Convective / storm Discussion - 5th June 2014 onwards

[Lauren]

I plan on doing just that Snow. Will sleep with the windows open so if it does start, it should wake me up.

[ancientsolar]

Looking at the satellites. That thundery downpour in Mid West wales was just the beginning. Yes I see the cloud building from the South of France. But also cloud developing over the channel into SW England, and West Wales. ~ So there could be some isolated thundery  showers becoming more frequent with in the next hour.

[dave48]

Latest 'high res' radar sw France

 

http://forums.infoclimat.fr/topic/84385-suivi-du-temps-dans-le-sud-ouest/page-4

[shaky]

Nothing has developed over france yet!!jheeez this is getting really close!!have a bad feeling about this!!

[Mapantz]

Nothing like like writing off something that hasn't fully developed yet!

I haven't even looked at the radar yet, no need to until much later.

[Roger J Smith]

I would suggest that the best chance for severe thunderstorm development on Saturday would be in parts of the east Midlands, some parts of inland East Anglia, and Yorkshire. Frontal wave moving northeast would be the trigger. It would trend more towards heavy thundery rain further north. Sunday might then provide further chances for locally heavy thunderstorms but these would form more randomly along various trough features and the chances might be better in the west or central regions than on Saturday.

 

 

[The PIT]

It better happen I'm hoping to save water when I wash my car. Soap it down and let nature do the rest.

[dave48]

Nothing has developed over france yet!!jheeez this is getting really close!!have a bad feeling about this!!

 

Initition expected from 7pm onwards for northern France, could be later though, several cells ongoing in SW.

[Azazel]

do we even need anything to happen over france? I thought we were looking at a pre-frontal trough coming in from the west?

[William Grimsley]

Lol this forum cracks me up sometimes. Still very early days and we have Gordon wishing for no weather and William wishing for an apocalypse.   What will be will be, no amount of wishing or hope casting will change the outcome, just sit back, relax and see what unfolds 

Best idea. I was like Gordon a few years ago and it mostly worked.

[Guest]

Well it does agree with the met office forecast for us. Heavy rain.

Headline:

Mainly dry overnight. Heavy, thundery rain developing through Saturday.

This Evening and Tonight:

Evening sunshine then many areas staying dry for much of the night but an increasing chance of heavy, thundery showers towards morning. A much milder night. Minimum Temperature 12 Â°C.

Saturday:

Heavy, thundery rain developing widely through the day, giving downpours in places, some quite prolonged, with a risk of hail and frequent lightning. Perhaps clearing from southern parts towards evening. Maximum Temperature 20 Â°C.

 

Not quite PIT. I know they mention the awful sounding 'thundery rain', but they never use the word 'thunderstorm anyway. It's as good as you're gonna get from them tbh

[saint]

Can we ban any mentions of nothing happening over France for the next hour of two?! It's far too early!

[William Grimsley]

do we even need anything to happen over france? I thought we were looking at a pre-frontal trough coming in from the west?

Not really but it would help but it probably wouldn't help here. Good convection and a front might do me but not sure about your area.

[Mapantz]

[sparky1972]

roll on storm time bring then south lincolnshire way camera is charged and ready no work for me either tomorrow so can be up all night 

i am with you on that one,  camera ready, fingers crossed we do get something in the way of storms tomorrow

[StormChaseUK]

Got this outside my house right now.

 

IMAG0193.jpg

Another good sign, often those little beauties grow into great storms

[William Grimsley]

i am with you on that one,  camera ready, fingers crossed we do get something in the way of storms tomorrow

This time I can probably stay up but there's no point until something happens because I might loose hours of sleep for nothing.

[SnowJoke]

do we even need anything to happen over france? I thought we were looking at a pre-frontal trough coming in from the west?

 

Indeed correct, it's the advection of the Theta-W plume coming north from France that will interact with the weather front from the SW that will destabilise the plume causing elevated thunderstorms to develop. The last thing we want is a huge cluster of surface based storms to develop over northern France pushing a blanket of cloud northwards inhibiting any development later on this evening.

[Supacell]

I wouldn't worry too much about the lack of developments over France. The high theta plume is in place over France, as it is now over Southern England, but just like here I should not imagine anything will happen until that colder air starts moving in aloft as this is what should allow the plume to destabilise. I reckon by midnight the radars will look very different from what they do now.

