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<p>Hi Jeff,</p>
<p>Have you downloaded our AWIPS bundles from RAC to compare the
precip sources? Here is the RAC Procedures Download Page (note you
can find this on AWIPS by doing a manual AIR search for rac using
the right click on any CAVE text legend):</p>
<p><a class="moz-txt-link-freetext" href="https://vlab.ncep.noaa.gov/web/wdtd/racproc">https://vlab.ncep.noaa.gov/web/wdtd/racproc</a><br>
</p>
<p> We have a methodology for quickly assessing differences in
precip type for choosing the best precip source and identifying
things like melting hail contamination that causes high biases in
Dual Pol QPE. A difference like this will stick out like a sore
thumb in the instantaneous rate six panel (see image below). You
should be able to see how the rates compare to Legacy and Dual Pol
and see if there is anything unusual in the patterns of surface
precip type. Most likely it is triggering the tropical convective
if it is overestimating. Watch for temporal continuity in SPT
during the period of heaviest rainfall and see if it is missing
any hail signals in the base data.<br>
</p>
<p>I've been looking at a number of heavy rainfall events throughout
the country for our flash flood training development, and my
perception is that MRMS tends to perform a little better than Dual
Pol which performs a bit better than Legacy most of the time but
it varies by environment/season and can change during an event, so
we recommend starting each event assessing if you have any
significant differences between sources and choosing a source that
looks to be the most reasonable to start with. Then spot check
your precip sources routinely during an event to see who is doing
best where it matters most. MRMS typically shines in hail
contamination events because its rate cap is 2"/hr for hail which
usually lowers MRMS estimates significantly (which is fine until
you have heavy rainfall rates >2"/hr with hail). MRMS
overestimates like your case are usually tropical convective SPT
when it shouldn't be or MRMS not identifying hail.<br>
</p>
<p>Differences of 10-25% are common among all our operational precip
sources, and I routinely find differences of 50% or larger at
times during heavy rainfall. The biases can sometimes vary
spatially and temporally in an event (and during the seasons) for
all precip sources, so we preach using all of your observations
and giving more weight to those in the strongest cores for flash
flood warnings, and only use the mean field bias corrections or
the MRMS spatially varying corrections as a first guess. Also pay
extra attention to MRMS biases because those biases will propagate
to the FLASH streamflows.<br>
</p>
<p>Accurate QPE is still a challenge for all of today's algorithms,
and those who rely too heavily on the precip source that worked in
the previous event are going to be susceptible to unpleasant
surprises (I see that a lot actually with many offices). Maybe we
will have more consistent separation for MRMS when it starts using
Dual Pol variables in one of the next versions, but I foresee the
best warning performance coming from carefully selecting and
re-assessing your precip source and blending that with the new
streamflow products. <br>
</p>
<p>At least the MRMS overestimates out west should be addressed now
that 11.5 has allowed continental ZRs instead of just tropical ZR
for heavy rainfall. Feel free to share some of your MRMS screen
captures with me offline, as I enjoy the challenge of quickly
getting to the bottom line for the differences in QPE.<br>
</p>
<p><img src="cid:part1.F106DD39.F8AD5AA4@noaa.gov" alt=""></p>
<p>Mike<br>
</p>
<br>
<div class="moz-cite-prefix">On 6/22/2018 12:55 PM, Jeffrey Hovis -
