General Storm Discussion Thread

[Nick F]

BBC seemed to hint at chance of some thundery showers later tomorrow across the far SE as cold front arrives, though models seem to have moved away from the idea, fax shows risk of any thunder staying over Nern France. Still slight potential IMO.

[sbiggs]

Met Office says pressure should be 1012 - 1014mb here, which also coincides with no rain or anything happening in Cambs, but since 9pm last night I've seen a drop from 1013 down to now just 1007mb.

Being a meteo-novice can anyone explain how this may favour anything happening?

[Harry]

MetO 'Invent' feature, shows potential for a convective line to develop across the SE tomorrow afternoon/evening...this is also mentioned in the forecast text for tomorrow. Seems to form a similar path to the now infamous 6th August 2008 storms which formed in a similar location and similar orientation...worth keeping an eye on IMO, especially as any chances for tonight seem very low at the moment.

[VillagePlank]

Best chance I reckon is Somerset, Dorset, Wiltshire, Hampshire as the southern part of the front passes at approximately 6am tomorrow morning. Not much CAPE to tap into, so might just be heavy showers. Outside chance of French imports for tomorrow afternoon/evening, but the wind at 500hPa is going to stop that possibility, and with sinking air in the last 200hPa, it looks like too many things have to go our way for a Kent thunderstorm. Sorry.

Met Office says pressure should be 1012 - 1014mb here, which also coincides with no rain or anything happening in Cambs, but since 9pm last night I've seen a drop from 1013 down to now just 1007mb.

Being a meteo-novice can anyone explain how this may favour anything happening?

Pressure is a measure of the mass of air above your shoulders. If the air is rising, like when a front or low pressure system moves over, then the effect on pressure at sea-level is a drop. The converse is also true - if the pressure is sinking (ie air pressing against your shoulders) it means an increase in air pressure.

That's also the basic reason why low pressure (and frontal systems) brings rain, and high pressure brings sunshine. In order to create clouds you need rising air, or low pressure - if the air isn't rising it is, generally, sinking which makes it very difficult indeed to make a cloud.

A frontal system is simply the boundary between two (or more) airmass types. Generally they have different temperatures, so, no matter which sort of front it is it is (somewhat) likely to bring rain since the hot bit will be forced about the cold bit and clouds will be created.

Of course, this is highly generalised, but hopefully it helps.

Edited July 1, 2010 by VillagePlank

[sbiggs]

After much thought to 100% understand I now do, although even though this pressure drop is happening (now down to 1006mb) and there being a decent cloud cover, there still seems to be no rain forecast for this area, or visually that occurrence happening. What would cause this?

Edited July 1, 2010 by sbiggs

[r6 steve]

The met office has now seemed to gone backwards in there forecast for next week saying at first "There is an increasing chance of thundery showers the southern part of England" to now "There is a low risk" etc : (

[johnholmes]

After much thought to 100% understand I now do, although even though this pressure drop is happening (now down to 1006mb) and there being a decent cloud cover, there still seems to be no rain forecast for this area, or visually that occurrence happening. What would cause this?

have a look at out Guides-a whole area with info on.

If that does not help then, if you are pm enabled(!?), depends on number of posts you have made, then please pm me and I'll do my best to answer.

welcome to the NW club-enjoy.

[ZONE 51]

could the cold front slow down as it edges east before entering the se so we can pull up the french storms friday night..is this what needs to happen for inports then?

Edited July 1, 2010 by nimbilus

[Lynxus]

That band of rain is sooooooo slow at shifting eastwards.

Some very heavy pulses in that, Wouldnt be surprised if theres some flooding.

[ZONE 51]

:cray:i hope something changes for the SE as its such a close one for storms il be reading the forums and hope i read what i want to here

-storms for se england-

[Costa Del Fal]

:cray:i hope something changes for the SE as its such a close one for storms il be reading the forums and hope i read what i want to here

-storms for se england-

No, storms for the SE look really quite unlikely now especially away from the very far corner of Kent and even ere the risk is very low.

That front out West looks like it will dump most of its rain further West now so here wont get much at all.

[vortex_liam]

Well, i acually do think there may be a storm fairly soon (and i hope i am right!) Because flash flood weather warning and its still hot but, its dropping in temp so i hope there could be a really good storm,rumbles and hail and even some rotation and a possiable tornado...

[Tim B]

Wouldnt be surprised to see some very heavy rain with thunder and lightning over my area during tonight and tomorrow given the front has travelled over land and a short distance of ocean before it arrives, much like the other night.

[Andy Bown]

:cc_confused:Where in the uk are you?

And where in the UK are you!? Putting it in your profile so it appears by your name/avatar will be very helpful!

At least Tim's profile/avatar says where he is!

