I note with some trepidation that GFS has been gunning for some very high
dewpoints in the coming week. In the 12z GFS, that reaches a ridiculous
extreme in a week:

http://i43.tinypic.com/sq5cba.gif

If that were to come off there'd be no end of moaning from Joe Public.

As a side note, it's been pleasant here in Kent, with dewpoints in single
figures this afternoon. A stark contrast to the rest of the UK, with the
Bristol area for example "enjoying" dewpoints of 17 or 18C as I write this.

I was going to ask where all this moisture has come from, seeing that we
have an easterly flow, it's not been especially wet in the past few days and
the sea's not even 15C. However, checking the archives I see Tudor Hughes
asked the same question back in 2003 - and the consensus then was that it
was evapotranspiration.

In article ,
Darren Prescott writes:
I note with some trepidation that GFS has been gunning for some very
high dewpoints in the coming week. In the 12z GFS, that reaches a
ridiculous extreme in a week:

http://i43.tinypic.com/sq5cba.gif

If that were to come off there'd be no end of moaning from Joe Public.

As a side note, it's been pleasant here in Kent, with dewpoints in
single figures this afternoon. A stark contrast to the rest of the UK,
with the Bristol area for example "enjoying" dewpoints of 17 or 18C as
I write this.
snip

I'd like a low dewpoint tomorrow, as I'm planning to defrost the
freezer. It lives in an outhouse, and it will be much easier to get it
dry if the humidity is low.
--
John Hall "Hard work often pays off after time, but laziness always
pays off now." Anon

On 22 June, 17:51, "Darren Prescott" wrote:
I note with some trepidation that GFS has been gunning for some very high
dewpoints in the coming week. In the 12z GFS, that reaches a ridiculous
extreme in a week:

http://i43.tinypic.com/sq5cba.gif

If that were to come off there'd be no end of moaning from Joe Public.

As a side note, it's been pleasant here in Kent, with dewpoints in single
figures this afternoon. A stark contrast to the rest of the UK, with the
Bristol area for example "enjoying" dewpoints of 17 or 18C as I write this.

I was going to ask where all this moisture has come from, seeing that we
have an easterly flow, it's not been especially wet in the past few days and
the sea's not even 15C. However, checking the archives I see Tudor Hughes
asked the same question back in 2003 - and the consensus then was that it
was evapotranspiration.

My 9-mile bike ride into town at 3pm today was probably the most
sweaty this year - I'm not looking forward to my rides later in the
week...

I was going to ask where all this moisture has come from, seeing that we
have an easterly flow, it's not been especially wet in the past few days and
the sea's not even 15C.

The SST is 16C off Cornwall now http://www.channelcoast.org/data_man...arts/?chart=75
There are some really warm patches of water even several miles out
(E.g. 62f out at Sevenstones this afternoon)

Although the flow is easterly, didn't the air originate behind a warm
front which went around the top of the high?

Graham
Penzance

"Graham Easterling" wrote
snip
Although the flow is easterly, didn't the air originate behind a
warm
front which went around the top of the high?

.... I haven't done a detailed trajectory back-track, but 'eyeballing'
the DWD archive, the air that is associated with the warm front now
quasi-stationary across Britain was in the vicinity of the Azores
17th/18th - and that location was behaving as a true 'air mass
source', i.e. with a slow-moving high cell there, the air could just
sit there and pick up the characteristics which (with modification
along the way) we're experiencing.

Martin.



--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

"Martin Rowley" wrote in message
news
the air that is associated with the warm front now quasi-stationary
across Britain was in the vicinity of the Azores 17th/18th - and that
location was behaving as a true 'air mass source'
Aha, yes - that'd explain it nicely. Looking at the current analysis chart
the UK is under a whacking great warm sector, which is just about perfectly
positioned in terms of high dewpoints for the UK.

It's not felt anything like a warm sector here (in Kent), of course, which
stayed on the cold side of the warm front. I guess I'm very lucky that the
warm front became quasi-stationary just up the road from here,
geographically speaking!

