Nick F

Senior forecaster
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About Nick F

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    Specialising in severe weather
  • Birthday 09/08/1975

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  • Gender Male
  • Location South Norwood, London (home), Hounslow/Heathrow (work)
  • Interests Weather - particularly thunderstorms, growing plants, walking, cycling, cooking and good food, wine.

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  1. 12z ECMWF shows a back edge snow event along the frontal boundary on weatherbell across England, even as far southeast as London area and E Anglia between 00z - 06z Thursday. So most likely the model has the air ahead of the frontal boundary too mixed out to have preceding snow. The slowing of the front as it arrives in the E/SE allowing colder and drier (dew points of AOB 0C) Pm flow to catch with the front. However, the rain/snow margin will probably change with the next run ... and I lose count of the amount of times GFS or ECM has shown back edge lowland snow from Pm cold following a front 3-4 days out or more - only for it end up an all-rain event. Still, I'm open to a surprise for mid-week. And for now, nice to see snow showers making it down close to east London this evening.
  2. Nice to see the reports and photos of snow in the NE today, the sleet and snow showers transfering further south tonight and through Monday morning, as high pressure begins to build across Scotland, some showers perhaps getting inland across the eastern half of England, but probably not amouting to much for most. The frontal system passing through mid-week dragging its heels more and more over recent few runs as it reaches SE England and E Anglia, big 3 GFS, UKMO and ECMWF not clearing the precip here until at least Thursday lunchtime, 00z GFS not from the far SE until Thursday evening. What's happening is that there is an increasingly amplified diffluent upper trough behind this frontal system, where jet winds are strongest going into the western side of the trough and weakest coming out of the eastern side allowing divergence aloft and one or two waves to develop along the frontal boundary - slowing its progress after moving through more swiftly across northern and western areas. Unfortunately,  the way things are going this winter, surface dew points and temperatures shown by the models are for now a few degrees the wrong side of marginal for snow on the front for most away from higher ground due mixing out ahead of the front, so unless the colder air and sufficiently low dew points catch up from the NW and undercuts, the less cold air occludes out quicker than modelled and/or, we see stronger advection of cold and dry air off the near continent ahead of the front - then it looks nothing to get excited about. Still a chance, that lowland areas may see some wet snow out of this front, particularly if the precip is heavy enough to allow evaporative cooling and coincides after dark (Weds night) with the added cooling that brings.  But it really is slim pickings from this cold snap for most, I will at least enjoy the frosty mornings while they last ...
  3. Yes, 00z ECM gives us the best straw to clutch from the 00z suite to salvage some snow from the frontal system passing through on Wednesday. The frontal system shows signs of slowing as it reaches this east and comes up against the retreating high to the east, it's enough on the high res to allow colder air to catch up from the NW, but also allow a cold and dry feed off the near continent ahead of the front, to encourage snow to develop along the front from northern Home Counties northward looking at EC snow charts on  Weatherbell, here's the freely available precip and T850s But, in the fashion this winter has gone so far, one can't help but think the frontal system will move through too quickly in the end with too much mixing out of colder air ahead of it to allow a transient lowland frontal snow event. Before then, snow showers to look forward to for those in eastern Scotland, NE England then the risk retreating further south along eastern coasts of England into Monday, as high pressure builds in across Scotland. Some showers penetrating inland at times. Frosts to look forward too for the rest of us. EDIT, at least the 06z GFS coming round to the EC idea with the slowing and disrupting front on Weds
  4. 12z EC on weatherbell showing a period of snow for Scotland, N England, Wales, Midlands, Lincs and E Anglia as that frontal system moves through, though not further south. So perhaps, just perhaps, some transitory snow in places even to lower levels next week for those not near the coasts before it's back to westerlies and snow confined to northern hills. Must admit the 00z GEFS stamps this morning were convincingly supporting the operational, but it appears now the GFS op could be playing catch up with ECM and the anomaly charts from EPS and NOAA which have maintained that troughing will push down from the NW and east into Scandinavia. All the more reason to follow these anomaly charts for guidance, as John Holmes helpfully updates us on, rather than the ops, when there are differences appearing between the models.  
