Nick F

The low leaving southern tip of Greenland Tuesday, which goes on to be the potential ‘trigger’ for an arctic northerly on Thursday and Friday next week on previous runs, deeper on this run and thus forcing the low on a more northerly trajectory towards the UK. This more northerly track could delay the colder sub -5C T850 air sinking across all of the UK, though fortunately again on the 18z it gets the -5C line to the south by Friday. Not quite so much upper flow amplification upstream following this trigger low either. But no huge downgrades for now, remarkably fairly consistent up to the end of next week with the evolution, given the timeframe.

Although it's still 9 days away, and subject to change, the weather models have have several runs indicating a cold Election Day Thursday next week, even with a risk of snow. View the full blog here

If high pressure doesn't build in too quickly, always potential for troughs or slider low in the cold N or NWly flow to bring more organised sleet/snow inland away from the usual windward or coastal areas which see showers in these arctic or polar flows. Then of course there is a southerly tracking jet near the south coast shown that could bring secondary lows along the south that may interact with cold air draining down from the north. Not saying these scenarios are on the cards, as too far off still to say we will even get a northerly, but highlights routes for wintry precipitation almost anywhere in such a setup.

I think the less said the better with regards to the EC weeklies updated this evening, seems to develop troughing in the Atlantic to our west from mid-month, though it does hint at higher heights over Scandinavia as the run goes on. EC longer range never that reliable anyway, so lets not worry too much, at least the potential for a northerly later next week on cue to coincide with the General Election is still on track, that's the 4th consecutive GFS operational run now to show it with a fairly similar evolution and timing. Really need the jet to dive further south in the wake of this northerly than shown, so we don't get mild sectors pushing out the cold air too easily. But … one step at a time ...

Looks primed on 06z thus far for the arctic floodgates to open again for General Election Day Shame it's too far out to have confidence in getting a clean northerly flow direct from the arctic for all.

The real interest showing in the models, i.e. a potentially cold northerly, frustratingly staying out at day 9-10 in the model runs. Originally it was looking like the period 8-10 Dec showed potential for a cold northerly, now goal post has moved to 10-12 Dec … waiting for that amplification in the flow to develop N over the N Atlantic. But I guess most of us seasoned model watchers are well-versed with this teasing by NWP. The background atmospheric drivers on a more global picture in the northern hemisphere aren't particularly conducive to any big upheaval in the pattern in the next few weeks that could lock us into a blocked pattern, MJO looks like crawling slowly through phases 2-3 or staying in COD … so not really impetus for change forced by the tropics. The trop PV organising and expanding over northern Canada and Greenland - which will increase energy over the N Atlantic. On a positive note ... -There are hints from GFS/GEFS of the AO and NAO going negative around mid-month, so small signs here and there that could be some steps to change. -GEFS strat zonal wind forecasts still heading in the right direction … so still that chance of a SSW later this month. -Outlook not particularly mild or particularly cold, looks average December fare. Any cold arctic incursions transitory, due to too much zonal upper flow energy over the Atlantic under the trop PV wrapping up, but any arctic incursions could bring some snow briefly to lower levels, northern hills certainly should see some white stuff next week in the PM flow.

Morning all. Cold over the next few days under high pressure (Sun-Weds) with inland temps perhaps struggling to get any higher than low to mid single figures during the day, perhaps staying around 0C where fog lingers. So feeling nice and seasonal, even festive for those Xmas shopping, for the opening of December. Thursday and Friday looks to turn milder for most as pressure falls from the NW and a southwesterly wind picks up, perhaps gales across Scotland Thurs night. However, it does look like a brief shot of PM air may visit this time next week, perhaps giving a little snow to Scottish hills for a time. But thereafter we could be at the mercy of energy feeding downstream over the N Atlantic, energy that feeds east from the Canadian vortex may hamper efforts to build a decent enough ridge in the Atlantic to get a half-decent northerly - see 00z EPS mean below. But we'll have to wait how this pans out over next few days.

Models have been hinting at a northerly in the 8-10th Dec timeframe over last few runs, still too far away to pin ones hopes on it occuring, but the 00z EPS 500mb mean this morning looks more encouraging for this to occur than the 00z GEFS 500mb mean - which has a weaker Atlantic ridging signal. 00z EPS T240 00z GEFS T240 Like the look of the arctic ridge separating the trop vortices over Scandi, Canada and Bering Sea on 00z EPS mean.

To be fair, Knocker was right to point out that the 'Short milder blip is all it is now mid next week' comment was not correct based on NWP forecasts for cold temperatures at the surface across England and Wales early to middle part of next week under high pressure. It does turn milder across England and Wales later next week into the following weekend, as pressure falls from the NW and a southwesterly wind picks up.

UK Severe Convective & Storm Forecast - Issued 2019-11-26 11:16:36 Valid: 26/11/2019 0600 - 27/11/2019 0600 CONVECTIVE / STORM FORECAST - TUES 26TH NOV 2019 Click here for the full forecast

Morning all, looking at today's 500mb chart for N Atlantic region and this time next week you can see for now there is a blocking upper level high over Greenland, displacing troughing further south and forcing a southerly tracking polar front jet across the Atlantic. But by next Tuesday Greenland upper level high is replaced by an upper level trough or trop PV, this going in tandem with a more northerly tracking jet across northern Europe - which forces a mid-latitude high in across NW Europe. Today Next Tuesday Besides the uncertainty from the NWP operational output over how far south the high over NE Atlantic/NW Europe will sink next week, which makes a difference between staying fine and settled with some chilly nights as per EC or turning unsettled and windy as per GFS, I'm pondering what will happen with the trop PV expanding across Greenland. Longer range the EC weeklies 500mb suggest troughing anomaly increasing across NE Europe and high pressure displaced further west over the Atlantic as we head through early December, which suggests to me low heights/PV migrating E from Greenland to NE Europe. This is a good thing for cold and snow lovers longer term Not too worried yet about the rumours recently of a +NAO dominated pattern of unsettled westerlies developing in early December, as doesn't look clear-cut that the upper patterns will stabilise in this manner. But still can't rule out this possibility for now.

