6th Aug 2011 - Storm/convective Forecasts, Discussion And Reports

[Staffordshire]

Looks like some very heavy rain for Scotland and Northern England, and some showers spreading from west-east.

[P-M]

Looks like some very heavy rain for Scotland and Northern England, and some showers spreading from west-east.

And local weather forecast here saying thundery rain / thunderstorms

[Jane Louise]

And there's even more potential for others too. An exciting couple of days methinks.

I wont be around all weekend but if I get a storm I'm sure you'll hear from me :lol:

I've probably jinxed it now. lol

[Stuart]

Last Updated: 18:58 Friday, 5th August 2011

Valid: 00:00 Saturday, 6th August 2011 - 23:59 Saturday, 6th August 2011

Areas Affected:

MDT: S + E Ireland

SLGT: N + E England, Borders, Ireland, Northern Ireland, Wales, SW England, West Country

Synopsis:

A large, elongated, vertically-stacked and multi-centred upper low becomes established across the British Isles on Saturday. Convection will be widespread, with a few thunderstorms expected.

Discussion:

Beneath the upper low, lowering geopotential heights and a cold pool will overspread the country, with T500's as low as -25C, steepening lapse rates. Diurnal heating will aid convection development, with as much as ~600 J/kg CAPE available. Consequently, showers will become widespread across Ireland and western Britain, and with ELT's as low as -30C over Ireland, thunder and lightning is likely in quite a few showers.

DLS of up to 50kts is forecast over Wales and W England during the day, which is likely to help organise the convection. However, relatively weaker DLS (less than 20kts) is likely across Ireland, and this will slowly spread eastwards into Wales by evening. Meagre LLS will preclude a tornado risk. Given the cold mid levels, small hail is likely in some of the showers, particularly over Ireland. Concern exists that excessive cloud cover may inhibit convection, particularly over Ireland. Strong steering winds will mean any showers that do develop will move fairly quickly, but much lighter upper level winds over Ireland, particularly the W, will allow slow-moving showers and local thunderstorms to exist. Showers that do develop will continue well into the evening, becoming mostly confined to coastal parts where the risk of lightning continues to exist.

A developing trough feature is also forecast to move northwards across England, into southern Scotland during the forecast period. Whilst high precipitation totals are likely over the Borders/NE England, the lack of any other severe conditions prevent us from issuing a SVR threat level. There are indications that there may be an increase in convection along this feature during the afternoon and early evening, but ELT's of only -20C and excessive cloud cover, combined with lower surface temperatures, are likely to mean that lightning, if any, will be quite isolated in nature.

http://www.ukasf.co.uk/storm-forecasts/63

[Stuart]

Good luck Jane and the Rest

[Jane Louise]

Good luck Jane and the Rest

Thank you Stu, good luck to you and all.

[Stuart]

Thank you Stu, good luck to you and all.

Thank you Jane this my last time to get a storm here

[Staffordshire]

I'll look forward to seeing the forecast for Sunday

[Jane Louise]

Thank you Jane this my last time to get a storm here

Don't worry Stu, there still is hope after all when you move. :winky:

and that was only back in 2009.

[I Cumbria Marra I]

Anyone think West Cumbria will get out?

[Stuart]

Don't worry Stu, there still is hope after all when you move. :winky:

and that was only back in 2009.

hope so jane

here this year 1

Edited August 5, 2011 by Stuart

[Aaron]

Torrential rain for Northern England and Southern Scotland. Local weather here saying thunder is possible too.

[Harry]

Nice to see MetO Invent has fallen in line with NAE precip chart from earlier...risk of possibly heavy (borderline thundery?) precip clipping E Kent...could be our only potential for anything tomorrow other than scattered showery rain in the afternoon.

[paul m]

Torrential rain for Northern England and Southern Scotland. Local weather here saying thunder is possible too.

Thats what i like to hear

[Chris K]

Thunderstorm symbol back on the met office chart for Sunday in Bristol and the GFS charts look decent I know these will probably be pulse type rather than anything organised but really hoping to finally see something!

