Cambrian

Differences between the main models in timing, location and intensity of the rain for Friday / Saturday and some heavy 24 hour rainfall totals in places peaking at various times in different locations on Saturday. GEM 12z, 24 hours to 4pm Saturday : 30-35mm clipping the south coast of Cornwall and Devon. GFS 12z, 24 hours to 9pm Saturday : 30-35mm off the coast of Cornwall and Devon and over parts of southwest Wales ECM 12z, 24 hours to 4pm Saturday : 60-70mm over the tip of Cornwall, a potentially quite severe outcome.

The Atlantic low is seemingly set on an intriguing little dance over the coming days as choreographed by the 12z GFS Op. Currently a shallow affair, lurking in the mid Atlantic at midnight tonight (+12h) with a central pressure of slightly less than 1016mb. It shows some intent by beginning to move northeast and deepening to 1004mb by 0z Wednesday A day later, however, it’s backed off a bit (oh what a tease!) and lost some intensity, 1012mb, with some nondescript pirouetting it’s back in the middle again, serving only to reinforce the heat and high pressure over the UK, back up to around 30 degrees widely on Thursday afternoon. It shuffles eastwards unimpressively by first thing Friday as the high gives way, a bit of improvised shape-changing but no real intensity…. ….before regathering itself and landing in just off Lands’ End by 0z Saturday, now deepened again to 1004mb, and ending the dance with a bit of a bang maybe, delivering some heavy rain to most parts of the south of England, Midlands and Wales.

A couple of particularly sultry evenings (ooh err missus) coming up for the weekend, dew points near 20 degrees or above at 8pm Saturday and Sunday across a good part of southern UK and Ireland according to the GFS 06z, driven by stubbornly high humidity levels despite the long sunny days, up around or above 80%. Sticky gussets alert, easing somewhat by Monday. Saturday 8pm Dew Points and Humidity Sunday 8pm

Less than 10mm of rain in the next 8 days for UK and Ireland, mostly not enough for a puddle, away from parts of NW Scotland (GFS and ECM) and maybe SW Ireland (GFS only). Accumulated total precipitation (+192h) GFS 12z and ECM 12z Some heavy rain from the southwest on day 10 itself with the GFS but most parts still waiting for “proper rain” in 10 days time according to ECM, creeping slowly into Munster and south Connacht from the southwest. Accumulated total precipitation (+240h) GFS 12z and ECM 12z So both GFS / ECM now broadly agreed on a generally dry spell of good length through the middle of July, good summer weather for 8-10 days in advance of less settled weather eventually arriving from the southwest, which has been pushed back a couple of days since yesterday to the 24th / 25th. I wouldn’t be surprised to see it pushed back further.

Another nice way of picking up on what many others are commenting on. Accumulated total precipitation charts from GFS 12z show an extended dry spell, with hints of more unsettled weather only in the less reliable timeframe. Other than today’s showers to 1am tonight (+12h)……. ….pretty much as you were with very little rain anywhere in UK or Ireland for the next 7 days (+168h)….a glorious full week of summer weather….(not such a good week for parts of the near continent though!) A bit different 48 hours later (+216h), some heavy rain coming up from the south. The equivalent charts from the ECM 12z - similar to GFS for 12h and 168h, but by 216h looks a much less striking outcome, more like some showers and more moderate rain from the northwest, a quite different solution all round at that stage, and so perhaps no great reason for confidence in either outcome at this range, could well stay largely dry throughout.

GEM gets London to 31 degrees on the 19th.

We had 40mm of rain yesterday from showers throughout the 24 hours, not so sure we need tonight and tomorrow’s rain so much now! Ah, the UK summer! That’ll teach me. After the immediate system is out of the way by later Tuesday, Thursday / Friday looks a bit better, though some showers remain, indeed 0z ECM and GFS are still struggling to settle it down even through next weekend, 1012-1016mb and a slow westerly isn’t going to cut it for a reliable spell just yet, though as others have said it does look more promising from around 10 days time. Leading up to then, general agreement at 120 hrs for a showery start to Saturday in a col / shallow trough (could that be called an “upper low” on the ECM?) ECM 0z +120h GFS 0z + 120h. GFS Precipitation The two models diverge by 168 hrs. ECM keeps us in the unremarkable temperatures “flab” but more immediately awaiting the AH nose, while the GFS extends the Atlantic low closer to the northwest which tucks us into a firmer westerly and sends some more persistent rain our way for later next Monday and Tuesday. ECM 0z +168h GFS 0z + 168h GFS Precipitation

Nice little summer low to break up some good periods of broadly usable weather. Approaches from the southwest Monday into Tuesday, with some heavy rain into the West Country. Then pivots and elongates, lying from Wales to Northern England during Tuesday morning. Heaviest and most persistent rain along that trough, still around at lunchtime, backed up by ECMWF CAPE - good bit of lift over East Anglia too. I’ve noticed the GFS over-egging the rainfall amounts at times, but this could bring an inch of rain to parts by the time it’s done. The football has been really enjoyable to follow, it’s been a great tournament. I’m obviously not an Englishman, but best of luck for a good game tonight.

