain if you look back. How often even at T+24 or less was the ppn not in the right place/not the correct intensity etc. With snow there are further 7 or 8 parameters to consider!

UK Met rarely, as far as I am aware, rarely make use of this model for UK forecasting

First practice day for the Lauberhorn races taking place today; nice backdrop! https://www.jungfrau.ch/webcams/lauberhorn/#/

Tuesday 9 th Jan NOAA 6-10==15-19th, in other words inside the approximate date of ‘deep’ cold predicted some time ago.the 6-10 chart keeps the meridional flow across the chart, the shape is not the classic one but no signal for a developing mobile Atlantic, not on the 8-14 really. As usual the high +ve anomaly is much reduced but this is normal. IF this persists and the upstream becomes less conducive to another trough-ridge downstream then a change could be signalled but not so far and the 8-14 takes us to 17-23rd Jan? ECMWF has never been as +ve about the deep cold scenario and its latest output for 15-19 Jan is pretty similar. The 850’s show the -5C extending during the period to cover all of the UK by the 15th then it is moved north again so that by the 19th is is predicted be N Wales to about the Wash area. This as the 500 flow backs more west or even south of west with time. UK Met of course only shows surface and 500MB outputs for 3 days (13-15 th) but it looks to be on the same page for just prior to the two above from the 15 th. Ridge dominated both 500 and surface, over/just NW of the UK to a more trough dominated by the end of its run, again surface and upper air. So overall then, after a temporary slight warming at the surface and height, over the weekend a deeper colder spell seem likely to occur. The direction of flow, initially, being N’ly not E’ly. Looking on Extra at the skew-T diagrams, the colder air seems to start arriving over Doncaster by 14 Jan and much colder air continues to advect into the area from a N’ly direction as far as the run goes=T+180. All the time with limited convection, to around 6000 ft. So even well inland it is ‘possible’ for snow to fall. This is way ahead of any reliability from the synoptic models so patience is needed as to just what will happen over the UK regarding snowfall. Be that from showers and any possible troughs in the flow or from the Atlantic trying to move in giving more general ppn. To me it seems unlikely that milder air is unlikely to make much, if any, real progress against the cold airmass in the period under discussion on this post. All really interesting though to see just how the actual weather will turn out. Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5003095

Tuesday 9 th Jan NOAA 6-10==15-19th, in other words inside the approximate date of ‘deep’ cold predicted some time ago.the 6-10 chart keeps the meridional flow across the chart, the shape is not the classic one but no signal for a developing mobile Atlantic, not on the 8-14 really. As usual the high +ve anomaly is much reduced but this is normal. IF this persists and the upstream becomes less conducive to another trough-ridge downstream then a change could be signalled but not so far and the 8-14 takes us to 17-23rd Jan? ECMWF has never been as +ve about the deep cold scenario and its latest output for 15-19 Jan is pretty similar. The 850’s show the -5C extending during the period to cover all of the UK by the 15th then it is moved north again so that by the 19th is is predicted be N Wales to about the Wash area. This as the 500 flow backs more west or even south of west with time. UK Met of course only shows surface and 500MB outputs for 3 days (13-15 th) but it looks to be on the same page for just prior to the two above from the 15 th. Ridge dominated both 500 and surface, over/just NW of the UK to a more trough dominated by the end of its run, again surface and upper air. So overall then, after a temporary slight warming at the surface and height, over the weekend a deeper colder spell seem likely to occur. The direction of flow, initially, being N’ly not E’ly. Looking on Extra at the skew-T diagrams, the colder air seems to start arriving over Doncaster by 14 Jan and much colder air continues to advect into the area from a N’ly direction as far as the run goes=T+180. All the time with limited convection, to around 6000 ft. So even well inland it is ‘possible’ for snow to fall. This is way ahead of any reliability from the synoptic models so patience is needed as to just what will happen over the UK regarding snowfall. Be that from showers and any possible troughs in the flow or from the Atlantic trying to move in giving more general ppn. To me it seems unlikely that milder air is unlikely to make much, if any, real progress against the cold airmass in the period under discussion on this post. All really interesting though to see just how the actual weather will turn out.

I suppose I will be talking to myself but comparing 06 to 00 at extended distances really is a waste of time. Compare like with like and you will get a better idea of where the particular model seems to be heading. I'm in the middle of doing my usual 500MB output, will post it before long but they seem to agree with the overall outlook of cold returning over the coming weekend, but with differences in how cold. re the how far north will any low get. Almost always IF the cold has been in place for 3 days or more then the initial modelling suggesting the Atlantic pushing the ridge/cold air away is very often too quick. The direction of travel of the depression at the surface and in the 3 dimension is fairly critical and is usually only seen accurately 24-48 hours out. Even then it can be several days before there is a real breakdown into genuinely milder gets there. Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5003059

I suppose I will be talking to myself but comparing 06 to 00 at extended distances really is a waste of time. Compare like with like and you will get a better idea of where the particular model seems to be heading. I'm in the middle of doing my usual 500MB output, will post it before long but they seem to agree with the overall outlook of cold returning over the coming weekend, but with differences in how cold. re the how far north will any low get. Almost always IF the cold has been in place for 3 days or more then the initial modelling suggesting the Atlantic pushing the ridge/cold air away is very often too quick. The direction of travel of the depression at the surface and in the 3 dimension is fairly critical and is usually only seen accurately 24-48 hours out. Even then it can be several days before there is a real breakdown into genuinely milder gets there.

Dry with about half cover of shallow CuSc much of time, some sunshine, cold with a low of 0.9C, with what I call a 'dry' ground frost. no windscreen scraping and nil white showing on the grass.