[Staffordshire]

Thunderstorm symbol back on the met office chart for Sunday in Bristol and the GFS charts look decent I know these will probably be pulse type rather than anything organised but really hoping to finally see something!

What pulse type mean?

[Chris K]

What pulse type mean?

I think it means sort of showers/single cells that are relatively short lived and move through quickly rather than when they merge into an MCS (mesoscale convective system) where it becomes more of a complex band of storms. Single cells usually last for up to an hour, whereas the more complex thunderstorm systems can last for up to several hours!

Edited August 5, 2011 by Bugganuts

[Jane Louise]

Thunderstorm symbol back on the met office chart for Sunday in Bristol and the GFS charts look decent I know these will probably be pulse type rather than anything organised but really hoping to finally see something!

Good luck Bugganuts, I did have a symbol for Sunday but it's now been replaced by heavy rain Oh well, I'm sure they'll change it back for me lol

What pulse type mean?

A pulse storm is a single cell thunderstorm that is usually not very strong; when it is of substantial intensity, it only produces severe weather for short periods of time. Such a storm weakens and then generates another short burst -- hence "pulse." Pulse storms ordinarily form in environments with low wind shear and moderate instability, with the low wind shear contributing a short average lifespan of less than an hour. Severe weather in a pulse storm will most often occur during a momentarily forceful updraft, taking the form of hail or particularly damaging winds brought about by downbursts. Rarely, a weak tornado develops in association with a pulse storm.

http://en.wikipedia.org/wiki/Pulse_storm

hope so jane

here this year 1

See, they do happen Stu. Who knows you may be moving to thunderstorm land after all lol. By the looks of things you may do better then where you live now.

[Chris K]

Good luck Bugganuts, I did have a symbol for Sunday but it's now been replaced by heavy rain Oh well, I'm sure they'll change it back for me lol

Cheers and you to But ye its changed a couple of times for me over the past day or two! A few hours ago it had the 'light shower' symbol over me but then it changed back to thunder... We will just have to see how things develop on the day

One thiing I did wonder, the fact its a lot cooler - will that hinder the potential convective activity a lot? (I know temps arent the only factor) but daytime surface heating does help development right? I'm no expert in these things

[Jane Louise]

Anyone think West Cumbria will get out?

You might get one. But most probably be heavy rain.

http://www.myweather2.com/City-Town/United-Kingdom/Cumbria/Newby-West.aspx

[Jane Louise]

Cheers and you to But ye its changed a couple of times for me over the past day or two! A few hours ago it had the 'light shower' symbol over me but then it changed back to thunder... We will just have to see how things develop on the day

One thiing I did wonder, the fact its a lot cooler - will that hinder the potential convective activity a lot? (I know temps arent the only factor) but daytime surface heating does help development right? I'm no expert in these things

Hmmm., correct me if I 'm wrong anyone! But I think cloud cover, lack of solar heating and a few other things are all signs that can prevent any convective activity. Cool air though, I am not sure of. I'm still learning too lol

If you haven't already seen it then here is an interesting article that Nick F wrote.

http://forum.netweather.tv/topic/29497-a-guide-to-uk-thunderstorm-setups/

[Jane Louise]

Estofex latest forecast.

SYNOPSIS

Upstream of a broad ridge over eastern Europe, a trough moves into western Europe. A trough/vorticity maximum initially located to the southwest of Ireland is expected across the southern North Sea on Sunday morning.

http://www.estofex.org/

[Staffordshire]

BBC don't seem to be making much of Sunday

[Mesoscale]

Oh look Scotland is going to be getting the storms again...

Good luck you guys!

[ZONE 51]

An interesting period coming up for the next few days with Thunderstorms for many areas at some point from North to South!

il leave the DATA for the early posters! so are be reading and wondering when and what where and if!

-

On a Serious note the very heavy rain saturday could cause big flooding problems and into sunday so this is a concern.

Edited August 6, 2011 by ElectricSnowStorm