Haven’t had the chance to post since March due to wall to wall work, but I’ve been following the great contributions here whenever I can. A few hours of quite heavy rain for large parts of England and Wales late Monday into the early hours of Tuesday if the GFS is to be believed, before moving up into Scotland and losing some intensity, could bring some well needed rain for the middle of Wales believe it or not, the uplands can dry off very quickly with the long days. I’ve been keeping an eye on this “now you see it now you don’t” intensity for a few days now, with charts even from yesterday taking all the heavy stuff up over Ireland, so it’ll be interesting to see the runs later on.

ECM 12z - life as an Atlantic low pressure system in the hard times of meridional flow..... Day 3 : low, eastern seaboard, 1000mb, - hey yeah, I’ve made it to the coast! Day 5 - this is easy man, past Newfoundland, 992mb, I’ll catch the jet for sure! Day 7 - this is the life, mid-Atlantic and deepening, 976mb! Day 8 - you know what, I fancy hangin’ out for a bit just off Greenland, 984mb Day 9 - nowhere to go so just filling in time, 1000mb Day 10 - Oh dear....hey, I’ll fall in with this new low, I’ve made it to the coast!

The 16-day outlook from NOAA for precipitation and temperature. Going on the flavour of the ECM and GFS over the last few days, scratching my head as to where as much as 25 mm for parts of Ireland is going to come from over the next 8 days. I’m assuming the 5-7.5mm for the hills of Northern England and Wales fell earlier today. More rain expected for England and Wales in the second week. The temperature chart optimistically shows a warm-up to near average for the UK for the second week, typically 2-4 degrees higher than the first week, away from the Northern Isles, supported by the flatlining GEFS 06z temperature ensemble for Shetland. But in general, UK for the next week cold and dry, the following week a bit warmer and a bit wetter, fits nicely with the ensembles. Desperately seeking something more eventful (!) - just joking, I will enjoy this dry spell and a slowly emerging spring gives us a bit more time to appreciate the turn of season - though changes in Europe are more striking in terms of heralding the spring, at least an 8 degree lift in day-night average for Southern Germany in the second week and a loss of sub-zero temperatures over the Alps - should get the edelweiss going. Some heavy rain over Northern Italy and Croatia in the first week extends westwards into Spain and Morocco in the second week, cooling Spain and Portugal down a tad while Sicily and the rest of the Med basin steadily warm up.

It’s slow, but the GEFS 12z run gives some better indication that spring is coming. The graph for London shows a steady increase in day temperatures in the reliable over the next 12 days, indeed double figures maxima from the 18th onwards, continuing to benefit from the strengthening sun, solid high pressure and a dry feed. This slow warming up stalls around the 23rd, well into the unreliable. Here for Aberdeen, the same broad trend in the more reliable timeframe, though a more modest warming up than further south, the mean maxima struggling to get into double figures. Night frosts a possibility north and south for several days to come.

The GFS has now pleasingly dropped the notion of a little rainy spoiler for next Sunday and has now fallen in with the ECM, keeping it all well to the south over Spain, although it took it’s time to let go of the idea. GFS op 18z yesterday 0z today 6z today The ECM 0z has remained consistent with its maintenance of the high pressure throughout next weekend, although not quite so intense, a few millibars less over the UK, 1028-1032mb. Another great example of model convergence around the 7 day mark, with the two models now plumbing for similar looking cells at that time in terms of central pressure and being centred to our east over the North Sea or Scandinavia. ECM 0z

The 18z GFS op, like the 12z, is bringing in a breakdown of the high pressure from the south for next Sunday (+186h), around 1016mb in the rain in the south of the UK. The rain really gets going more widely later in the afternoon over much of the UK and Ireland (+192h). The ECM from 12z is having nothing to do with it, keeping the high pressure firmly in charge over the whole of the UK and Ireland, 1032-1036mb for the same time.

Before we get to what looks like a lovely high pressure building in for the middle of next week, there could be some snow on the ground for some tomorrow and Monday morning, the last couple of wags of winter’s tail getting on half way through meteorological spring. EURO4 shows snow showers, quite organised over Southern Scotland, these move south later in the night, with some accumulations predicted, on ground frozen pretty much nationwide by dawn tomorrow. ICON picks up on the same showers for the Edinburgh area around midnight, moving down to NE England, and a batch of showers for the West Midlands working their way into the Marches, though it doesn’t really expect accumulations away from Scotland. Agreement on something working in for NW England and Wales for early Monday morning, different angles on where exactly the showers will be. Aaah, and then to the middle of next week, GFS 0z for Thursday lunch time, now that is going to feel good during the day, medium / strong sunshine and hardly a puff of wind. Probably still wearing the pullover at that stage, though the high warming up in situ by next weekend.

