We have slight rain in Tideswell at present and it has been almost continuous
since before sunrise. The radar imagery suggests there is plenty more to come.

The automated forecast for Tideswell issued at 0600 this morning gave the
precipitation probabilities as

0700: 50%
0800: 50%
0900: 10%
1000: 20%
1100: 10%
1200: 10%
1300: 10%
1400: 10%
1500: 10%
1600: 10%
1700: 20%
1800: 10%

The automated forecast that's currently on the Met Office website, issued at
0900, gives the following precipitation probabilities:

1100: 10%
1200: 5%
1300: 10%
1400: 10%
1500: 5%
1600: 10%
1700: 10%
1800: 5%

It's not a very impressive performance.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org
@TideswellWeathr

On 22 Feb 2017 11:05:36 GMT
"Norman Lynagh" wrote:

We have slight rain in Tideswell at present and it has been almost continuous
since before sunrise. The radar imagery suggests there is plenty more to come.

The automated forecast for Tideswell issued at 0600 this morning gave the
precipitation probabilities as

0700: 50%
0800: 50%
0900: 10%
1000: 20%
1100: 10%
1200: 10%
1300: 10%
1400: 10%
1500: 10%
1600: 10%
1700: 20%
1800: 10%

The automated forecast that's currently on the Met Office website, issued at
0900, gives the following precipitation probabilities:

1100: 10%
1200: 5%
1300: 10%
1400: 10%
1500: 5%
1600: 10%
1700: 10%
1800: 5%

It's not a very impressive performance.


Is the rain showing up on radar? The radar rainfall nowcast is used for the
first three hours and then blended in with the model by 6 hours. If there is no
rain on radar then there will be no rain on the nowcast part of the automated
forecast. Failing that there may be a bug or something has stopped working
properly so that raw model is used.

Will
--

Will Hand wrote:

On 22 Feb 2017 11:05:36 GMT
"Norman Lynagh" wrote:

We have slight rain in Tideswell at present and it has been almost
continuous since before sunrise. The radar imagery suggests there is plenty
more to come.

The automated forecast for Tideswell issued at 0600 this morning gave the
precipitation probabilities as

0700: 50%
0800: 50%
0900: 10%
1000: 20%
1100: 10%
1200: 10%
1300: 10%
1400: 10%
1500: 10%
1600: 10%
1700: 20%
1800: 10%

The automated forecast that's currently on the Met Office website, issued at
0900, gives the following precipitation probabilities:

1100: 10%
1200: 5%
1300: 10%
1400: 10%
1500: 5%
1600: 10%
1700: 10%
1800: 5%

It's not a very impressive performance.


Is the rain showing up on radar? The radar rainfall nowcast is used for the
first three hours and then blended in with the model by 6 hours. If there is
no rain on radar then there will be no rain on the nowcast part of the
automated forecast. Failing that there may be a bug or something has stopped
working properly so that raw model is used.

Will

Currently under dark blue on the radar with green and some yellow approaching
from WNW. Throughout the morning the radar imagery has been pretty consistent
with the weather experienced, i.e. it has been raining most of the time and the
radar has indicated that it has been raining most of the time.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org
@TideswellWeathr

On 22 Feb 2017 11:29:37 GMT
"Norman Lynagh" wrote:

Will Hand wrote:

On 22 Feb 2017 11:05:36 GMT
"Norman Lynagh" wrote:

We have slight rain in Tideswell at present and it has been almost
continuous since before sunrise. The radar imagery suggests there is
plenty more to come.

The automated forecast for Tideswell issued at 0600 this morning gave the
precipitation probabilities as

0700: 50%
0800: 50%
0900: 10%
1000: 20%
1100: 10%
1200: 10%
1300: 10%
1400: 10%
1500: 10%
1600: 10%
1700: 20%
1800: 10%

The automated forecast that's currently on the Met Office website, issued
at 0900, gives the following precipitation probabilities:

1100: 10%
1200: 5%
1300: 10%
1400: 10%
1500: 5%
1600: 10%
1700: 10%
1800: 5%

It's not a very impressive performance.


Is the rain showing up on radar? The radar rainfall nowcast is used for the
first three hours and then blended in with the model by 6 hours. If there is
no rain on radar then there will be no rain on the nowcast part of the
automated forecast. Failing that there may be a bug or something has stopped
working properly so that raw model is used.

Will

Currently under dark blue on the radar with green and some yellow approaching
from WNW. Throughout the morning the radar imagery has been pretty consistent
with the weather experienced, i.e. it has been raining most of the time and
the radar has indicated that it has been raining most of the time.


Then there is a problem Houston. The nowcast should be used for the first 3
hours. Unless of course they have changed it now to make it all model based but
then that would be ridiculous as there is a huge amount of software to take in
the rainfall nowcast and smoothly blend it with NWP at later lead times. They
would not simply discard that. I really think you should report this just in
case it has not been spotted by the post-processing team. I suspect the bench
"forecasters" in the Ops Centre are overly occupied with tomorrow's pending
disasterous impacts :-(

Will
--

Will Hand wrote:

On 22 Feb 2017 11:29:37 GMT
"Norman Lynagh" wrote:

Will Hand wrote:

On 22 Feb 2017 11:05:36 GMT
"Norman Lynagh" wrote:

We have slight rain in Tideswell at present and it has been almost
continuous since before sunrise. The radar imagery suggests there is
plenty more to come.

