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

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
storms.
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.

-
Jian

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
> Ncep.list.idp.mrms.users at lstsrv.ncep.noaa.gov
> 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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