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Roger J Smith

Bill's Evil Twin Arrives Thursday Night

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Well, if Bill was worth a thread, so is Bill's evil twin. This disturbance is rapidly developing in a much stronger jet stream than Bill had to work with, which is the main reason why it should produce stronger winds and more convective showers rather than the sort of drizzly muck that Bill had left over from the moderate rain it dumped across southern Ireland (some places there had 30-40 mms and wind gusts to (gasp) 45 mph).

Well, this new system is deepening and developing as it races across Ireland and southern Scotland late Thursday into Friday morning. A strong jet with tight contours and 120-kt winds aloft will allow this frontal wave to mix strong winds down to the surface more easily, and a low freezing level behind the cold fronts will allow hail to become a widespread risk. Cold air (12-14 C) rushing in behind the fronts and crossing the warmer waters of the Atlantic and Irish Sea will give some risk of local, probably weak, tornadoes in some of the showers developing.

Check the models and you'll see that a strong westerly gradient rapidly develops in Ireland on Thursday afternoon, and spreads to northern England overnight. This is reinforced on Friday early morning by a secondary trough that leads in the colder air at low levels. I expect the results to be fairly dramatic especially in western Ireland on Thursday afternoon, Northern Ireland on Thursday night, and a large part of the central UK including southern Scotland on Friday (from early morning in the northwest). Wind gusts to about 60 mph may develop, and higher on mountain summits, which would argue for caution in hiking or trekking in the relevant time frames. Strong convective showers may develop hail, small tornadoes locally, and thunder. The effects in southern England may be a little less extreme but there would still be a severe storm risk with any troughs that move across the south.

And it will be much cooler than people have become used to seeing this month, especially in the zone of the strongest winds. The air mass will try to drop temperatures to about 10-12 C, this may recover somewhat due to interaction with the warmer seas, but with a steep lapse rate, some higher locations may report mid-day temps on Friday not far from 10 C, and it would only be 3-6 C on some summits especially in Scotland and the Lake District.

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Dunno Rodger GFS has already started downgrading it so maybe another damp squib. Hopefully not need something interesting this week.

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Rainfall amounts won't generally be the big deal with this, 5-10 mms may be about the average, 15-20 mms tops, but it's the wind and convective shower potential that should make this a more interesting event.

Perhaps evil needs to be restyled as grumpy, or ill-tempered, not saying this will be a rampaging beast, but if Bill was a poodle, this is a German shepherd. The pit-bull could be Danny if he decides to be.

It is coming along on plan, not seeing much of a downgrade myself, ship reports from the developing wave and WNW flow behind it show 35-40 knot sustained winds, and remember this thing is nowhere near fully developed yet. Western Ireland should be seeing the rain by morning and the wind shift and possible squally showers by noon to 2 p.m.

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The evil twin is looking a bit less grumpy and possibly just mildly upset now.

I agree with you about Danny, though it has everything going for it, a more southerly track, better JS interaction, it's due to turn extra tropical sooner and the models and NHC are going for extra tropical strengthening, rather than Bill who had extra tropical weakening.

Still early days, but ECM shows a classic storm coming up from the SW with the possibility of some RI even.

post-6326-12513670884618_thumb.gif

post-6326-12513671084281_thumb.gif

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Further downgrade on the GFS 06 oz nothing but a leave twitcher I'm afraid now. Certainly can call it Bills twin. Both whimps.

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it used to give me a lot of comfort knowing that at least here in Scotland we could still rely on stormy weather strong howling winds below zero

nights and days. given our geographical location now we don't get anything like the storms we used to it seems to be more freak weather, flash

flooding. with the prospect of Bill's Twin not looking like its going to do much climate change comes more to mind.

another let down in prospect of a storm..

I apologize in advance if this was the wrong area of the forum but it was Bill's twin related.

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At least a nice change in airmass occuring overnight, the dominance of yucky mild TM winds has ruined my CET guess.

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Actually it has hit western and now northern Ireland with the expected force, winds gusted to 54 kts at Belmullet and 58 kts at Malin Head. Think you'll find that winds will pick up rapidly soon in southwest Scotland and overnight in northwest England, then fall off slightly, then pick up again in the morning with a secondary feature rotating around. I'm expecting this to be more of a wind and convective event than rainfall amounts as such.

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quite a strong blow from this feature....at 8pm close to me at st bees head the wind was sustained at 37mph gusting around 50mph+

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Northerly airflow ain't what I'm looking forward to, especialy in August (wind chill factor) as this feature moves into Cromarty Firth area tomorrow.

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Well nothing really to get excited about. Up too force 5 but nothing special. A leaf rustler but rustles them a little more than Bill.

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give it a few months then we will get these proper atlantic storms, not thses small fry.

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give it a few months then we will get these proper atlantic storms, not thses small fry.

Unless it's like last winter when we're depending on a few puffs of wind of a fast moving cold front.