Dry and mainly cloudy with a low of 2.0 C, no visible ground frost at all

Very late this morning but mostly cloudy, even the odd spot of rain during my short Sunday walk; a low of 3.3 C

Tends to support the idea of 'real' cold around 14 th, using the system I played around with 10-12 years ago. Only about 50% success though! Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=4997510

Saturday 6 January re 500 charts etc The ECMWF looks to show deeper cold air advecting south of the 500 and surface ridging moving to around Iceland area. Date shown is 16 Jan, a week Tuesday! How long the upper ridge might last here is not clear as a largish upper trough is shown on the far nw of the EC chart. The NOAA 500 charts continue out to 8-14 with the upper ridge shown se-nw Greenland, the actual contour centre is about 55N 20W with the +ve height now shown as +390 DM over se Greenland on the 6-10 day chart. Similar on the 8-14, +ve is 270 DM. Upstream of this the pattern looks conducive to this probably extending some way beyond the 14 day period? This pattern has been consistently shown since about Xmas Day, obviously a developing set of charts but consistent in its direction and development. Just how long this pattern will last, how cold the UK will get, let alone will it snow is for the synoptic charts to gradually converge on what is likely. The UK surface and upper air only extend to the 12 th so obviously little of the above is on their public available charts. Given the consistency of the NOAA charts, now being picked up by ECMWF I would be surprised if deep cold was not being forecast by UK Met before next weekend! Egg on face possible! Usual charts below Climate Prediction Center - 6-10 Day 500mb Outlook WWW.CPC.NCEP.NOAA.GOV UK Met Office Fax Charts - UKMOMSLP Analysis and Prognosis WWW.WEATHERCHARTS.ORG UK Met Office . . Europe and North Atlantic MSLP analysis and prognosis charts Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=4997528

Saturday 6 January re 500 charts etc The ECMWF looks to show deeper cold air advecting south of the 500 and surface ridging moving to around Iceland area. Date shown is 16 Jan, a week Tuesday! How long the upper ridge might last here is not clear as a largish upper trough is shown on the far nw of the EC chart. The NOAA 500 charts continue out to 8-14 with the upper ridge shown se-nw Greenland, the actual contour centre is about 55N 20W with the +ve height now shown as +390 DM over se Greenland on the 6-10 day chart. Similar on the 8-14, +ve is 270 DM. Upstream of this the pattern looks conducive to this probably extending some way beyond the 14 day period? This pattern has been consistently shown since about Xmas Day, obviously a developing set of charts but consistent in its direction and development. Just how long this pattern will last, how cold the UK will get, let alone will it snow is for the synoptic charts to gradually converge on what is likely. The UK surface and upper air only extend to the 12 th so obviously little of the above is on their public available charts. Given the consistency of the NOAA charts, now being picked up by ECMWF I would be surprised if deep cold was not being forecast by UK Met before next weekend! Egg on face possible! Usual charts below Climate Prediction Center - 6-10 Day 500mb Outlook WWW.CPC.NCEP.NOAA.GOV UK Met Office Fax Charts - UKMOMSLP Analysis and Prognosis WWW.WEATHERCHARTS.ORG UK Met Office . . Europe and North Atlantic MSLP analysis and prognosis charts

see my post below!

Tends to support the idea of 'real' cold around 14 th, using the system I played around with 10-12 years ago. Only about 50% success though!

Dry with variable cloud, temperature fell from around 4.5 C at dawn to 2.4 C a short time ago.

Dry and mostly cloudy, Davis showed slight rain around 0300=0.2 mm, the low from midnight was 3.6 C but it had fallen late last evening to 1.4 C, currently on 5.8 C

Friday 15 Jan update using the upper air charts (500 MB chiefly) Taking ECMWF first and it has changed today from the last couple of days with both the upper and surface ridge shown as further NW than before. There is also in the last 2 days a signal for colder sir to advect west as the ridge conditions give way to a bit more cyclonic looking. 850 temperatures are brought down below -5 C in the last 2 charts. Is this a trend that will continue? Time will tell The NOAA charts for 6-10 especially have shifted the C of G of the ridge first east and now again more west. In the more westerly position the European trough is obviously further west thus allowing the possibility of colder upper air moving west. Currently the version yesterday showed the actual contour centre in the NW of the UK with the very high +ve anomaly (+390 DM) being just SW of Iceland. The UK is currently not in any deep cold air on the 6-10 or the 8-14, although this hint at temperatures falling somewhat at 500 MB. UK Met in the period 9-11 Jan ( their furthest public charts) show both the upper and surface ridge staying just north of northern Scotland. They have the European trough well east with a cut off upper low just south of the UK/nw France edging south over that period. So with all 3 outputs in the 6-10 day period seem to suggest no deep cold air but with upper and surface ridging being somewhere over or WNW of northern/western Scotland. This suggests a mainly dry spell with frost becoming more widespread but depending on cloud cover for its intensity. The upper pattern to me suggests little probability further out of any break down in the block. Obviously its actual position is going to vary slightly but remaining north rather than south. Models predicting further ahead do seem to suggest that deep cold is possibly 14-20 days away from today? Not my scene so that comment may be incorrect but I’ll leave that to others to firm up on. Climate Prediction Center - 6-10 Day 500mb Outlook WWW.CPC.NCEP.NOAA.GOV UK Met Office Fax Charts - UKMOMSLP Analysis and Prognosis WWW.WEATHERCHARTS.ORG UK Met Office . . Europe and North Atlantic MSLP analysis and prognosis charts Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=4996040