Pat Butcher

Radar update from Leeds. That'll teach me not to leave it outside...

Amazing, thanks a lot for your help - I understand now. You're spot on as well - Met Office echoed your sentiments immediately after you posted that.

Hi folks, Just a quick one - in a non-sheared environment, do CAPE values actually matter above a certain threshold in terms of storm strength/probability? These CAPE maps tend to throw up anything from 200 to 1,500 j/kg CAPE on weekends like this one, but is it a variable that matters?

Just Health and Safety gone mad as usual, looks fine to me mate.

Wow. Red warning out from Met Office for Cumbria now. Stay safe mate.

Out of interest, how do airlines deal with this situation? I'll be surprised if much lands at any airport north of Manchester tomorrow, do planes carry extra fuel in case they need to divert a fair distance away (e.g. divert from Edinburgh to Luton)?

This is a model of max wind gusts by location over the next 72hrs. We're looking at 60-70mph max gusts widely, with 85mph not ruled out for more rural areas. Right in the middle of a busy shopping weekend, too. If the Met Office don't upgrade to an Amber, I'm a turnip.

Hi folks, Has anyone got any explanation/Wiki link for this bizarre split going on? It's not something I've come across before..

There's also some convective activity in the works (courtesy of ESTOFEX)... Storm Forecast Valid: Tue 17 Nov 2015 06:00 to Wed 18 Nov 2015 06:00 UTC Issued: Mon 16 Nov 2015 22:35 Forecaster: GROENEMEIJER A level 2 was issued for the Benelux countries, a large part of Germany, the NW Czech Republic and W Poland mainly for severe wind gusts and to a lesser extent for tornadoes. A level 1 was issued for and area surrounding the level 1, including S Ireland, the S United Kingdom, larger parts of Poland and the Czech Republic, all of Germany and parts of Denmark, France, Switzerland, and Austria, mainly for severe wind gusts and to a lesser extent for tornadoes. SYNOPSIS During the forecast period, a strong mid-level jetstreak will rapidly enter western Europe from the Atlantic Ocean. On the southern flank of an associated eastward moving area of low pressure, a strong wind field develops and moves across South Ireland, the southern UK, Benelux, Germany and later Western Poland. Within the seasonably mild and humid air-mass organized severe convective storms are expected. DISCUSSION S Ireland, S UK, North Sea, Bneelux, N France, Germany, Poland, Czech Republic, W Poland, N Austria... Upon approach of a strong mid-level jet, upward vertical motion will ovespread the mild and humid warm sector (with dew point temperatures of 11-14 C) first across southern Ireland, then the southern UK and subsequently further eastward. In response, surface-based convection coverage will increase and probably organize linearly. These storms will be embedded in a strong wind field and gusts that they produce will likely attain severe levels (> 25 m/s). According to the GFS model, the strongest upward motion should be in the left exit region of the jet streak that becomes particularly focused during the evening. This area of upward motion will move from west to east across the indicated level 2 area, i.e from the Benelux Countries to W Poland in the 21 - 06 UTC time frame. It appears likely that well-organized linear convection with a particularly high risk of severe wind gusts will develop there as the system moves eastward. This will happen in an environment that - per GFS - will boast 200-400 J/kg CAPE, which is quite substantial for the time of year. The environment of the convection is characterized by strong wind shear (~ 30 m/s 0-6 km) particularly in low levels (~ 15 - 18 m/s 0-1 km). If mor or less isolated convective storms are able to form, a high tornado threat would be present, but it appears more likely that a line will be the dominant mode given the strongly localized forcing and absent CIN. As it presently seems unlikely that a large wind shift will occur across the line, the risk of tornadoes wih the line seems to be redduced, in accrodance with the results of Clark and Parker. Nevertheless, a few tornadoes cannot be ruled out given the otherwise favourable circumstances including high wind shear, very low LCL and the strong forcing for upward motion that may locally steepen lapse rates considerably. Behind the area of greatest convective activity, strong non-convective winds are expected occur with similar or even higher gusts.

Some pretty spectacular flying going on thanks to the Jetstream...

Strong synoptic lift approaches Sicily beyond 00Z which should support a rapidly eroding cap and increasing chances for CI. MLCAPE in excess of 3 kJ/kg, 20 m/s 0-3 km shear and SRH-1 in excess of 300 m^2/s^2 will overlap and supercells with very large hail, excessive rain, damaging wind gusts and tornadoes are anticipated. A significant tornado event can't be excluded as forecast hodographs show a looped signature with 50 kt at 800 hPa around 03Z over W-Sicily (GFS). This activity spreads E/NE until 06Z and affects S-Italy, too. A level 3 was strongly considered, but timing issues of DMC activity and ongoing model discrepancies in coverage of storms kept this event in an high-end level 2. Flippin' eck, that is a severe setup! I hope you've got a balcony and a crate of beers to enjoy the show, then a basement to hide in if it kicks off..

