Jump to content

Nick F

Senior forecaster
  • Content Count

  • Joined

  • Days Won


Everything posted by Nick F

  1. Quite! Storm Brendan is way to the NW centred between Iceland and Scotland. This evening's gales in the SE related to open wave secondary low to the SE of parent Brendan low. I suppose one could argue its part of the circulation of the big low to the NW, but looking at current gusts you can see swathe of gales in the SE is quite separate to the strong winds around Brendan low to the NW. Two fence panels down in our garden, but as it's dark before and after I come home from work, not getting fixed until weekend!
  2. Cold Pm airmass filters in from the west end of this week into the weekend, sub -5C air across all parts. This cold air becoming trapped at the surface as high pressure builds in across the UK, with high pressure hanging around through much of next week, so with light winds or cold flow off near continent in the south, cold air doesn't look like going far at the surface even if 850mb warms up. On the 12z GFS you can even see 'home-grown' cold pools intensifying over the continent, with sub -10C T850 cold pool developing over Bavaria and shifting west over Alsace and Black Forest area Certainly not a mild look as high pressure builds from the weekend.
  3. Not a great set of 12z operational runs that go out to day 10. Not a great 3 op runs from GFS so far today. However, I remain philosophical in that any amplification that leads to a few days of cold we've been teased with around 21-23 Jan is a bonus. Given the lag of 10-12 days, we are unlikely to see the effect on the upper patterns of the MJO wave through 7 after 18th/19th, and even P8 late Jan, which takes us to the very end of Jan into early Feb for potential blocking to manifest. Still way off for operationals to latch onto. So no need to panic and cancel winter just yet ...
  4. Look at the difference between 12z UKMO and GFS at T+144 UKMO GFS UKMO has a low close to the SW SE-bound for France, GFS doesn't have it. EC had this low tracking like UKMO too on its 00z run. Quite a big difference. So … do we have much faith in model output after T+144? Is it worth getting all down in the dumps over another poor GFS run? Maybe not for now.
  5. Blog bringing you the latest on what is looking to be a stormy week ahead, starting with #StormBrendan on Monday, then another deepening low arrives further south for Tuesday. View the full blog here
  6. Trough digging down across NE/central Europe and Atlantic ridge building north by day 10 got support from 00z GEFS mean though And reasonable support from members in the stamps, though variations between NWly and Nly.
  7. Yeah, saw his tweet earlier in twitter and retweeted it myself. Scandi high seems a good bet before end of Jan as the TPV is torn apart into separate vortices by wave 1 and 2. Hopefully we are looking at blocking gaining higher latitude than MLB as the pattern over Pac, NA and N Atlantic begins to get a shake up.
  8. Now that was a sneaky but cold easterly popping up in FI, didn't see that coming looking at the evolution beforehand! Always find WZ looks so much better than meteociel charts everyone posts, maybe it's just me
  9. Nice to see some BOOM charts from the operational for once, probably first time this winter? albeit too far out to have confidence. But a pattern change may well be afoot in next few weeks as we see a reshuffle in the upper patterns upstream in next 7 days or so, thanks perhaps in part the coherent movement of MJO into phase 7. Upper level ridge pushing poleward over NE Pacific helping to amplify the pattern and split up the raging PV sat to our NW. However, we all know too well these teases can be a false lead, especially as we've been at the mercy of a strong PV since late December - a pattern which history tells us can set in for the rest of winter if it sets in by early January.
  10. I suspect the EC weekly updated last night is following similar route as the EC/EPS in killing the wave in 6 - which probably explains it’s lack of appetite in building heights at higher latitudes this side of the northern hemisphere. Killing the wave in 7 is not such a bad thing, but ideally want to head through 8-1 too at a decent amplitude, which is possible. Depends whether one approaches the possibility of change for us given changes in teleconnections upstream over the Pacific and N America with a glass half full or half empty? It is difficult given our run of poor opportunities for cold and snow over recent winters, bar late Feb/early March 2018 to not be sceptical, but it is all too easy to dismiss outright all signals that may normally indicate change, because they happened before but we didn’t benefit. The model guidance can quickly change if it picks up confidence in a new signal, so no alarm bells ringing yet for me. Although central and eastern US has been relatively mild and snow free away from New England, like us, and will be torching over the coming week, with forecast temps as high as 20C expected in New York, the trough and cold in NW US is expected to transfer to the east by next weekend. This marks a pattern change upstream, with an upper level ridge building poleward over Alaska, this should push part of the TPV toward Siberia. For us unfortunately we are still at the mercy of a +NAO regime until we get some decent amplification working through. The TPV being shoved towards Siberia may help ease the strong zonal jet somewhat, but the Canadian/Greenland lobe is still too close for comfort to allow high latitude blocking for next few weeks.
