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Jane Louise

Uk Convective General Discussion & Forecasts, 3rd July 2012>

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Thursday and Friday are looking the best days for around these parts, thats not to rule out anything developing through the course of today, even though conditions aren't very favourable for anything to severe.

Temp 17.8c, Dew 15.7c, Humidity 95% - Heat index feels much warmer than it actually is given the DP & high humidity, sticky sad.png A few brighter intervals managing to poke through the cloud.

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Blimey, the NAE has some torrential rain moving into SE Thursday night and spreading across many central/S. Areas and probably eventually Wales/SW England.

12070606_0406.gif

The NMM is similar but further North

nmm-1-53-0_sdt1.png

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Blimey, the NAE has some torrential rain moving into SE Thursday night and spreading across many central/S. Areas and probably eventually Wales/SW England.

12070606_0406.gif

The NMM is similar but further North

nmm-1-53-0_sdt1.png

I thought it was moving North Westwards... Would explain the weather warnings by the metoffice for both Friday & Saturday for the highlighted areas?

gEAsTu.png

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Blimey, the NAE has some torrential rain moving into SE Thursday night and spreading across many central/S. Areas and probably eventually Wales/SW England.

12070606_0406.gif

The NMM is similar but further North

nmm-1-53-0_sdt1.png

WOW now that would be a severe event with flash flooding occuring if the PPN was near that intensity. Could these be imported thunderstorms off the continent? Not sure how the models cope with modelling that sort of event.

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I thought it was moving North Westwards... Would explain the weather warnings by the metoffice for both Friday & Saturday for the highlighted areas?

gEAsTu.png

That was it how it was but things have been revised South since yesterday it seems. Perhaps now more central/S areas at most at risk from that stalling front.

The GEM has a possible major flood event for SW Britain as an area of heavy rain becomes stalled, 24+ hours of heavy rain

gem-2-84_nkd2.png

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I thought it was moving North Westwards... Would explain the weather warnings by the metoffice for both Friday & Saturday for the highlighted areas?

gEAsTu.png

Yeah, local weather on the BBC said 'all eyes on Friday' for very heavy rain.

GFS and UKMO still show the heaviest rain to move NW

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That was it how it was but things have been revised South since yesterday it seems. Central/S Areas now at most at risk from that stalling front.

The GEM has a possible major flood event for SW Britain as an area of heavy rain becomes stalled, 24+ hours of heavy rain

gem-2-84_nkd2.png

I see, it's going to be a case of keeping an eye on the models, all different models have a different scenario. I don't want flooding, and neither does anyone else, but I fail to see very heavy rain bringing flooding here in Hull, and every time the metoffice do slap a yellow warning over me for heavy rain, it never happens.

Lewis

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Lol the way it's gone this year, would not be surprised to see the area of Heavy rain and storms move up from France, dry up completely over the South East and strengthen again across the SE Midlands into a huge MCS.

You would not put it out of the question this year rofl.gifblum.gif

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I remember a simpler time when a level1 from estofex pretty much meant thunder and was 99% certain.

Now its almost always wrong :)

Can only dream

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I see, it's going to be a case of keeping an eye on the models, all different models have a different scenario. I don't want flooding, and neither does anyone else, but I fail to see very heavy rain bringing flooding here in Hull, and every time the metoffice do slap a yellow warning over me for heavy rain, it never happens.

Lewis

These cut off lows are nightmares for trying to forecast where the rain falls, but unfortunately some will see some flooding I would think. The Met Office but warnings out 3-4 days in advance, they don't tend to do that unless they're concerned.

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So the gods are throwing everything at us this Summer and the 'will we won't we?' of thunderstorms is more difficult than ever and tainted with a very real possibility of heavy rain and maybe flooding. What a crazy country we live in!

Pushing GFS out as far as it will safely go currently, they see the rain as:

gfs_prec_eur72.png

I'm sure this is going to impact on already wet ground and also on sporting events that would normally be expected to be reasonably dry.

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Lol the way it's gone this year, would not be surprised to see the area of Heavy rain and storms move up from France, dry up completely over the South East and strengthen again across the SE Midlands into a huge MCS.

You would not put it out of the question this year rofl.gifblum.gif

You know it makes sense! laugh.png

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Valid: 04/07/2012 11:00 - 05/07/2012 06:00

Headline: ... THERE IS A RISK OF THUNDERSTORMS FORECAST...

post-1052-0-67796700-1341398174_thumb.jp

Synopsis

Upper low and collocated surface low drift slowly SE close to the SW of Ireland, while a cold front lying from IoM - west Wales - SW England at 10z pivots east on southern extent to lie IoM - Midlands - SE England by 00z Thurs.

... S SCOTLAND, ENGLAND AND WALES ...

Humid airmass advecting north across the UK ahead of cold front moving in from the west, with dew points 16-18C across England, will become increasingly unstable with surface heating - with 600-800 j/kg of CAPE indicated by GFS over a broad area with similar DPs. Destabilisation is likely by the afternoon, as patchy insolation takes place along with general height falls from the west to create ascent of warm/moist air. Scattered heavy showers and thunderstorms are likely to develop quite widely ahead of cold front with isolated embedded storms likely along front too. Vertical shear will be fairly weak, due to winds blowing from same direction at all heights of the troposphere, though fairly strong mid-upper winds will allow sufficient updrafts/downdraft seperation for some organised storm clusters. Saturated profiles up to 400-500mb with PWAT values of up to 34mm on morning soundings suggests excessive rainfall may pose a problem, along with gusty winds, though hail seems less likely.

... IRELAND ...

Moist rPm airmass will be unstable to surface heating, with scattered slow-moving heavy showers and thnnderstorms likely, capable of hail, torrential rain and gusty winds.

Also can be found here: http://www.netweather.tv/index.cgi?action=convective;sess=

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I remember a simpler time when a level1 from estofex pretty much meant thunder and was 99% certain.

Now its almost always wrong smile.png

Can only dream

If you read the Estofex output for today you'll see that the UK Level 1 is for excessive rainfall, so clearly they apply the warnings to more than just thundery activity.

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If you read the Estofex output for today you'll see that the UK Level 1 is for excessive rainfall, so clearly they apply the warnings to more than just thundery activity.

Well, kind of -- they are referring to excessive convective rainfall -- they don't/won't issue level X warnings for non-convective excessive rainfall (same for non-convective wind gusts, otherwise we'd be seeing level X warnings issued all the time in the UK for the sheer number of non-thunderstorm wind events we encounter annually).

This is all covered in their FAQs; for example:

Q: Why does ESTOFEX not forecast all severe wind gusts and all precipitation, convective or not?

A: It was chosen not do this, because of limitations of our available time, and our wish to focus on deep organized convection. [...]

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Some sferics across the north coast of France and a smattering of heavy showers across Eastern England.

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Can't see there been any thunder here today, the cloud cover is ridiculous haven't seen the sun all day!

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Some sferics across the north coast of France and a smattering of heavy showers across Eastern England.

Looking good mate, heavy shower just to my south but no thunder as of yet. Fingers crossed

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Some heavy downpours here as that cold front inches towards us.

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Some promising looking cumulonimbus around me at the moment. Looking like they are intensifying! Already had a heavy but thunderless shower :/ hope they get going more in the next 2-3 hours.

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Some sferics across the north coast of France and a smattering of heavy showers across Eastern England.

The French stuff looks like it's on its way into the North Sea unfortunately.

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