Jump to content
Will it snow? 7 day forecast Weather Radar Will it be cold?
Snow?
Local
Radar
Cold?

nick sussex

Members
 View Profile  See their activity

  • Posts

    20,280

  • Joined

  • Last visited

  • Days Won

    150

 Content Type 

Everything posted by nick sussex

  1. nick sussex
    At T192hrs what we need to see is a shortwave forming at the base of the upstream trough heading se and cutting off the high, this will force the high centre to shift west and bring lower heights to the south. We need a more amplified upstream shortwave circled red to downstream sharpen up the flow, this will also help to pull the PV further to the nw as it phases with that. If that happens we could develop a cut off high to the nw and bingo a cold Christmas!
  2. nick sussex
    We're going to need some trough disruption to cut the limpet high off. A good trend at least and miles better than the ECM Scrooge runs of recent days.
  3. nick sussex
    Happy Christmas from the GFS 12hrs run! Much better than this morning. We do get some phasing with that shortwave but have a better tilt to the upstream troughing.
  4. nick sussex
    The GFS 12hrs run looks more amplified over the USA than the 06hrs. The issue is whether shortwave energy in the mid Atlantic will complicate any WAA into Greenland as happened this morning. Shortwave behaving so far!
  5. nick sussex
    Great detail from New Hampshire state forecast talking about the overall NH pattern into late December: Overview... Interpreting through late December. Considerable forecast warming in the stratosphere, polar low / night-time jet displaced to the other side of the N hemisphere subsequent of noteworthy anomalous ridging across Northern N America. Beneath which warm air continues to surge into the Arctic from the NW Pacific (with perhaps MJO contributions) and the NW Atlantic displacing colder air S where it becomes bowled up across NE Asia / NE N America. Ensemble means continue to signal an active weather pattern with an amplified H5 ridge-trof pattern over the CONUS, anomalous H85 T warming over the N Pacific with cold anomalies continually reloaded over Central/E N America, however a trend towards higher heights / surface mean sea level pressure with stratospheric cross-polar flow shifting into NW Europe.
  6. nick sussex
    Just looking at some US state forecasts theres hope that the ECM isn't correct upstream. New York state forecast: Thereafter, the forecast is much more uncertain. Downstream shortwave begins to make eastward progresses as ridge flattens. Weak PVA noted in fast zonal flow approaching area Sunday night, which could trigger some light precip. Then, operational ECMWF remains a fast and stronger outlier as this mid west shortwave moves east. This would result in higher precip chances Monday when compared to GFS and Canadian NH. Maine State forecast: For now, have favored a solution similar to the 13/12Z GEFS with a coastal low on Wednesday bringing potentially significant snow. The 13/12Z operational ECMWF shows a coastal low on Monday night, but this solution involves kicking a Four Corners low out of the SW US too quickly and it is not supported by the majority of ECMWF ensemble members. There is though still the complication regarding whether shortwaves in the mid Atlantic phase with the upstream trough as happened on last nights GFS 18hrs run which stopped better WAA up to Greenland. This mornings GFS run avoided that at the key timeframe so even if its correct versus the ECM there are still hurdles to overcome.
  7. nick sussex
    Operation Save Christmas hangs on the GFS trend being correct! The ECM hits the buffers early with a poor upstream pattern. However NOAA have not sided with the ECM and have highlighted huge uncertainty . More about that later after my coffee!
  8. nick sussex
    Signs of life once again from the GFS which at least is playing with some different solutions towards day 10 as opposed to the ECM. I'd be less willing to believe in the Christmas Miracle of 2017 if the MJO wasn't on the move and expected to enter some favourable phases.
  9. nick sussex
    Looking at the ECM De Bilt ensembles shows next Monday and Tuesday showing some east/se/ne solutions for there which means a cluster do have the high further north. The spreads also showing the main spread to the nw and se of the UK between T144 and T168hrs.
  10. nick sussex