  11. You have to bear in mind that there is usually a 10-12 day lagged response to the phase of the MJO, so unlikely to see the effects on the upper patterns over N Atlantic as far as the GFS/GEFS goes for now. However, as the composites are a blend of different pressure/height patterns in response to phase 7 in different ENSO modes in a particular month with no reflection of the base state of the atmosphere, e.g very strong but increasingly stretched PV, we cannot expect the pattern change to exactly what is shown in the Jan or Feb composites.
  12. GEFS still trucking nicely at decent amplitude through 7 and towards 8. EC/EPS not been updated yet on the RMMs, but be interesting to see if it's still killing the MJO wave in 6 - which may explain the lack of amplification and appetite of building a ridge N over Northern Europe.
  13. Some tentative good news for those who’ve given up on a pattern change, GFS/GEFS now taking the MJO wave into phase 7 around 20th Jan. EC still kills the wave in phase 6, but it does appear the model has a prone bias at killing the wave too early. The MJO is no silver bullet, but this tropical forcing on upper patterns further north can alter the wave lengths of the upper flow in the high latitudes of the northern hemisphere and amplify the troughs and ridges, depending on which phase. Phase 7 tends to force a cooler pattern rather than cold, but it’s P8-1 that force more blocking to bring colder patterns. Given the corrections of the MJO to move through to 7 rather than stalling it in warm phases, every chance we head through to 8 and 1 and decent amplitude. Lag effects unlikely until late Jan or early Feb if the GFS RMM plots are modelling progression correctly. Still uncertainty whether the MJO wave will make it across the western Pacific. In the meantime, expect more of the same zonal stuff next few weeks.
  14. Yep, sPV gets increasingly stretched through the 00z op From this ... ... to this signs that the sPV reaching its peak of strength wrt to zonal winds around mid Jan before winds decline in strength according to GEFS, though I guess this is within climo norm of it weakening second half of winter Remains to be seen if this will be just a minor warming or start of a major warming.
  15. Increasingly looks like January will be a lost cause in the hunt for snow, so we cancel 2 thirds of winter lol. Although the MJO is not directly responsible for the very positive +AO, +4 sigma over coming days, it does have an impact on the wave patterns moving around the base of the polar vortex in the temperate northern hemisphere. It’s stuck in the warm phases of 4/5/6 until at least Jan 20th, i.e. maintaining the status quo with little shake up the wave lengths and positions of the troughs of the polar vortex. There is chance that the MJO stalls in the 'warm' phases over the maritime continent for a long time before the wave fades. However, some of the alternatives to the RMM plots, which can often play catch up to what’s actually going on, have suggested the MJO wave moving through to the western hemisphere 8/1 late Jan / early Feb, so the RMM plots perhaps too eager to kill off the MJO in the maritime continent. So, if we see the MJO move through to the western hemisphere, we could see a shake up in the upper flow to amplify it combining with the increasing stress on the PV from the descending QBO, such that it weakens or is displaced, that we manage to get some blocking in February. The 12z extended EPS dangles the carrot of ridging to our east signal and the PV relaxing its grip. But we’ve seen promising signs of this at day 8-10 only for it to evaporate or shoved further away into the extended range. Besides, the ridging is useless unless we get troughing to undercut it over southern/central Europe. This winter of waiting for snow potential is tough, but we've been here before. Still Feb and March to deliver the goods though.
  16. A strong polar vortex over the arctic over the next few weeks and strong jet stream close to northern Britain will mean is snow is unlikely for most until at least mid-month View the full blog here
  17. Morning all, although the ops look grim this morning, the extended ensemble means of both 00z GFS and EC out to day 15 still entertain the idea of ridging over Scandi and digging deep troughing over Atlantic toward mid-month. GEFS day 15 below,: however, even if we get to this situation, can we get any decent cold around the high, Norway broke it's own and Scandinavia's highest winter temp record with 19C yesterday, so really need to see a cool down of NE Europe, though it can happen quickly in Jan / Feb. Other issue could be the high is too far east and we get a not particularly cold SE flow. But worth keeping up hope of height rises to the NE second half of Jan
