Stormy weather - Thursday 10th May

[Hodgheg]

Ohh dear have i missed something? just seen this thread. The forecast by the bbc has just rain followed by nothing tomorrow, are they missing something too?

[Norfolk Sheep]

I sincerely hope we get some thunder storms in Norwich soon. We missed out last week when Lowestoft area was being hit. I am becoming utterly despondent. But by all accounts......maybe tomorrow?

I'm up on thunder days compared with last year - I've heard 2 rumbles (yes, TWO!!) and on different days, how fab is that? As usual it's wait and see for us (but I have bought a new rain gauge so I apologise now if nothing materialises )

[Cakie]

Is it me or are southern areas not really going to get a soaking tonight, the radar looks pretty petty right now.

Not sure of your definition of a soaking but we have had a shed load of rain tonight. Thankfully our builder managed a temporary repair to the damage done the other week

[Eskimo]

Not sure of your definition of a soaking but we have had a shed load of rain tonight. Thankfully our builder managed a temporary repair to the damage done the other week

Looking at the models we were going to get rain from pretty much now until the early hours but it seems to me that it will all be over and done with very soon.

[multi cellular thunderstorm]

I was just wondering if anyone here watched natures fury last night, I'm about to watch it on record now! Was it a repeat of the old ones, and how great would it be if we had that here tommorow.... Well we all have dreams!

It is a repeat yes, but I watched it again for the 3rd time. I really like it.

Did you know our own Paul Sherman features in it, as well and some appearances from Nick F, Ian Cameron, Tom Lynch.

[multi cellular thunderstorm]

Forecast from UKASF...

Areas Affected:

SVR: Yorkshire, Lincolnshire

SLGT: Yorkshire, Midlands, N East Anglia

Synopsis:

Surface low migrates northeastwards through the Irish Sea, across Northern England and eventually the North Sea. Strong thermal contrast across this low, with jet streak aloft poses the chance for severe convection.

Discussion:Behind the warm front tonight, significant advection of high WBPT will occur over England and Wales. Several WRF models simulate 300-400J/kg MLCAPE over much of southern Britain behind the main frontal rain during the early hours. However, by this stage saturated vertical profiles and slight warming aloft is likely to lead to very little in the way of convection. Nevertheless, there is a low risk of perhaps an elevated thunderstorm developing in an environment with >35kts LLS and 60kts DLS. Confidence of this, though, is not high enough to expand the SLGT threat area to cater for this.

The main interest during this forecast period, however, is late morning through to the early evening across central and eastern England in particular. To the south of the occlusion, strong moisture convergence is forecast over parts of northern England where the thermal gradient is greatest. It is possible that a shortwave may run northeastwards around the southern/eastern flank of the low during the afternoon, initiating convection.

Most models agree on 18-19C, possibly 20C, sfc temperatures being possible, with dewpoints of 13-14C. This in turn will generate anywhere up to 700J/kg CAPE, and thus scattered thunderstorms may to form, with the greatest sferic activity likely in Yorkshire and Lincolnshire with the longest land track and greatest instability. Orographic forcing may play a role in convection initiation too from the Pennines northeastwards.

30kts LLS and 50-60kts DLS would allow convection to become well-organised and long-lived. Some directional shear, albeit weak, coupled with >150m^2s^-2 of helicity may allow a low-topped supercell to develop, capable of producing moderately-sized hail and a tornado. If surface winds ease slightly compared to model simulations, and a slight seabreeze develop locally, then sufficient backing to the low-level winds would greatly enhance the potential for supercellular characteristics to develop.

There is certainly potential for some severe convective weather, but it is very much dependent on the final position and track of the low, and any cloud debris left within the flow around the low. This will need careful monitoring throughout the day.

http://ukasf.co.uk/storm-forecasts/169 - (Click link for risk map)

That makes very pleasant reading

I have looked at the latest high resolution NMM model run and it fits with the risk area above...

