16th Sept - 18th Sept 2011 Storm/convective Forecast Discussion And Reports

[Jane Louise]

Morning all,

A new thread here to discuss the potential of thunderstorms this weekend. A few storms around today and maybe tomorrow. Good luck all, hope you get one as for me I 'll still probably be in the NSC lol

[Stuart]

Good Morning all

Good luck jane

Last Updated: 22:59 Thursday, 15th September 2011

Valid: 00:00 Friday, 16th September 2011 - 23:59 Friday, 16th September 2011

Severe: Northern Ireland, N parts of the Republic of Ireland. Slight: the northern half of Ireland, N Wales, NW England, S Scotland.

Areas Affected:

Synopsis:Low pressure centred south of Iceland will extend an occluded front to the southeast, this will push across Ireland and into western Britain during the day. This will be followed by an upper trough that will help to trigger showers over Ireland and potentially NW Britain in the afternoon.

Discussion:An interesting set-up on Friday. An occluded front will produce some showery rain during the morning, but this should clear away to the east during the middle part of the day allowing for some sunshine into the afternoon.

A negatively tilted upper level trough with 500mb temperatures of around -23C will push into Ireland and western Britain during the afternoon, providing unstable air aloft. This will produce modest CAPE values 300-500j/kg during the afternoon, highest of which will be over N Ireland. ELTs will be -20C across the area, but as low as -35C over parts of N Ireland for a time during the afternoon.

Surface winds will be south to southwesterly for much of the day, but they will veer around to the west or northwest into parts of Ireland later in the afternoon. 0-6km shear values will be in the region of 30-40kts, this along with 0-1km shear values of 20-25kts will produce the potential for a few tornadoes into the afternoon coinciding with the largest amount of instability. Shear values also lend themselves to the potential of some large hail, with values in the region of 1.5-2cm.

It should be stressed that overall potential for this severe weather remains low. Instability is marginal, and large amounts of cloud may linger into the afternoon limiting surface insolation.

Showers are not likely to be severe outside of the the zone in northern parts of Eire

http://www.ukasf.co....m-forecasts/106

[Jane Louise]

Good Morning all

Good luck jane

Last Updated: 22:59 Thursday, 15th September 2011

Valid: 00:00 Friday, 16th September 2011 - 23:59 Friday, 16th September 2011

Severe: Northern Ireland, N parts of the Republic of Ireland. Slight: the northern half of Ireland, N Wales, NW England, S Scotland.

Areas Affected:

Synopsis:Low pressure centred south of Iceland will extend an occluded front to the southeast, this will push across Ireland and into western Britain during the day. This will be followed by an upper trough that will help to trigger showers over Ireland and potentially NW Britain in the afternoon.

Discussion:An interesting set-up on Friday. An occluded front will produce some showery rain during the morning, but this should clear away to the east during the middle part of the day allowing for some sunshine into the afternoon.

A negatively tilted upper level trough with 500mb temperatures of around -23C will push into Ireland and western Britain during the afternoon, providing unstable air aloft. This will produce modest CAPE values 300-500j/kg during the afternoon, highest of which will be over N Ireland. ELTs will be -20C across the area, but as low as -35C over parts of N Ireland for a time during the afternoon.

Surface winds will be south to southwesterly for much of the day, but they will veer around to the west or northwest into parts of Ireland later in the afternoon. 0-6km shear values will be in the region of 30-40kts, this along with 0-1km shear values of 20-25kts will produce the potential for a few tornadoes into the afternoon coinciding with the largest amount of instability. Shear values also lend themselves to the potential of some large hail, with values in the region of 1.5-2cm.

It should be stressed that overall potential for this severe weather remains low. Instability is marginal, and large amounts of cloud may linger into the afternoon limiting surface insolation.

Showers are not likely to be severe outside of the the zone in northern parts of Eire

http://www.ukasf.co....m-forecasts/106

Morning Stu, Good luck to you too It'll be your first storm in Inverness if one occurs . Wheelie bins are being moved around here today grrrr, so I must not try and mistake it for thunder lol. I think you and anyone else much further North have more of a chance then us down South.

