Transcriber Weather

[Morgan]

Randi wrote:

Snow has advantages
Porch pirate gets stuck in snowbank during attempted getaway

It took him just a little too long!

That is weather justice!
We just replaced the rain gauge, now for some rain!

[Randi]

Snow!
There isn't too much on the ground yet, but it is coming down pretty enthusiastically

[Michael]

This is how the Norwegian Met Service interprets the European Community Medium Range Weather Forecast numerical data for Pittsburgh...

Code: Select all

YYYY/MM/DD/ Hour Day       Weather          TT DDD/FFF   Pcp
2021/01/16/12:00 Saturday  Sleet             2 WSW/004   0.7
2021/01/16/13:00 Saturday  Snow              1 WSW/011   0.8
2021/01/16/14:00 Saturday  Cloudy            1 WSW/011   0.1
2021/01/16/15:00 Saturday  Light sleet       2 WSW/011   0.1
2021/01/16/16:00 Saturday  Snow              2 WSW/014   0.3
2021/01/16/17:00 Saturday  Light snow        0   W/018   0.1
2021/01/16/18:00 Saturday  Partly cloudy     0   W/014     0
2021/01/16/19:00 Saturday  Partly cloudy     0 WSW/014   0.1
2021/01/16/20:00 Saturday  Light flurries   -1 WSW/014   0.2
2021/01/16/21:00 Saturday  Partly cloudy    -1 WSW/014   0.1
2021/01/16/22:00 Saturday  Partly cloudy    -2 WSW/014     0
2021/01/16/23:00 Saturday  Partly cloudy    -2 WSW/014     0

Here's how I interpret the Canadian Met Service Regional Model forecast data for Pittsburgh...

Code: Select all

Date        Hour Wx                    TT Dir/Spd  RH   Pcp Max/Min
Sat Jan 16  1 PM Light Snow             0 SSW/005 100   1.4
Sat Jan 16  2 PM Light Snow             0  SW/005 100   1.6
Sat Jan 16  3 PM Light Snow             0 WSW/007 100   1.0
Sat Jan 16  4 PM Cloudy                 1 WSW/008  93     0
Sat Jan 16  5 PM Cloudy                 1 WSW/009  93     0
Sat Jan 16  6 PM Mainly Cloudy          0 WSW/009 100     0
Sat Jan 16  7 PM Mainly Cloudy          0 WSW/009 100     0
Sat Jan 16  8 PM Cloudy                 0 WSW/011 100     0
Sat Jan 16  9 PM Mainly Cloudy          0 WSW/011 100     0
Sat Jan 16 10 PM Cloudy                 0 WSW/013 100     0 Max   3
Sat Jan 16 11 PM Cloudy                 0 WSW/013 100     0

[Randi]

For the moment the snow has stopped and it is overcast

[jil]

Just at the start of an Amber warning for rain from Storm Christophe that goes on until Thursday. I'm only just inside the area covered so I'm hoping it won't be too bad. Bring back the snow and ice!

[Morgan]

I am interested in your "Amber Alert." I presume from looking at the website that this is a warning midpoint between "red" or high and something "green" and lower level? In California an "Amber" alert is a broadcast warning of a child abduction. It is named for a young girl named "Amber." If, in a group of people, everyone's phone goes off at the same time, we know an alert has been issued. Occasionally there will be a weather related alert and we are just starting to get seismic alerts this way. But "Amber" is for Amber.

[studentforever]

Yes, it represents the middle light on our traffic lights which signals 'be prepared to act'. In the case of floods it suggests in properties at risk that you start moving belongings upstairs, packing emergency bag, including insurance details, passport, driving licence etc and prepare any house defences you have etc,
The red warning often means evacuating for properties at risk. Obviously, in the red areas not all properties will be at risk but it also says that you are likely to find many roads flooded so moving around the district may be dangerous. If the plans are working well then inhabitants of properties at risk should be guided on safe evacuation routes and there should be emergency shelter available - often halls, schools or similar for people who haven't got family or friends who can offer shelter - my brother used to be on the team manning his local 'command' centre.

[jil]

The UK Met Office has 3 levels of alert Yellow, Amber & Red all used for the different problematic weather conditions rain, wind, snow/ice. Then the Environment Agency (who deal with river and sea flooding in England) also have 3 levels but call them something different although the symbol for lowest one is a yellowy/orange colour and the 2 serious ones are coloured red.

[Michael]

I have been having fun analyzing the data produced by the Canadian Meteorological Centre. The amount of data is HUGE, but I have been using just a select few datafiles. For these two images, I have been calculating the height at which rain changes to snow, and comparing it to the elevation at a given point. In this case, I downloaded the High Resolution data for western Canada, which gives data for about 50 vertical levels for points on a 2.5x2.5 km grid. The grid itself has 332,226 points and Google Earth just can't cope with that many. So, I selected points just to cover Vancouver Island. In this case, from a few days ago, Rain is Green and Snow is White. You can see in this image that Victoria is blessed by being in the rain shadow from the Olympic Peninsula across the Strait of Juan de Fuca.



For this image, I zoomed in with Google Earth. You can see the density of the points, and the amount of snow forecast in the six hour period for the one point that I clicked on.



If I had more time, more computer horsepower and better display tools, I could generate images like this to show Snow and Rain moving in from the Pacific Ocean over a 48 hour period. CMC does have data that covers the world on a 25x25 km grid every three hours out for ten days, so I could do a similar thing for Scotland or any other part of the world.

[Morgan]

WOW! This is really interesting. This is a long ways from handwritten logs!

[jil]

Cool maps, Michael!

If you're interested in the Met Office weather warnings have a look at Thursday's map. I don't think I've ever seen so many different ones at once: Yellow for rain, snow, wind & ice; Amber for rain and snow.

The temperature's definitely dropping, it was 10C overnight last night, about 5C now and predicted to drop to 1C tonight.

[Randi]

Sunny here for the moment!

[AvastMH]

Great maps Michael

Here's the Met Office that jil posted:


And here's the Warning impact matrix that you get in the details:


Forget the umbrella - fetch a boat

[Randi]

We had sun today although it stayed below freezing almost the whole day.

[jil]

Joan, I'm glad you posted that image. This morning the weather (or the Met Office!) has calmed down and most of the rain and wind warnings have gone, so the link doesn't look as impressive now. Although I think the warnings were originally in effect until noon.

[studentforever]

This is the market town where I grew up and my brother still lives. Fortunately his house is at the top of the river valley so safe from flooding. However, a friend of my late father lives in Weaver Court so I hope he is OK.
https://www.bbc.co.uk/news/uk-england-m ... e-55750420

[Michael]

That's terrible! Poor people.

[Randi]

And what a mess to come home to

[studentforever]

They're now evacuating people

https://www.bbc.co.uk/news/uk-england-m ... e-55750420

Mind you, I don't remember it but I was assured that when I was a baby the floods were several feet deep in the town centre. The WHOLE town centre was raised by some 3 feet. Because of medieval salt mines (small and unrecorded) subsidence was common so all buildings were built with rafts, including some of the wooden framed ones. So, clear the foundations, jack up building, put in extension to services, connect up and brick up extension. I do remember seeing some of those buildings, including my future bank, being raised. They've now attempted to stabilise things with lots of grout but I await developments. I do remember seeing a mark part way up the stairs of the local cinema marking the extent of the flood.

[jil]

It's bad enough being flooded out in normal times but extra stressful at the moment.