Nick F

A look at the 12z ECM CAPE for midnight shows why the lightning seems to be staying mostly over the East English Channel and pushing NNE toward the areas to east of IoW, this is where the instability is

Been away most the weekend, so only just had chance to update my convective forecasts on Netweather. Storm & Convective Forecast Issued 2017-05-28 22:08:52 Valid: 28/05/2017 18Z to 30/05/2017 06Z CONVECTIVE/ STORM 2 DAY OUTLOOK- 28TH / 29TH Synopsis Upper trough axis approaches EIRE, Bay of Biscay and Iberia from the west Sunday night into Monday morning, as upper ridge extending north from the Mediterranean across Central Europe begins to relax. A plume of warm, moist and unstable air will spread north from France during Sunday evening/night across southern U.K., with thunderstorms likely on the leading edge of the plume as is to arrives overnight. Storms will clear away NE and weaken Monday morning, though diurnal heating of warm humid air across SE UK on Monday could trigger some isolated thunderstorms. DAY 1 OUTLOOK - UNTIL 06Z MONDAY 29TH MAY ... S ENGLAND SUNDAY NIGHT ... As upper trough approaches from the west, colder air aloft from the west overrunning warm moist conveyor ahead of surface cold front to west of France combined with large scale ascent is triggering a cluster of thunderstorms across NW France and into western English Channel this evening. These elevated storms are quite electrically active and are modelled to grow upscale into a MCS, given increase in southerly low-level jet and around 40-50 knots of deep layer shear. This MCSs will likely track into southern England tonight, bringing locally torrential,rain leading to flash flooding, frequent cloud-to-ground lightning, strong and isolated damaging wind gusts and also isolated large hail. Storms should weaken later in the night as they move away NE from southern England into more stable environment. DAY 2 OUTLOOK - 06Z MONDAY 29TH MAY - 06Z TUESDAY 30TH MAY ... S ENGLAND, MIDLANDS, LINCS AND E ANGLIA ... Atmosphere will likely be largely turned over by overnight storms, however, residual mositure and surface heating combined with breeze convergence along a diffuse cold front may trigger isolated thunderstorms during the afternoon across the above areas. Localised torrential rainfall leading to flash-flooding, isolated large hail and gusty winds are possible from any storms. Issued by: Nick Finnis

UK Severe Convective & Storm Forecast - Issued 2017-05-28 22:08:52 Valid: 28/05/2017 18Z to 30/05/2017 06Z CONVECTIVE/ STORM 2 DAY OUTLOOK- 28TH / 29TH Click here for the full forecastCheck the full storm forecast here

