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Kevin49068487

Help with graphic, please.

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I've noticed these graphics become more popular recently. I "think" I understand it, but I've been mistaken before.

I grabbed this image from the East Coast Feb thread. I did not put in the brown/black circles. The poster I snagged this image from said they represented good chances for snow.

 

The way I read this:

Date is clear enough.

Top half on the left represents the Ensemble number; swatches in the center represent the amount of snow that ensemble called for, with color code chart on the right.

Bottom half shows snowfall amount the Mean calls for.

 

So in this example, the time frame of 21 Feb +/- is promising due to nearly every ensemble showing snow, with many/most 2"+. While some other dates show higher amounts in some ensembles, there are also many with no snow, so those dates are less promising.

 

Am I correct in my interpretation?

 

 

 

image.png.d93a1a303fd25209d17a5422d7fac2ee.png

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Yes you are very correct. The more ensemble members showing snowfall, increases the chances of snowfall in the opinion of model. But don't take individual members too literally. Try and look at all the members as a mean, and look at what they mean together. IMHO you don't need to look at the actual mean to understand the direction of the wider model, you can use this chart.

 

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53 minutes ago, Snowy Hibbo said:

Yes you are very correct. The more ensemble members showing snowfall, increases the chances of snowfall in the opinion of model. But don't take individual members too literally. Try and look at all the members as a mean, and look at what they mean together. IMHO you don't need to look at the actual mean to understand the direction of the wider model, you can use this chart.

 

 

 

To piggy back on this comment you can also use this sort of visual chart to follow trends.  If all you knew about this chart was the more color you saw lined up top to bottom over a given date, Feb 21st vs Feb 18th in the chart above, then the more individual members are producing snow for that particular location(Bedford Mass) on that particular date, meaning this model thinks there will be snow.   HOWEVER, that doesn't mean that some of the individual members that do not produce snow on that date aren't correct. Also it doesn't mean that if most models show blue colors (2-6" snow) but yesterday they were showing pink and purple(6-12") that by looking at the a single snap shot or image will tell you very much about where things are headed.   You should simply look at this chart and interpret what's going on based on several model cycles rather than any specific details on a chart like this to see what the trend is.  Do more and more members start to show the pretty colors?  Do the colors amongst the individual members start to match or are there large variations to the colors indicating some members show a foot and others an inch, and others  6 inches?  Do the colors begin to get consistent in color and do they line up over the top of one another indicating the model is converging on a specific soln for snow amts and timing?(I modified the the original image above to show how consistent the colors are and how lined up they are for todays date(black line with yellow stars)  Blah blah blah.   Its these sorts of trends that one might find useful in determining where the final soln might be headed.  Of course comparing the trends within the EPS as well as comparing this models trends with other models is useful as well.    

 

For instance that graphic was yesterdays 12z.  Here is last nights 00z for comparison.  The mean for the Feb 18th dropped a little.  Overall the mean for the Feb 21st did not do a whole lot one way or the other.

 

image_png_d93a1a303fd25209d17a5422d7fac2ee.png.8123d539a2bebe80723b491d3e1e7f69.png

 

 hghg.png.4ed0935a10515a1b2688c61c3714a0a4.png    

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