    Looking at the latest MJO forecasts, disagreement between the GEFS and ECM, we've been in phase 7 then a brief entry into the COD. The ECM brings the signal out quickly into phase 7, the GEFS into phase 6 taking a few extra days to go into 7. However the GEFS has a large increase in amplitude in phase 7. The ECM a slight increase. The EMM which includes climatology has a big increase in amplitude in phase 7. For those interested we have a further MJO update out this evening from the Global Tropics Hazards outlook which goes into more detail. For newer members the amplitude of the signal is important: That's the GEFS so the further the signal is away from that inner circle the stronger it is. There are other factors that can mute out the MJO but you have a much better chance of a NH pattern change with a stronger signal. PS The COD which you often see referred to stands for circle of death! basically the signal isn't doing anything and won't have any impact.
  11. nick sussex
    Interesting MJO update from NOAA which doesn't match the current longer range outputs apart from the GFS 06hrs run which is the first to hint at the MJO possibly bringing in another pattern change. The CPC velocity potential-based and RMM-based MJO indices indicate a MJO signal with the enhanced phase approaching the Western Hemisphere.  This envelope is forecast to continue eastward over the next two weeks, although the propagation may be masked somewhat in the RMM index by a competing easterly signal in association with a Kelvin wave approaching the Indian Ocean at present. Equatorial Rossby wave activity in the Central Pacific may further muddy this perspective.  The MJO is favored to continue propagating eastward over the West Pacific (Phase- 7) for the majority of Week-1, before progressing into Phase-8 during Week-2.  An active MJO over the West Pacific suggests a colder solution from the Northern Plains through the East in approximately two weeks. As the MJO envelope shifts into the Western Hemisphere, lagged impacts over the U.S. become less robust. The above suggests the return of troughing to the east/ne USA with a dig of cold there, depending on the amplitude of that we could see high pressure to the sw pulled further west/nw and colder conditions in western Europe. They're suggesting that the RMM index might be incorrect and the models might be having problems picking up the correct signal. Its notable that the forecasts had originally wanted to take the MJO into the COD for about a week before strengthening it once again with movement into phase 7 , yesterdays shortened the time in the COD. Operation Save Christmas given a further lift but a long way to go yet!
  12. nick sussex
    Operation Save Christmas! The GFS 06hrs run develops more amplitude upstream and tries to retrogress the high within T240hrs. That's a welcome sign after the early morning runs which were poor for cold prospects. I wouldn't look further than that when the lower resolution kicks in but we'll take any better news today. Only one run so we'll have to see if this trend continues.
  13. nick sussex
    A very poor start for coldies today with a hideous looking upstream pattern! We've lost the shortwave which could track se through the UK and although one forms its simply too flat upstream to get that se and shear some energy away from the advancing tide of doom! I think the absolute best in terms of hanging onto some surface cold is the Euro high getting far enough north, apart from that the GEFS look like a bloodbath with any colder solutions within T240hrs meeting a grisly end at the hands of the menacing PV to the nw! The ECM ensembles for London do show the op once again one of the mildest solutions at times and in terms of pressure a lot of ensembles have higher values than the op so suggestions high pressure could get further north but its about the orientation and placement in terms of hanging onto a surface feed from mainland Europe. Before that as we head towards the weekend another colder few days with a chance of something wintry so its not all bad.
  14. nick sussex
    Looking at the ECM ensembles for London some room there to extend the cold for a few days. The op is at the top end of solutions towards days 6 and 7 although good support for milder weather after that.
  15. nick sussex
    Yes its been strange because its normally the GFS which is often flatter upstream. Don't discount the GFS trend though , its really how much dig we can see upstream in that troughing to force some ridging more ne ahead of it and a shortwave heading se through the UK. Energy distribution in these scenarios is poorly handled by the models. Theres I would say enough time to extend the cold given the timeframes but its going to be a struggle to hold on to that , perhaps a few days but the Atlantic looks in no mood to be denied at the moment.
  16. nick sussex
