"VivienB" wrote in message
...

This might be of interest:

http://uk.weather.com/activities/farmandgarden/


For a local 5 day forecast for your nearest weather
station in the UK, often quite close by, just type in
your postcode in the box at the bottom.

http://www.bbc.co.uk/weather/5day.shtml


Caution: the figures often change on a daily basis,
and so may need constant monitoring. A reminder perhaps of
how inexact forecasting can still sometimes be.

The danger of frost is often specific to certain
locations. Even within a matter of a few yards, frost
pockets can form in hollows, and up against fences and
other barriers to the free circulation of air.


michael adams

....

In article ,
"michael adams" writes:
|
| Caution: the figures often change on a daily basis,
| and so may need constant monitoring. A reminder perhaps of
| how inexact forecasting can still sometimes be.

Oh, yes, indeed.

| The danger of frost is often specific to certain
| locations. Even within a matter of a few yards, frost
| pockets can form in hollows, and up against fences and
| other barriers to the free circulation of air.

That phenomenon is relatively rare in the UK, as it applies only
in very still conditions. A more common one here is the reverse,
i.e. that a freezing wind will leave hollows and barrier-shielded
areas untouched. Note that can apply with even the lightest winds.


Regards,
Nick Maclaren.

The message
from (Nick Maclaren) contains these words:


In article ,
"michael adams" writes:

| The danger of frost is often specific to certain
| locations. Even within a matter of a few yards, frost
| pockets can form in hollows, and up against fences and
| other barriers to the free circulation of air.

That phenomenon is relatively rare in the UK, as it applies only
in very still conditions.

I don't think so Nick, though living on the flatlands perhaps you may
not see frostpockets as often as I do. Many gardeners (even in windy
Scotland) with a hillside/sloping/valley garden will be only too
familiar with frost pockets exactly as Michael describes, and they are
very frequently referred to in UK gardening books.

Janet

In article ,
Janet Baraclough writes:
|
| | The danger of frost is often specific to certain
| | locations. Even within a matter of a few yards, frost
| | pockets can form in hollows, and up against fences and
| | other barriers to the free circulation of air.
|
| That phenomenon is relatively rare in the UK, as it applies only
| in very still conditions.
|
| I don't think so Nick, though living on the flatlands perhaps you may
| not see frostpockets as often as I do. Many gardeners (even in windy
| Scotland) with a hillside/sloping/valley garden will be only too
| familiar with frost pockets exactly as Michael describes, and they are
| very frequently referred to in UK gardening books.

Even in hilly areas, you will see the phenomenon I refer to more often.
Indeed, one might say ESPECIALLY in hilly areas! Frost often occurs
on hilltops and not on the bottoms, even when the adiabatic cooling
phenomenon is negligible, due to the effect of a freezing wind.

I know that books often refer to the frost-pocket phenomenon, but my
observation is that it is a lot rarer (in the UK) than is often made
out. Yes, it occurs, but it is nowhere near as common as the shelter
phenomenon, which is what I referred to in the section that you snipped.

Michael Adams was correct that the danger is very location-specific,
but a little misleading when he described the frost-pocket phenomenon
alone. The shelter phenomenon is a much more important cause of the
variations with precise location.


Regards,
Nick Maclaren.

Following up to (Nick Maclaren) :

I know that books often refer to the frost-pocket phenomenon, but my
observation is that it is a lot rarer (in the UK) than is often made
out. Yes, it occurs, but it is nowhere near as common as the shelter
phenomenon, which is what I referred to in the section that you snipped.

Find a spot displaying the shelter-phenomenon and look on the other side of
the hedge. ;-)
--
Tim C.

Is there any website that details when you would EXPECT the last frosts
to have gone. I remember seeing Mr Titchmarsh showing some graphic on
one of his programs say when you would expect the last frost to have
gone by.

I am aware that this is not a promise I'm just after an indicator i.e.
when in Berkshire would the last frost be expected to be over by ?

Cheers

Colin

In article ,
Tim C. writes:
|
| I know that books often refer to the frost-pocket phenomenon, but my
| observation is that it is a lot rarer (in the UK) than is often made
| out. Yes, it occurs, but it is nowhere near as common as the shelter
| phenomenon, which is what I referred to in the section that you snipped.
|
| Find a spot displaying the shelter-phenomenon and look on the other side of
| the hedge. ;-)

It's usually partially sheltered, too!

In most of the UK, frost is associated with wind more often than with
still conditions. The main question is whether the scale of the
turbulence is larger or smaller than the scale of the topographical
feature. The Reynolds number is only part of the story.

You can often see this effect very clearly with sloes and other wild
flowers and fruit. While there is a very strong south=early effect,
and a fairly strong exposed=colder effect, there is a relatively weak
air-trap=colder effect.


Regards,
Nick Maclaren.

In article . com,
"Gardening_Convert" writes:
| Is there any website that details when you would EXPECT the last frosts
| to have gone. I remember seeing Mr Titchmarsh showing some graphic on
| one of his programs say when you would expect the last frost to have
| gone by.

Not a useful one, as far as I know. When writing the climate FAQ, I
found some old data on this and summarised it there. I forget the
details but, if I recall, the expected variation is a month each way,
and variations of two months are not all that rare.

| I am aware that this is not a promise I'm just after an indicator i.e.
| when in Berkshire would the last frost be expected to be over by ?

Anywhere from February 1st to June 1st :-( Sorry.


Regards,
Nick Maclaren.

The message . com
from "Gardening_Convert" contains these words:

Is there any website that details when you would EXPECT the last frosts
to have gone. I remember seeing Mr Titchmarsh showing some graphic on
one of his programs say when you would expect the last frost to have
gone by.

go to http://www.google.co.uk/ and type the four words last frost
date map into the search box; tick "UK" just underneath it, click enter.

Janet

The message
from (Nick Maclaren) contains these words:

In most of the UK, frost is associated with wind more often than with
still conditions.

I'd have to disagree with that too!. One of the predictors of night
frost risk that I use in either spring or autumn, is a cloudless night
sky. They are often still, with very little wind, and even after a sunny
warm day the temp can drop like a stone.

Janet (Scotland).

In article , Janet Baraclough
writes
The message
from (Nick Maclaren) contains these words:

In most of the UK, frost is associated with wind more often than with
still conditions.

I'd have to disagree with that too!. One of the predictors of night
frost risk that I use in either spring or autumn, is a cloudless night
sky. They are often still, with very little wind, and even after a sunny
warm day the temp can drop like a stone.

Janet (Scotland).

I live quite near Nick, as the crow flies, and I have to agree with
Janet, I look at the sky at night, and a clear, still night is the one
when I get frosts. Last night was a prime example at Norwich.

--
Judith Lea

In article ,
Judith Lea writes:
|
| I live quite near Nick, as the crow flies, and I have to agree with
| Janet, I look at the sky at night, and a clear, still night is the one
| when I get frosts. Last night was a prime example at Norwich.

Yes, we do here, but we are not typical of the UK. Last night was
not still, anyway! There was quite enough wind to reduce the frost
pocket phenomenon and increase the shelter one with me. Note that
a force 2 wind really does make a difference in this respect, and
even a force 1 one has some effect!

The result is that, if you consider the potential for frost-damage
and not the occurrence of frost as such, what I say is true. As I
said, I based my remarks on looking for sloes, looking at frost damage
of ornamentals and similar, in both hilly and flat places.


Regards,
Nick Maclaren.