Convective/Thunderstorm Discussion: Spring/Summer 15

WheatenBriar

dubscottie wrote: »

What happened to give us the 2 days of thunder in 2003 or 2004? I remember it started on the Wed night and didn't stop till the Friday morning.

That was very cold air moving over a warm sea causing huge showers similar to the thunder snow of 2010,despite it being October,it did give snow high in the Wicklow mountains
Google lapse rates,I'm on my phone

Iancar29

So as some models have been hinting at , an Irish sea storm looks more likely with a strong cap in place over land tomorrow.

This could certainly be a supercell with conditions ripe for it.


DLS up to 50knts !


LLS up to 35knts .


Some strong convergence in the region too .


I'll say it would be nice to watch the tops go up from the east coast tomorrow if it does indeed go bang! :cool:

maquiladora

HIRLAM still showing precip moving up the southeast and east coast here around noon tomorrow with some more showers popping up in the evening but the beefy stuff does look like kicking off around the Cumbria region tomorrow.

Oneiric 3

maquiladora wrote: »

HIRLAM still showing precip moving up the southeast and east coast here around noon tomorrow with some more showers popping up in the evening but the beefy stuff does look like kicking off around the Cumbria region tomorrow.

The Beeb at 1pm warned of potentially severe thunderstorms tomorrow eve over NW England and later Scotland. Their model seems to be hinting at some thundery potential for the South and midlands here tomorrow eve also. But with each of the top hi-res models showing an array of different solutions regarding convective potential, guess it is safe to say that some areas will see some, while others won't (and I can safefy guess with area will have the greatest chance of missing them... )

Iancar29

Oneiric 3 wrote: »

The Beeb at 1pm warned of potentially severe thunderstorms tomorrow eve over NW England and later Scotland. Their model seems to be hinting at some thundery potential for the South and midlands here tomorrow eve also. But with each of the top hi-res models showing an array of different solutions regarding convective potential, guess it is safe to say that some areas will see some, while others won't (and I can safefy guess with area will have the greatest chance of missing them... )

Yeah thats the supercell moving up into Scotland... i'll be gobsmacked if theres no funnel clouds reported let alone a brief tornado!

WheatenBriar

maquiladora wrote: »

HIRLAM still showing precip moving up the southeast and east coast here around noon tomorrow with some more showers popping up in the evening but the beefy stuff does look like kicking off around the Cumbria region tomorrow.

BBC news 24 graphics now also showing groups of showers heading into the southeast and east from the south at that time

maquiladora

Iancar29 wrote: »

Yeah thats the supercell moving up into Scotland... i'll be gobsmacked if theres no funnel clouds reported let alone a brief tornado!

Iancar29

^^^ Ya never know , the cap may magically break with the help of the Dublin Mountains and put down a waterspout at bull island!

FWVT

I think most storms will be elevated and not surface-based, so they will form where the DLS overlaps the tongue of maximum theta-e , i.e. Wales and NW England.

Danno

A couple of sparks over Cornwall at the moment.

Iancar29

For anyone having thunderstorm withdrawal symptoms , my video from last week in South Dakota may help

https://www.youtube.com/watch?v=xI629qTUAK8

maquiladora

Thunderstorm near the Channel Islands at the moment.

http://www.meteociel.fr/observations-meteo/foudre-direct.php?region=uk


Could see this activity continue to develop over southwest England/Wales/Irish Sea through the night and into early tomorrow morning. If that happens, there is a slim chance something makes it as far as the east coast here.

jimmynokia

Iancar29 wrote: »

For anyone having thunderstorm withdrawal symptoms , my video from last week in South Dakota may help

https://www.youtube.com/watch?v=xI629qTUAK8

Why cant we have stuff like that here :mad::mad:

Oneiric 3

Not sure where the EURO4 is coming from but showing prep totals over parts of the west up to and over 20 mm over the course of tomorrow? It must be seeing more 'oomph' in that Atlantic front than the other hi-res models.

jimmynokia

Weather report on RTE was pretty boring

Rikand

Could that "oomph" mean thunder for those of us in the whest?

