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uk.sci.weather (UK Weather) (uk.sci.weather) For the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged. |
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#1
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I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog?
http://wp.me/p2VSmb-2no |
#2
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On 02/10/2017 20:51, Scott W wrote:
I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no second attempt on e-s A repeat for the Midlands and East Anglia tonight? GFS has the 1mB/hour drop character in place of cyclogenic upper air coupling. I'm surprised no heads-up on this board so far |
#3
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On Wednesday, 4 October 2017 08:37:25 UTC+1, N_Cook wrote:
On 02/10/2017 20:51, Scott W wrote: I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no second attempt on e-s A repeat for the Midlands and East Anglia tonight? GFS has the 1mB/hour drop character in place of cyclogenic upper air coupling. I'm surprised no heads-up on this board so far The 1 hPa per hour drop is just the threshold for explosive cyclogenisis. It doesn't tell you much about likely strength of wind. Looking at the 1987 storm, the pressure gradient between 51N and 54N on the meridian at 0600UTC was 24 hPa. Tne same measurement at midnight tonight (when the low is in a similar position to 1987) is 16 hPa. So a repeat is unlikely with tonight's storm. Remember also that a pressure gradient doesn't instantaneously give you the wind strength indicated - it takes a finite amount of time for the force exerted by the pressure gradient to accelerate the air to the indicated velocity. The 1987 storm centre had been at 959 hPa for approximately 10 hours before 0600 UTC. Even 6 hours before 0000 UTC, tonight's storm was 4-5 hPa shallower. I think impacts in the Netherlands and Belgium will comfortably exceed anything we experience in the UK tonight. The low tonight isn't anything like 1987 IMHO. -- Freddie Fishpool Farm Hyssington Powys 296m AMSL http://www.fishpoolfarmweather.co.uk/ https://twitter.com/FishpoolFarmWx for hourly reports |
#4
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On 04/10/2017 13:02, Freddie wrote:
On Wednesday, 4 October 2017 08:37:25 UTC+1, N_Cook wrote: On 02/10/2017 20:51, Scott W wrote: I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no second attempt on e-s A repeat for the Midlands and East Anglia tonight? GFS has the 1mB/hour drop character in place of cyclogenic upper air coupling. I'm surprised no heads-up on this board so far The 1 hPa per hour drop is just the threshold for explosive cyclogenisis. It doesn't tell you much about likely strength of wind. Looking at the 1987 storm, the pressure gradient between 51N and 54N on the meridian at 0600UTC was 24 hPa. Tne same measurement at midnight tonight (when the low is in a similar position to 1987) is 16 hPa. So a repeat is unlikely with tonight's storm. Remember also that a pressure gradient doesn't instantaneously give you the wind strength indicated - it takes a finite amount of time for the force exerted by the pressure gradient to accelerate the air to the indicated velocity. The 1987 storm centre had been at 959 hPa for approximately 10 hours before 0600 UTC. Even 6 hours before 0000 UTC, tonight's storm was 4-5 hPa shallower. I think impacts in the Netherlands and Belgium will comfortably exceed anything we experience in the UK tonight. The low tonight isn't anything like 1987 IMHO. Is your historic data , hindsight data from after the event or the data ,as it was, 1 day before the '87 great felling? ie like for like |
#5
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On Wednesday, 4 October 2017 14:06:57 UTC+1, N_Cook wrote:
On 04/10/2017 13:02, Freddie wrote: On Wednesday, 4 October 2017 08:37:25 UTC+1, N_Cook wrote: On 02/10/2017 20:51, Scott W wrote: I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no second attempt on e-s A repeat for the Midlands and East Anglia tonight? GFS has the 1mB/hour drop character in place of cyclogenic upper air coupling. I'm surprised no heads-up on this board so far The 1 hPa per hour drop is just the threshold for explosive cyclogenisis. It doesn't tell you much about likely strength of wind. Looking at the 1987 storm, the pressure gradient between 51N and 54N on the meridian at 0600UTC was 24 hPa. Tne same measurement at midnight tonight (when the low is in a similar position to 1987) is 16 hPa. So a repeat is unlikely with tonight's storm. Remember also that a pressure gradient doesn't instantaneously give you the wind strength indicated - it takes a finite amount of time for the force exerted by the pressure gradient to accelerate the air to the indicated velocity. The 1987 storm centre had been at 959 hPa for approximately 10 hours before 0600 UTC. Even 6 hours before 0000 UTC, tonight's storm was 4-5 hPa shallower. I think impacts in the Netherlands and Belgium will comfortably exceed anything we experience in the UK tonight. The low tonight isn't anything like 1987 IMHO. Is your historic data , hindsight data from after the event or the data ,as it was, 1 day before the '87 great felling? ie like for like It is analysed actual data from the time of the event. It isn't forecast data. Even if it was, it wouldn't be "like for like" as models and their methods of assimilating observational data have changed massively since 1987. -- Freddie Fishpool Farm Hyssington Powys 296m AMSL http://www.fishpoolfarmweather.co.uk/ https://twitter.com/FishpoolFarmWx for hourly reports |
#6
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On 04/10/2017 14:12, Freddie wrote:
