All,
Here is
an example from overnight with strong northeast onshore flow @
Duluth Sky Harbor Airport (KDYT) with the METAR obs:
Location for
reference with 3/24 03 UTC observations:
Nick
is correct here. Patrick, I am assuming the plan view plot is
from the time of your message. This suggests the RTMA matches
the actual observation well. So, the observation trace on the
time series comparison is likely the bogus value from the GLERL
adjusted synthetic observation (which is not a good truth
source). Given this time series is with offshore flow, the GLERL
adjustment will be artificially high. With the HRRRv4 background
in place, the synthetic observations will need to be sunsetted
in the next version of RTMA / URMA.
Greg Mann, Ph.D.
-
Science
& Operations Officer
NOAA /
National Weather Service,
Detroit MI
Mobile:
810.423.5188 (currently on Telework)
Hi Patrick,
I think I might know what is going on here....maybe.
I pulled up the
RTMA QC kml and opened it with Google
Earth for 1/30/2021 00 UTC. KDYT is in there twice, once as
"KDYT" with the provider as "METAR"
showing an observed wind speed of 13.02 knots. It is also
listed as "KDYT" with the provider "GLERL
ADJUSTED" with an observed value of 22.04 knots. That
value in your plot looks like it matches the GLERL
ADJUSTED. Greg Mann would know way more about this, but
basically, the GLERL Adjusted obs were created to help with
the lake/land mask when the RTMA was using a course
background, RAP I think. Around a year ago this topic came
up and we were able to blacklist the GLERL adjusted
because they were causing issues in the RTMA/URMA analysis
and therefore NBM bias correction, and not really necessary
with the HRRR as the background.
I've cc'd Greg Mann, maybe he can chime in.
Best,
-Nick
All,
I
noticed winds at KDYT Duluth Sky Harbor Airport in the
marine environment (see map below) have been really
too low the past couple of days. All of our sites
outside of the marine environment have been tracking
much better:
Thanks!
--
Patrick Ayd
Science
and Operations Officer
NOAA/NWS
WFO Duluth, MN
Office: 218-729-6697
Cell: 651-245-7829
--
Nick Langlieb
Science and Operations Officer
National Weather Service
WFO Marquette, MI
906-475-5782
ext 766
--
Patrick Ayd
Science and
Operations Officer
NOAA/NWS WFO
Duluth, MN
Office: 218-729-6697
Cell: 651-245-7829
