Ideal Conditions for a Storm?

[storm12w]

What are the ideal conditions for a storm to develop in the UK?

I want to know:

- The ideal CAPE for a storm develop

- The ideal Dew point for a storm develop

- The ideal LI for a storm develop

- The ideal Humidty & Temp for a storm develop

Any help will be appreciated

[Coast]

What are the ideal conditions for a storm to develop in the UK?

Here's a great starting point for you: LINKY

[Nick F]

What are the ideal conditions for a storm to develop in the UK?

I want to know:

- The ideal CAPE for a storm develop

- The ideal Dew point for a storm develop

- The ideal LI for a storm develop

- The ideal Humidty & Temp for a storm develop

Any help will be appreciated

There are no hard and fast rules for the ideal parameters that you suggest for thunderstorms to develop. The ideal values of CAPE, LI, DPs, humidity and temp will vary greatly depending on time of year - and not all are needed together for storms to form. First and foremost, for storms to develop any time of year - lapse rates (drop of temp rising up through atmopshere) needs to be steep - ideally 850-500mb lapse rate of >25C.

In winter: you only need CAPE values as low as 100-150 for thunderstorms to form - provided there's sufficenct forcing - dew points tend to be lower and less relevant in winter as storms form mostly over the sea.

In summer, when most surface based storms develop overland, dew points/moisture content is fairly important as if air is too dry then storms are unlikely - there's no hard and fast rules - but I'd be looking at >14C DPs for thunderstorms if temps are greater than 20C. CAPE and LI is related to sfc moisture, temp and lapse rates - so in case of CAPE the higher the better or LI the lower the better - but there's no hard and fast rules. For severe t-storms with large hail you ideally need CAPE >1000 j/kg and strong vertical wind shear. In summer you often get elevated storms developing when elevated warm moist plumes destabilise when colder moves above it - SB/MLCAPE charts often do not pick out this level as they are derived from the boundary layer below - so CAPE charts are less relevant here - but wet-bulb potential charts (theta-w) for say 700 or 850mb can be useful in this instance for picking out areas where storms may form.

I have done a guide on storms here: http://www.netweather.tv/forum/index.php?s...t=0&start=0

[WhiteXmas]

What are the ideal conditions for a storm to develop in the UK? B)

I want to know:

- The ideal CAPE for a storm develop

- The ideal Dew point for a storm develop

- The ideal LI for a storm develop

- The ideal Humidty & Temp for a storm develop

Any help will be appreciated

It really depends on all of these factors together not just individually. ie: you could have the right dew point for a storm but the humidity may only be in the 20% region or less. However I do have some old sayings and beliefs on hand which I will share with you.

1. Red skies at night, sailors delight.

Red skies in morning , sailors take warning.

2. When the leaves of trees start turning over ---

it's going to rain.

3. A circle around the moon means rain is coming soon.

4. When the clouds look like a herd of sheep it's going to snow.

5. When you see birds flying close to the ground this usually means that rain will come soon. When seagulls fly to land, a storm is at hand.

Remember the following: Seagull, seagull sit on the sand It's never good weather while you're on land

6. If a cow moos three times in a row, rain will come soon.

7. Wide brown bands on a woolly bear caterpillar mean a mild winter.

8. When you see bees out flying, there will be good weather. But when they stay close to their beehive, a rainstorm is coming. Bees never swarm before a storm.

9. Keep an eye out for anthills. Ants always cover their entrance to their home when a storm is approaching.

10. Look out for clouds. The higher they are in the sky, the better the weather. The more types of clouds in the sky, the greater the chance of upcoming rain or snow.

11. When smoke floats towards the ground you can bet that a storm will soon come. Keep your eye out for toadstools and mushrooms. Usually when they spring overnight a storm is coming.

Obviously we don't know if these are generally true/correct. Although I do believe there to be definite substance in number 1 in particular.

Hope this helps in any way :lol: