UPDATE 2010-02-26: Back on track. Scaling issue is resolved, now working on calibration. If these are online, they’ll be tagged on the Mosaics page. Initial results look promising. The 10:1 model can have a large margin for error based on the fact that the ratio can actually range from 1:7 to more than 1:10 depending on how wet the snow is, or to say it another way, how cold the atmosphere is. So, 1:10 is a generally accepted approximation. There are other, more complex models, but these are beyond the scope of the software to evaluate.
When viewing the mosaic, the large scale version has an important time and date immediately after the station name at the top of the display. The precipitation products are sample on a “per storm basis” and start at the onset of significant weather and run until there is a definable break in the precipitation.

Storm Total Precipitation is the estimated accumulated rainfall (snowfall), continuously updated, since the last one-hour break in precipitation. In practice, radar operators frequently hold open the register until the storm has completed, as storms of long duration often have lulls lasting more than an hour, and are not reset until the defined storm has moved out of the area. This can result in variable displays. I have to manually input the start time on the mosaic, as there is no way for the software to auto insert it into the mosaic. The mosaic scan itself will show the last update time in Z time (-5 hours EST, -4 DST).

UPDATE 2010-02-24: Well, this isn’t working. Still having a scaling issue. Can’t get it to display as cm of snow, instead still giving the rain equivalent. Might not have the flexibility in the sofware to do the 10x factor. Work continues…

I’m trying an experiment to see if I can produce a screen mosaic for rate of snowfall and projected snowfall accumulation, based on a re-interpretation of the one hour, three hour, storm total precipitation and digital storm precipitation products (in the case of DSP, I just noticed the latest version of my software has dropped the DSP, in which case I’ll insert a reflectivity product such as base reflectivity or composite reflectivity. This will also apply to the rain mosaic as well. I’m awaiting confirmation on the future of the DSP product.)

The presentation uses the familiar 10:1 snow:rain model and the scales have been recalibrated accordingly. The usual display will be in metric to meet local needs, but it is also available upon request in imperial measure. The 1024×768 version is here, and the large version is here. The rest of the mosaic stream can be selected from the “Mosaics” tag in the selector bar on EWR. It should be noted that the mosaics are only populated when there is weather supporting them, due to the high bandwidth requirement.

The only thing missing now this winter is the snow…