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Storm and Convective Discussion 10th June Onwards


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What is going on tomorrow? I see the local forecast saying just a few showers, i look at the charts and there showing lots of cape and a convergence zone right over me. The met office precip looks quite good too. Sorry to be ignorant but is there something I'm missing?

We have high pressure over the uk , but some weak fronts slipping south east will add a llttle bit of moisture and instability to the atmosphere. East looks best for any storms. The cold front producing this change is weak in the west, somewhat stronger in the East , further away from the high pressure system... :closedeyes:

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Hi all,

 

Must say I was pleasantly surprised when I saw that I may have a chance of something thundery tomorrow, makes all the hot stickiness worth it. Been loving reading all about lightning in the above threads too. :good:

 

So eyes on the radar and up to the sky then tomorrow! :shok:

Edited by Dami
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Any chance of an estofex being issued tonight for tomorrow for the East Of England?

 

I would imagine that estofex would put the east of England into a 15% lightning risk zone and I think this would be about right. Euro 4 on board now too in breaking out showers during the evening across E England, spreading southwards into the night. Ironically, if they do happen and do turn thundery we could be in the unusual position of importing storms across the channel to France during the early hours of Saturday :)

 

I would not go higher than the 15% risk because of the isolated nature of any cells, reducing the risk of any one location getting lightning. No chance of severe weather due to the lack of directional or speed shear at any level on current charts. However, if the CAPE being shown is realised, and the cap is broken I would imagine lightning may well be prevalent for a brief time before cells kill themselves off (i.e. storm updrafts choked by the storm downdrafts). 

Edited by Supacell
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Yup, could get some moderate values, though not comparable to the storms earlier in the week though! I'm looking at UKPP, which is post processed data to match location better from UKV at this lead time.

No offence Mark but what, if anything does that mean in plain simple English ?

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I would imagine that estofex would put the east of England into a 15% lightning risk zone and I think this would be about right. Euro 4 on board now too in breaking out showers during the evening across E England, spreading southwards into the night. Ironically, if they do happen and do turn thundery we could be in the unusual position of importing storms across the channel to France during the early hours of Saturday :) I would not go higher than the 15% risk because of the isolated nature of any cells, reducing the risk of any one location getting lightning. No chance of severe weather due to the lack of directional or speed shear at any level on current charts. However, if the CAPE being shown is realised, and the cap is broken I would imagine lightning may well be prevalent for a brief time before cells kill themselves off (i.e. storm updrafts choked by the storm downdrafts).

Certainly a surprise this is! Some real beefy cape values and instability is being shown though. What a convergence setup it looks to be too! 7th August 2008 had a setup like this with a notable storm giving a late evening display over South lincs and into West Norfolk. Got the day off too before I depart for France Saturday :D
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No offence Mark but what, if anything does that mean in plain simple English ?

Apologies, UKPP = UK post processed, a suite we have here at the Met Office, which means our model output from the Unified Model has additional algorithms and corrections applied to the raw data to better fit reality. At the shortest lead times (the next 6 hours) Nowcast data will be blended, then UKV (which is the Met Office high resolution model for the UK, with a resolution of 1.5km), up to Euro4 for the longest lead time (the Met Office 4km gridded model covering the Europe domain). So what I was referring to earlier was post processed output from our highest resolution model, regarding the potential for isolated storms in the south east, and possibly more significant convective activity in Lincolnshire tomorrow evening.Post processed data at short lead times (close to a weather event) for site specific forecasting, are generally regarded as the most reasonable prediction of what will occur. Broadscale considerations are still taken into account though, as sometimes UKPP looks too much like reality as opposed to forecast!

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Apologies, UKPP = UK post processed, a suite we have here at the Met Office, which means our model output from the Unified Model has additional algorithms and corrections applied to the raw data to better fit reality. At the shortest lead times (the next 6 hours) Nowcast data will be blended, then UKV (which is the Met Office high resolution model for the UK, with a resolution of 1.5km), up to Euro4 for the longest lead time (the Met Office 4km gridded model covering the Europe domain). So what I was referring to earlier was post processed output from our highest resolution model, regarding the potential for isolated storms in the south east, and possibly more significant convective activity in Lincolnshire tomorrow evening.Post processed data at short lead times (close to a weather event) for site specific forecasting, are generally regarded as the most reasonable prediction of what will occur. Broadscale considerations are still taken into account though, as sometimes UKPP looks too much like reality as opposed to forecast!

Significant convective weather in Lincs??? You don't need a high res post processed model to tell you that nugget, CAPE over Lincs = thunderstorm, CAPE near Lincs = thunderstorm, no CAPE with an LI of +10, RH of 10% and a rising pressure reading of 1300 millibars = isolated thunderstorm...Lincs is like a lightning substation and would manage to conjure a supercell if experiencing Antarctic conditions !! :D Edited by Harry
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Significant convective weather in Lincs??? You don't need a high res post processed model to tell you that nugget, CAPE over Lincs = thunderstorm, CAPE near Lincs = thunderstorm, no CAPE with an LI of +10, RH of 10% and a rising pressure reading of 1300 millibars = isolated thunderstorm...Lincs is like a lightning substation and would manage to conjure a supercell if experiencing Antarctic conditions !! :D

 

:rofl: One day we will relinquish the crown honest  :angel:

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Local forecast going for Thunderstorms and Showers later beeb met office site saying dry and sunny. GFS seems to show good signs for us.

