RADAR Future time steps question

[Dorsetbred]

Hiya, can I comment & seek some reasoning behind why the following happens.

When stepping through the radar time sequence, you arrive at a point where the next four updates are projected.

I have noticed that on many occasions certainly yesterday AND today, when you step through the four future time steps, they take any precipitation on a different path to the historical mapping. Yesterday rain showers were coming in from the west up to the future time step, and it project this rain to suddenly change course & head northwards.

Again this morning, rain across the channel is heading SE, run the future time step and it suddenly changes to NE.

How are the future time steps produced?

[Paul]

Hi Quentin, funny enough was about to reply in the other thread. It looks like we had a bug on the forecast radar recently which was throwing it off course, that's literally just been fixed in the last 10 minutes though (may take a few updates to filter through).

 

To answer your question, we use upper wind data to decide where the rain is moved to. 

[Dorsetbred]

Thanks Paul for the info and correction.

[Dorsetbred]

Strange as I'm seeing the same thing again today. After the front passed through showers behind it are heading into a SE direction. then hit the step forward and the incoming showers are suddenly heading NE. 

I have to say that the step forward function has always been fair (accepting how it works) but recently it seems so different to how it historically performed.

Really has lost some of it's usefulness as clearly the incoming showers wont suddenly veer 90degrees the wrong way.

[Mapantz]

Strange as I'm seeing the same thing again today. After the front passed through showers behind it are heading into a SE direction. then hit the step forward and the incoming showers are suddenly heading NE. 

I have to say that the step forward function has always been fair (accepting how it works) but recently it seems so different to how it historically performed.

Really has lost some of it's usefulness as clearly the incoming showers wont suddenly veer 90degrees the wrong way.

 

If you overlay the upper wind vectors, you can see why it makes the decision to follow them on the future radar, except that the blob of rain isn't following those upper winds. Strange!

[Paul]

It sounds like there's a bug in there again - will get Karl to check it asap.