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Message: fix to BUFR date, 00Z pireps, info on snow depth

Posted by Stan Benjamin on 7 Jan 98, 14:14 MT

A few more changes went into RUC2 this morning.

1. Date on BUFR soundings corrected.

2. Fix to data ingest so that aircraft reports will now be used at 0000Z. Previously, they had not been!

On the snow depth field, I gave some erroneous information in the web posting on this. I said that this field is in water equivalent. This is incorrect. The GRIB identifier for SNO D just says "snow depth", and this is what we are doing.
It is, in effect, a water equivalent, but we use an "old snow" density of 2.5 inches of snow to 1 inch of water. Thus, the current maximum value of about 2 m of snow in British Columbia corresponds to about 0.8 m of water.

Also, in Monday's web page posting, I said that the snow cover field had not been updating properly due to a GRIB precision problem and that we had restarted from a 40km MAPS snow field from FSL. Well, unfortunately, the 40-km MAPS was down for a few days near Christmas, so missed some of the East Coast snow
that occurred then (and perhaps other regions also). Now that we have the snow cycling going properly in the more-reliable RUC2, the snow depth field should evolve toward better accuracy.

Hope this explanation help.


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