Edited by The PIT
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Local forecast going for Thunderstorms and Showers later beeb met office site saying dry and sunny. GFS seems to show good signs for us.

Yes Met Office not going for much. Any showers they do mention they play down as 'possibly on the heavy side'.

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This in my opinion is the area at highest risk of storms occurring between 6-9pm. I fear the action will be just to my west today although hoping im wrong.

 

post-1766-0-78671100-1402644832_thumb.jp

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Yes Met Office not going for much. Any showers they do mention they play down as 'possibly on the heavy side'.

 

Different for our region...odd shower but becoming more frequent and perhaps heavy and thundery after midnight....interesting!

Edited by Harry
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Still some moderate SB CAPE on offer according to the NMM-6, highest over more northern areas around lunchtime/early afternoon then higher amounts this afternoon/evening for more central and eastern areas.

 

post-9615-0-15571800-1402646536_thumb.pnpost-9615-0-26176600-1402646161_thumb.pnpost-9615-0-86838500-1402646167_thumb.pn

 

Lapse rates

 

post-9615-0-30969500-1402646245_thumb.pn

 

Low layer shear & deep layer shear - fairly low values. 

 

post-9615-0-53213300-1402646368_thumb.pnpost-9615-0-41558600-1402646372_thumb.pn

 

 

 

Edited by Liam J
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Done a quick risk map for today based on the NMM-6 00z output. Not expecting anything on a widespread scale but the risk is there nonetheless (don't get too excited), it'll be a case of radar watching as the day goes on. 

 

Yellow - Low risk

Orange - low/moderate risk

Red - moderate/high risk

 

post-9615-0-74668700-1402648938_thumb.jp

 

 

Edited by Liam J
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here's a few pics taken about 30 mins ago denoting the mid level instability already in place, with a mixture of Ac Cas with virga as well as Ac Floccus with virga...very nice!

 

post-4149-0-82415500-1402648108_thumb.jppost-4149-0-12801300-1402648126_thumb.jppost-4149-0-16224300-1402648144_thumb.jppost-4149-0-41090500-1402648159_thumb.jppost-4149-0-10491400-1402648178_thumb.jp

Edited by ajpoolshark
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 Early on today most of the Uk is under High Pressure and this will prevent any convective development.

Its not really till late afternoon and then into the eveing that widespread lift is available.

 

A small low pressure is expected to build just to the west of Ireland.

Satelite seems to confirm this.

 

This should increase mid level lapse rates across the UK as it develops.

 

Mid to late afternoon on shore wind breezes set up a convergence zone across eastern England and perhaps wales. This looks like the trigger for convection as moisture is pooled along this convergence area.

 

As the afternoon progresses it looks like the weak low towards Ireland begins to collapse just leaving a trough reminant which should cross the UK into the night.

This may pop up a few showers late into the evening, but they are at best weakly surface based. I am not quite sure about this in terms of storm potential.

 

Key risk I think for me is localized flooding as storms are likely to be slow moving and keep building into the evening.

 

Slight risk of a convergence zone very weak funnel, but upper and mid level winds look weak so supercell development looks unlikely (Perhaps a very slight chance south wales). Some wind divergence aloft (300hpa) should help tops to overshoot slightly during the late afternoon.

 

Key areas I think are the wash area, lincolnshire, humberside and north east yorkshire late afternoon.

 

 

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Been on holiday recently, so missed all the storm fun last w/e and Monday, but back with a storm forecast for today. After today, perhaps an isolated risk on Saturday, but quiet for a while thereafter as anticyclonic conditions set in truly. But lets hope it's not unlucky for some today!

 

Storm & Convective Forecast

Issued 2014-06-13 08:49:47

Valid: 13/06/2014 0900z to 14/06/2014 0900z

 

post-1052-0-73210200-1402650243_thumb.pn

  THERE IS A RISK OF THUNDERSTORMS FORECAST
Synopsis
An anticyclone covers western British Isles on Friday, with a frontal zone lying SE from Scotland to Nern Holland at noon, before drifting slowly S across northern and eastern England Friday PM/early Saturday AM.

... SE SCOTLAND, N and E ENGLAND ...

A warm and humid airmass will exist across England and SE Scotland this afternoon. Fairly strong instability is indicated to develop, as temperatures reach the mid-20s and cooler air arrives aloft from the N/NW in association with a weakening of heights from the NW. Sea breeze convergence zone is indicated to set-up inland across SE Scotland and E England, which could trigger isolated heavy showers or perhaps thunderstorms later this afternoon/early evening when peak heating occurs. But showers and some storms are looking likely to become more widespread later this evening and overnight across E/SE England, spreading south as cold front moving down from Scotland/N Sea begins to interact with warm/moist airmass in situ over recent days. Vertical shear will be rather weak, so no severe weather is anticipated. Storms may produce hail and localised flooding. Heavier showers and isolated storms should clear SE/CS England Saturday morning.
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Significant convective weather in Lincs??? You don't need a high res post processed model to tell you that nugget, CAPE over Lincs = thunderstorm, CAPE near Lincs = thunderstorm, no CAPE with an LI of +10, RH of 10% and a rising pressure reading of 1300 millibars = isolated thunderstorm...Lincs is like a lightning substation and would manage to conjure a supercell if experiencing Antarctic conditions !! :D

Lincolnshire has an invisible physical link with the near continent. The residents of Lincolnshire have known of this link for years but they don't want the rest of the UK knowing about it. This link is the reason why they get so many storms.
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