NOAA Federal wrote:<br>
</div>
<blockquote type="cite"
cite="mid:LYRIS-21262-562610-2018.06.22-13.56.12--Michael.A.Magsig%23noaa.gov@infolist.nws.noaa.gov">
<div dir="ltr">All,
<div><br>
</div>
<div>I want to thank everyone for answering. It did answer some
of my questions. I am going to read through everything and
see where</div>
<div>I go with any additional questions.</div>
<div><br>
</div>
<div><br>
</div>
<div>Jeff</div>
<div><br>
</div>
<div> </div>
<div class="gmail_extra">
<br>
<div class="gmail_quote">On Fri, Jun 22, 2018 at 10:54 AM,
Joseph Moore - NOAA Federal <span dir="ltr"><<a
href="mailto:joseph.moore@noaa.gov" target="_blank"
moz-do-not-send="true">joseph.moore@noaa.gov</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>Jeffery, I'll definitely agree with you that for
where the most precip fell, MRMS was on the hot side
(mrms-radar-only.PNG). The gauge-adjusted product
doesn't seem to have really changed much of that
(mrms-gauge-adj.PNG), though looking at the diagnostic
provided by MRMS (the <i>Gauge Influence Index</i>,
viewable on MRMS Op Product Viewer site) there doesn't
appear to be <i>any </i>gauge correction going on
anywhere right now or in the past 24 hours for any
precip accumulation timeframe. (<b>I think the issue
of no gauge adjustment happening is an actual
problem with MRMS, so I'm looping the MRMS Users
email list on this thread</b>.)<br>
</div>
<div><br>
</div>
<div>Compared to the RLX radar (STA, STA-hires, and STP
images), the MRMS data certainly has a broader area of
3"+ and a fairly broad area of 4"+ compared to the
legacy and dual-pol estimates. So even compared to
other precip estimates, MRMS seems on the high side.
Why the MRMS estimates are running too hot? As I said
in my first message, it is probably a case of
mis-classification of the type of rainfall occurring -
maybe using the tropical algorithm when it should be
using a standard convection one. Looking through the
Reflectivity Cube (see the Op Product Viewer), during
the most intense parts of the rain yesterday MRMS
certainly seems to have ingested your radar and
surrounding radars correctly with no gross errors
obvious to me. The MRMS Ops folks on the Users
listserv may be able to diagnose what's going on in
this case better than I can.</div>
<div><br>
</div>
<div>We can't expect MRMS to be perfect, just like we
know the radar-based legacy and dual-pol estimates are
going to have errors for various reasons. For what
it's worth, on our recent heavy rainfall event last
weekend MRMS absolutely <i>nailed </i>the precip
estimation with no strong high or low bias - it got
the maximum amounts just about as spot-on as you can
expect... and that was with our primary radar down!
(MPX's radar provided sufficient radar data to help
fill in the gap to our radar being down, but at a
higher elevation than DLH would have been scanning if
it were up.) <br>
</div>
<div><br>
</div>
<div>If there is a noticeable problem with MRMS data,
this should be reported to the MRMS/NCEP folks so they
can investigate (I think <i><a
href="mailto:ncep.list.idp.mrms.users@noaa.gov"
target="_blank" moz-do-not-send="true">ncep.list.idp.mrms.users@noaa.<wbr>gov</a></i>
is the best choice but someone else chime in there's a
better option!)</div>
<div><br>
</div>
<div>-Joe<br>
</div>
<div><br>
</div>
<div>MRMS Op Product Viewer: <a
href="https://mrms.nssl.noaa.gov/qvs/product_viewer.php"
target="_blank" moz-do-not-send="true">https://mrms.nssl.noaa.gov/qvs<wbr>/product_viewer.php</a></div>
<div>WRH Wx and Hazard Viewer: <a
href="https://www.wrh.noaa.gov/map/" target="_blank"
moz-do-not-send="true">https://www.wrh.noaa.gov/map/</a></div>
<div><br>