Storm & Convective Forecast Issued 2017-05-27 07:47:02 Valid: 27/05/2017 06z to 28/05/2017 06z CONVECTIVE/STORM 2 DAY OUTLOOK - 27TH-28TH MAY 2017 Synopsis An upper-level trough to the west of the UK will advance east toward the British Isles over the weekend, while upper ridge extending north over mainland Europe weakens. At the surface, an area of low pressure will track NE across the Irish Sea today, to be centred over E Scotland by 18z, a cold front while pivot N and E across England and Wales, bringing a line of thundery rain and thunderstorms pushing NE this morning, while further thunderstorms may develop across N England and S Scotland this evening as the area of low pressure arrives. Sunday sees another thundery low move up from the Bay of Biscay, introducing storms to southern areas later on Sunday and overnight into Monday morning. DAY 1 OUTLOOK – SATURDAY 06z to SUNDAY 06z … ENGLAND and WALES AM … A moist and unstable airmass will be in place ahead of the cold front across the British Isles, contributing to moderate to strong instability, a marked short-wave trough approaching from the SW and surface cold front moving NE will creating forcing for ascent to push an arc of thunderstorms N and E across England and Wales this morning. 40-50 knot mid-level flow and some backing of winds at the surface should favour some organisation of storms in the line pushing N and E, with stronger updrafts capable of producing isolated marginally large hail (up to an inch) – particularly later this morning, though main risk will be large rainfall totals in a short space of time, perhaps isolated 20-30 mm per hour, leading to flash flooding. … N ENGLAND and SCOTLAND PM ,,, Atmosphere should stabilise across S England and S Wales this afternoon in wake of shortwave trough moving NE. Further north, moderate to strong instability is forecast to develop across N and NE England, S and Central Scotland this afternoon in the warm moist airmass ahead of approaching cold front, with 1000-1500 j/kg CAPE possible. 30-40 knot mid-level Swly flow and backed SEly flow at the surface combined with large CAPE values may support the development of organised storms across the above areas, a forcing for ascent increases with arrival of shortwave upper trough from the SW. Storm clusters or bowing line segments, perhaps even an isolated supercell, may develop and track NE, capable of large hail (up to an inch), 20-30mm rain per hour leading to flash flooding, strong wind gusts and frequent cloud-to-ground lightning. An isolated brief tornado can’t be ruled out too. Therefore have issued a SLIGHT risk here. Storms will ease across the north Saturday night. DAY 2 OUTLOOK – SUNDAY 06z to MONDAY 06z … S ENGLAND and S WALES … Another shortwave trough is forecast to swing into the Bay of Biscay on Sunday before ejecting NE towards the British Isles, surface low and attendant occluding frontal system will move north from the Bay of Biscay toward S UK ahead of shortwave by 00z Monday. Another surge of warm moist air, characterised by high theta-w values (wet bulb potential temps) will return to S England and will destabilise as shortwave trough and frontal boundary combine to create forcing for ascent, so thunderstorms are likely to develop initially across SW England and S Wales Sunday evening, before perhaps developing more widely and pushing N across S England Sunday night. A MARGINAL risk of severe weather has been included on the forecast map to account for risk of heavy rainfall leading to flash-flooding and also a risk of marginally large hail. Storms will also be capable of frequent cloud-to-ground lightning. Issued by: Nick Finnis

Storm & Convective Forecast Issued 2017-05-26 10:34:00 Valid: 26/05/2017 06z to 27/05/2017 06z CONVECTIVE/STORM 2 DAY OUTLOOK - 26TH-27TH MAY 2017 Synopsis An upper-level trough to the west of the UK is forecast to only slowly advance east toward the British Isles over the next few days as it encounters a slowly weakening upper ridge extending north over mainland Europe. At the surface, a cold front will advance from the west across western EIRE tonight before continuing east across England and Wales during Saturday, tending to fracture as an area of low pressure develops across EIRE before tracking NE across Scotland. An increasingly moist and unstable airmass will be in place ahead of the cold front across the British Isles, contributing to moderate to strong instability which will be mostly capped until forcing for ascent from a short-wave trough arrives across the far west tonight and across all parts on Saturday into early Sunday. Elevated thunderstorms are possible across western EIRE this afternoon/evening, then the rest of EIRE, SW England and Wales early hours of Saturday. Then on Saturday, there is a broader risk of thunderstorms developing over parts of the UK, ahead of cold front advancing E and NE, with a MARGINAL or SLIGHT risk of severe weather associated with these storms. DAY 1 OUTLOOK – VALID UNTIL 06Z SATURDAY 27/05 … EIRE, WALES, SW ENGLAND … A plume of higher theta-e and steep lapse rates, associated with an Elevated Mixed Layer (EML) originating over NW Africa, will advect north across western British Isles this evening an overnight. This warm moist conveyor with steep lapse rates is forecast to destabilise later from the south with approach of shortwave trough ejecting NE, currently west of Iberia triggering storms off NW Spain and western Portugal. Elevated thunderstorms are possible across western parts of EIRE this afternoon and into the evening, before developing more widely across EIRE overnight, perhaps upscale into a MCS, then thunderstorms perhaps developing/arriving across SW England in the early hours of Saturday morning, before spreading north across parts of Wales too by breakfast time. There is a risk from these storms of heavy rainfall leading to flash-flooding, hail, gusty winds and also frequent cloud-to-ground lightning. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ DAY 2 OUTLOOK – VALID 06z SATURDAY 27/05 – 06z SUNDAY 28/05 … EIRE, N IRELAND, IRISH SEA, SCOTLAND … A Mesoscale Convective System or storm clusters maybe ongoing across parts of EIRE/N. Ireland and Irish Sea fringes of Wales and NW England on Saturday morning along slow-moving frontal boundary augmented by developing area of low pressure. This area of heavy rain and embedded t-storms is forecast to drift NE across Scotland into the afternoon, with other storms breaking out further SE away from this MCS, any storms bringing a risk of 20-30mm of rain in an hour less with heavy bursts and also a risk of hail, gusty winds and lightning. … ENGLAND and WALES … Warm moist conveyor / theta-e plume aloft will continue to spread N and NE across the England and Wales on Saturday morning ahead of cold front advancing from the west. Low-level moisture will increase too, perhaps dew point reaching 19-20C towards SE UK – which will yield impressively large CAPE values of 1000-1500 j/kg over this area by lunchtime. Heavy showers or thunderstorms are likely to be ongoing across SW England and Wales in the morning, these then spreading or developing in an arc that will shift north and east across England and Wales during the morning and into the early afternoon – as upper shortwave and attendant surface cold front advances NE. 40-50 knts SWly flow aloft and backed S to SEly flow at the surface in the unstable air ahead of cold front will yield 20-30 knts of deep layer shear which will be sufficient to sustain strong updrafts capable of large hail up to 1 inch in diameter, given large CAPE values indicated. Storm-relative helicity charts indicate the potential for a tornado too with any more discrete storms, though more linear mode of storm organisation modelled suggest this would be a very isolated/brief risk. Otherwise, storms may produce rainfall totals of 20-30mm or more locally – leading to a risk of flash-flooding and hazardous driving conditions, also a risk of isolated strong wind gusts and frequent cloud-to-ground lightning. A SLIGHT risk area for all severe hazards is shown on the forecast map across central, northern and eastern England - where CAPE and forcing will be strongest. Issued by: Nick Finnis