[lukemc]

Hi,

Why is it that there has been very little in the way of thundery activity for my area this year so far? Yes I know it has been drier than usual but normally we do get a few storms in June/July it is possible that quite severe thunderstorms are possible in my area I remember being woken up by a bad thunderstorm when I was a kid would have been in the late 1980s - with thunder directly overhead and lightning every few seconds or so - I was scared then but I like thunderstorms now and find then quite exciting what sort of synoptical setup could have produced a storm like that Spanish Plume type event it was in the early hours of the morning we also had a similar "night storm" last July I always find night storms the most spectacular what are the prospects for some good storms for the next few weeks or so I really need July to deliver storm wise for my area - also does anyone else remember any really severe thunderstorms that have stuck in thier minds? Also with it being really warm and humid with southely winds why isn't thier any thundery activity with this front we have passing over us at the moment why is it just plain old rain?

Luke

[Nick F]

Also with it being really warm and humid with southely winds why isn't thier any thundery activity with this front we have passing over us at the moment why is it just plain old rain?

Luke

The key to lack of thundery activity along the cold front lies to what's going on aloft, this evening/tonight the airmass is saturated and warm (relatively) all the way up to the tropopause over western areas above where the surface cold front lies. A warm and saturated profile in the troposphere tends to mean weak lapse rates and thus prohibitive for convection and thunderstorms.

As an example, the forecast skew-t for Cardiff, near the cold front, at midnight shows a saturated profile from the surface up to 200mb - saturated because the dew point line (left) is very close to the temperature line (right):

The very saturated airmass is, of course, contributing to heavy rainfall in the west tonight, especially with uplift over high ground and through dynamic uplift along frontal boundary.

[viking_smb]

The key to lack of thundery activity along the cold front lies to what's going on aloft, this evening/tonight the airmass is saturated and warm (relatively) all the way up to the tropopause over western areas where the cold front lies. A warm and saturated profile in the troposphere tends to mean weak lapse rates and thus prohibitive for convection and thunderstorms.

As an example, the forecast skew-t for Cardiff, near the cold front, at midnight shows a saturated profile from the surface up to 200mb - saturated because the dew point line (left) is very close to the temperature line (right):

thanks for mentioning cardiff....

I don't think we will have thunder,

[Lewis]

Cant take this any longer, 22c at 11pm :|

When the cold front passed here the other night i thought it was suppose to destabalize things and bring slightly fresher conditions, far from it infact.

I hate heat and long lasting dry spells when theres no end too it (gone with a bang type of thing).

Edited July 1, 2010 by North Sea Breeze

[Coast]

Now how long am I going to stay up on Beachy Head tonight watching the French having a light show?

[Harry]

Cant take this any longer, 22c at 11pm :|

When the cold front passed here the other night i thought it was suppose to destabalize things and bring slightly fresher conditions, far from it infact.

I hate heat and long lasting dry spells when theres no end too it (gone with a bang type of thing).

Ahh I love it!! Not great for sleeping granted, but its so nice to sit outside late evening/night and be warm...yesterday evening there was a fairly strong but very warm breeze...paradise!!

As for the Franco-Benelux - hogging all the glory yet again!!! Starting to really get on my tits, lol!

[Azores Hi]

Well, tonight I will be sitting on the beach at Hythe eating fish and chips as the sun goes down. Probably as good as anywhere for catching a distant flash of lightning??

Also as a bonus I will have the fishing rods in the car just in case the mackerel are in and the storms are not overhead!! :unsure:

[staplehurst]

Ah gotta love Mr Fish, even he seems to 'want' a thunderstorm, saying that although the computer model keeps them out to sea that may not be the case :unsure:

Edited July 2, 2010 by staplehurst

[Coast]

A new one for me, not sure of the significance (if any) at the moment:

RASP - Regional Atmospheric Soaring Predictions, one for the glider boys!

RASP bases on the fundamental concept of convective boundary layer (CBL). To interpret RASP maps and profiles, I can only invite you to read about this subject in the present web site (www.soaringmeteo.ch). In the same web site you can also find documents about general considerations of models as well as how to practically, easily and rapidly interpret RASP sounding and RASP charts. CBL predictions are particularly affected by grid resolution errors resulting from surface averaging effects (lack of resolved topography) and from the model's finite-difference equations lacking proper resolution of actual atmospheric differences and are often much less affected by other errors, so better model resolution is especially valuable for soaring predictions.

EDIT: Here we go - got an hour? www.drjack.info/BLIP/INFO

Ah gotta love Mr Fish, even he seems to 'want' a thunderstorm, saying that although the computer model keeps them out to sea that may not be the case

Thunderstorm ramper!!! :unsure:

[Stuart]

no thunderstorm ramp here

[Joey.G]

Well, tonight I will be sitting on the beach at Hythe eating fish and chips as the sun goes down. Probably as good as anywhere for catching a distant flash of lightning??

Also as a bonus I will have the fishing rods in the car just in case the mackerel are in and the storms are not overhead!!

Tonight ill be getting the ferry and staying in Calais for the first part of a week long break in France. Actually cant wait! So much CAPE progged there for tomorrow