Pub run’s not looking too bad for the pub run.......... ........at least later on in the day. Good vest and a thick pair of socks might come in handy though.

I’m just loving this front, as drawn first on the fax from yesterday for midnight tonight spanning about 65 degrees of longitude west to east, as an apron hanging from the 60 degrees North line of latitude, serving as a warm front at its western end between Canada and Greenland and a cold front for the rest of the Atlantic. Then, from the midnight fax for noon tomorrow, despite the mid-Atlantic high asserting itself and snapping it in two, it has the last laugh becoming a 100% cold front and spreading out as it sinks south, still pretty much 60 degrees of longitude west to east, about 3000 miles, from above the mid-Atlantic ridge to Finland, fins to Finns, a single feature traversing a sixth of the northern hemisphere, and bringing a modest but widely felt 4 degree drop in temperature according to EURO4 and some very cold air following in its wake into the north of Scotland.

Frostwatch UK and Ireland for the next 6 nights, courtesy of GFS Ens and ICON, with fleeting appearances from the GFS op Thursday 6z - Below freezing widely early in the night but frost restricted to parts of Southern England if anywhere by dawn tomorrow. Friday 6z - Southern halves of Ireland and the UK largely spared an air frost Saturday 6z - frost possible anywhere away from the coast and SE England, ICON not so keen for the south of the UK Sunday 6z - the coldest night in the series, old Jack will likely be nipping at all our bits as the high pressure noses in from the west, slack northeasterly in the cold air. Monday 6z - another widespread frost but beginning to lose its grip on Ireland Tuesday 6z - much more patchy frost as low pressure moving down from the NW brings in a westerly. A series of unseasonably cold nights, with the most widespread cold Saturday into Sunday by the current charts.

Yes. Cross-model agreement for some increased instability and further south compared to today, over Scotland, Northern England and Wales in the early afternoon allowing development of afternoon / evening showers well inland over England and Wales, moving SE. Temperatures mostly just within a couple of degrees of freezing (mind you, the EURO4 shown here was a bit lower than the others) so possibly settling for a while in places if you land a shower. However locally white in the event notable weather for the first week of April in terms of air mass.

Yes, fair enough, I would agree, the expected convection is generally low. There is a bit more lift though across Wales late Tuesday morning which might serve to pep up the showers, if it’s enough to be a factor in helping them on their way through to the south coast (at least that’s what I was thinking!).

More of a NNW than a true northerly on the way for the UK itself. More progress inland for the showers on the western side by Tuesday with nice little squiggles in the isobars and a long uninterrupted sea track all the way down from the Arctic, and development of one or two more general disturbances embedded in the showery airstream. Combined with some convection inland, possibly why the ICON 18z still reckons on bringing snow showers in over a good chunk of England as well as Wales for Tuesday afternoon despite 1024mb pressure.

The EURO4 is showing a band of snow for tomorrow morning (from the second of the two cold fronts I guess) across Northern Ireland, Wales, through Yorkshire, Humberside, Lincolnshire and Norfolk. In subsequent frames, though decaying, this moves down to the London area. Looking at the temperatures in front of it, most likely to settle only on the higher ground, but generally below freezing after the front. By Tuesday morning, snow showers over Scotland, much of Ireland, with some into Wales and South West England. This looks like the beginning of that little feature that the GEM is still showing to move down the UK on Tuesday, shown clipping Belfast at 7am. Temperatures below freezing in most places by then. Happy Easter to all.

GEM 12z keeping with yesterday’s idea of 1-2 centimetres of snow for large parts of England and Wales by Wednesday morning from the little feature running down the west coast of Scotland and down the Irish Sea early Tuesday clipping North Wales and then SE across England, looks like some lines of showers set up as it comes through. Good part of Ireland in the mix too and many parts of Scotland already pasted by then!

Some snow maybe not just for “ the usual places” next Tuesday / Wednesday if the GEM has it right. It’s picking up on the potential for an interesting little disturbance / polar low running down off the west coast of Scotland Tuesday morning, over North Wales by mid afternoon moving down over the Midlands to exit off the Sussex Coast by early hours Wednesday. Maybe gone on the next run, but shows the potential.

GFS op sticking to its guns at 06z with the low developing away from Greenland in a weeks time, wrapping some slightly colder air around it maybe compared with the 0z GFS 0z 192h. GFS 06z 186h