Convective Potential - June 13Th >>>>

[BrickFielder]

I am not convinced about storms for Saturday since the mid level lapse rates are not that impressive where as on Sunday they are.

A quick look at the forecast SkewT's shows a potential cap that Nick mentioned on Sunday but also some drier air aloft.Isolated quite severe storms come to mind, perhaps triggered by the heat island effect of cities. For once dewpoints do not look over done, but it might mean moisture is at a premium. Mid level winds look moderate but unidirectional,so super cells don't look like being on the cards. Later on winds begin to turn in the lower levels and when combined with localized effects from isolated storms you may get some weak tornado potential. Of course if the cap holds we will get nothing.

[A.J]

same old, same old.....everything shunted east...we breed them, the east gets them.....geez, I hope it doesnt pan out as per 06z GFS, otherwise they'll be some mightily disgruntled storm fans in the west midlands...still,its all T48-72+ so time for things to change....

[Paul Sherman]

Very True Aj - The Storm bit shifting East

If the GooFuS is showing 1,800jkg of Cape on Thursday for Sunday's risk I usually put the following rule in place to determine how much Cape should be realised. It is a bit like the RUC Model in the USA Where we knock off 1,500jkg to get the amount of Cape pretty much spot on. It always show 5,000jkg when in reality the other models will show around 3,000jkg etc

So if GFS Is showing 1,800jkg today knock off about 30% per day for the following days Model Runs

Friday will probably show somewhere near 1,250jkg

Saturday will probably show about 900jkg

Sunday will probably show around 600jkg - Which in itself is not a bad amount for Uk Standards and should get it done for marginally severe Storms if the Cap can be eroded and maybe convergence/sea breeze boundaries set up in favoured areas.

I personally think some places could get some nice Storms on Sunday with the possibility of some marginal sized Hail.

Paul S

[Harry]

same old, same old.....everything shunted east...we breed them, the east gets them.....geez, I hope it doesnt pan out as per 06z GFS, otherwise they'll be some mightily disgruntled storm fans in the west midlands...still,its all T48-72+ so time for things to change....

Ahem...don't feel too downtrodden in respect of 'breeding' storms - do you know how often thunderstorms are bred across N Kent/London to drift E/NE away from us!! I share your pain my friend!

Not too sure what will happen to those storms across N France and whether we can squeeze some imports...not looking likely atm!

Edited June 24, 2010 by Harry

[BlueHedgehog074]

The concentratation of the storms does look like it will be focused on Eastern areas of the U.K. according to GFS's latest update, which is where the highest CAPE values look to be.

Why did I have to fill my hopes up so much for yesterday?

Suppose still time for modifications, though, and is good news for the East who are looking forward to another storm/heavy showers.

[Nick F]

well my storm risk forecasted for sunday has now gone from 51% 13:00 and 41% the next time after down to a measly 0%.

i hope it goes up again as the charts get closer to sunday.

Down here on the South coast we used to get some cracking storms but now we are lucky if we get one or two,but im guessing that seems to be the same

in other places too.

Whats happened to the spanish plumes in the last few years? el nino/nina?

Atm I would say the south coast is unlikely to see any storms, as upper steering winds will be SW'erly and any storms over Nern France will likely stay there. There looks to be plenty of potential instability across Sern and SE England inland, but it may stay capped without a trigger to release it. Front moving in from the west looks weak, but sea breeze convergence inland may trigger the odd isolated storm Sunday afternoon north of London. Though trying not to be too specific this far out.

[Nick F]

Worth mentioning that, according to GFS, Saturday could see some isolated heavy showers or storms over northern England and perhaps north Wales. On Sunday quite strong forcing looks evident over N Ireland and western Scotland thanks to strong vorticity around the low just the NW - so maybe a greater chance of a storm here in the afternoon and more isolated but perhaps stronger storms over England.

[The PIT]

Lunchtime forecast dry and hot over the weekend and staying dry for the foreseeable future. So looks like storms off the menu at the present time although GFS shows different.

[Coast]

Hi guys! I've opened a new thread to talk in general terms about storms, a kind of 'convective banter' if you will!

We'll keep the convective discussion thread as a focused area for slightly more technical posts regarding the potential for thunderstorms, hail, tornadoes etc.

I'll shift a few posts across to get us started. Cheers

netweather.tv/general-storm-discussion-thread

[ZONE 51]

EXPLANATION OF SPC SEVERE WEATHER PARAMETERS

for those that dont know and for those that do..its interesting reading.

[liambailey09]

EXPLANATION OF SPC SEVERE WEATHER PARAMETERS

for those that dont know and for those that do..its interesting reading.

Will give this a read later, but i don't think i will understand much of it

[r6 steve]

i have noticed the term Thundery has vanished from the 3 to 5 day forecast from the met office,but they have been wrong before!!

(on the national forecast anyway) it still has the term Thundery in my local (SE) forecast. but who knows?