[Stuart]

Morning Stu, Good luck to you too It'll be your first storm in Inverness if one occurs . Wheelie bins are being moved around here today grrrr, so I must not try and mistake it for thunder lol. I think you and anyone else much further North have more of a chance then us down South.

no if we get 1 at the weekend that be 3

[Nick F]

A few sferics showing across the Midlands earlier this morning, seems some sharp thundery showers have broken out drifting NNE associated with an upper disturbance in the moist southerly flow.

[Craigers]

i can confirm that the showers were very convective on way to work. Set off from home and no rain, got down the street and it was torrential!

[knightrider]

Cloudy and overcast start here 1st thing this morning but now the sun has come out, bright and breezy. The wind has picked up noticably in the last hour and now is gusting 15-20mph temperature around 15C, I'm not expecting much in the way of showers of thunderstorms today but we are forecast some heavy downpours tommorow!

[staplehurst]

Thunder heard in Norwich with 2 CGs to my S about 10-15mins ago, nothing since

[knightrider]

Thunder heard in Norwich with 2 CGs to my S about 10-15mins ago, nothing since

There are some dark looking clouds in the distance I wonder if 1 will venture our way, would luv some thunder it's been awhile since we had some!

[Nick F]

Netweather storm forecast for today: http://www.netweather.tv/index.cgi?action=convective;sess=

... some elevated storms earlier across Midlands and E Anglia ... then for rest of the day an isolated risk of thunder embedded along band of heavy rain moving NE across the north and west later, but I think main action from now on will be overnight across the far west as the unstable rPm flow moves in.

Saturday and Sunday should see plenty of heavy showers and thunderstorms across the UK as low beocmes anchored over northern Britain.

[staplehurst]

More thunder heard from Norwich from the cell to the SW

[Stuart]

Thanks Nick for that update

[Raidan]

Hope to see something over the weekend,Constant radar & sky watching me thinks,accept when the footy is on of course.

[SNOW_JOKE]

Met Office has the occluded front stalling mid-wales between now and Midnight, with a nice trough pattern moving across central parts of the country into tomorrow afternoon & midnight hours. Going to be a photogenic weekend convective wise, with the airmass around aswell. The Camera is already on charge.

[knightrider]

Mostly sunny here with hazy cloud cover, quite breezy temperature now up to 17C.

[Matty M]

A tornado has been reported in Co. Louth this morning around 1145am.

It occurred as the front just moved into the Irish sea.

Radar imagery supports the report.

Can any experts give this further attention?

Many thanks.

http://www.boards.ie/vbulletin/showthread.php?t=2056391286

[Buzzard]

Dry and sunny here in NW1 - although classic castellaneus? (probably spelt wrong) drifted over this morning. This is supposed to be the 'sign of a summer thunderstorm' if I remember rightly.

Presume it meant a little bit of disturbance in the upper atmosphere.....

[TonyH]

Torrential shower recently here in Cardiff now warm sunny.

[Andy Bown]

Torrential shower recently here in Cardiff now warm sunny.

That was at the southern tip of a line stretching SSE from the main rain band, there's a similar line maybe 75 miles West with some

heavy cells within it.

[Liam J]

You would think the sun has set here it's so dark! Hoping for some activity later....

[Eskimo]

Any news on what the outlook is for tonight/early hours into tomorrow afternoon?

[Herefordweather]

Looks pretty stormy here. Winds picked up, clouds rolling in.

Little bit of rain in the air but I presume the worst is expected to move NE and avoid us here?

[Andy Bown]

So there I was 5 minutes ago reading my book and a sudden loud noise starts outside - a downpour!

Quickly checked the sky all around and it's gone very black, logged on and radar at 15.45 shows quite quickly developing

showers around this area (BA12) but no heavy cells, awaiting the next few 5 minute updates with interest.

[Jane Louise]

Gone rather dark here, starting to rain, looks like there's going to be a downpour.

[Lancashire Lass]

Torrential rain currently. 36mm/hr.