General Storm Discussion Thread

[Coast]

A new thread for general conversation about convective storms. Remember for more 'in depth', technical analysis or information on convective activity, please use this thread: http://forum.netweather.tv/topic/63084-convective-potential-forecast-and-in-depth-discussion-june-27th-onwards/

[VillagePlank]

As we look like we heading into possible thunderstorms, I thought I'd show you my 'is all hell going to break loose?' index.

Here it is:

You can get the values from the skew-t charts. On the day look them up from Herstmonceaux or similar, and for forecasting you can use the free ones on this site. All you do is you read down the K index from the top row of numbers against the TT index from the left list of numbers, and you get the % chance of all hell breaking loose.

Sunday at midnight, for London, for instance has K of 34, and TT of 49. Therefore, the chances of all hell breaking loose are between 53% and 61%. I wouldn't charge my camera batteries, and put fuel in my car, for less than 70%.

Of course: this is no way replaces any of the guides, forecasts, and advice from people who really know what they're talking about on this website and others. I am not one of those people. It's just a bit of fun.

Edited July 10, 2010 by VillagePlank

[vortex_liam]

its really humid

[VillagePlank]

Yeah - it is, and humidity will increase as winds swing around to SW'lies (Tc to Tm?). I've decided to call my index Will All Hell Break Loose, or WAHBL, for short - pronounced as 'wobble'

Edited July 10, 2010 by VillagePlank

[tcc]

On the BBC website this morning it mentions the chance of Thundery showers for overnight, best chance for Sussex! Then more chances on Monday for the SE in general

[Stuart]

and for today

Storm Forecast Issued: 2010-07-09 22:59:00

Valid: 2010-07-10 00:00:00 - 2010-07-10 23:59:00

Regions Affected

SW Scotland, NW England, Northern Ireland and N + W Wales (W Midlands and remainder of Scotland and Wales are included in the WATCH)

Synopsis

A deepening area of Low pressure progresses slowly northeastwards across Ireland during Saturday, dominating the weather across the United Kingdom.

Increasing instability during the day may allow convection to occur along the cold front and close to the triple point of the associated weather fronts with this Low pressure system. Embedded thunderstorms seem likely to develop during the afternoon and evening hours, moving E/NE with the bands of rain.

Locally enhanced high rainfall totals are possible due to persistent, torrential downpours. There exists the chance of a weak-moderate tornado to develop across Ireland/Northern Ireland, especially close to the triple-point of the system. Hail to 1cm in diameter may accompany any intense local downpours. However, this scenario will depend quite heavily on the amount of insolation available.

Scattered thunderstorms are forecast to develop over the BeNeLux countries and Northern France during the late afternoon, becoming more widespread during the evening and merging into a large MCS, with hail possible to 4cm in diameter.

http://www.ukasf.co.uk/module-Storm/mode-forecast/id-307/

[dogs32]

Estofex have there warning out..but mainly for Euro with a level 2 for Holland,Belguim

[frostyjoe]

Omg 26c in norwich now!! Hopefully i get tons of storms today would love one really big shower to bucket down for hours!

[twister2005]

Good morning, its so hot here already 22.8c, is there the slightest risk of any thundery weather around here over the next few days ?

[Paul Sherman]

Interesting Update from the Meto for Tonight for the Southern Most of the Eastern Counties

Today:

Dry, largely sunny and hot, with only a little cloud at times. Highest temperatures will be across Norfolk. However eastern coast will be a little cooler than inland areas, as a southerly breeze develops. Maximum temperature 31 °C.

Tonight:

Dry, sunny and very warm this evening. Overnight there is an increasing chance of heavy, perhaps thundery, showers arriving. Essex, Suffolk and Norfolk are most likely to have showers. Minimum temperature 16 °C.

We shall see but not convinced at all by this, most of the fun should stay the other side of the Dover Straights

Paul S

Edit Also For The Far South East

Tonight:

Dry, sunny and very warm this evening. Overnight there is an increasing chance of heavy, perhaps thundery, showers arriving. Kent and East Sussex are most likely to have showers. Minimum temperature 15 °C.