Edited June 24, 2010 by r6 steve

[dogs32]

according to netweather I am at 45% chance for a Storm around Bishops Cleave

6% Sunday

the drought continues

Edited June 24, 2010 by dogs32

[The PIT]

Like I posted earlier the Met office don't seem to think that storms are a risk this lunchtime and went for a dry weekend. GFS 06 oz and 12 oz don't agree though so I guess it's a case of waiting until Saturday evening to find out.

[ANYWEATHER]

Like I posted earlier the Met office don't seem to think that storms are a risk this lunchtime and went for a dry weekend. GFS 06 oz and 12 oz don't agree though so I guess it's a case of waiting until Saturday evening to find out.

Yes true, but only 24 hrs ago the forecast was somewhat different with more in the way of storms! Anyway it will be a case of watching the sky/radar because its virtually an impossible task to say where and when storms will develop,its a case of wait and see....

[The PIT]

Evening Forecast confirming the lunchtime forecast. Dry increasingly warm/hot and sunny perhaps a light shower northern island. So that's it folks no storms this weekend.

[Coast]

Sunday sees the storm risk becoming even more isolated across eastern England. Quite a contrast in output between today and yesterday! But just illustrates the difficulties of storms forecasting a few days out.

Yep shifting around a bit and heading East at the moment, I would still wait and see if you're in that middle band of the country. Never say never until Monday morning!!!! (and even then we can look towards Tuesday into Wednesday)

[Nick F]

Now we are coming into a more reliable timeframe for the weekend for convective forecasting, looking at 00z GFS progs - tomorrow may see some heavy showers develop across Wales/England Borders, W Midlands, NW England, N Ireland and Scotland - where some instability develops as increasingly moist airmass is heated into the mid-20s and wind convergence zone(s) looks to develop:

CINH (convective inhibition shouldn't be too much of an issue by evening in these areas:

Though 850-500mb lapse rates look a bit restricitive for deep convection and thunderstorm development - ideally need 25C+.

Sunday ... not looking so good for England and Wales - with best area of potential instability building across eastern England in the afternoon, convergence looks possible, but a strong cap (CINH) to overcome here. If CINH is overcome by convergence lift and high temps - we just might get an isolated storm develop over eastern England by evening:

However, Scotland looks to have a better environment for storm development - with little if any CINH and plenty of instability developing through the day as heights fall from the west and temperatures fall aloft with approach of upper low. So some storms possible here.

[staplehurst]

Convection has been bubbling up all day here in Kent as a sea breeze develops, it has turned notably breezy in the last hour and actually feels a touch less humid now. However, it looks very threatening out there with dark purpley/blue bases to the clouds and I have a nasty headache slowly setting in. Interesting stuff!

[Methuselah]

My guess (And it is a guess!) is that later next week will see a better chance of something interesting developing, as Atlantic fronts push into very warm air being advected northwards out of France...That said, later next week is a long way off!

[Mesoscale]

im hopeing its before thursday that something develops as im off too mexico that day!

knowing my luck ill miss out on the biggest thunderstorm london has seen in ages!

Pretty hot at the moment and a bit hazey but nothing conducive of thunderstorm or electrical activity!

This is what sky news said

Look out the barbecue and suntan lotion as a mini heatwave hits the UK this weekend.

Three days of sunshine and thunder storms are being predicted by forecasters.

Sunday is to be the hottest day with the South East seeing the best of the sunshine with highs of 30C.

But thunder storms could be triggered by the heat.

I aint having none of it!

Edited June 25, 2010 by Mesodiscussion

[dogs32]

My guess (And it is a guess!) is that later next week will see a better chance of something interesting developing, as Atlantic fronts push into very warm air being advected northwards out of France...That said, later next week is a long way off!

I have a feeling that our Local BBC guy was hinting at this also...Thursday maybe

for us anyway..S/W

Edited June 25, 2010 by dogs32

[A.J]

Why the two threads for convective discussion?? ....I've been reading them both, and its seems there's no difference in the content, indeed some posts are being duplicated by posters almost word for word in each thread!

[A.J]

I think this thread is for discussing, in somewhat greater detail, any convective potential being shown from the models and the general convective outlook. The other thread is for general convective/storms chat, which would otherwise a lot of time clog up the one thread and make it difficult for members to sort out the informative posts from the less informative. I think it's a good idea, though whether members post in the appropriate thread is another matter.

Sorry bud...lol.......There's was actually just a hint of sarcasm in my post...I'm aware of the nature of the threads, there's just far too much off-topic stuff in this thread....C'mon mods, earn your keep!....thought I'd better edit this post before I get told off....Mods, you do a great job, just this thread needs a little housekeeping

Edited June 25, 2010 by ajpoolshark

[Noctilucid]

Inetersting to note some fairly substantial cumulus congestus has popped up just South of here.

The majority of convection today has been somewhat flat.

Edited June 25, 2010 by jshaw