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Message: fix to CAPE, add snow depth to isobaric output

Posted by Stan Benjamin on 6 Jan 98, 7:37 MT

A couple more small changes went in at 12Z this morning.

The CAPE calculation for the forecast is now the same as for the analysis. There may still be less CAPE in forecasts compared to analyses due to mixing out of high energy sfc parcels that get into the analysis, but the CAPEs from analyses and forecasts should have a little more continuity now.

Snow depth was added as a new output field for the isobaric main (*.pgrbanl, *.pgrbf01, ...) files. This field is a cycled snow depth that can increase from the explicit snow accumulation from the microphysics in RUC2 and can decrease from melting via a snow energy budget also in the model. It has been cycled since March 1997, although all of the snow in the domain melted off over the summer. Thus, there is a memory in this field from storms many days back. Orographic effects are quite prominent also. The hourly insertion of sfc temps into RUC2 tends to keep this field fairly honest. And with it, you can see where RUC2 thinks snow cover is and how much there is. This variable is a real snow depth assuming 2.5 to 1 snow/water ratio, so divide by 2.5 to get water equivalent.


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