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a lot windier this evening than anything from ex-Bill! :rolleyes:

Which says a lot about Bill.

I wonder what was the weakest ex Hurricane to reach the uk. Bill must be in the top ten.

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Can I ask, do you know the date of when an Atlantic LP system caused the Met Office to issue an 'Extreme' weather warning for the far North of Scotland? There were gusts of 90-100+mph in some areas. Down here in B'ham we reached gusts of 60mph and had some torrential rain, was certainly fun to watch. But I forgot the date. I think it was January of this year but I might be getting mixed up with other strong wind events.

Saturday 17th - Sunday 18th January 2009

"Severe gale or storm force winds are expected over the Hebrides and the western fringes of the mainland later today and tonight. Gusts of 90 to100mph are likely with some disruption to power supplies and transport and danger to life."

To my knowledge, so far the MetO have only issued 3 Extreme warnings since they implemented the system:

- 7th Aug 2008 for severe storms in Lincs & S Yorks (which died straight after the warning was issued!)

- 17/18th Jan 2009 for Extreme Gales

- 2nd Feb for very heavy snow along the Surrey Downs.

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Can I ask, do you know the date of when an Atlantic LP system caused the Met Office to issue an 'Extreme' weather warning for the far North of Scotland? There were gusts of 90-100+mph in some areas. Down here in B'ham we reached gusts of 60mph and had some torrential rain, was certainly fun to watch. But I forgot the date. I think it was January of this year but I might be getting mixed up with other strong wind events.

Jan 18th ??? 59 mph gust here. Now March 2008 was much tastier. 68 mph and 73 mph gusts.

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Wind certainly gusting here, and once again Humberside is the warmest of the country again! Not as humid though, netweather local stations say 18c my station is show 18.6c

Wind must be gusting 15-25mph here already!

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Thanks MW :) I remember looking at the pressure charts and then seeing Met Office issue a 'Extreme' weather warning and though, man, it's gonna be windy up there! :rolleyes: It was certainly windy in B'ham too but nothing compared to what they got up there!

For here the only date I can recall for deep atlantic Low is Jan 18th 07, an pfficial gust of 77mph was recorded in B'ham but the gust were much higher in the SE. I remember watching the news and seeing a cargo plane being buffeted sideways after taking off on the runway.

If my memory serves me right, that was a Thursday? I think there was a similar depression either the week before or the week after (again, on a Thursday). Am I right in thinking it caused powercuts in the East Midlands and havoc in Germany?

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Thanks MW :) I remember looking at the pressure charts and then seeing Met Office issue a 'Extreme' weather warning and thought, man, it's gonna be windy up there! :rolleyes: It was certainly windy in B'ham too but nothing compared to what they got up there!

For here the only date I can recall for a deep atlantic Low is Jan 18th 07, an official gust of 77mph was recorded in B'ham but the gust were much higher in the SE. I remember watching the news and seeing a cargo plane being buffeted sideways after taking off on the runway at B'ham airport . There has been much better deep LP systems in the past but I can't remember the dates.

If memory serves me right wasn't this a frontal squall. Certainly not a maintained gale as there wasn't any here last winter at all. TM agrees with me on this before you think I'm splitting hairs.

By the way all quiet here at the moment. Windows wide open curtains not moving.

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january 2005 was the worse storm to affect my area taking into account damage scale which saw whole oak trees blown down in town centres and chimneys and house roofs tore off,

official gust at st bees head was 104mph, i remember the met office issuing an emergency weather warning that afternoon. check the link its very interesting to read describing the storm development and official readings

http://www.wiseweather.co.uk/id84.html

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january 2005 was the worse storm to affect my area taking into account damage scale which saw whole oak trees blown down in town centres and chimneys and house roofs tore off,

official gust at st bees head was 104mph, i remember the met office issuing an emergency weather warning that afternoon. check the link its very interesting to read describing the storm development and official readings

http://www.wiseweather.co.uk/id84.html

jan 2005 was a good month. We recorded a gust of 83 mph that month. Mind you Feb wasn't bad either with another 83 mph recorded.

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Unless it's like last winter when we're depending on a few puffs of wind of a fast moving cold front.

you already know I was going say january 2009

Jan 18th ??? 59 mph gust here. Now March 2008 was much tastier. 68 mph and 73 mph gusts.

twice last winter winds between 95 mph and 100 mph recorded on lewis

january 2005 was the worse storm to affect my area taking into account damage scale which saw whole oak trees blown down in town centres and chimneys and house roofs tore off,

official gust at st bees head was 104mph, i remember the met office issuing an emergency weather warning that afternoon. check the link its very interesting to read describing the storm development and official readings

http://www.wiseweather.co.uk/id84.html

will never get sick of seeing this chart

bracka20050112.gif

off topic slightly can anyone tell me about NAO and weather it will be postive or negative this winter? or dose it change all the time?

a handy link for those who havent got it already

http://en.wikipedia.org/wiki/European_windstorm

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