Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Stormy Wednesday 15th August 2012


AWD

Recommended Posts

Posted
  • Location: South Gloucestershire BS35
  • Weather Preferences: Severe weather enthusiast
  • Location: South Gloucestershire BS35

can someone explain to me why the Met office don't seem onboard for Thunderstorms to develop? Ukasf, Met monkey, Net weather tease.gif all seem convinced storms will break out.

To be honest, most of the forecasts I've read state there is a fair amount of uncertainty with the developing situation. All talk of potential but also possible inhibiting factors that could reduce the risk of severe convective weather occurring, apart from very heavy rainfall. So in that sense, I get the impression they aren't as convinced of thunderstorms breaking out as some people are interpreting.

As Robbie said, bit odd the Met Office only have yellow warnings for some western regions, whereas others are stating some severe potential over a wider area across England.

It could be a case of them sitting on the fence until its more certain in the morning as the fronts approach our shores, then updating if necessary. We will see soon enough...

Edited by Chris K
Link to comment
Share on other sites

Posted
  • Location: London, UK
  • Weather Preferences: MCC/MCS Thunderstorms
  • Location: London, UK

To be honest, most of the forecasts I've read state there is a fair amount of uncertainty with the developing situation. All talk of potential but also possible inhibiting factors that could reduce the risk of severe convective weather occurring, apart from very heavy rainfall. So in that sense, I get the impression they aren't as convinced as some people are interpreting.

As Robbie said, bit odd the Met Office only have yellow warnings for some western regions, whereas others are stating some severe potential over a wider area across England.

It could be a case of them sitting on the fence until its more certain in the morning, as it approaches our shores, then updating if necessary. We will see soon enough...

Probably an MCS if anything, I think the cold front is just a pure cold front...

18-779.GIF?14-18

Cloud Cover may be the inhibiting factor. The uncertainty, may be what goes ahead and behind the front.

21-779.GIF?14-18

Cape and MUCape doesn't look all that on the Hi-Resolution neither. If that said 1000 j/kg of CAPE and -10LI then I'd issue that sort of warning.

18-505.GIF?14-18

18-109.GIF?14-18

Humidity higher than temperature as well tomorrow.

18-103.GIF?14-18

18-102.GIF?14-18

21-102.GIF?14-18

Definitely a lot of rain tomorrow.

Link to comment
Share on other sites

Posted
  • Location: South Gloucestershire BS35
  • Weather Preferences: Severe weather enthusiast
  • Location: South Gloucestershire BS35

Probably an MCS if anything, I think the cold front is just a pure cold front...

Cloud Cover may be the inhibiting factor. The uncertainty, may be what goes ahead and behind the front.

Cape and MUCape doesn't look all that on the Hi-Resolution neither. If that said 1000 j/kg of CAPE and -10LI then I'd issue that sort of warning.

Humidity higher than temperature as well tomorrow.

Definitely a lot of rain tomorrow.

Cheers Robbie for that info. Yep definitely going to be a wet day, although for me its forecast to clear off by 1500hrs. A brighter but windier evening to come after that. It will be interesting to find out what happens tomorrow anyway, although i'm stuck doing presentations at work most of the day so won't really see whats going on.

Edited by Chris K
Link to comment
Share on other sites

Posted
  • Location: London, UK
  • Weather Preferences: MCC/MCS Thunderstorms
  • Location: London, UK

Cheers Robbie for that info. Yep definitely going to be a wet day, although for me its forecast to clear off by 1500hrs. A brighter but windier evening to come after that. It will be interesting to find out what happens tomorrow anyway, although i'm stuck doing presentations at work most of the day so won't really see whats going on.

No worries, the internet is an amazing resource. Ahah, try working in Regent Street - I am surrounded by buildings and customers, so wont' get regular peeps of the sky. Was quite amazing though during the Womans Olympic Marathon last weekend, with storms that I got that rolled through West End.

I shall keep my eyes and ears pealed tomorrow.