Going by the above charts, I might be more tempted to head for the southern part of the risk area, due to slightly higher temps and lapse rates. Also that precipitation chart has me picturing an MCS cluster around Humberside/Yorkshire, with a lone supercell in Lincolnshire. That's probably just my optimism, but I am definitely leaning towards Lincolnshire rather than going further north.

I'll check things again in the morning, but I'm pretty sure I'll be out tomorrow heading east.

I'm seriously in need of a good storm, so it's time I went out to find them, they certainly aren't finding me!

Edited May 9, 2012 by multi cellular thunderstorm

[weatherobsuk]

OOOH just fringing to the west of the ukasf risk map, once again I have a feeling i'll be watching TCu after TCu firing up overhead before maturing across the central/eastern Pennines into Yorks/Lincs. Better get everything on charge just incase anyhow.

[Supacell]

BBC weather forecast now going with thunderstorms across the E Mids and Lincolnshire. Still no update from estofex but the ukasf update is making me feel just a little excited about todays prospects.

21c possible across Lincolnshire this afternoon - i think this has to be the primary target area for anyone chasing (me included).

[robt]

I've got a sneaking suspicion I'll be heading east later on today. Probably have the stuff thats building over Snow Joke going just to the south of me..

[Coast]

Is it me or are southern areas not really going to get a soaking tonight, the radar looks pretty petty right now.

Well a few hours later and I can tell you we've had 15mm overnight and most of that seems to be laying on the surface of the roads!

[Coast]

Still no update from estofex but the ukasf update is making me feel just a little excited about todays prospects.

There is now!

Storm Forecast

Valid: Thu 10 May 2012 06:00 to Fri 11 May 2012 06:00 UTC

Issued: Thu 10 May 2012 06:20

Forecaster: GATZEN

A level 1 was issued for northern and central France, Benelux, northern and central Germany, Denmark and the western Baltic Sea mainly for severe wind gusts, large hail and tornadoes.

SYNOPSIS

An Atlantic short-wave trough will move eastward during the period, reaching Ireland at Friday morning. A strong jet streak from the northern Bay of Biscay to the North Sea will expand into the Baltic Sea. To the south-east of this jet streak, an unstable air mass characterized by steep lapse rates is present from Iberia to central France and further into the Baltic States and south-east Europe. Best lapse rates have developed over Spain, but rather steep low-level lapse rates can also be found north of the Alps. The best low-level moisture is situated along a broad frontal boundary stretching from the Bay of Biscay over The Channel region into northern Germany. Rich boundary-layer moisture is also present over France and Germany, where 0-1 km mixing ratio exceeds 8 g/kg.

While the jet streak will only slowly progress eastward, strong quasi-geostrophic forcing is not expected over most places. Low-level convergence near the frontal boundary will be likely, though.

British Isles

Strong QG forcing can be expected at the cyclonically-sheared flank of the mid-level jet streak. The affected air mass indicates nearly moist-adiabatic lapse rates and may become unstable due to diurnal heating. Low-level moisture will further improve from the south-west during the day. CAPE may develop with the best potential across northern/eastern England in the noon and afternoon hours.

Given the strong forcing ahead of a convergence moving eastward during the day, showers and thunderstorms are forecast. These storms have a good potential to organize given the very strong vertical wind shear of 20 m/s in the lowest 3 km. Mesocyclones may develop that can produce tornadoes given strong low-level vertical wind shear of 15 m/s. Large hail and severe wind gusts may be possible as well. Limiting factor is the broad cloud coverage and associated weak low-level heating.

[Staffordshire]

Looks like showers starting to kick off in Wales... Let it begin!

[Coast]

21st OWS have the area of possibilities moving out of the UK during the morning?

But they have the lightning possibility running through the day and stronger in the middle of the country:

GFS based generally forecast has the action out to our East in Europe this morning:

But a chance later in the day in the 'target' area of the Midlands into Lincolnshire:

CAPE is minimal:

Shear is still OK:

That Eastern side into Lincolnshire does look like the place to be later this afternoon:

Little bit of helicity mixed in too:

[Aaron]

BBC weather forecast now going with thunderstorms across the E Mids and Lincolnshire. Still no update from estofex but the ukasf update is making me feel just a little excited about todays prospects.