Due to tomorrow's forecast of naff all windshear and an alright chunk of CAPE, it's time for a davethedog convective forecast. Storm Forecast Valid: Tue 06 Oct 2015 06:00 to Wed 06 Oct 2015 06:00 UTC Issued: Mon 05 Oct 2015 16:10 Forecaster: DAVETHEDOG A HUMDINGER FREE ZONE was forecast for mainland Britain. Due to a sizeable chunk of CAPE floating above our cities and towns like an alien invasion if aliens were made out of slightly unstable airmasses, a few storms will pop up somewhere. There's no cool stuff like wind shear floating around, so whilst the odd high street might become a massive puddle for a bit, we don't expect anything other than the odd flash punctuating an otherwise rainy autumn day, as Brits everywhere complain and sneeze into their Lemsips. Winter is coming.

I remember watching that Aire Valley supercell from Leeds. It was never closer than 25 miles away, but that strobing lightning was beyond anything I've ever witnessed before. Sorry to hear about your dog. You can use a Youtube Downloader service if you want your own copy of that video - do a quick Google search. Give me a shout if you need any help.

As far as I'm aware, the impact will be pretty minimal. If you weren't told about it, you'd just think that it was a normal gloomy Autumn rainy day with a stiff breeze. The Tropical Storm itself barely edged the Tropical Storm threshold (sustained winds >40mph) and the whole thing dissipated on Friday! The media have made a lot of fuss over nothing here...

Good shout - it's still showing on the latest run over East Yorkshire. Does anyone know wtf that cross in the bottom left-hand corner is? The white circle around it is mine to highlight it!

Interesting little temperature anomaly up here in Leeds, on a very dull 10*C (confirmed by airport weather station) despite 17*C and 14*C predicted by GFS and Met Office respectively. Any idea what would normally cause such an anomaly?

Funny little setup for Thursday night into Friday morning. We've got reasonable non surface based CAPE but very little to suggest organisation - it more seems like pulse storms popping up across much of England over the course of the night with the potential for some chunky hail. Broadly, the severe risk is low, but some storm training, especially around the south coast, could turn really nasty despite being unlikely.

Sorry, but some of this moaning about Estofex is a little bit silly. A Level 2 across an area doesn't mean that apocalyptic supercells will lay siege to every corner of the area noted. It means that there is a <15% chance that severe convective weather will occur within 40km of a point. This means that if you're in Charing Cross and receive a Level 2 forecast six nights in a row, the forecast is correct if severe weather (big hail, very heavy rain, strong convective wind, tornado etc) is detected near you, once. This could be in Luton, Croydon, or in your backyard. Estofex forecast risk, not the weather.

Right on cue, Estofex have climbed on board! Are you storm guys all wired into some sort of matrix together? Storm Forecast Valid: Thu 16 Jul 2015 06:00 to Fri 17 Jul 2015 06:00 UTC Issued: Wed 15 Jul 2015 22:04 Forecaster: GATZEN A level 2 was issued for parts of NW Germany, Benelux, N France, and S UK mainly for large hail, severe wind gusts, and to a lesser extend tornadoes and excessive precipitation. A level 1 was issued for central and southern France, and NE Spain mainly for large hail and severe wind gusts. SYNOPSIS At the southern flank of low geopotential across Scandinavia and between Iceland and the British Isles, a rather zonal flow has advected moist air into Europe. Soundings from northern France/southern UK to western Germany indicate rich and deep moisture with surface dewpoints around 16°C. South of this frontal zone, a ridge is present, and steep lapse rates have spread from northern Africa into SW Europe. On Thursday, the north-west European trough will move southward. Together with another low W of Iberia, it yields a south-westerly flow across western Europe. Advection of warm and well-mixed air masses is expected until the end of the period, when the axis of warm air will reach from central France to south-western Germany. Ahead of a cold front across the eastern UK and western France, a strong low-level jet will spread into the Benelux countries and NW Germany at the end of the period. DISCUSSION Southern/eastern UK into northern France, Benelux, and NW Germany The warm air advection regime will see quickly improving lapse rates atop of a moist boundary layer from W Germany across Benelux into northern France and the southern UK. Given the rich low-level moisture, model CAPE values of 1000 J/kg MLCAPE seem to be reasonable during the afternoon and evening. Initiation becomes likely in the evening hours due to the approaching cold front and frontogenetical forcing. QG forcing will increase across the UK due to DCVA. Storms are forecast to form across northern France in the late afternoon, spreading eastward into the Benelux in the evening. Additional storms may develop across southern and eastern UK. Due to the strong low-level jet, 15 m/s low-level vertical wind shear will be available, and storms can quickly become supercells, capable of producing large hail, severe wind gusts, and flash flood. Tornadoes are also forecast with the highest threat in the evening hours from Belgium into the SE UK. Strong tornadoes are not ruled out given the strong low-level jet and associated vertical wind shear. In the evening and night hours, storms are forecast to cluster, spreading north-east. Severe threat will gradually weaken as storms become elevated, but given the strong low-level jet and ongoing frontogenetical forcing, threat of large hail, severe winds, tornadoes, and excessive rain is expected to continue until the early morning when the main activity is expected to shift to western Germany. Central and southern France, north-eastern Spain Hot and well-mixed air mass will be present ahead of an approaching cold front from the west. Low-level moisture is expected to be limited, but some moisture advection takes place from the north Mediterranean, especially to the north of the Pyrenees. Initiation of storms is forecast ahead of the approaching cold front from SE Spain to southern France and further into central France. Storms that form will have a potential to produce severe downbursts given the well-mixed low-level air mass. Additionally, vertical wind shear around 10-15 m/s in the lowest 3 km will allow for well-organized storms including supercells, capable of producing large or very large hail. Given the large cold pool potential, storms are forecast to cluster before they spread north-eastward in the evening and night.

