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22-12-2012, 12:37   #1
Storm 10
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Storm Saturday Night: Winds rapidly increasing with extreme gusts to 70kts+

Dont see anything on this so I will start the thread if its ok with the mods.

What are the conditions going to be like with this low pressure system

Last edited by Sleety_Rain; 22-12-2012 at 23:51.
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22-12-2012, 12:44   #2
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I posted this in the model thread last night. Might as well re-post it here. Probably won't be very significant but there is feck all else happening at the moment anyway.




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A level 1 was issued across Ireland mainly for severe straight-line wind gusts.

Around 00 UTC on Sunday, a rather vigorous vorticity maximum and an associated SFC cold front will cross Ireland and the westen UK. The cold front may be accompanied by a narrow and shallow line of strongly-forced convection, capable of mixing some 30 m/s winds (present at 850 hPa) to the ground. WRF supports this scenario by simulating a band of weak CAPE near the location of the cold front. Will place a LVL1 threat where forcing for upward motion will be the strongest (and presumably, convection the deepest), which should be the most likely location for effective vertical momentum transfer.
30 m/s = 108 km/hour

NAE shows 850 hPa winds up to 130 km/hour. Will be interesting to see if anything like that does get mixed down to the surface.



Met Eireann have issued an advisory.

Quote:

Issued at 21 December 2012 - 18:31

Weather Advisory

On Saturday night and Sunday morning, southwest to west winds are likely to increase in most parts of the country with mean speeds and gusts that have the potential to be damaging. Typical values may range 55 to 70 km/hr mean, 85 to 110 km/hr gust. Valid 22:00/22-12-2012 to 10:00/23-12-2012
Edit : Weather alert issued now :

Quote:
Issued at 22 December 2012 - 12:12
Weather Alert
West to southwest winds will become very strong and gusty tonight with damaging gusts possible in Co. Clare and in coastal counties of Connacht and Ulster, where mean wind speeds will reach 55 to 70 km/hr with gusts of 85 to 110 km/hr.

Over the rest of the country winds speeds will range from 45 to 60 km/hr with gusts of 65 to 80 km/hr, strongest in coastal areas

Valid time 2200z 22/12/2012 to 0600z 23/12/12

Last edited by maquiladora; 22-12-2012 at 12:47.
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22-12-2012, 16:42   #3
Oscar Bravo
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A downgrade on the 1602 update from Met Eireann -Outbreaks of rain will continue to be persistent at times this evening and tonight, before finally clearing later in the night. It will be windy overnight with lowest temperatures of 5 to 7 degrees.
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22-12-2012, 17:06   #4
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Originally Posted by Oscar Bravo View Post
A downgrade on the 1602 update from Met Eireann -Outbreaks of rain will continue to be persistent at times this evening and tonight, before finally clearing later in the night. It will be windy overnight with lowest temperatures of 5 to 7 degrees.
move along please. Nothing happening here. Very calm here. Another FALSE alarm. Just pure Atlantic muck here. Rain and very mild 13c
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22-12-2012, 17:58   #5
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Quote:
Originally Posted by snaps View Post
move along please. Nothing happening here. Very calm here. Another FALSE alarm. Just pure Atlantic muck here. Rain and very mild 13c
You're jumping the gun a bit there aren't you?

The alert is for 2200z 22/12/2012 to 0500Z 23/12/2012. Doesn't even start for another 4 hours.

In fact, the latest NAE is showing even stronger 850 hpa winds than earlier.




Thats showing 850 hpa winds close to 140 km/h at 3am Sunday. The Estofex warning is becaue they believe some of those winds could get mixed down to the surface in convective gusts.

Time will tell if the models and Estofex are right or wrong, and it may not end up being very significant, but it hasn't even happened yet.
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22-12-2012, 18:35   #6
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Where do you think the worst winds are likely to be.
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22-12-2012, 18:57   #7
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Quote:
Originally Posted by Storm 10 View Post
Where do you think the worst winds are likely to be.
Well it will be windy anyway on west and northwest coasts due to the tighter isobars from that low pressure system, but nothing very strong. The Estofex warning is for something else though, straight-line wind gusts from "a narrow and shallow line of strongly-forced convection" possibly bringing winds that would normally be high up, down to the surface. Between around midnight and 3am. If it does happen it could be in a fairly limited area and pass by very fast. The warning covers pretty much all of the island though.

I wouldn't expect anything too serious, but it will be interesting to see what happens anyway.
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22-12-2012, 19:45   #8
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I've heard of high winds occasionally coming down to the surface as mentioned above. In simple-speak (Secondary school geography, 30 years ago), what has to happen for this to occur? What happens to the winds/air that should be at the surface?
Thanks.
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22-12-2012, 20:14   #9
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Quote:
Originally Posted by greysides View Post
I've heard of high winds occasionally coming down to the surface as mentioned above. In simple-speak (Secondary school geography, 30 years ago), what has to happen for this to occur? What happens to the winds/air that should be at the surface?
Thanks.
Found this informative:
http://www.theweatherprediction.com/habyhints2/406/
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22-12-2012, 20:19   #10
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Thank you.
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22-12-2012, 22:30   #11
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Has gotten very windy here in Kerry, worse than i expected even though not extreme.
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22-12-2012, 22:37   #12
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Quote:
Originally Posted by downwiththatsor View Post
Has gotten very windy here in Kerry, worse than i expected even though not extreme.
Yeah should be getting quite windy around Kerry and Clare, peaking around midnight to 1am. You can see the tight spacing of the isobars around there.

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22-12-2012, 22:48   #13
 
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Met 3 hour. Moving in.



Valentia, Sherkin Is, Roches Pt, Mace and Knock all reporting gale gusts on 10pm reports. Hardly a breeze here.
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22-12-2012, 22:53   #14
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18Z NAE has 850 hpa winds at 3am up to 148km/h. If Estofex are right and some of those higher level winds do get mixed down to the surface overnight there will certainly be potential for some damaging gusts somewhere. Still remains to be seen if that will actually happen though.

Last edited by maquiladora; 22-12-2012 at 23:13.
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22-12-2012, 23:19   #15
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Wind is howling here ... very strong gusts
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