Video clip off dash cam of us intercepting the wedge tornado which then moved north across Elk City. We got caught in the outer circulation of it! http://content.bitsontherun.com/previews/41sv5ql1-ALJ3XQCI

All the ingredients coming together today for one of if not the biggest tornado outbreaks of the season thus far. A deep upper low is slowly rotating east off the Four Corners over the Mountain west, strong SWly flow aloft ahead of this low across the southern and central Plains, surface low over southern high plains drawing rich low-level moisture north from Gulf of Mexico across much of southern plains south of warm front, eventually lifting into Kansas. 3000-4000 j/kg CAPE this afternoon in this moisture as temps hit 80-90F and lapse rates steepen as upper low approaches from west. Winds backing SEly below SWly flow aloft will create strong low-level shear -especially along triple point and warm front moving Into western Kansas and dry line edging in across SW Kansas and W Oklahoma. Ideal conditions for tornadoes should storms that form remain discrete. some concerns with regards to recent model runs though. HRRR a little messy with one round of storms pushing up from the south across Oklahoma this afternoon as moisture surges north and is lifted by a disturbance in upper flow ejecting NE, then another round developing early evening along dryline, which should be more discrete and pose the greatest tornado risk. Best not to get suckered in to the first round this afternoon perhaps. Still waiting for the decent moisture to arrive here in Woodward in NW Oklahoma, where we have stayed overnight ... but the big guns of the storm chasing and research world were at our hotel last night https://mobile.twitter.com/NickJF75/status/865197656800415744

A few photos of yesterday's storms 70 miles east of Amarillo in the eastern Texas Panhandle as the sun was going down.

SPC 4-8 day outlook picking up on the idea of an increase in severe weather over central and southern Plains from Tuesday 9th (First chase for Tour 1 on the 10th), though predictability is too low for them to delineate areas for now: http://www.spc.noaa.gov/products/exper/day4-8/ The 500mb height loop below shows upper low moving east from California early next week. Moisture return and heat building ahead of the low, building CAPE as mid-levels cool from the west. The lift of this warm and moist GoM airmass by approaching upper low, aided by shortwaves rounding the low, will. combined with increasing wind shear of backed surface low against strengthening SWly wind with height, likely bring a few days of severe storms which will move eastward in spatial extent across central and southern Plains through the week. Possible severe threat further NE over northern Plains associated with edge strong NWly jet up and moisture return up there too. Weds 00z 500mb HGT/winds and MUCAPE (Tues 6pm CDT) Thurs 00z 500mb HGT/winds and MUCAPE (Weds 6pm CDT) So all-in-all, not looking too bad a start to tour 1, some uncertainties over how quickly the upper low will move out of the Desert southwest, prefer it to slow down a bit vs current model output.