Link to comment
Share on other sites

Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

Valid: 15/08/2012 06:00 - 16/08/2012 06:00

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

post-1052-0-45170700-1344986425_thumb.jp

Synopsis

An upper level trough to the W of Spain and Bay of Biscay will deepen over the next 12hrs and become negatively-tilted. A strong 150mph + jet stream rounding the base of this trough will allow a depression to rapidly deepen in its left exit and move N close to the SW of Ireland in next 12hrs. Associated warm sector and cold front will move NE ahead of this low across England and Wales on Weds, bringing heavy rain and embedded convection with a risk of storms (perhaps severe) in places.

... E WALES, MIDLANDS, C S ENGLAND, SE ENGLAND, E ENGLAND ...

Advection N and NW out of France of rather warm and moist plume (WBPTs of 16-18C) and cooling at mid-levels with approach of upper trough from the SW will create reasonably steep lapse rates England and Wales on Weds.

If there is sufficient cloud breaks to allow insolation, surface heating could generate 300-700 j/kg CAPE in the warm sector moving NE across central, S and E England late morning into afternoon. Large scale ascent of warm moist plume as heights/pressure falls from the SW and forced ascent along cold front moving NE may allow thunderstorms to develop. Strong mid-level jet and 0-6km shear in the order of 30-50 knts would allow storm that develop to organise into multicell line segments that could merge upscale into a MCS, with a risk of strong convective wind gusts, hail and torrential rain leading to flash flooding.

If sufficient cloud breaks occur in the warm sector, more discrete storms may develop away from the main mass of rain and embedded convection ... and with the stronger instability combined with strong wind shear and mid-level dry slot over-running the warm sector ... these storms could develop into supercells with a risk of damaging wind gusts, flash flooding and large hail (up to 6cm). A few tornadoes are also possible given low LCLs, rich low-level moisture and winds backing ESE'erly ahead of cold front moving in from the SW.

Given uncertainty over extent and severity of any storms developing (which maybe limited by extensive frontal cloud and rainfall) will only issue a SLIGHT risk for now, though may upgrade to MODERATE should conditions transpire favourably.

... SW WALES, SW ENGLAND and S IRELAND...

Cooler rPm airmass moving over increasingly warm late summer SSTs in the SW, will follow cold front which clears much of the UK by late evening, so a few storms may affect some SW'ern coastal areas in the evening and into the night as a result. Strong vorticity around deep depression near Ireland will also drive convection/storms here.

Issued by: Nick F - Forecaster for Netweather

Also can be found here: http://www.netweathe...onvective;sess=

Link to comment
Share on other sites

Posted
  • Location: Longwell Green, near Bristol
  • Weather Preferences: Storms, Gales, frost, fog & snow
  • Location: Longwell Green, near Bristol

Oooooh, I'm in the severe! Don't think I have seen you do a severe this summer yet either Nick.

Don't know if this has been posted yet or not, but this is Met Monkey's view on things:

http://null.co.uk/

Wacky Wednesday – Heavy Rain, Gales and Severe Thunderstorms

post-12721-0-79559900-1344987155_thumb.p

Published on August 14, 2012 by Keithy Joe

Quite a wide risk of thunderstorms on Wednesday as a strong jet-streak overrides developing CAPE 200-700j/kg. Current thoughts are that the Midlands and parts of Northern England will be at risk of stronger storms, perhaps severe with very gusty winds and a tornado watch. Elsewhere, very heavy and locally torrential rain will develop and strong winds – locally damaging. Some of these will be thundery in nature too.

All eyes are focused on the Western Atlantic approaches right now as conditions look perfect for intense low pressure development. Colder and drier air is beginning to stream down from Iceland to the West of Ireland whilst very warm or even hot moist air gets drawn into the circulation from as far South as Southern Portugal.

