[Ncep.list.idp.mrms.users] Some bad Canadian Radar data not getting QC'd out of MRMS, impacting QPE

Kenneth Howard - NOAA Federal kenneth.howard at noaa.gov
Wed Jul 18 23:57:31 UTC 2018

Hi Joseph,

Thanks very much for your detailed
​inputs.  As you've identified, the clutter were due to anomalous
propagation under morning inversions.  The clutter are difficult to remove
at far ranges due to their characteristics being similar to shallow
​We did try to use satellite data to mitigate such APs a while back,
although the satellite data had lower frequencies (15min) than radar
(4-5min) and caused temporal discontinuities in the QCed fields. And
non-precip clouds in satellite data often masked the clutter making the
benefits limited. Therefore the satellite check was not implemented in the
operational MRMS.

Now with the higher frequency GOES-16, we
​ are​
​reconsidering the satellite check for the next build (v12.5).  Meanwhile,
the Environment Canada is upgrading their network to S-band dual-pol
​ in the next a few years​
, which
​will make the clutter
​ removal much more efficient.​


On Wed, Jul 18, 2018 at 6:57 AM, Joseph Moore - NOAA Federal <
joseph.moore at noaa.gov> wrote:

> Good morning,
> I just wanted to share some feedback on MRMS and Canadian Radar data.
> We've noticed that some mornings we see the Canadian radar reflectivity
> data not being QC'd out of MRMS, causing errors in QPE. This was an issue a
> week ago when we had a period of heavy rainfall, but then the QPE got
> exaggerated (values increased due to bad reflectivity) along the
> international border in northern Minnesota. I have attached (via Google
> Drive) a few GIFs of MRMS products this morning demonstrating the bad
> reflectivity values being ingested and accumulating on the QPE product in
> northern Minnesota.
> Problem: Some high reflectivity values from morning inversions are being
> ingested into MRMS precip products from our Canadian radars. (Specifically
> Dryden radar and occasionally the Superior West (Thunder Bay) radar site.)
> Expected behavior: Since there is no precip in the area (no clouds), I
> would expect these values to be QC'd out like MRMS usually does.
> When the problem occurs: Usually in the morning hours when a strong
> inversion is present.
> Urgency: This is not an urgent issue, but it would be good to see
> addressed eventually since MRMS precip impacts so many things downstream,
> like FLASH.
> Linked GIFs show (from top left, clockwise): GOES-16 Clean IR Ch 11,
> GOES-16 Red Vis Ch 2, 0.5 degree NEXRAD Reflectivity composite, and the
> MRMS product in question. (In one GIF I included the MRMS 1-hour QPE to
> show that MRMS is accumulating these reflectivity values as precip.)
> Let me know if you have any other questions. I can continue to send
> examples if it would help diagnose the issue.
> **NOTE** This has NOTHING to do with the MRMS outage this morning even
> though some of the frames in this GIF are from when the issues were
> happening.
> -Joe Moore
>>  2018-07-18-12z-mrms-Composite-1KM.gif
> <https://drive.google.com/a/noaa.gov/file/d/17tHY7INKLiHiFBgI6I9xuB0ZnYElTyRA/view?usp=drive_web>
> ​​
>  2018-07-18-12z-mrms-RALA.gif
> <https://drive.google.com/a/noaa.gov/file/d/1NhS2-2jMclsi6bEB38Z-J0Ubvak35wx3/view?usp=drive_web>
> ​​
>  2018-07-18-12z-mrms-SHSR+1hr-QPE.gif
> <https://drive.google.com/a/noaa.gov/file/d/15f0nxGsdgU_uFUzy9MEywXrNdOU0e5xw/view?usp=drive_web>
> ​​
>  2018-07-18-12z-mrms-SHSR.gif
> <https://drive.google.com/a/noaa.gov/file/d/1T7TIPx5Hh7Fk8L3Vfj-D8csl95NkJtCy/view?usp=drive_web>
> --
> *Joseph J. Moore*
> Meteorologist | WFO Duluth Social Media & IDSS Program Leader | Open
> Source GIS Evangelist
> NOAA/National Weather Service Duluth, MN
> _______________________________________________
> Ncep.list.idp.mrms.users mailing list
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> https://www.lstsrv.ncep.noaa.gov/mailman/listinfo/ncep.list.idp.mrms.users

*Kenneth W. Howard*
*Program Manager and Research Meteorologist*,
Stormscale Hydro Meteorology Group (SHMET), WRDD
National Severe Storms Laboratory
120 David L Boren Blvd, Norman, OK 73072
Phone: (405) 535  <(405)%20325-6485>9863        Email: kenneth.howard
@noaa.gov <jian.zhang at noaa.gov>
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