The automated forecast for Tideswell issued at 0600 this morning gave
the precipitation probabilities as

0700: 50%
0800: 50%
0900: 10%
1000: 20%
1100: 10%
1200: 10%
1300: 10%
1400: 10%
1500: 10%
1600: 10%
1700: 20%
1800: 10%

The automated forecast that's currently on the Met Office website,
issued at 0900, gives the following precipitation probabilities:

1100: 10%
1200: 5%
1300: 10%
1400: 10%
1500: 5%
1600: 10%
1700: 10%
1800: 5%

It's not a very impressive performance.


Is the rain showing up on radar? The radar rainfall nowcast is used for
the first three hours and then blended in with the model by 6 hours. If
there is no rain on radar then there will be no rain on the nowcast part
of the automated forecast. Failing that there may be a bug or something
has stopped working properly so that raw model is used.

Will

Currently under dark blue on the radar with green and some yellow
approaching from WNW. Throughout the morning the radar imagery has been
pretty consistent with the weather experienced, i.e. it has been raining
most of the time and the radar has indicated that it has been raining most
of the time.


Then there is a problem Houston. The nowcast should be used for the first 3
hours. Unless of course they have changed it now to make it all model based
but then that would be ridiculous as there is a huge amount of software to
take in the rainfall nowcast and smoothly blend it with NWP at later lead
times. They would not simply discard that. I really think you should report
this just in case it has not been spotted by the post-processing team. I
suspect the bench "forecasters" in the Ops Centre are overly occupied with
tomorrow's pending disasterous impacts :-(

Will

This isn't a one-off. With a WNW wind we often get rain that just goes on and
on while the forecast rainfall probabilities are often very low. The fact that
the rain shows up on the radar doesn't seem to impact on the forecasts.

In contrast, in SW winds the forecast rainfall probabilities are often quite
high while we don't get a lot of rain thanks to the shadow effect of Wales.
Again, the fact that the radar shows there to be no rain here, doesn't appear
to impact on the forecasts. I don't get the impression that the radar imagery
is blended into the short-term forecasts (nowcasts). If it is, then the system
doesn't work very well.

Rain is getting close to moderate intensity now. Greens and yellows on radar
support that.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org
@TideswellWeathr

On 22 Feb 2017 11:53:44 GMT
"Norman Lynagh" wrote:

Will Hand wrote:

On 22 Feb 2017 11:29:37 GMT
"Norman Lynagh" wrote:

Will Hand wrote:

On 22 Feb 2017 11:05:36 GMT
"Norman Lynagh" wrote:

We have slight rain in Tideswell at present and it has been almost
continuous since before sunrise. The radar imagery suggests there is
plenty more to come.

The automated forecast for Tideswell issued at 0600 this morning gave
the precipitation probabilities as

0700: 50%
0800: 50%
0900: 10%
1000: 20%
1100: 10%
1200: 10%
1300: 10%
1400: 10%
1500: 10%
1600: 10%
1700: 20%
1800: 10%

The automated forecast that's currently on the Met Office website,
issued at 0900, gives the following precipitation probabilities:

1100: 10%
1200: 5%
1300: 10%
1400: 10%
1500: 5%
1600: 10%
1700: 10%
1800: 5%

It's not a very impressive performance.


Is the rain showing up on radar? The radar rainfall nowcast is used for
the first three hours and then blended in with the model by 6 hours. If
there is no rain on radar then there will be no rain on the nowcast part
of the automated forecast. Failing that there may be a bug or something
has stopped working properly so that raw model is used.

Will

Currently under dark blue on the radar with green and some yellow
approaching from WNW. Throughout the morning the radar imagery has been
pretty consistent with the weather experienced, i.e. it has been raining
most of the time and the radar has indicated that it has been raining most
of the time.


Then there is a problem Houston. The nowcast should be used for the first 3
hours. Unless of course they have changed it now to make it all model based
but then that would be ridiculous as there is a huge amount of software to
take in the rainfall nowcast and smoothly blend it with NWP at later lead
times. They would not simply discard that. I really think you should report
this just in case it has not been spotted by the post-processing team. I
suspect the bench "forecasters" in the Ops Centre are overly occupied with
tomorrow's pending disasterous impacts :-(

Will

This isn't a one-off. With a WNW wind we often get rain that just goes on and
on while the forecast rainfall probabilities are often very low. The fact that
the rain shows up on the radar doesn't seem to impact on the forecasts.

In contrast, in SW winds the forecast rainfall probabilities are often quite
high while we don't get a lot of rain thanks to the shadow effect of Wales.
Again, the fact that the radar shows there to be no rain here, doesn't appear
to impact on the forecasts. I don't get the impression that the radar imagery
is blended into the short-term forecasts (nowcasts). If it is, then the system
doesn't work very well.

Rain is getting close to moderate intensity now. Greens and yellows on radar
support that.


Oh dear. All very sad. That is clearly then not the system I left in 2012. I
suspect that weightings between model and radar have been "tweaked" in favour
of the model. Does not bode well for the future as it looks like the MetO is
abandoning proper nowcasting.

Will
--