  5. Looks like UKMO has gone the same way as GFS towards 00z ECM and pushed the high east into Russia to allow heights to fall across Scandi ...
  6. Again, we see the Scandi ridge being the major player on the 06z in squeezing out any milder air making it in from the west next week, as the upper trough dropping down from the NW is forced to disrupt S/SE across the UK keeping cold air in place right up to the end of the week. EC doesn't build the block over Scandi, so we see Atlantic systems drive through to the north rather than slowing and disrupting.  12z ECMWF backtrack tonight? Well, the 00z deterministic was almost a mild outlier after the the 19th, but the 00z GFS op was right at the cold end too!
  7. A look at the GEFS postage stamps and GEFS mean leaves me less than convinced with the ECMWF high res progressiveness of returning us to cyclonic westerlies. The 00z GEFS mean and good number of invidual members point to the Atlantic and Scandi ridges bridging across the UK to bring a mid-latitude high pressure belt - though the far north perhaps exposed to more of an Atlantic cyclonic westerly influence. GEFS stamps t+168 and 240 GEFS mean T+168 and 240   GEFS mslp mean for North Yorkshire as a UK mid-point looks to stay fairly high until late in the run: Funny, it's normally GFS that's too progressive in returning us to cyclonic westerlies, rather than ECMWF.  The differences EC vs GFS occur quite early on with regards to pressure to the east, EC is hasty to move ridging over Scandinavia so is quite quick to drop heights here, whereas GFS and UKMO have blocking high at t+144 over Scandi/Baltic Sea which is harder to remove and thus creates better angled trough disruption further west over the UK. Let's hope the GFS sticks to its guns and the ECMWF backtracks.  
  8. Maybe I should have said 'parts of' in hindsight? On a different note, my quick look at the EC32 control run, and apart from the trough disruption over western UK next THursday, the run looks generally anticyclonic up until day 16 or so, after which a more mobile and cyclonic westerly flow takes over.
  9. Basically where opposing wind/breezes meet or the breeze off the sea meets the discontinuity of land and forces the air upward, hence convergenze zone near or along a coast that can move inland. Often they form off Pembrokeshire over the Irish Sea in a northerly, or through the Cheshire Gap in a NWly, also the Wash in an easterly, as well as The Thames estuary into Kent/ E Sussex - setting up lines or streamers of showers.
  10. Not particularly clear with my bad eyes either, but the similar UKMO GM, synopticaly, has some pretty cold T850s still at t+120
  11. See that twig looking thing over the SE? A covergence zone. Shame it's t+120 from a purely IMBY perspective.
  12. Aren't they yesterday's updates? T+120 would be Tuesday now  t+96 updated but not 120  http://weather.noaa.gov/fax/otherfax.shtml  
  13. If it wasn't for the development of the Scandi ridge and also rise in pressure/ heights over Svalbard, GFS would not be showing this trough disruption over the UK later next week, rather the trough dropping from the NW remains intact  with energy piling east into Scandi with us back in mobile cyclonic westerlies. I suppose this is the downfall of 12z ECM, that it doesn't build heights over Scandi and Svalbard, though does have brief trough disruption before the return to westerlies. Having said that, 18z GFS more progressive in pushing through the frontal system  next Thursday before the trough disruption takes place. Ideally would like to see trough disruption take place over western UK with the frontal system stalling over the UK. Less risk then of cold air pushed out from the west eventually as shown by the later frames of the medium range of 12z EC and 18z GFS. Still, plenty of twists and turns to come next week, as the NWP models, even today with their powerful computers, are notorious for having difficulty handling trough disruption. For now, at least, any mild sectors moving in from the west next week should hopefully be squeezed out as they come up against the cold block over Northern Europe.
  14. Yep, Wales and West Country waking up to a valentine snowfall according 18z GFS, but may change ... -5C T850s digging further south Sunday on last few runs which is good to see.  
  15. Except northern Scandinavia where we will source colder air from Sunday. Though daytime maxima of 5-6C progged by GFS for lowland England & Wales early next week not very cold and just below average for mid Feb.  Temps shown struggling more Weds though, as we lose the wind Tuesday and cold strengthens from overnight radiative cooling under clear skies and little mixing under high pressure. Question mark by Thurs on how much mixing out of cold air there will be while the models grapple with trough disruption from the NW, 06z GFS holds on to a cold surface all week in the E and SE.