Skies have looked modestly threatening for rain all afternoon and finally we have some sporadic heavy downpours here in south London. Felt like months since I last heard thunder, but my craving for it will be satisfied as I head stateside to deliberately hunt for storms next Monday.

Storm & Convective Forecast Issued 2017-04-30 21:42:00 Valid: 01/05/2017 00z to 02/05/2017 00z THUNDERSTORM FORECAST - MONDAY 1ST MAY 2017 Synopsis Cut-off upper low will slide east across France and the far S of England on Monday. At the surface, a shallow area of low pressure will drift N/NE across SW England/S Wales before sinking back S into the W English Channel by 00z Tues. Cold front will lift north Sunday night/Monday morning to lie from the Scottish Borders SW and S across Ern Ireland by 12z Mon, with wrap around occlusion extending from there across S England. ... S ENGLAND and S WALES ... Cold front lifting N Sunday night/Monday morning will bring outbreaks of rain, locally heavy, northwards across England and Wales. Behind this frontal rain, which will be mostly non-convective, insolation and cold air aloft will create steepening lapse rates to support heavy showers and a few thunderstorms, which will spiral around slow-moving low pressure across S England & S Wales and may focus into bands along wrap around occlusion. Any thunderstorms maybe accompanied by small hail and gusty winds. Also, locally heavy rainfall, where convection does align/organise along occluded front, may lead to localised flooding. Vertical shear, deep layer and low-level, will be weak where greatest instability will be, so any thunderstorms will be short-lived, so severe weather not expected on Monday. Surface convergence under slack low pressure centre may aid in the development of one or two funnel clouds that may extend toward the surface with stronger updrafts. Issued by: Nick Finnis

Blog looking at why it's not entirely unusual for wintry weather and even snow to return after a taste of early summer in April and May. View the full blog here

Hopefully another day of interesting convective skies today across England - especially towards the SE - where there will be greatest instability beneath departing upper trough Here's my storm forecast for today: Storm & Convective Forecast Issued 2017-04-26 09:23:12 Valid: 26/04/2017 06z to 27/04/2017 06z STORM FORECAST - WEDS 26TH APRIL 2017 Synopsis Upper trough will continue to push SE into mainland northern Europe today, the back edge of the trough influencing eastern England, while heights rise off the Atlantic across northern and western Britain. At the surface, an area of low pressure will drop SE from the Norwegian Sea toward the North Sea by midnight, associated frontal system ahead of the low will bring cloud and rain to Scotland, mostly dry EIRE + Wales, with an unstable and showery Nly flow across England. ... ENGLAND ... Cold air aloft towards SE UK (500mb temps AOB -35C) in association with departing upper trough will create steepest lapse rates here and the strongest likelihood of thunderstorms as diurnal heating increases instability by and through the afternoon. Isolated lightning from heavier showers can't be ruled out anywhere across England though. Any storms will be weak, given dry polar airmass and lack of warmth, but will produce small hail or graupel locally and perhaps gusty winds too. Issued by: Nick Finnis

Morning, not posted in a while. After the unseasonably cold snap this week, although I like cold and snow in winter when it hangs around, it seems a waste of a potent northerly in late April with the strong sun and longer days, though it did bring some dramatic convective skies, hail and even thundersnow for some. But I like many others are probably hunting for a nice warm up. Having spent 10 days on Easter hols recently in Spain with blue skies, temps in the low to mid 20s, getting some colour and vitamin D, it's been a bit of a shock. The GFS was offering the low 20s for the middle of next week, but seems to have shifted temps downwards on the last few runs. The reason is the orientation of the high which seems to have shifted north and west on last few runs, so we get more of a cool easterly or northeasterly flow rather than light and variable winds. So temperatures not hitting 20s, rather mid to high teens at best. But should be pleasant out the breeze in the sun. Yesterday's 12z run for 1500hrs next Wednesday: Same time but from this morning's run, the high further north and west:

