Question about shaded Spread on Srefs

[Confuzzled]

Are the bolded isobars the ensemble mean and the colored shading indicates the amount of deviation over the area that is shaded area?

And the scale on the left (0-12), is that a a measure of the number of deviations from the mean?

[am19psu]

Are the bolded isobars the ensemble mean and the colored shading indicates the amount of deviation over the area that is shaded area?

Yes.

And the scale on the left (0-12), is that a a measure of the number of deviations from the mean?

No, it's the value of the standard deviation at each grid point.

[Confuzzled]

Yes.

No, it's the value of the standard deviation at each grid point.

Thanks for the response.

So operationally, the higher the satandard deviation is over a shaded region the more spread the ensembles are over that particular region?

So is that saying that the northern half of the 1000mb low off the coast of new england is much more uncertain in its northern half than southern half (essentially the precipitation shield as expected?)?

Or is that simply a spread of the pressure field on this map?

[am19psu]

It means that within the ensemble, the spread of the pressure values is higher NW of the low. In terms of weather, that means a few members likely have deeper lows to the northwest of the mean position.

[Confuzzled]

Thanks for the responses. I appreciate it!