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Interitus

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  1. Well here is an alternative view to take some account of seasonality. Using the month of easterly wind onset at 30mb as the start of a QBO cycle, the current cycle began June this year. There are five other cycles since 1960 (data prior to this is generally poor) which began in June - 2009, 1991, 1986, 1981 and 1967. All show an apparent weakening of the easterlies in the autumn or early winter apart from 1981, which does at least display a moderation in strengthening. Then 4 out of 5 have a 25/26 month cycle, with maximum easterlies in the spring or early summer the year after onset. The exception being the long 32 month QBO of 1967 which started out looking like it might return westerly at the beginning. This did happen for the QBO beginning in July '64, which switched back to westerly in October, before commencing again in January '65. In any case, it can be seen in the graph that this year is stronger than all these previous years at the four month stage (though this could be because QBO amplitude has tended to increase with time in the data).
  2. Whatever happens, the QBO is following a more typical course at present and is already totally different to the 'failed easterly' of last year, as can be seen in the chart below of monthly 30mb equatorial zonal wind -
  3. Yes, there have been record weak wind speeds in the MERRA 2 dataset, from 50 mb and below related to troposphere circulalion, but some have been getting a bit carried away with the significance of this, and the upper level vortex has been developing as normal. A weak vortex in October is a poor predictor for strength later in the winter, at least as measured as measured by 10mb wind speed (NCEP reanalysis). There is a weak correlation by persistence to the strength in November (0.27) but none for other months. Persistence leads to higher correlation for consecutive months November-December (0.42), December-January (0.54) and January-February (0.41) but no correlation for lead times more than a month apart. The stopping the plate spinning analogy doesn't seem to apply.
  4. The World's Glaciers

    https://translate.google.co.uk/translate?hl=en&sl=auto&tl=en&u=https%3A%2F%2Fwww.nrk.no%2Fnorge%2Fsatellittbilder-viser-at-isbreene-i-norge-har-krympet-med-326-kvadratkilometer-1.13701086
  5. They are free to download, though registration may be required. Beware, as these packages are generally supplied as source code they may need a certain level of skill to install and compile. Hardware requirements depend on how intensive the simulations are, obviously NWP can take as much processing power as you can chuck at it! However, minimum levels can be surprisingly low. MM5 traces its roots back to the 1970s, with the final release of v.3.7 in December 2004, supported to 2008. The stated minimum requirements are a Unix workstation with just 128 Mb memory and 1-2 Gb disk. (Note - version 2 was transportable to MS windows but not v3) MM5 - http://www2.mmm.ucar.edu/mm5/ WRF is the replacement for MM5 and contains two dynamical solvers, referred to as the ARW (Advanced Research WRF) core and the NMM (Nonhydrostatic Mesoscale Model) core https://www.mmm.ucar.edu/weather-research-and-forecasting-model There is a helpful online tutorial - http://www2.mmm.ucar.edu/wrf/OnLineTutorial/index.htm - and a fairly busy user's forum - http://forum.wrfforum.com/ WRF can also be installed on windows 64-bit versions. A selection of sites using WRF can be seen here - http://www2.mmm.ucar.edu/projects/wrf-model/plots/wrfrealtime.php An interesting development is WRF EMS which combines both WRF cores above with the NCEP non-hydrostatic mesoscale model (NMM). Different versions are also known as STRC EMS and the latest STRC UEMS, and as they are precompiled, the intention is that is should be possible to get a simulation running within 30 minutes - http://strc.comet.ucar.edu/software/uems/ For more info on usage checkout the UEMS/WRF EMS Unofficial Forums - http://www.wrfems.info/index.php Also with regards to hardware it is worth looking at WRF etc implementations which take advantage of using GPU parallel processing with CUDA/OpenCL code on the graphics card to enhance performance.
  6. Hjerkinn at just over 1000 metres in central southern Norway this morning - Though much of the precipitation likely falls as snow at any time of the year, accumulations are probably small. Bearing in mind how western Norway is one of the wettest places in Europe, it is interesting how strong the rain-shadow is, with this reasonably high altitude location being one the driest places in the country, having a desert-like annual precipitation total of only 222mm on average - https://en.wikipedia.org/wiki/Hjerkinn
  7. Have you considered weather models such as MM5 and WRF or climate models such as GISS/EdGCM for example? They are professional grade and freely available (30-day trial for EdGCM).
  8. Not sure the links can be as precise as to determine a cold, snowy spell for the UK in the last third of December, but certainly links between June temperatures and winter NAO have been investigated eg. Summer snow extent heralding of the winter North Atlantic Oscillation http://onlinelibrary.wiley.com/doi/10.1029/2002GL016832/full Clearly the conditions leading to these situations would probably also influence June CET to some degree.
  9. Annual CET

    After the warm June, this year had moved up to 5th place, 0.22°C behind leader 2007. The previous 30 year average (1987-2016) would see 2017 end up in 7th place with 10.61/10.63°C (monthly/daily values). The provisional figures up to July 29th show that briefly 2017 became the warmest year on record to July 20th (though of course only a small downgrade at month end would prevent it) - this is as a result of ongoing cooler weather in 2007, and the next day sees record warm year 2014 hit top spot for the first time. Interestingly, the previous 30 year average would see 2017 return to 1st place from 20th-23rd August before ending 0.04°C warmer on 10.65/10.67°C which in a close cluster of years means 3 places higher in 4th.
  10. Back in the here and now, just glad the GFS is moving away from this - 4-5 inches of rain for the Lake District this weekend.and a camping trip? Ugh, the 3 inches instead will be just a bit of drizzle.
  11. The 0z ECM may appear more mobile with the low not lingering into next weekend, however it brings lower 850 temps on Thurs/Fri than any other model.
  12. Autumn thoughts

    Not virus, it's the Horse Chestnut leaf miner - the caterpillars of a moth which live in and eat the inside of the leaves. First spotted in Wimbledon in 2002, it has now spread over most of England and Wales and has been spotted in Scotland. Discovered as recently as 1985 in Greece and described as a new species in 1986, where was it before then? Strange, because the damage they cause appears devastating when seen for the first time, but apparently does not seem to cause the trees too much harm - though, to bring things back to the weather, how the trees will respond under our different climatic conditions is unknown and is being monitored. https://www.forestry.gov.uk/horsechestnutleafminer
  13. This set-up is reminiscent of an article in the journal Weather regarding a sea-breeze front in June 1995 during a spell of the then highest June temperatures since 1976. Not strictly the same synoptics as not a pure sea breeze in this instance, but the similar effect of the penetration of low level cool maritime boundary layer and associated cloud from the North Sea, it's an interesting read - 'Sea breeze front reaches Birmingham and beyond!' http://onlinelibrary.wiley.com/doi/10.1002/j.1477-8696.1997.tb06266.x/pdf In the 1995 instance, temperatures had been in the 30s before falling back into the teens, with falls of 10 degrees within an hour.
  14. Not just high temperatures, look at these dew points, tropical values in some places
  15. Annual CET

    Correction, pipping 2014 by one-hundredth of a degree! The warm first half of June (provisional figures to 17th) has seen this year reach 5th place from the start of the year on a number of days, and the 30-year average to 2016 would see the year end at 10.55 / 10.57°C (monthly / daily values) in 8th place. Having made up some ground, 2017 is now 0.17 deg behind 2014 (currently 2nd) but quite some way off the warmest year to this point, 2007, by 0.44 degrees.
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