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Author Topic: Possible Convective Weather Tomorrow 21/07/2010  (Read 191 times)
Danny Power
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« on: July 20, 2010, 09:54:10 PM »

Regions:  Wales, N. Ireland, N & W Midlands and parts of NW England
Issued: 21.45 Tuesday 20th July, 2010.
Threat(s): Funnel clouds, Tornadoes, Moderate sized Hail.

*Any heavy rain and thunderstorms which persist through tonight will spread NE'wrd and out into the North Sea during the early hours. Then an area of low pressure sits across the United Kingdom, dominating the weather on Wednesday. Between 15z and 18z GFS suggests that temperatures will reach 19°C and dewpoints up to 15°C will be present.  With these values SBCAPE could reach 1000j/kg with MLCAPE around 500j/kg and LI down to -4. Thunderstorms are expected to develop as instability increases, aided by solar heating and a trough which crosses the region after midday, this along with deep layer shear of up to 40 knots, present throughout the region, means any storms which do develop could sustain themselves and become locally severe in nature. A convergence zone along with the decent CAPE values and low lying cloud present could mean a risk of gusty winds, moderate sized hail and perhaps the odd funnel/tornado could develop although they should be relatively weak in nature. Any storms which do develop should die off during the evening hours although there is still a risk of these continuing along coastal area.

Please correct me if I am wrong. I am still learning and want to know of my mistakes.

Thanks

Danny
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http://thenorthwestchaser.blogspot.com/

Spotter ID-LA001

To Date:-
Seen 2 Tornadoes
Caught by the RFD of a 3rd Tornado
Lost count on funnel clouds I have seen, estimated at 17
Kent Weather
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« Reply #1 on: July 20, 2010, 10:28:47 PM »

I'm no where near Godlike on meteorology but one thing id highlight.  Your focusing on tonights rain towards the NE England coastline.  The heavy rain over Wales could be seen as a 2nd area and to go by a nowcasting situation, 500hpa wind vectors are showing a southerly which wouldnt push the rain over wales out into the north sea but due north instead
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Danny Power
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« Reply #2 on: July 20, 2010, 10:48:36 PM »

You know what Shaun, I wasnt even thinking about the rain to my south, lol. Thanks for pointing it out to me. Vluable tip learned-"look more closely at the whole area/country before typing it up" lol

Cheers for the advice mate, its all needed and good to be told/warned
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http://thenorthwestchaser.blogspot.com/

Spotter ID-LA001

To Date:-
Seen 2 Tornadoes
Caught by the RFD of a 3rd Tornado
Lost count on funnel clouds I have seen, estimated at 17
Glyn Jones
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« Reply #3 on: July 21, 2010, 12:43:10 AM »

Great work Danny, only you've put the thread in "Current Severe Weather Alerts" rather than "Upcoming..."  Embarrassed
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Still just spotting, US chase made me poor so no car yet Sad
Danny Power
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« Reply #4 on: July 21, 2010, 07:11:33 AM »

Lol very good point Glyn haha, thanks mate.

Does my forecast sound about right then?
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http://thenorthwestchaser.blogspot.com/

Spotter ID-LA001

To Date:-
Seen 2 Tornadoes
Caught by the RFD of a 3rd Tornado
Lost count on funnel clouds I have seen, estimated at 17
Glyn Jones
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« Reply #5 on: July 21, 2010, 11:25:07 AM »

Sounds fine Danny, but you have to remember it's only as good as the data/charts its based upon (with a dash of gut instinct and hope, until years of experience calms us down later in life?). You've interpreted the GFS and kept the detail concise which is what is needed I suppose. However sometimes we need to pick out the governing factors in a type of situation (say plume versus triple point) as heat-induced convection is a different animal to shear forced convection, also by referencing other model output you can pick out the stronger chances of parameters occurring.

My only thought was about "a convergence zone", as in can you point out which areas this is happening? It's unlikely that a convergence zone would cover the entire UK.

A valiant effort, impressively presented too. I'd ask a proper forecasters opinion though! I only post in "Upcoming..." to encourage other people's opinions - the more the merrier!  Smiley
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Still just spotting, US chase made me poor so no car yet Sad
Danny Power
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« Reply #6 on: July 21, 2010, 02:06:43 PM »

Cheers for the feedback Glyn. Much appreciated. I will take on board the bits you pointed out and hopefully next time it will be better. I havent been doing this long so im quite suprised I did as well as I did lol. Its all thanks to Sean who has taken the time out to help me, still a few more lessons needed yet though.

As for the convergence zone, I saw to charts on the lightning wizard site one was for 10m wind convergence which was over N.Ireland around Lough Neagh which I should have pointed out like you say. The other was 0-2 km Deep Convergence which covered the rest of the forecasting regions.

As for for the plume etc I wouldnt know how to forcast that as I havent got that far in my learning lol.

Thanks again mate
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http://thenorthwestchaser.blogspot.com/

Spotter ID-LA001

To Date:-
Seen 2 Tornadoes
Caught by the RFD of a 3rd Tornado
Lost count on funnel clouds I have seen, estimated at 17
Benzo
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« Reply #7 on: July 21, 2010, 10:16:03 PM »

Well chaps, I'm utterly angry with the gods! A large storm cell developed behind me, passed by me and then decided to let it rip. Absolute sods law. Although I did get some lightning footage, which again I'm unable to post due to lack of a computer. Sorry guys
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Ben Deakin - SkyWarn UK - CH001
Danny Power
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« Reply #8 on: July 25, 2010, 12:54:53 AM »

Looks like this forecast turned out great with numerous funnels reported over N.Ireland, and SFerics showing plenty of activity across the forecast regions  Grin
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http://thenorthwestchaser.blogspot.com/

Spotter ID-LA001

To Date:-
Seen 2 Tornadoes
Caught by the RFD of a 3rd Tornado
Lost count on funnel clouds I have seen, estimated at 17
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