SREF - ARW precipitation type Problem

SREF - Precipitation Type Problem

A recent fix to the instantaneous precipitation rates in the SREF (in order to fix errors in the ceiling and visibility) has inadvertently caused erroneous precipitation type fields in the ARW members. The error has resulted in no precipiation type being assigned to the vast majority of freezing or frozen precipitation areas in the ARW members. This will cause the following ensemble products related to precipiation type to be too low in magnitude:

[MAX]:3hr_Snowfall(inches)

[MN]:3hr_Snowfall(inches)

[MN]:6hr_Snowfall(inches)

[MN]:12hr_Snowfall(inches)

[MN]:Snowfall_Ratio(Snow:Liquid_Eqv)

[PR]:Snowfall_Rate_>=1in(perhr)

[PR]:Snowfall_Rate_>=2in(perhr)

[PR]:Snowfall_Rate_>=3in(perhr)

[PR]:Freezing_Rain_Rate_>=0.05_in(per3hr)

[PR]:Freezing_Rain_lasting_>=3hrs

[PR]:Rain_Change_to_Freezing_Rain

[PR]:Freezing_Rain_Change_to_Rain

[PR]:Probability_Snow(All_members)

[PR]:Probability_Ice_Pellets(All_members)

[PR]:Probability_Freezing_Rain(All_members)

Until the problem is fixed, users are referred to the SREF plumes page, which provides QPF and snow amount data from each member of the SREF:

SREF Plumes page (clicking this link will open a new window)

While the ARW data in the plumes will be incorrect, the NMM and NMM-B data can be used to provide better ensemble forecast data compared to what is in the adversely affected fields listed above.

The source of the problem has been identified and a fix is expected to be applied sometime in January 2013.