Convective Outlook

[Nick F]

Sorry if I am being dippy, but how does an ANA CF differ from a regular CF? I notice on Ian's post it states 'rear sloping'...does this mean effectively, that where normally a WF is rear sloping ( like a '/') the CF takes on this form?

There are 2 types of cold front: 'ana' and 'kata'

Here's a good explanation of the differences of the two:

http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Cf/backgr.htm

In the case of an Ana Cold Front, the jet axis and dry intrusion are parallel to the frontal cloud band, and form a well pronounced rear cloud edge.

[dogs32]

There are 2 types of cold front: 'ana' and 'kata'

Here's a good explanation of the differences of the two:

http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Cf/backgr.htm

Nick or Paul

plz correct me if I am wrong but Im sure I read a ANA Cf is more likely to produce Tornadic cells than a Kata..

Again if I am correct there have been many tornado outbreak's in the States

associated with the ANA type front than Kata..

if I remember correctly????

Edit

JUST GOOGLED

found this quote

However, kata cold fronts are more common than ana cold fronts, ... 5b) is quite a rare occurrence (with, fortunately, few tornadoes in evidence

so there is more possabilties for tongiht folks

Edited November 24, 2009 by dogs32

[Cookie]

have just caught up with this very intresting indeed

[hobbielancie]

Probably stay up for this one as Norfolk does not have many of these events. Will check the Radar as it gets closer to here.

[risk of sleet]

That was fairly wild for a time. Seems quite calm all of a sudden. Lid blew off the compost heap - nothing that can't be fixed.

[Lewis]

Sorry guys, been a lil busy.

can anyone confirm if this "squal line" will hit me

thanks

[West Sussex Kate]

very calm here too after a very windy day!!

Bring on the *squal line*

[Ian Fergusson]

Nifty line convection elements now very conspicuous into parts of Wales (e.g. nr Carmarthen) approaching Bristol Channel on local radar. Looks potentially wild around those as they come through.

[Interitus]

That was fairly wild for a time. Seems quite calm all of a sudden. Lid blew off the compost heap - nothing that can't be fixed.

This concurs with the data from a number of sites in southwest Wales. It passed through the Milford Haven area at around 8pm and marked a change to calmer conditions after winds had been strong for a few hours, rather than a strong peak.

[TonyH]

Line has arrived with 10 minutes very heavy rain so far, but less windy here too, with a veer to the west from SSW earlier.

Edited November 24, 2009 by Tonyh

[johnholmes]

Sorry if I am being dippy, but how does an ANA CF differ from a regular CF? I notice on Ian's post it states 'rear sloping'...does this mean effectively, that where normally a WF is rear sloping ( like a '/') the CF takes on this form?

this link may help understand slopes of warm and cold fronts

http://forum.netweather.tv/topic/13372-frontal-depressions-by-john-holmes/

as to Ana and Kata cold fronts

remember Ana=rising air

Kata=falling air

put very simply

rising air gives clouds and precip so more active

Kata=falling air so less activity

[Ian Fergusson]

I've just pasted a frame (21Z) from MetO 1km rainfall radar showing the developing linear elements across Wales on my blog, for those interested - - see

http://www.bbc.co.uk/ianfergusson

[Interitus]

I've just pasted a frame (21Z) from MetO 1km rainfall radar showing the developing linear elements across Wales on my blog, for those interested - - see

http://www.bbc.co.uk/ianfergusson

Interesting blog, thanks.

[sammie]

I've just pasted a frame (21Z) from MetO 1km rainfall radar showing the developing linear elements across Wales on my blog, for those interested - - see

http://www.bbc.co.uk/ianfergusson

Is it wrong I just thought "what a pretty radar frame!"

Its getting hard to pick out the squall line on the free metoffice radar now. Thinking its about time I got a subscription to the netweather radar

[TonyH]

Not up to much here...3mm rain in 10 minutes, moderate breeze behind it. Nothing special before it either.

[dogs32]

nice blog Ian.

wind realy picked here with strong gusts at time's with light rain in the air.

Hope my fence can handle the stronger wind's later.

Edited November 24, 2009 by dogs32

[SmartD]

Evenin' All,

can I put in plea for AWS users to switch to high frequency logging as per my post here-

and am also interested in hearing damage reports (in the appropriate thread.)

BTW I should have written 'confluent trough' and 'appended' !

I'm interested in collecting AWS/damage records in support of very-high resolution modelling of this type of front. Further details see here-

http://www.abuhrc.org/newsmedia/Pages/news_view.aspx?news=29

Thanks,

David Smart

'waghorn'

[Harry]

Wind really picking up here - even though the 'event' is some hours away, the wind already is something. Very gusty and making the trees do hula dances, lol.

The squall is pretty distinct on the NW radar (quite impressive actually), whereas the MetO radar is clumping it all together, rather misleadingly.

[West Sussex Kate]

Great blog Ian...thanks for the update!

[chapmanslade]

Amazing squall line!

Interesting breaks in the line forming like waves which are LEWP as far as I understand separated by small mesocyclones along the squall line ??

[Cookie]

I've just pasted a frame (21Z) from MetO 1km rainfall radar showing the developing linear elements across Wales on my blog, for those interested - - see

http://www.bbc.co.uk/ianfergusson

very good blog thanks for shareing

[A.J]

Can't wait for the squall to hit, winds are already gusting impressively here into the mid-high 40s. Add another 20mph on that, plus some heavy rainfall and I'm happy! Just love hearing the roar of the wind through the trees!

I've just got in from work, and Its made for difficult driving conditions, especially on the elevated section of the M5 between J2 & J1....Here in Penkridge, its blowing a hooly, with quite a pronounced squall line showing up on radar about 40 miles to my west

[PeterDoswell]

it is actually becoming quite scary in southampton . weather sounding like something very nasty is brewing

[dave48]

Looks like a really interesting night, the mention of a possible tornado outbreak in the net weather severe forecast is possibly the first one I have ever seen. Looks like I will get my share of the squall line in about an hour ish.

[West Sussex Kate]

batten down the hatches !!