In essence, we can expect fireworks! The presence of the low will be begin to exert its force during the early hours of Wednesday as heavy or even very heavy rainfall develops across much of Ireland and Western England and Wales. Winds will begin to increase through the day with gales around exposed coasts of Western Britain, these could gust to 50-60mph locally perhaps as high as 70mph across exposed Southern Ireland. Needless to say that the trees at this time of the year are still in full bloom and top heavy, a combination of heavy rainfall and gales will likely lead to some uprooting of trees and extremely dangerous driving conditions.

Our next attention turns to the South West of England and increasing concern and focus towards parts of West Wales, The Midlands, Lincolnshire and parts of Northern England including Yorkshire. A strong jet streak is forecast to over-run very warm and moist air flooding up from the South, combined with a forceful cold front acting as a strong lifting mechanism we are expecting a round of severe thunderstorms to develop.

The highest risk of severe thunderstorm development during Wednesday is most likely to be across the Midlands extending its finger into Lincolnshire, although more detail will be issued in tonight’s advanced convective warning. Due to high wind-shear, storms are likely to become locally severe with large hail, frequent lightning, locally damaging winds and the additional threat of a few tornadoes. The storm threat could well extend into parts of Yorkshire and North East England towards evening, perhaps becoming less surface based with a higher threat of excessive rainfall.

Edited by Active Weather Dude
Link to comment
Share on other sites

Posted
  • Location: Newton-le-Willows, Warrington, Merseyside
  • Location: Newton-le-Willows, Warrington, Merseyside

I seem to be just on the edge. Chances are we will just get very heavy rain, still very interesting 24-36 hours coming up! Could it make the headlines?

Edited by Darren Bown
Link to comment
Share on other sites

Posted
  • Location: Douglas, Isle of Man - 380ft/116m ASL
  • Weather Preferences: Warm summers, cold winters.. How it should be!
  • Location: Douglas, Isle of Man - 380ft/116m ASL

Here it comes! :D

post-16268-0-70704800-1344995451_thumb.p

Edited by Convective
Link to comment
Share on other sites

Posted
  • Location: Morley, Leeds West Yorkshire
  • Weather Preferences: Snow and thunderstorms
  • Location: Morley, Leeds West Yorkshire

BBC weather still going for heavy showers and strong winds. Nowt else though

Link to comment
Share on other sites

Posted
  • Location: HANDSWORTH BIRMINGHAM B21. 130MASL. 427FT.
  • Weather Preferences: WINTERS WITH HEAVY DISRUPTIVE SNOWFALL AVRAGE SPRING HOT SUMMERS.
  • Location: HANDSWORTH BIRMINGHAM B21. 130MASL. 427FT.

Morning guys this storm risk for later on today, the met office arnt going for t-storms for wm they got heavy rain and wind but no mension of thunder, so what makes nw and others so convince? Just thot i ask. Im sure the pros at the met would have some idea.

Link to comment
Share on other sites

Posted
  • Location: Whaley Bridge - Peak District
  • Location: Whaley Bridge - Peak District

Looking good on the RADAR, and to think in 2 hours time the sun will be rising once more raising CAPE ahead of this front across the Midlands & North. For storms we have to watch the frontal speed over the next 6 hours, for rain we have to watch where the pivot-point of the frontal intersections lie which going by current GFS is around North Wales.

Link to comment
Share on other sites

Posted
  • Location: Morley, Leeds West Yorkshire
  • Weather Preferences: Snow and thunderstorms
  • Location: Morley, Leeds West Yorkshire

Few stikes showing up in the south on Blitzortung and a lot creeping into France heading our way

Link to comment
Share on other sites

Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

The mass of rain is encroaching nicely for sure, however does anyone know where can I find real-time charts which indicate frontal positions etc. or should this be gleaned from satellite/radar images? Being as where the fronts are positioned and other factors are so important today, I would like to be able to track it if I can.