Seems to be agreement from some of the convective guys - UKASF have just bashed this one out: Day 2 Convective Outlook VALID 06:00 UTC Thu 16 Jul 2015 - 05:59 UTC Fri 17 Jul 2015 ISSUED 21:53 UTC Wed 15 Jul 2015 ISSUED BY: Dan On Thursday, an Atlantic low will be located to the SW of Ireland, moving progressively due north. At the surface, a warm front will migrate northwards across the southern half of Britain, allowing poleward-advection of a very warm, moist low-level airmass across the aforementioned areas. The arrival of this high ThetaW air will be quite late in the day, as diurnal heating begins to subside, and will probably act as a cap to any potential surface-based convection given limited maximum temperatures in the upper 20s Celsius, despite increasing dewpoints through the evening hours. However, there is some scope across parts of Wales/West Country for isolated sfc-based convection to develop late afternoon/evening hours, given 700-900 Jkg-1 SBCAPE, increased forcing from aloft and some surface convergence. Forecast profiles look quite dry, and so whilst convective cloud will likely develop, it is uncertain whether it will reach a depth sufficient for lightning activity - hence for now we remain with an ISOL and will monitor convective trends for any potential upgrades. Greatest attention is then turned to the potential for elevated thunderstorms to develop during the mid/late evening hours and thereafter, as the forward-side of the large-scale Atlantic upper trough, and an attendant shortwave, serve as the focus for convective initiation. Naturally there is still a reasonable amount uncertainty as to the exact detail in development and areas affected. Current thinking is a few scattered thunderstorms may develop during the mid/late evening hours across some southern counties of England, with activity becoming more widespread as the plume axis tracks northeastwards, eventually exiting to the North Sea - areas at greatest risk are thus highlighted with a SLGT and MDT (20z-04z), with instability increasing (but upper forcing decreasing) as one heads farther to the SE. At present there appears to be a lack of upper forcing to generate imported elevated convection from France (especially Cherbourg and environs), and hence for now Channel and adjacent coastal areas remain at ISOL. Several models also simulate an increase in lightning potential over the Irish Sea, running NNEwards into adjacent parts of Cumbria / S/SE Scotland 00z-06z. Have included a SLGT here for now to highlight slightly higher chances of lightning, albeit this signal less clear compared with NWP guidance yesterday. Retaining SLGT for now, but may need a downgrade if this trend continues. Conversely, parts of Ireland/Northern Ireland may need an upgrade to SLGT, especially northern and western areas. Source:http://www.convectiveweather.co.uk/forecast.php?date=2015-07-16 largethumb.php

I'm not sure if all the pessimism in this thread is justified. Whilst there certainly won't be as large a convective outbreak as there was a couple of weeks ago, there certainly appears to be the possibility of elevated storms with a risk of severe hail/wind overnight on Thurs over a small patch anywhere within 100 or so miles of Northampton.. Am I missing something?

So it's not a particularly hot day, there's very little CAPE in the models, yet the usually conservative Met Office have issued a warning for an apocalyptic squall line. I haven't been paying attention today, whats going on?

Looking at the radar there's a fresh storm around Whitley Bay...

That bloke from Otley I was conversing with earlier - good luck mate, enjoy!

Not too fussed to have missed a direct hit, been serenely sat on the step watching it strobing away into the distance. What a show!