Storm & Convective Forecast Issued 2017-04-24 21:24:12 Valid: 25/04/2017 00z to 26/04/2017 00z CONVECTIVE / STORM FORECAST - TUESDAY 24TH APRIL 2017 Synopsis Upper trough will dig south across the UK on Tuesday, at the surface - an area of high pressure will be situated to the W of the UK over the N Atlantic while a low pressure system will be slow-moving across Scandinavia. A cold and showery northerly flow will cover the UK with sufficient diurnal instability to support thunder and hail. ... E IRELAND, WALES, ENGLAND, S and E SCOTLAND ... Upper trough pushing south, containing unseasonably cold mid-level temperatures (500mb temps below -35C), will create steep lapse rates with surface heating in the strong late April sunshine, yeilding a few 100 j/kg CAPE across much of the UK. As a result, heavy showers will readily develop inland after a dry/clear start, scattered weak thunderstorms are likely too. Any showers/storms will be accompanied by hail and gusty winds, with a wintry mix of sleet or snow too - given low dew points/temps. No severe weather is expected. Issued by: Nick Finnis

Cloud seeding is being used more extensively to protect French vineyards from damaging hail storms this year. It has been used for years to also increase rain or snow or even dissipate clouds. View the full blog here

Unless your passport runs out like mine in mid-Jan 2018, so I guess would have to apply again if I'm going to the U.S. next year.

My ESTA application was accepted within a five minutes of making payment. Only 34 days now until I fly out, can't wait.

Storm & Convective Forecast Issued 2017-04-01 06:36:07 Valid: 01/04/2017 06z to 02/04/2017 06z CONVECTIVE / STORM FORECAST - SATURDAY 1ST APRIL 2017 Synopsis Upper trough will slide east across western Europe including the UK and Ireland today, bringing scattered showers and some thunderstorms across many parts today. ... E IRELAND, N. IRELAND, WALES, ENGLAND. S, CENTRAL and E SCOTLAND ... Cold mid-level temperatures of the upper troughing moving across the UK and Ireland today will create steep lapse rates with surface heating in sunny spells, allowing instability to develop. GFS indicates up to 300-600 j/kg CAPE from late morning and through the afternoon across E Ireland, E Wales, central and S England - which will support the highest likelihood of thunderstorms, outside these areas thunderstorms will be much more isolated. Vertical wind shear will be rather weak at all levels, so any storms will be dis-organised and of the 'pulse type', i.e. updrafts aren't seperated from downdrafts which means that any one storm is shortlived. As a result, no severe weather is forecast, any storms may produce small hail, and slow-movement of cells may cause some minor surface flooding. Light winds and surface breeze convergence may support funnel clouds with stronger updrafts. Issued by: Nick Finnis

UK Severe Convective & Storm Forecast - Issued 2017-04-01 06:36:07 Valid: 01/04/2017 06z to 02/04/2017 06z CONVECTIVE / STORM FORECAST - SATURDAY 1ST APRIL 2017 Click here for the full forecastCheck the full storm forecast here

A look at where's warm, dry and sunny in Europe (and where's not) this weekend and next weekend as the school Easter Holidays begin for many. View the full blog here

Yes very sad news, goes to show there is more risk of being injured in a road traffic accident than by from the storms themselves. Unfortunately it looks like a mis-judgement by whoever was driving by overshooting the junction at speed, perhaps because they were distracted. On big chase days 100s of chasers converging on one storm can increase the danger on the roads too, especially when chasers get out the car to take photos. But I don't think huge numbers on the roads was the case yesterday in that area where the accident occured.

Supercell SW of Abilene looks most interesting at the moment, as it's discrete still ahead of the squall a little further west. Live coverage from Abilene local news KTXS http://www.ktxs.com/news/live-stream

Lightning detected over Midlands in the past hour, thundery showers now moving away NE toward N England. Were sferics over Ireland too earlier.