On Wednesday, 4 October 2017 14:06:57 UTC+1, N_Cook wrote: On 04/10/2017 13:02, Freddie wrote: On Wednesday, 4 October 2017 08:37:25 UTC+1, N_Cook wrote: On 02/10/2017 20:51, Scott W wrote: I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no second attempt on e-s A repeat for the Midlands and East Anglia tonight? GFS has the 1mB/hour drop character in place of cyclogenic upper air coupling. I'm surprised no heads-up on this board so far The 1 hPa per hour drop is just the threshold for explosive cyclogenisis. It doesn't tell you much about likely strength of wind. Looking at the 1987 storm, the pressure gradient between 51N and 54N on the meridian at 0600UTC was 24 hPa. Tne same measurement at midnight tonight (when the low is in a similar position to 1987) is 16 hPa. So a repeat is unlikely with tonight's storm. Remember also that a pressure gradient doesn't instantaneously give you the wind strength indicated - it takes a finite amount of time for the force exerted by the pressure gradient to accelerate the air to the indicated velocity. The 1987 storm centre had been at 959 hPa for approximately 10 hours before 0600 UTC. Even 6 hours before 0000 UTC, tonight's storm was 4-5 hPa shallower. I think impacts in the Netherlands and Belgium will comfortably exceed anything we experience in the UK tonight. The low tonight isn't anything like 1987 IMHO. Is your historic data , hindsight data from after the event or the data ,as it was, 1 day before the '87 great felling? ie like for like It is analysed actual data from the time of the event. It isn't forecast data. Even if it was, it wouldn't be "like for like" as models and their methods of assimilating observational data have changed massively since 1987. From what I remember of the storm, there was no awareness by anyone ,prior to the 87 storm, about its upcoming severity, during the day before. Is there an analysis somewhere , of the data available at the time,to see if there was any pointers at all, prior to the event. Had French metmen got a better handle on it , the day before , for instance. |
#7
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Freddie writes:
On Wednesday, 4 October 2017 08:37:25 UTC+1, N_Cook wrote: On 02/10/2017 20:51, Scott W wrote: I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no second attempt on e-s A repeat for the Midlands and East Anglia tonight? GFS has the 1mB/hour drop character in place of cyclogenic upper air coupling. I'm surprised no heads-up on this board so far The 1 hPa per hour drop is just the threshold for explosive cyclogenisis. It doesn't tell you much about likely strength of wind. Looking at the 1987 storm, the pressure gradient between 51N and 54N on the meridian at 0600UTC was 24 hPa. Tne same measurement at midnight tonight (when the low is in a similar position to 1987) is 16 hPa. So a repeat is unlikely with tonight's storm. Remember also that a pressure gradient doesn't instantaneously give you the wind strength indicated - it takes a finite amount of time for the force I hope you will forgive my pointing out a linguistic detail here. You mean 'non-zero' not 'finite'. Zero time /is/ a finite time but you want to exclude that. (Mathematicians might argue that non-zero is not precise enough because it include negative numbers, but when the context is informal and the quantity something like time, that would be pointlessly pedantic.) exerted by the pressure gradient to accelerate the air to the indicated velocity. The wrong phrasing is very tempting in this sort of context because you are thinking of a division -- it's the acceleration that must be finite and that requires a change of velocity over a non-zero period of time. The 1987 storm centre had been at 959 hPa for approximately 10 hours before 0600 UTC. Even 6 hours before 0000 UTC, tonight's storm was 4-5 hPa shallower. I think impacts in the Netherlands and Belgium will comfortably exceed anything we experience in the UK tonight. The low tonight isn't anything like 1987 IMHO. BTW, I like and appreciate this sort of posting. That I don't contribute anything but nit-picking like the above is just due to my not knowing enough meteorology. It does not mean I don't like reading about it! -- Ben. |
#8
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My daughter was born on the night of the 16 th Oct 1987 at St James hospital Leeds, it was a very windy night but not exceptional in Leeds, but I did listen to all the news reports coming in . I mentioned Michael Fish in my father of the bride speech on 10 th September 2017, By chance at the Grande hotel Brighton . Along the coast where some of the highest gusts were measured.
The wedding was exciting also as we had to evacuate the hotel due to a bomb threat, and continue next door in the Hilton. Didn’t help that the TUC conference was on next door. Happy days. |
#9
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On 02/10/2017 20:51, Scott W wrote:
I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no I've just seen what GEM met model is predicting for 15-16 Oct 2017. Same track of the low across Biscay. All too far off and a definite outlier of the main 5 global met models though. |
#10
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On 07/10/2017 08:48, N_Cook wrote:
On 02/10/2017 20:51, Scott W wrote: I've written a few lines on October 1987. Similar to my account of the January 1987 cold spell would anyone be interested in adding their account of that night to this blog? http://wp.me/p2VSmb-2no I've just seen what GEM met model is predicting for 15-16 Oct 2017. Same track of the low across Biscay. All too far off and a definite outlier of the main 5 global met models though. I've only just seen the latest NHC Atlantic TD output (Nate + another) http://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2 , explains the otherwise "errant" GEM manifestation of a compact mid-atlantic low on the UK scene for 15-16 oct |
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