Oneiric 3

Rikand wrote: »

Could that "oomph" mean thunder for those of us in the whest?

I would doubt it* Think thundery showers would more likely develop further east towards the midlands &east away from the main frontal band.



*but secretly hopes

maquiladora

Hot off the presses. The east coast catches the edge of a Level 1. :P Northern England looking like being the place to be though....

DISCUSSION

... England, Scotland ...

Potentially very severe situation with number of question marks will develop over parts of UK. As the plume of steep lapse rates overspreads the low level airmass characterised by dewpoints of 16 - 18 deg C, moderate degree of latent instability will develop over the region. CAPE values will stay mostly between 500 - 1500 J/kg, but some models allow up to 2000 J/kg of CAPE, especially over N England / S Scotland. Strong flow at low to mid-troposphere will result in 15 - 25 m/s of 0-3 and 0-6 km bulk wind shear, values well conducive for organised convection. Furthermore, veering of wind with height will favour curved hodographs and more than 200 m2/s2 of SREH in the 0-3 km layer. Such conditions would be very conducive for supercells, probably in the HP mode, or bow echoes, as much of the wind shear is confined to the surface to 700 hPa layer. Large (or even very large hail), damaging winds and even tornadoes (especially in the northern part of Lvl 2 with low LCLs) could accompany such well organised storms.

There are two factor that may limit the overall severity of the situation:
A/ Degree of initiation. With no strong synoptic-scale upward motion and in the capped airmass, it may be difficult to initiate storms. Initiation will be more likely in the evening hours as 850 and 700 hPa temperatures begin to drop from the west and cold front affects the area.
B/ Stable boundary layer. Due to the very hot airmass around 850 hPa, it will require a lot of heating to destabilise the boundary layer and allow storms to root in it. Thus, especially in the early period, most storms will stay elevated (with primarily hail threat), as they move from France towards England. Surface based development will be most likely in the late afternoon and early evening hours.

Level 2 is introduced for the area, where best CAPE/shear overlap is simulated, as well as with the best chances for the surface based storm initiation.

FWVT

Just flown home from Luton and there were some nice Cbs over SW England alright

maquiladora

Oneiric 3 wrote: »

Not sure where the EURO4 is coming from but showing prep totals over parts of the west up to and over 20 mm over the course of tomorrow? It must be seeing more 'oomph' in that Atlantic front than the other hi-res models.

Hooter23

They mentioned torrential rain in the west of ireland also on Sky News weather...

Iancar29

maquiladora wrote: »

Hooter23 wrote: »

They mentioned torrential rain in the west of ireland also on Sky News weather...

Non convective stuff ... aka messy

maquiladora

Iancar29 wrote: »

Non convective stuff ... aka messy

Yeah some of it is frontal but there could be some convective stuff mixed in too. Probably nothing significant though....

Danno

Looking south on the IR animation and there appears to be a band forming between the cell off W France and the cold front. This could develop and hit us tomorrow?

Iancar29

maquiladora wrote: »

Yeah some of it is frontal but there could be some convective stuff mixed in too. Probably nothing significant though....

Latest WRF has some hope for the east within some modest instability tomorrow evening. Also in line with estofex's thoughts for a late cap break for N.England and Scotland

maquiladora

WheatenBriar

Some showers heading towards wexford no sparks
I can see them from Arklow
Fair warm in the cloud 21c
Breeze coming from direction of showers

Wanderer78

maquiladora wrote: »

what app you using?

maquiladora

Wanderer78 wrote: »

what app you using?

http://www.sat24.com/en/gb

Some cells getting a bit closer to the southeast coast now.

WheatenBriar

Raining here near Arklow at the moment
Sky has that I've come a long way from France and I'm a bit jaded look about it
Wavy and disturbed but all the action dried out of it