[staplehurst]

Indeed Paul, several consecutive runs from the NAE model yesterday (12z and 18z at least) were showing scattered showers for Sunday morning, but today's 0z and 6z NAE runs have removed the risk and so it stays dry. I think it is now unlikely, and the MetO made that forecast based on yesterday evening's output.

[pottyprof]

The NMM has an area of reasonable CAPE+LI clipping the SE during the early hours tomorrow. There is a lack of precipitation though. If something could cross the channel then there could be a short lived light show. Case of wait and see.

[mac_]

Continuing chance of something for Ireland, latest from Met Eireann:

Today: Dry for a time this afternoon across the southeast, north and northwest. However rain will soon become widespread, turning heavy and persistent, with some spot flooding likely. Risk of thunder too. Very mild and humid, with highest temperatures 17 to 21 degrees. Winds will be mainly moderate variable, increasing fresh along eastern counties later.

Tonight: The heavy rain will persist into the early part of tonight, clearing northeastwards later, with the continued risk of spot flooding as well as thunder. Breezy, with lowest temperatures 9 to 12 degrees, and fresh and gusty northwest winds.

Edited July 10, 2010 by mac_

[frostyjoe]

Continuing chance of something for Ireland, latest from Met Eireann:

Today: Dry for a time this afternoon across the southeast, north and northwest. However rain will soon become widespread, turning heavy and persistent, with some spot flooding likely. Risk of thunder too. Very mild and humid, with highest temperatures 17 to 21 degrees. Winds will be mainly moderate variable, increasing fresh along eastern counties later.

Tonight: The heavy rain will persist into the early part of tonight, clearing northeastwards later, with the continued risk of spot flooding as well as thunder. Breezy, with lowest temperatures 9 to 12 degrees, and fresh and gusty northwest winds.

Why do they never mention us? The bbc clearly showed us having the worst rain with big green dots over us, anyhow i can't wait until it comes but it looks like its here earlier than forecasted!

[ZONE 51]

The NMM has an area of reasonable CAPE+LI clipping the SE during the early hours tomorrow. There is a lack of precipitation though. If something could cross the channel then there could be a short lived light show. Case of wait and see.

if there is a possibility of storms being imported across SE (overnight tonight)then could they be what is called (dry thunderstorms)and thats why NMM shows little ppn ? maybe some intense single cells, if one went through say gatwick/crawley i would have a distance light show

[Stuart]

Rain will often become heavy late this afternoon and through this evening across many areas, with further heavy falls of rain expected to continue through the night. Rainfall totals of 15mm within 3 hours can be expected and locally falls of around 30mm could accumulate in some areas by dawn on Sunday.

The public are advised to take extra care and refer to the latest Scottish Environment Protection Agency Live Flood Warning Information, and also to Traffic Scotland for further advice on road conditions.

Issued at: 1509 Sat 10 Jul

http://www.metoffice.gov.uk/weather/uk/dg/dg_forecast_warnings.html

[ZONE 51]

dry thunderstorms

if anyone wants to read up on what a dry thunderstorm is heres a good page..

it is raining in the storm but dont reach the surface.

[BornFromTheVoid]

Surprised that there has been no storms in Ireland so far today. Some very heavy rain about. Suppose there's still time

[ZONE 51]

ive circled an area i think gives some a risk of thunderstorms late eve/overnight for SE maybe other areas

[dogs32]

We always miss out

[Stuart]

yes we do but but next week not look to bad right now if things dont get move to the east:cray:

[dave48]

Nothing very interesting yet today, some quite strong echoes on the radar over Ireland though. I wonder if anything will be able to get a bit more organised for later into Northern England/Scotland.

[Supacell]

Any ideas if the convective forecast issued last night still stands? Was wondering if northern England is still in with a chance later?

[multi cellular thunderstorm]

I'm in Jarrow now and a shower went up right above here, and is now showing rain rates of around 70mm per hour on the Netweather radar as it pushes off the coast.

Also had this very interesting swirl below it and yes it was rotating just a little...

[vortex_liam]

Something is forming west of plymouth. Watchin it

It seems to be getting weeker it might still turn into a isolated weak thunderstorm