Edited June 6, 2014 by Supacell

[Azazel]

Not really but it would help but it probably wouldn't help here. Good convection and a front might do me but not sure about your area.

 

im gonna be honest, i'm pretty clueless haha. I've had a fascination with the weather since childhood, I'm 29 now and still dont quite understand the complex physics that come into play.

Back when i was a young teenager I didnt have forums like this or access to data, I used to go by sight and smell etc

[ancientsolar]

To my east

To my west

[William Grimsley]

To my east image.jpg

To my west

image.jpg

Nice altocumulus to your west not quite altocumulus castellanus yet but hopefully you might see some.

[ancientsolar]

Nice altocumulus to your west not quite altocumulus castellanus yet but hopefully you might see some.

I'll have to find my DSLR charger get some rich photos on the go ! ~ I pad just doesnt quite cut it ^_^ ~~ mean while the Camcorder is still time lapsing. 

[William Grimsley]

I'll have to find my DSLR charger get some rich photos on the go ! ~ I pad just doesnt quite cut it ^_^ ~~ mean while the Camcorder is still time lapsing. 

Ah the photo was quite fuzzy. Are the clouds towering?

[Snowshine]

A level 1 was issued for W France and S England for severe wind gusts and to a lesser extent for excessive precipitation, large hail and tornadoes.

A level 1 was issed for E Spain, S and Central France mainly for large hail and severe wind gusts.A level 1 was issued for W-most Russia, parts of Belarus and the Ukraine mainly for large hail and excessive precipitation.A level 1 was issued for E Romania, E Bulgaria and N Turkey mainly for excessive precipitation and to a lesser extent for waterspouts.

 

Between a pronounced cyclone over the Atlantic Ocean near 45°N and a weak ridge over Central Europe, a deep Southwesterly flow with strong warm air advection spreads over Spain, France, England, BeNeLux and Germany. This configuration will open up a prolonged severe thunderstorm episode in these countries.Further East, a compact upper-level low slowly moves from Denmark into Southern Sweden. Rather low geopotential connects it with a second upper-level low over Turkey. An anticyclone sits over Western Russia.

 

DISCUSSIONE Spain, France, EnglandUnder strong insolation and a capping inversion created by the warm air advection, rapid diurnal heating and moistening of low-levels can be expected. Forecast models agree on the buildup of CAPE on the order of 1000 to 2000 J/kg in France till the evening with realistically looking surface dewpoints of 16-18°C. The instability maximum is expected in the Northern foreland of the Pyrenees. Deep-layer shear strengthens to 20-25 m/s, and at least slightly enhanced shear and helicity will also be present at lower levels. The conditions look prime that any forming storm can turn into a well-developed supercell. Main uncertainties will be if convective initiation can be achieved with such a strong cap, and if forming updrafts can grow persistent enough to withstand entrainment of very dry mid-level air.Diurnal timing of large-scale lift is adverse to widespread storm development: after a first short-wave departs eastward until 09 UTC, peak daytime heating hours will rather see large-scale subsidence over most of Spain and France. Only in the evening hours, stronger vorticity maxima will start to overspread the Bay of Biscay and Western France. Though their exact timing and placement is still uncertain, their contribution to lift will likely erode and finally break the cap. The most plausible scenario is that elevated storms will form over the Bay of Biscay in the evening and move northward into Western France (Pays de la Loire, Bretagne) overnight. Severe wind gusts will be the main risk. Other kinds of severe weather (excessive precipitation, large hail and tornadoes) are also possible, but do more critically depend on the question if storms will be able to root down to the surface. If they succeed, they can fully benefit from moist low-level air and further improving wind profiles overnight.Late in the forecast period, elevated storms will likely extend into Southern England with a slowly decreasing severe weather risk.Further East and South, isolated storms may form over orographic features of France and Eastern Spain between noon and sunset, but will struggle to still penetrate the strong cap as soon as the detach from their points of initiation. If they succeed, supercells with a risk of large hail and severe downbursts are forecast, an even an isolated extreme event is possible.Relatively highest probability for initiation seem to exist over Southwestern France in the wake of the Pyrenees, where Northeasterly upslope flow meets with Northwesterly onshore flow from the Bay of Biscay. This region will also see a second chance for initiation overnight when an outflow boundary will move onshore in the wake of the aforementioned MCS. However, with slim to none precipitation signals in all models, confidence in convective initiation is not high enough for a level 2 despite the impressive thermodynamic and kinematic setup.