  18. Was shocked to see the +15C T850 line touching Cornwall next Tuesday on EC op. That would be not bad going on a summer's day!
  19. Those CPC charts tie in with the extended 12z EPS mean suggesting perhaps some cross polar pinch on the tPV from both the EPO ridge extending north towards the pole and Scandi ridge doing likewise from the other side. This cross polar ridging, albeit not a strong signal yet, may push the tPV lobes further south over N America and N Atlantic. signs of the strongly positive AO relaxing to more neutral values too in the ens toward mid-month NAO going same way too Long road to recovery of some weather resembling winter rather than autumn, but a few tentative signs appearing ... for now
  20. The general consensus is that cold winters are more likely just after the solar minimum, as oceans tend to take more time to react to reduced solar input, thus there would be a lag in ocean to atmosphere interaction. Ocean temperatures, particularly the Pacific being the largest, having a large effect on driving weather patterns. However, you are correct to say some of the coldest winters have been during or just after the solar maximum such as 1947 or 1962/63 and 1981/82. So the solar min is not the only silver bullet to bring a cold winter. There must be some other drivers.
  21. 10 day horror show from 12z EC operational. Ridge building in across Euro land where you least want it. A long road to wintry nirvana. No hints of cold zonality with the jet sinking south of UK like GFS. With GFS cold bias in medium range you kind of feel EC will be more likely, lets hope not. Lets hope this monster PV this winter relaxes to salvage something resembling winter.
  22. Some warming at the top of the stratosphere showing on yesterday's Berlin EC strat diagnotics, uncertainty whether it will propagate downwards, but I suppose worth keeping an eye on in the bleak January days ahead with the formidable strong sPV/tPV
  23. Happy New Year all! The best we can salvage from the strong westerly onslaught, as the strong jet and low heights of the PV over Greenland shunt increasingly south over the Atlantic is some cold zonality. GFS ops been advertising this over recent runs, albeit in the medium range - which it has a well-known cold bias in that timeframe. If UK can get north of the jet, as T+198 shows below, then we may at least get some snow potential for the north, particularly hills. But, we need to get the jet south and also wary of the GFS op cold bias. Otherwise little in the way of crumbs of comfort for snow lovers for now.
  24. GFS on its own against UKMO, EC, GEM and ICON with regards to how far south it gets the Europe bound cold plunge this weekend, models other than GFS barely get -5C T850s across Scotland. So will be a triumph for GFS if it proves nearer the mark. That said, we are chasing a very brief cold shot, only likely to bring snow to Scotland and northern hills briefly, if there's ppn, before it warms up again.
  25. I think, if you’ve not already, that we will have to lower expectations for January re: cold and snow, history indicates that once a strong +AO along with +NAO sets in by the New Year, it could last for the rest of the winter. We only have to look at real stinkers of winters for cold and snow with +AO/+NAO most of the winter to be worried: to name a few 2013/2014; 2007/2008; 1999/2000; 1997/1998; 1989/1990; 1988/1989. Once the +AO/+NAO combo sets in, the models generally tend to perform better over longer time frames than when these indices are negative. Although the MJO briefly orbits through 7-8, it does so at low amplitude, so will likely have little effect on changing the wavelengths over the N Atlantic, furthermore there is strong support for the MJO to swiftly die into COD then emerge into the Maritime Continent, phases 4-5, which are warm phases, so there will likely be no help from the MJO through much of January. Though it is possible that the MJO will progress onwards to colder phases by mid-January – but the lag of this probably not having an effect until towards end of the month. The AO flipped suddenly from -2 to +3 in a space of a few days recently in December, so I suppose there’s chance that it may flip back –ve later in January or February – though it’s not quite clear what the precursor for this would be. But there is also every likelihood that it could remain +ve through much of the rest of the winter. The QBO has only recently turned easterly, so unlikely this will have an impact on the PV until later in winter, when the PV would normally start to wane anyway. So we are kind of reliant on tropical forcing over the Pacific changing the patterns at high latitudes, of which there is unlikely to be much help from for a few weeks at least. There is EAMT and GLAAM to consider, but that’s not my forte, so cannot really suggest if these will have positive impacts.
  • Create New...