Fun with Ensemble QPF from the SREF

Last evening I was examining the latest SREF guidance to get a feel for how the latest in a series of winter storms would impact central NC. I took a peek at the 21 UTC 2011/01/23 SREF BUFR soundings for KRDU via Bufkit. This winter our office has had some success using the SREF BUFR soundings for QPF, determining p-type, getting a qualitative feel about confidence, and more.

 I found the precipitation plumes from 21 UTC 2011/01/23 SREF BUFR soundings for KRDU as shown in Bufkit image below very interesting. Bufkit allows users to filter the 21 member SREF by model core, convective parameterization, perturbations and more. When I initially examined the SREF forecasts for KRDU using all of the members there were nearly 25% of the members or 5out of 21 had between 2.5 – 4.0 inches of QPF.  The rest of the members were clustered between 0.75 and 1.5 inches.

After I filtered the display and removed the NMM members, the group of large QPF forecasts was gone and a fairly tight cluster of solutions were left. So the NMM members were going crazy! More information on the various members of the SREF including the grid spacing, convective parameterizations, and more is available at the bottom of the reference chart at this URL:

The probabilistic and max/min values from the SPC SREF page were showing the MAX 24 hour total precipitation ending 03 UTC 01/27 had over 3 inches in central NC.

Unfortunately AWIPS has a limited data set for the various SREF members. Most of the AWIPS data is limited to the mean and some probabilistic data. WFO Raleigh has recently installed the ALPS workstation and it is hoped that we can acquire SREF data and allow our forecasters to manipulate and evaluate the ensemble data using ALPS.

In the mean time, we can examine the SREF via the web. The EMC web page showed the surface low positions for each of the various SREF members (shown below on top). A matrix view of some data from each of the members is available on the PSU e-wall site. This second image below is of the 87 hour total accumulated liquid.

Enjoy, JB

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1 Response to Fun with Ensemble QPF from the SREF

  1. Jonathan Blaes @ WFO RAH says:

    Here’s the verification for 3 day precipitation totals ending at 12 UTC 1/27
    KRDU 0.54
    KGSO 0.45
    KFAY 0.16

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