    The ECM is most progressive of the big 3. It does actually manage to eject the shortwave from Scotland to ne Spain between T144 and T168hrs. This would become the trigger if we had something that could lead to but too much energy upstream so no chance of developing any ridging to the ne. There are differences between the big 3 upstream with views of the trough and how far east it gets. I still wouldn't rule out a GFS type outcome because its not really outlandish given the overall set up but its hard to see this as anything other than the dam holding a few more days before the Atlantic flood moves in. It would need some bigger changes to develop a stronger ridge to the ne and sufficient trough disruption upstream.
  17. nick sussex
    The cold air putting up a fight in both the GFS and UKMO. The latter would have looked similar to the GFS if it had developed that ne USA low, the phasing of the GFS low with the PV acts to pull that further to the nw. We'll have to see what the ECM makes of that low and NOAA will definitely commenting on that upstream low later on.
  18. nick sussex
    Yes I just saw its output, not bad at all. The ECM currently looks the most progressive out of the GFS/UKMO/GEM and strangely its been this way for the last few weeks which is a reversal of whats happened before with the GFS normally doing that. I think the problem at the moment is the pattern change upstream with a breakdown of the strong amplified west USA ridge and the ejection east of the trough which is currently over the ne USA and east Canada. NOAA suggest the positive PNA might return some time next week with cold conditions returning to those areas. Its likely we will though see a lot more energy heading east, the uncertainty is whether some of that breaks se or whether the lot goes ne or east.
  19. nick sussex
    It does look like an Atlantic attack is imminent ! However how you get there looks different across the big 3, the ECM is most progressive and is much quicker with bringing in milder conditions. The GFS keeps the candle burning for cold much longer with a chance of a shortwave cutting se, perhaps some wintry interest there. The UKMO is between the GFS and ECM at T144hrs. The GEFS shows a small cluster of support for the GFS op but given the Euros are less interested its a lower probability solution although its possible we might end up with a halfway house like the UKMO. Still time for changes and the ECM has in recent weeks often been the most progressive output but its hard to see the Atlantic being repelled unless the GFS trend accelerates further with a stronger ridge to the ne and more upstream trough disruption. Interestingly it looks like yet again temps will drop towards the weekend which has been the case for the last few weeks.
  20. nick sussex
    OMG that’s a classic! you certainly need a good sense of humour if you’re a UK snow lover!
  21. nick sussex
    NOAA seem to think the troughing in the east USA could well return the week after next and dependent on the amplitude of that this could downstream deliver some interest to the UK. The possible renewed upstream amplification could well be in relation to the lagged MJO effect, have the models got the correct timing of that if does verify? In terms of tonights ECM op it is at times both a pressure outlier aswell as the warmest solution for London and I wouldn't discount the GFS 12hrs trend just yet.
  22. nick sussex
    Morning dip in hopes now rebounding with an improved GFS 12hrs run, a little more amplified upstream. A better trend even if the GFS doesn't deliver a Scandi high past day 8 but importantly this more amplified upstream pattern is showing within T144hrs. The UKMO isn't as good but better than this morning but there are some differences upstream between it and the GFS with timing of shortwave energy across the USA and Canada. Above is your pointer around T174hrs as to whether the trend is good or bad for the Scandi high. The more the troughing digs south the more stronger your ridge will develop to the ne and also the shape of the trough, the shape signifies say your movement so if you see a round base that's bad news that means the main energy is shifting east with little going se, the more sharper that trough becomes and digs south the better chance of developing that ridge to the ne.
  23. nick sussex
    You’re my hero! I did exactly the same thing here, even though I’ve got the mountains close by it’s always nice to see snow falling in your back garden. I remember you were hacked off about your previous home because it was like 3 feet above sea level!
  24. nick sussex
    Steve I hope you don’t mind me asking but when you decided to move to your new home did you factor in elevation ?
  25. nick sussex
    Our positive trend of yesterday has hit the buffers this morning! The upstream pattern doesn’t re-amplify and a lobe of the PV ne of Scandi runs west re-invigorating the PV near Greenland . The cold extension is looking ropy this morning but we’ll have to wait to see what tonight brings. There has been a pattern recently of flatter 00hrs runs and more amplified 12 hrs so let’s hope that continues.
×
×
  • Create New...