Uk General Convective Discussion & Forecasts, 10th October 2012>

[Nick F]

The NMM is painting a very colourful picture for halloween! Gusty winds and flash flooding if things develop as shown here when the cold font moves in and heads south and eastwards, an interesting weather day coming up!?

Yes, models suggesting quite an active cold front moving through tomorrow - perhaps a squall line developing on the rear as colder air undercuts - though GFS suggesting very little in the way of instability. However, the model doesn't always pick up instability in these situations - so could still be some shallow convection with low topped linear cells bringing some intense rainfall and strong wind gusts. Strong deep-layer and low-level shear along front - so *if* some instability can develop - there is potential for tornadoes - but big question mark over instability.

[gottolovethisweather]

The NMM is painting a very colourful picture for halloween! Gusty winds and flash flooding if things develop as shown here when the cold font moves in and heads south and eastwards, an interesting weather day coming up!?

Especially for your neck of the woods, you lucky bugger. Mind you, I can only hope that will retain its activeness as the squall comes my way, which I suppose it might.

Edited October 30, 2012 by gottolovethisweather

[Liam J]

I'd certainly back the NMM model predictions due to the much higher grid resolutions - Also wind shear and lapse rates are pretty high according to the NMM. Very interesting....

Meto have issued a very localised warning over Cumbria for strong winds and high rainfall totals - http://www.metoffice...0637F31480_1_NW

NAE rainfall totals

Edited October 30, 2012 by Liam J

[Nick F]

Especially for your neck of the woods, you lucky bugger. Mind you, I can only hope that will retain its activeness as the squall comes my way, which I suppose it might.

Makes pretty slow progress the front though, so it probably won't pass over the SE until early Thursday morning.

Plenty of heavy showers with hail and thunder look to pack in across western coastal areas and through the Channel following the front on Thursday.

[Coast]

HiRLAM coming into the timescale now and showing the possibilities up through The Channel on Thursday morning:

The rain now looking 'substantial'

Tornado chances more to the South of us on current predictions:

Plenty of gusty winds throughout Thursday and increasing into Friday:

Hang on to your hats!

[Liam J]

A pretty turbulent day coming up tomorrow it has to be said with the risk of some localised extreme conditions materialising. Gusty winds, hail, lightning, flash flooding and also the threat of tornadic activity can't be ruled out if we have some decent instability. NMM 12z highlighting the potential for a marked squall line along the cold front to develop as the colder air undercuts.

Vertical vorticity off the scale

PPN rate - very intense

Wind gusts, 12z upgrades the speeds slightly 40-50mph gusts over land

Deep layer shear - off the scale

The risk of severe weather then transfers eastwards across the UK, bare this potential in mind if you are out and about tomorrow!

Edited October 30, 2012 by Liam J

[Dorsetbred]

Look VERY interesting from those screen grabs. If I were a kid doing the trick or treat tomorrow night down here, I'd have one on on the nearest shelter

[Supacell]

Yes some interesting charts floating about, with the chance of a squall line affecting a good proportion of the country at some point in the next 36 hours. My area may get hit about this time tomorrow. Not sure about lightning chances here, with little instability being shown, but could be some wild conditions for a short while as it passes over. I will look at more charts in the morning and decide whether to dust the cobwebs off the camcorder for the evening

[Coast]

Just a general note for the next few days from me this morning. Looks like we have an extended period of potential for thunderstorms in the far South right the way through to Saturday according to GFS. Might be straining a bit as you look out to sea, but still worth keeping an eye on!

Edited October 31, 2012 by Coast

[fergieweather]

If interested, refer to my post in forecast model discussion re UKMO view re this evening's squally front/line convection/convective wind potential.

[Coast]

If interested, refer to my post in forecast model discussion re UKMO view re this evening's squally front/line convection/convective wind potential.

Yep saw that one Ian, a lot more technical and professionally presented, but glad it follows what I saw generally and the 'threat' is still for the South coast areas, as we have missed out quite a bit this year!

[Liam J]

Nasty drive to work this morning, the weather is certainly suitable for Halloween! Gusty winds and intense rainfall atm with surface flooding on main roads. Latest radar showing the front becoming more organised and meaning business. Winds gusting 40-60mph over Western areas.

Edited October 31, 2012 by Liam J

[Coast]

ESTOFEX have the beginning of things starting in the West for us:

SYNOPSIS

A complex synoptic scenario will unfold over Europe with several disturbances observed. Over western half of the continent a significant trough amplifying from the deep cyclonix vortex at 500 hPa towards southeast will affect British Isles and Western France till Thursday morning. Next, a short-wave trough moved off the Iberia and is beggining to affect Western Mediterranean. In the strong 500 hPa flow exeeding 20 m/s, the axis of the trough should be situated over the Adriatics by the end of the forecast period. Significant surface cyclogenesis is forecast at the forward flank of the trough. A ridge is forecast to start building over Eastern Europe, behind the retreating trough that will move towards northeast. This ridge is associated with a development of very large high pressure system centered over southern Russia. Between this feature and a large-scale low system over Western Europe a strong southerly low level flow will establish from the Central Mediterranean to Central Europe.

[legritter]

Regards todays front . just had a look on radar and sat ,going by latest movements the front looks like coming through slightly slower than what was forecast early this morning ,i might be wrong .already got some gusts here but nothing big yet also the odd very large spot of rain which isnt showing up on radar yet . not the sort of weather for pumpkins to be out and about ,they will need their umbrellas tonight . certainly an interesting day coming ,will todays action hit the headlines ,stay tuned .

[Coast]

Regards todays front . just had a look on radar and sat ,going by latest movements the front looks like coming through slightly slower than what was forecast early this morning

Latest from SatRep with positioning of the front by 18 UTC:

[andymusic]

some electrical activity in this squall line showing up over mid wales now

[legritter]

Just had a gust of 28 mph ,gone very dark towards w/ s west ,still probably a good hour or more before main rain band hits .not sure about any action here ,as quite often the case the worse either further north or south .just need to see a few more dark reds and blacks as it aproaches .looks impressive over wales and west bristol channel .just seen updated Met fax looks good for potential ,cheers

[andymusic]

rain has finally arrived here now and wind has picked up slightly

[mikeocarroll]

Just came through here, not particular violent as cold fronts go, 'squall line' much less defined than I expected. Max rain rate of 10.8mm/hr a few minutes ago, no particularly strong gusts. This is a pretty sheltered location though in the rain and wind shadow of the Cambrian mountains. Temp has dropped a couple of degrees.

[Staffordshire]

Its weakening alot now

[andymusic]

heavier rain now and squally winds

edit:- winds didn't last long and all of a sudden died leaving overcast, rain and quite chilly conditions

Edited October 31, 2012 by andymusic

[matty40s]

The squall line is building intensity now from the South coast up towards Nottingham.

I seem to be sheltered from the wind now it has shifted, but the rain is very heavy.

[gottolovethisweather]

The squall line is building intensity now from the South coast up towards Nottingham.

I seem to be sheltered from the wind now it has shifted, but the rain is very heavy.

Indeed it is.

I'm anticipating crossing over my location and about 2030GMT and should reach the London area from approximately 2130GMT onwards, maybe clearing the far East between 2300 and 2330GMT. Having said that, I think it is forecast to drag its feet somehat, even if it maintains its shape.

[Buzzard]

Seem to be in the area of decent rainfall here in Poole, straddling the front of the squall line.

[TropicThunder]

Just had an unexpected bright flash of lightning here, with torrential rain which knocked out the Sky signal.