21c possible across Lincolnshire this afternoon - i think this has to be the primary target area for anyone chasing (me included).

I think Yorkshire is in a prime location today - maybe you'll see something at home!

[Supacell]

I think Yorkshire is in a prime location today - maybe you'll see something at home!

I think the further east in Yorkshire the better so places like Leeds have a chance, but I doubt it for my location. There is a lot of thick cloud here and it feels cold. It may change later but looks more akin to a morning in November out there at the minute. If anything, this area will be the breeding ground as orographic lifting off the Pennines may help to build those shower clouds as they push east.

Of course this is dependent on the sun getting out here.

[Snowangel-MK]

Good luck to those of you chasing in the Yorkshire/Lincolnshire area today - it's a bit too far for me especially on a day I've got to be working late !

[robt]

I think the further east in Yorkshire the better so places like Leeds have a chance, but I doubt it for my location. There is a lot of thick cloud here and it feels cold. It may change later but looks more akin to a morning in November out there at the minute. If anything, this area will be the breeding ground as orographic lifting off the Pennines may help to build those shower clouds as they push east.

Of course this is dependent on the sun getting out here.

Its a bit muggy over here at the moment, with a few bits of blue sky showing through. I've got a feeling its going to be mid/late afternoon before we see anything.

[Lewis]

Could they be a water spout/tornado in the Humber again

[multi cellular thunderstorm]

Nice to see a few breaks in the cloud here and a bit of sunshine.

I'm still planning to go out this afternoon, possibly north Lincolnshire, but Nottingham is also fairly well placed so I'm worried that my chase might fail and I miss a storm in Nottingham.

I should be able to decide fairly late, if I head for north lincs then Nottingham might be the breeding ground, but with pretty fast storm motion, I probably can't watch a storm in Nottingham and then drive ahead of it again.

Anyway everything is charged and ready to go, good luck anyone chasing, and everyone else.

[Chris.R]

I know we're not likely to get anythimg here, but it's really humid and thundery feeling here. Almost feels like we're in a spannish ploom. Currently 16c as well.

[Lewis]

Sunshine trying to break through, It needs to come out fully for a good length of time, can tell thunderstorms are due! Was cutting the grass yesterday and said to the other half it's so muggy, wouldn't surprise me if were due some storms soon, ain't been online for a bit so have not looked at models, and bugger me Lincolnshire and Yorkshire are for once in the prime position for some serious electrical weather!

It would be nice to have a traditional slow moving storm, with thunder like bombs going off, and lightning strikes a dozen a minute

Something like this from 3 years ago at mine would do, quite amazed it's had over 3,000 views!

[Supacell]

Clouds not as dark but still overcast here, starting to feel a bit warmer now too. I will be heading east shortly and will then make my decision whether to target Humberside or Lincolnshire. A1 or A15 possibly a good road for heading north to south on this afternoon.

Not a good day for being behind a storm trying to chase and get ahead of it as the storm motion will be quite fast and on British roads on a weekday (specifically around rush hour) it will be a hard task. Believe me, I have lost out on a few storms because of traffic and it is very frustrating watching a developing storm skooting off into the distance whilst you sit in a traffic queue.

[Aaron]

Still cloudy here and cool at 9.3C but at least it is getting brighter. If the sun doesn't come out today then I suspect nothing will crop up here.

Edited May 10, 2012 by Aaron

[robt]

Clouds not as dark but still overcast here, starting to feel a bit warmer now too. I will be heading east shortly and will then make my decision whether to target Humberside or Lincolnshire. A1 or A15 possibly a good road for heading north to south on this afternoon.

I've got a hunch that North Lincolnshire is going to be the place this afternoon, heat is definitely building, and its muggy as well. I'm between the A1 and A15, so I'm in a pretty decent spot.

[sunny scunny]

It seems like scunny is one of the hot spots for later then lol. Quite a few breaks in the clouds at the moment and 17c.