Astronomy, Photography and Weather

General Category => Weather & Atmospherics => Topic started by: martinastro on August 13, 2008, 09:52:19 pm



Title: Thunderstorm & Funnel Outlook - Thurs August 14th
Post by: martinastro on August 13, 2008, 09:52:19 pm
A good forecast for us from Tony Gilbert...

(http://i38.tinypic.com/2nrd98h.jpg)

Slight Risk Gen Tstorms Eire, S. Wales & Southern UK regions 09Z-21Z Thurs 14th Aug o8

Occluded front initiates convective showers northern Eire early in period. Some of which could become thundery. A very moist profile and sustained surface convergence could trigger funnel cloud development. Southern Ireland initiates further convective showers later in the period.

Deep upper trough influences SW UK. Though it is noted that surface moisture is initially limited and could delay convection till later in the day. Exceptional lapse rate potential could well occur given enough solar heating. Some convergence at surface within a very slack regime looks conducive to more funnel activity. Even without strong convergence, the slow storm motion and almost variable winds at surface will create various boundaries and on to horizontal shear zones.

A good day to get out with the camera to see some spectacular anvils and hopefully the odd funnel cloud.

A very good day for storm Chasing IMO.



Title: Re: Thunderstorm & Funnel Outlook - Thurs August 14th
Post by: brianb on August 14, 2008, 08:26:12 am
Quote
A good day to get out with the camera to see some spectacular anvils and hopefully the odd funnel cloud.
Hmmm, I'm getting heartily sick of all forms of cloud, it would be nice to see a clear sky occasionally!

Anyhow, I don't know about convection, but it doesn't seem likely from here - the sky is overcast, at 7am I would have said it was thick altostratus but it's now quite definitely nimbostratus, there is steady light to moderate rain, the flat calm which we had yesterday persists and the light level is EV 11.6 (1/60  sec f/6.3 ISO 100)


Title: Re: Thunderstorm & Funnel Outlook - Thurs August 14th
Post by: martinastro on August 14, 2008, 11:02:43 am
The convection can only develop if the sky breaks and the Sun heats the ground up. Convective showers and thunder might develop if that happens. It's a hit and miss affair really. NE N. Ireland now has the best chance.

To tell you the truth, I'm loving every minute of it. Missing the Perseids was a kick in the teeth but we have been getting some serious weather action around here lately which has made up for it big time!.


Title: Re: Thunderstorm & Funnel Outlook - Thurs August 14th
Post by: martinastro on August 14, 2008, 01:10:22 pm
Update from Tony Gilbert.

(http://i37.tinypic.com/jkwpaa.jpg)

UPDATE 1pm

As per earlier post with moderate risk of funnel development as per red boxes on map. GFS pull convection back across N.Ireland once again and increase convergence with striking confluence vector. A very good funnel risk here IMO.

Convergence is now apparent and stronger than earlier predictions from a line Bristol Channel  through to Wash. Given the level of heating already attained along this line I have added a moderate risk here also.

Sharp isolated convection has already initiated across SW. No sferics as yet.