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View Poll Results: Rate
A 2 4.26%
B 11 23.40%
C 15 31.91%
D 11 23.40%
E 4 8.51%
F 4 8.51%
Voters: 47. You may not vote on this poll

 
 
Old 11-27-2014, 06:46 PM
 
Location: Top of the South, NZ
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Quote:
Originally Posted by B87 View Post
A Mediterranean rainfall pattern has the wettest winter month with 3x the driest summer month. Portsmouth misses out on being Mediterranean by 4mm.
Even if it did fit within the threshold, I'm not sure I would regard it as Mediterranean.

Med summers get high summer sunshine due to extended high pressure suppressing convection and frontal activity. Portsmouth gets comparatively cloudy summers, so that would suggest that the suppressive effect isn't happening to any great degree..

I'd say it's similar to many Oceanic climates, that see increased high pressure, but not enough to keep fronts away or suppress convection. My climate also sees a large decrease in the rainfall total from winter to summer, but has it's cloudiest month in summer -definitely not a Mediterranean trait.

Last edited by Joe90; 11-27-2014 at 06:59 PM..
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Old 11-28-2014, 10:45 AM
 
Location: Portsmouth, UK/Swanage, UK
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Quote:
Originally Posted by Joe90 View Post
Even if it did fit within the threshold, I'm not sure I would regard it as Mediterranean.

Med summers get high summer sunshine due to extended high pressure suppressing convection and frontal activity. Portsmouth gets comparatively cloudy summers, so that would suggest that the suppressive effect isn't happening to any great degree..

I'd say it's similar to many Oceanic climates, that see increased high pressure, but not enough to keep fronts away or suppress convection. My climate also sees a large decrease in the rainfall total from winter to summer, but has it's cloudiest month in summer -definitely not a Mediterranean trait.
I agree.
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Old 11-28-2014, 11:21 AM
 
Location: St Paul's Bay, Malta
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Quote:
Originally Posted by Joe90 View Post
Even if it did fit within the threshold, I'm not sure I would regard it as Mediterranean.

Med summers get high summer sunshine due to extended high pressure suppressing convection and frontal activity. Portsmouth gets comparatively cloudy summers, so that would suggest that the suppressive effect isn't happening to any great degree..

I'd say it's similar to many Oceanic climates, that see increased high pressure, but not enough to keep fronts away or suppress convection. My climate also sees a large decrease in the rainfall total from winter to summer, but has it's cloudiest month in summer -definitely not a Mediterranean trait.
Maybe not compared to proper Mediterranean climates, but compared to the rest of the UK Portsmouth does see more sunshine & less rainfall during the summer, especially from convection, more than even places a couple of miles inland... It will often be sunny right on the coast, but shower clouds just inland & the number of times my Mum used to phone me & say it was raining or cloudy where she was (8 miles inland) & it was clear blue sky & sunshine in Southsea, the same is true also for Hayling Island...

This can be seen in the Met Office maps as well, with more sunshine & less rainfall in a fairly narrow strip close to the coast...

Portsea Island (marked with an arrow) & the surrounding area can clearly be seen to have a rainfall anomoly, compared to much of the rest of southern England. Infact comparable to the far south east, which is the driest part of the UK


And the sunshine, which again is highest on the extreme coastal strip only & these maps are only comparing to the rest of southern England, not the rest of the UK, which would show even greater differences
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Old 11-28-2014, 12:07 PM
 
Location: Top of the South, NZ
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Quote:
Originally Posted by flamingGalah! View Post
Maybe not compared to proper Mediterranean climates, but compared to the rest of the UK Portsmouth does see more sunshine & less rainfall during the summer, especially from convection, more than even places a couple of miles inland... It will often be sunny right on the coast, but shower clouds just inland & the number of times my Mum used to phone me & say it was raining or cloudy where she was (8 miles inland) & it was clear blue sky & sunshine in Southsea, the same is true also for Hayling Island...

This can be seen in the Met Office maps as well, with more sunshine & less rainfall in a fairly narrow strip close to the coast...

Portsea Island (marked with an arrow) & the surrounding area can clearly be seen to have a rainfall anomoly, compared to much of the rest of southern England. Infact comparable to the far south east, which is the driest part of the UK


And the sunshine, which again is highest on the extreme coastal strip only & these maps are only comparing to the rest of southern England, not the rest of the UK, which would show even greater differences
Yep, I guess it's all relative. There's definitely a big shift to a Med type pattern in that area. Is it from high pressure dominating for extended periods, or just local geography giving Portsmouth a moderately sunny summer, in a region of cloudy-ish summers?