More rain on the cards this week, as an ex tropical storm pays a visit by mid-week, could bring further flooding issues. Turning colder from Friday, leading to a cold but drier start to December View the full blog here

Indeed, naturally the focus on this thread is for cold and snow at this time of year, indeed ECMWF hints at snow showers in the north later in the run as cold arctic air digs in, leading edge snow on Atlantic front pushing into cold air right at the end of the run. But before this uncertain possibility, I find it quite interesting that the deep low arriving in the southwest for Tuesday, as low as 961mb south of Ireland before it fills and tracks across UK on Wednesday, is the remnants of Tropical Storm Sebastien, quite late in the year to get tropical systems heading our way, think it nearly became a hurricane too.

Weather warnings have been issued by the Met Office for strong winds gusting to 60-70mph, isolated 80mph along south coasts. Also warnings for rain and flooding for the west and NE Scotland. View the full blog here

Amazing how far north it is, intensified over waters of only 19-20C according to the National Hurricane Center forecast discussion, which throws away the usual 26C+ for a hurricane to form. Given it will soon move over SSTs of 17-18C, like you say it will be a brief Hurricane.

Turning very wet across Wales, western and northern England on Friday, prolonged rain lingering into Saturday - leading to a risk of flooding. Turning Colder & Drier from Sunday. View the full blog here

UK Severe Convective & Storm Forecast - Issued 2019-10-18 08:05:07 Valid: 18/10/2019 0000 - 19/09/2019 0600 CONVECTIVE / STORM FORECAST - FRI 18TH OCT 2019 Click here for the full forecast

Quite an active line of storms off western France, drifting NNE, if these continue across NW France and English Channel, wouldn't be surprised if Met O issue upgrade warning for SE England as storms may co-incide with rush hour ... and yes, have to pinch yourself that it's mid October. But it's 25-26C and humid across central France right now, so plenty of fuel

Disrupting/slowing upper trough moves in across far W of Europe today - engages frontal boundary lying SW-NE across W and N France, a wave low forming along frontal boundary as front lifts back north in response to winds backing ahead of approaching upper trough from the west. This low along boundary, currently over NW France, moving NE across SE England this evening. Severe thunderstorms forecast across western, central and northern France from lift created by convergence of warm moist plume ahead of cold front moving in from the west in combination with increasing ascent and cooling aloft with approaching upper trough, strong southerly jet aloft and backing surface winds suggests strong deep layer shear leading to organised multi-cells and perhaps supercells capable of producing all severe hazards, including tornadoes, see estofex and orange alerts from Meteo France For us in the UK, instability developing over France this afternoon looks to clip SE England this afternoon and early evening in warm sector to east of low and cold front pushing in from the SW, so we could see some thunderstorms push N/NE over the English Channel to affect parts of SE England (inc. London) and East Anglia towards the end of the evening rush hour, before this activity clears NE as cold front clears to allow more stable cooler Atlantic air in from the southwest. Precipitation charts from 06z UKV (courtesy of Netweather Extra): UK weather warnings WWW.METOFFICE.GOV.UK Met Office UK weather warnings for rain, snow, wind, fog and ice. Choose your location to keep up to date with local weather warnings. Netweather Convective / Storm Forecast for today: Severe Convective Weather & Storms Forecast - Netweather.tv WWW.NETWEATHER.TV

UK Severe Convective & Storm Forecast - Issued 2019-10-14 09:24:02 Valid: 14/10/2019 0600 - 15/10/2019 0600 CONVECTIVE / STORM FORECAST - MON 14 OCT 2019 Click here for the full forecast

UK Severe Convective & Storm Forecast - Issued 2019-10-08 08:37:39 Valid: 08/10/2019 0600 to 09/10/2019 0600 CONVECTIVE / STORM FORECAST - TUES 8TH OCT 2019 Click here for the full forecast

UK Severe Convective & Storm Forecast - Issued 2019-09-30 22:14:54 Valid: 01/09/2019 0600 - 02/09/2019 0600 CONVECTIVE / STORM FORECAST - TUES 1ST OCT 2019 Click here for the full forecast

Hurricane Lorenzo hits the Azores later on Tuesday before heading northeast transitioning into a deep extra-tropical depression which could bring impacts to the UK and Ireland on Thursday View the full blog here

UK Severe Convective & Storm Forecast - Issued 2019-09-26 21:06:11 Valid: 27/09/2019 0600 - 28/09/2019 CONVECTIVE / STORM FORECAST - FRI 27TH SEPT 2019 Click here for the full forecastCheck the full storm forecast here

UK Severe Convective & Storm Forecast - Issued 2019-09-23 21:39:54 Valid: 24/09/2019 00z - 25/09/2019 00z CONVECTIVE / STORM FORECAST - TUES 24TH SEPT 2019 Click here for the full forecastCheck the full storm forecast here