</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote"><span class="">On Fri, Jun 22,
2018 at 9:19 AM, Timothy Humphrey - NOAA Federal <span
dir="ltr"><<a
href="mailto:timothy.humphrey@noaa.gov"
target="_blank" moz-do-not-send="true">timothy.humphrey@noaa.gov</a>></span>
wrote:<br>
</span>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">
<div dir="ltr">Over the past several days here at
the Lake Charles office, we also noticed that
the MRMS-QPE Radar only was running quite hot
compared to our individual radars' estimates and
surface observations. Comparing this morning's
12Z 72 hour MRMS estimates to a variety of
observation sites including ASOS/ALERT/COOP
confirmed this with a few comparisons listed
below:
<div><br>
</div>
<div>JYDT2: 7.91" MRMS: 10.33"</div>
<div>JYET2: 7.76" MRMS: 13.18"<br>
<div>JYGT2: 6.38" MRMS: 7.48"</div>
<div>KBPT: 5.79" MRMS: 8.11"</div>
<div>ORNT2: 4.91" MRMS: 6.06"</div>
<div><br>
</div>
<div>Based on our experience, the QPE-Radar
Only seemed that it was running much hotter
compared to previous events and we were also
curious what might have been causing such a
large difference. Our concern is that these
large differences could result in derived
FLASH products being less reliable for
warning decision making.<br>
</div>
</div>
</div>
</span>
<div class="gmail_extra">
<div>
<div class="h5">
<div>
<div class="m_-251700852220942345h5"><br>
<div class="gmail_quote">On Fri, Jun 22,
2018 at 8:54 AM, Jeffrey Hovis - NOAA
Federal <span dir="ltr"><<a
href="mailto:jeffrey.hovis@noaa.gov"
target="_blank"
moz-do-not-send="true">jeffrey.hovis@noaa.gov</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div dir="ltr">Jack,
<div><br>
</div>
<div>It was approximately 10 miles
from the area of heaviest rainfall
to the radar site (RLX) . As you
indicated, COOPS are not included
in the MRMS data.</div>
<div><br>
</div>
<div>I just wanted to see what might
have caused the large difference
in rainfall amounts. </div>
<div><br>
</div>
<div>We issued a Flash Flood Warning
based on the MRMS data. It was a
good warning as we did have lots
of flash flooding reports. </div>
<div><br>
</div>
<div>Jeff</div>
<div>
<div
class="m_-251700852220942345m_7024192615613847659h5">
<div><br>
</div>
<div class="gmail_extra">
<div class="gmail_quote">On
Fri, Jun 22, 2018 at 9:42
AM, Jack Settelmaier - NOAA
Federal <span dir="ltr"><<a
href="mailto:jack.settelmaier@noaa.gov" target="_blank"
moz-do-not-send="true">jack.settelmaier@noaa.gov</a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div dir="ltr">I may be
mistaken, but I'm
guessing MRMS does not
use COOP data in its
algorithms, as it's more
real-time (not QCd too
much) and mostly just
uses radar data. How
far from the nearest
radar was the site?
<div><br>
</div>
<div><a
href="https://training.weather.gov/wdtd/courses/MRMS/index.php"
target="_blank"
moz-do-not-send="true">https://training.weather.gov/w<wbr>dtd/courses/MRMS/index.php</a>
</div>
</div>
<div class="gmail_extra">
<div>
<div
class="m_-251700852220942345m_7024192615613847659m_-4156293075502595429h5"><br>
<div
class="gmail_quote">On
Fri, Jun 22, 2018
at 8:10 AM,
Jeffrey Hovis -
NOAA Federal <span
dir="ltr"><<a
href="mailto:jeffrey.hovis@noaa.gov" target="_blank"
moz-do-not-send="true">jeffrey.hovis@noaa.gov</a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0
0 0
.8ex;border-left:1px
#ccc
solid;padding-left:1ex">
<div dir="ltr">All,
<div><br>
</div>
<div>I just
wanted to give
you an
update. When
I came into
the office
this morning,
I checked the
MRMS 24 hour
QPE amount
against our
COOPs, We had
a COOP that
was located in
the area of
heavy rain.
MRMS indicated
that rainfall
amounts
between 3.54
and 5.11
inches near
the location
of our COOP.