As climate is on a spectrum, climates in one group will steadily transition to other climates. I'm trying to figure out where Portsmouth is on that transition. It's summer influence could actually be more Med than Oceanic. I don't really know, because I don't have an understanding of the weather patterns during summer there.

There are some good TV programs showing UK coastal areas. Looks like a lot to see.
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Old 11-28-2014, 12:30 PM
 
Location: St Paul's Bay, Malta
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Quote:
Originally Posted by Joe90 View Post
Yep, I guess it's all relative. There's definitely a big shift to a Med type pattern in that area. Is it from high pressure dominating for extended periods, or just local geography giving Portsmouth a moderately sunny summer, in a region of cloudy-ish summers?

As climate is on a spectrum, climates in one group will steadily transition to other climates. I'm trying to figure out where Portsmouth is on that transition. It's summer influence could actually be more Med than Oceanic. I don't really know, because I don't have an understanding of the weather patterns during summer there.

There are some good TV programs showing UK coastal areas. Looks like a lot to see.
It can't be from high pressure sytems alone as that would make a much larger area drier & sunny, geography most probably plays a part as the south downs run just to the north of Portsmouth (infact the highest point, Butser Hill, is just north of Horndean, about 12 miles inland) & can be seen on both maps, (blue on rainfall & grey on sunshine). Just north of Portsea Island itself also lies Portsdown Hill & Portsea Island is completely flat, not to mention the protection from the Isle of Wight, so I'm sure all these geographical quirks help...

I also assumed it was due to the prevailing winds in the UK, which come from a SW'ly direction, so any convection formed clouds are pushed further inland, so the coastal strip stays dry. It can really be extreme in some summers with the grass in Portsmouth yellow but just a little inland it will be much greener...
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Old 11-28-2014, 12:42 PM
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Location: Western Massachusetts
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Portsmouth looks much cloudier than any usual Mediterranean climate in the winter, long lasting bouts of high pressure must be rather rare.
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Old 11-28-2014, 12:43 PM
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Location: Western Massachusetts
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New England tends to be sunniest along the coast as well. Not sure why.
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Old 11-28-2014, 01:00 PM
 
Location: Top of the South, NZ
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Quote:
Originally Posted by flamingGalah! View Post
It can't be from high pressure sytems alone as that would make a much larger area drier & sunny, geography most probably plays a part as the south downs run just to the north of Portsmouth (infact the highest point, Butser Hill, is just north of Horndean, about 12 miles inland) & can be seen on both maps, (blue on rainfall & grey on sunshine). Just north of Portsea Island itself also lies Portsdown Hill & Portsea Island is completely flat, not to mention the protection from the Isle of Wight, so I'm sure all these geographical quirks help...

I also assumed it was due to the prevailing winds in the UK, which come from a SW'ly direction, so any convection formed clouds are pushed further inland, so the coastal strip stays dry. It can really be extreme in some summers with the grass in Portsmouth yellow but just a little inland it will be much greener...

An interesting contrast to here, where coastal areas are greener and inland areas are drier looking. Nice photo. The wine palm doesn't have the blue tinge, even with the dry conditions.

We're getting our cloudiest weather now, as convection is at it's most active, so towering cumulus is an almost daily event, which often extends cloud cover out over the coast. January and feb are the sunniest months at about 62%, due to longer lasting high pressure reducing convection a bit. Fronts are less frequent, but the 5 days of rain a month, will still bring 80-100mm on average.

Did the warmest/sunniest areas of the south coast have a distinct vegetation type from other parts of Southern England?
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Old 11-29-2014, 10:40 AM
 
Location: St Paul's Bay, Malta
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Quote:
Originally Posted by Joe90 View Post
An interesting contrast to here, where coastal areas are greener and inland areas are drier looking. Nice photo. The wine palm doesn't have the blue tinge, even with the dry conditions.

We're getting our cloudiest weather now, as convection is at it's most active, so towering cumulus is an almost daily event, which often extends cloud cover out over the coast. January and feb are the sunniest months at about 62%, due to longer lasting high pressure reducing convection a bit. Fronts are less frequent, but the 5 days of rain a month, will still bring 80-100mm on average.

Did the warmest/sunniest areas of the south coast have a distinct vegetation type from other parts of Southern England?
I can't say I have noticed much of a difference in vegetation, as these areas tend to be built up anyway so lack any natural vegetation any more, although some of the woodlands inland, particularly around Butser Hill, tend to have Pine trees...
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Old 11-29-2014, 10:48 AM
 
Location: London, UK
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Quote:
Originally Posted by flamingGalah! View Post
I can't say I have noticed much of a difference in vegetation, as these areas tend to be built up anyway so lack any natural vegetation any more, although some of the woodlands inland, particularly around Butser Hill, tend to have Pine trees...
Are they natives?
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