Anyway, here is the latest radar image, the heaviest rain currently over the Southwest (right above my mother and father's caravan) and Southwest Ireland. Sadly, no sferics as of yet but very very early days. good.gif

post-7183-0-59644100-1345008654_thumb.gipost-7183-0-04882800-1345008674_thumb.gi

Any help on my questions is greatly appreciated

Cheers

gottolovethisweather

EDIT: now a solitary sferic off Isles of Scilly

Edited by gottolovethisweather
Link to comment
Share on other sites

Posted
  • Location: Belper, Derbyshire
  • Weather Preferences: Thunderstorms
  • Location: Belper, Derbyshire

Look North weather forecasts just said heavy and thundery rain for later on this afternoon... so the word thunder is creeping in there :)

Link to comment
Share on other sites

Posted
  • Location: Morley, Leeds West Yorkshire
  • Weather Preferences: Snow and thunderstorms
  • Location: Morley, Leeds West Yorkshire

Look North weather forecasts just said heavy and thundery rain for later on this afternoon... so the word thunder is creeping in there smile.png

Yessssss

Link to comment
Share on other sites

Posted
  • Location: Abbeymead ,Glos Member Since: July 16, 2003
  • Weather Preferences: Hot and thundery or Cold and snowy.
  • Location: Abbeymead ,Glos Member Since: July 16, 2003

Getting windy here now.

The skies are very storm like today. Very humid and currently 18.9c

Link to comment
Share on other sites

Posted
  • Location: East Devon
  • Location: East Devon

All mid-level cloud (like those thundery elevated storm set ups) with some pretty thundery skies to the E,NE from those cells developing ahead of the main band a short while ago, wouldn't be surprised to see sefrics off them soon.

Some torrential rain quite widely in that band on radar though! breezy and very mild/warm last night (min 18.3c and rose to 19.9c at 5am) can tell it's a nice warm airmass.

Edited by Stormmad26
Link to comment
Share on other sites

Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

Would agree that thunderstorm potential seems good for Midlands and Yorkshire. The front may at first be a case of moderate to heavy rain with the odd rumble of thunder, but as it fragments somewhat mid-day it should then be able to sustain some thunderstorm development, possibly one or two severe cells with hail and gusty winds.

Link to comment
Share on other sites

Posted
  • Location: Abbeymead ,Glos Member Since: July 16, 2003
  • Weather Preferences: Hot and thundery or Cold and snowy.
  • Location: Abbeymead ,Glos Member Since: July 16, 2003

Sferics appearing far south inside the main bulk of the rainfall.

Fingers crossed it increases as it moves over land.

Link to comment
Share on other sites

Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset
help.gif advance guard as arrived over s/west ,a few cells popping up now over devon .dorset , main band expanding some good colours in there , i would say at present its game on let the battle commence . if you look on sat view you can see the eastern euro low and our new low very clearly now , it does look a bit odd for mid august . a bit of light ning showing up in channel , well today could bring all sorts and potential for rest of week ,wouldnt be surprised to see some storms pop up later after the main action drinks.gif
Link to comment
Share on other sites

Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

Sferics appearing far south inside the main bulk of the rainfall.

Fingers crossed it increases as it moves over land.

Pretty sure it will. Not wanting to scaremonger or overhype it but I feel this has some serious potential for fun and games in quite a few places. The timing and coming together of the factors as illustrated by the knowledgeable few on here being the key to anything severe developing. drinks.gif I can't say I know enough about that aspect but I'm sure a few folk will post charts to inform us all.

Chaotic looking skies out there along with high humidity and dewpoints, warm temperatures by early morning standards and a fair few sferics in the right areas already. Surely it has to go boom and for once for me, it should happen overhead.

Good luck all.

Edited by gottolovethisweather
Link to comment
Share on other sites

Posted
  • Location: Whitkirk, Leeds 86m asl
  • Weather Preferences: Anything but mild south-westeries in winter
  • Location: Whitkirk, Leeds 86m asl

I think there is definitely warmer air arriving.. the temperature has risen more than a degree in less than 30 minutes (depsite lots of high cloud) and my window has made thast strange sound when the wind is starting to get stronger..

Edited by Aaron
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...