On Jun 22, 5:51*pm, "Darren Prescott"
wrote:
I note with some trepidation that GFS has been gunning for some very high
dewpoints in the coming week. In the 12z GFS, that reaches a ridiculous
extreme in a week:

http://i43.tinypic.com/sq5cba.gif

If that were to come off there'd be no end of moaning from Joe Public.

As a side note, it's been pleasant here in Kent, with dewpoints in single
figures this afternoon. A stark contrast to the rest of the UK, with the
Bristol area for example "enjoying" dewpoints of 17 or 18C as I write this.

I was going to ask where all this moisture has come from, seeing that we
have an easterly flow, it's not been especially wet in the past few days and
the sea's not even 15C. However, checking the archives I see Tudor Hughes
asked the same question back in 2003 - and the consensus then was that it
was evapotranspiration.

Dewpoints in the southeast are falling at the moment
(typically 9°C at midnight) but are higher further west due to the
origin of the air as pointed out by Martin Rowley. I think
evapotranspiration always has quite a large effect in summer, there
being really no other way of explaining why the dewpoint rises during
the day and and can sometimes exceed the sea temperature at the
airmass's origin.
I see the latest GFS has toned it down considerably and it
makes me wonder how they arrived at the original sauna conditions.
Living in a climate where the actual weather was GFS T+168 would be a
bizarre and unsettling experience.

Tudor Hughes, Warlingham, Surrey.

In article
,
Tudor Hughes writes:
I see the latest GFS has toned it down considerably and it
makes me wonder how they arrived at the original sauna conditions.
Living in a climate where the actual weather was GFS T+168 would be a
bizarre and unsettling experience.


T least you wouldn't be able to claim that the weather was "bland".
--
John Hall "Hard work often pays off after time, but laziness always
pays off now." Anon

On 23 June, 00:14, Tudor Hughes wrote:
On Jun 22, 5:51*pm, "Darren Prescott"
wrote:



I note with some trepidation that GFS has been gunning for some very high
dewpoints in the coming week. In the 12z GFS, that reaches a ridiculous
extreme in a week:

http://i43.tinypic.com/sq5cba.gif

If that were to come off there'd be no end of moaning from Joe Public.

As a side note, it's been pleasant here in Kent, with dewpoints in single
figures this afternoon. A stark contrast to the rest of the UK, with the
Bristol area for example "enjoying" dewpoints of 17 or 18C as I write this.

I was going to ask where all this moisture has come from, seeing that we
have an easterly flow, it's not been especially wet in the past few days and
the sea's not even 15C. However, checking the archives I see Tudor Hughes
asked the same question back in 2003 - and the consensus then was that it
was evapotranspiration.

* * * * Dewpoints in the southeast are falling at the moment
(typically 9°C at midnight) but are higher further west due to the
origin of the air as pointed out by Martin Rowley. *I think
evapotranspiration always has quite a large effect in summer, there
being really no other way of explaining why the dewpoint rises during
the day and and can sometimes exceed the sea temperature at the
airmass's origin.
* * * * *I see the latest GFS has toned it down considerably and it
makes me wonder how they arrived at the original sauna conditions.
Living in a climate where the actual weather was GFS T+168 would be a
bizarre and unsettling experience.

Tudor Hughes, Warlingham, Surrey.

It always amazes me how mid-20s dewpoints get into the heartland of
America considering the distance from the sea. I realise that air
originates in Gulf of Mexico with 25-30 C SSTs but there seems to be
no loss due to the usual condensation processes (rainfall, dew).

Martin

On 2009-06-23, JPG wrote:

It always amazes me how mid-20s dewpoints get into the heartland of
America considering the distance from the sea. I realise that air
originates in Gulf of Mexico with 25-30 C SSTs but there seems to be
no loss due to the usual condensation processes (rainfall, dew).

I think you'll find the exceptionally high RH experienced in some states
is down to irrigation/crops evapotranspiration, particularly corn. (just
what I've read, I'm not an expert)
--
comp.john