Our COOP
actually
reported 2.20
inches of
rain.</div>
<div>This is a
very big
difference.<br>
</div>
<div><br>
</div>
<div>There was
Flash Flooding
in the area.
However if the
MRMS data had
verified, the
flooding would
likely have
been much
worse.</div>
<div><br>
</div>
<div>Jeff </div>
<div
class="gmail_extra"> <br>
<br>
<div
class="gmail_quote">On
Thu, Jun 21,
2018 at 3:23
PM, Jeffrey S.
Hovis <span
dir="ltr"><<a
href="mailto:jeffrey.hovis@noaa.gov" target="_blank"
moz-do-not-send="true">jeffrey.hovis@noaa.gov</a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">All,<br>
<br>
We are
currently
experiencing
an area of
heavy rain
north of our
office. The
MRMS QPE-Radar
Only product
is indicating
as much as
3.42 inches of
rain had
fallen over a
location in
the past 3
hours.
However, none
of the
surrounding
radars are
indicating
that much rain
has fallen.
In fact, the
highest 3 hour
rainfall
amount based
on radar that
I have found
is closer to
2.5 inches.<br>
<br>
What could be
causing this
difference
between these
two products?<br>
<span
class="m_-251700852220942345m_7024192615613847659m_-4156293075502595429m_-3672412057387341659m_-8035783454247603723m_7772369388418594077HOEnZb"><font
color="#888888"><br>
Jeffrey Hovis
<br>
</font></span></blockquote>
</div>
<br>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
</div>
</div>
<span
class="m_-251700852220942345m_7024192615613847659m_-4156293075502595429HOEnZb"><font
color="#888888">-- <br>
<div
class="m_-251700852220942345m_7024192615613847659m_-4156293075502595429m_-3672412057387341659gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<div
style="font-size:small">Jack
Settelmaier</div>
<div
style="font-size:small">Digital
Techniques
Meteorologist</div>
<div
style="font-size:small">NOAA/NWS,
Southern
Region HQ</div>
<div
style="font-size:small">Fort
Worth, TX </div>
<div
style="font-size:small">Work:
682 703 3685</div>
</div>
</div>
</font></span></div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
</div>
</div>
</div>
</div>
<span class=""><span
class="m_-251700852220942345HOEnZb"><font
color="#888888">-- <br>
<div
class="m_-251700852220942345m_7024192615613847659gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div
style="margin-left:40px"><font
face="arial,helvetica,sans-serif">Tim Humphrey</font></div>
<div
style="margin-left:40px"><font
face="arial,helvetica,sans-serif"><br>
Meteorologist</font></div>
<div
style="margin-left:40px"><font
face="arial,helvetica,sans-serif">National Weather Service</font></div>
<div
style="margin-left:40px"><font
face="arial,helvetica,sans-serif">Lake Charles, Louisiana</font></div>
<div
style="margin-left:40px"><font
face="arial,helvetica,sans-serif">337.477.5285<br>
</font></div>
<div
style="margin-left:40px"><br>
</div>
<div
style="margin-left:40px">Follow
us on <a
href="http://www.facebook.com/NWSLakeCharles"
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</font></span></span></div>
</blockquote>
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-- <br>
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data-smartmail="gmail_signature">
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<div>
<div>
<div><b>Joseph J.
Moore</b><br>
</div>
Meteorologist | WFO
Duluth Social Media
& IDSS Program
Leader | Open Source
GIS Evangelist <br>
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<div>NOAA/National
Weather Service
Duluth, MN<br>
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</span></div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Michael A. Magsig - KD5YKJ
Meteorologist Instructor
Warning Decision Training Division
120 David L. Boren Blvd, Suite 2640, Norman, Oklahoma, 73072
Email: <a class="moz-txt-link-abbreviated" href="mailto:Michael.A.Magsig@noaa.gov">Michael.A.Magsig@noaa.gov</a> Phone:(405)-325-2995 Fax:(405)-325-3203 </pre>
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