NOUS41 KWBC
092012
PNSWSH
Technical
Implementation Notice 15-53
National Weather
Service Headquarters Washington DC
412 PM EST Mon
Nov 9 2015
To: Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather
Information Network
-NOAAPORT
Other NWS Partners and Employees
From: Tim McClung
Portfolio Manager
Office of Science and Technology
Integration
Subject: RTMA and
URMA Upgrade: Effective December 15, 2015
Effective on or
about December 15, 2015, beginning with the 1300
Universal
Coordinated Time (UTC) cycle, the National Centers for
Environmental
Prediction (NCEP) will upgrade the Real-Time
Mesoscale
Analysis (RTMA) and the Unrestricted Mesoscale
Analysis (URMA)
to:
- Change model
components
- Add new product
fields
- Change product
output
1) Model
Component Changes
-Add a variational quality control for the observations to RTMA-
CONUS,
RTMA-Alaska and URMA-CONUS
-Add an
observation buddy-check for temperature to RTMA-Alaska -
-Relax the
observation quality control for coastal mass
observations in RTMA-Hawaii
-Add a 3.0 km
resolution URMA-Alaska system
The analysis runs
hourly for 00z, 01Z, 02Z ... to 23Z. Compared
with the corresponding RTMA-Alaska, the analysis
is initiated
with a 6-hour delay so that late arriving
observations can also
be assimilated. For example, the 02Z
URMA-Alaska analysis is
initiated at approximately 0835Z.
The new variational quality control helps reduce the intensity
of the bulls eyes that might occur in the
analysis due the
assimilation of bad observations. Because of its relaxed
observation cutoff time, the new URMA-Alaska uses more
observations than the existing RTMA-Alaska, thus
providing users
with a superior analysis for verification
purposes.
- For hourly
precipitation RTMA: uses Stage IV hourly as primary
source of precipitation RTMA, supplemented by Stage
II hourly
when Stage IV is not available at the time
precipitation RTMA is
made. At present, only Stage II hourly is used
for the RTMA.
NCEP now receives
hourly QPEs from some RFCs before the RTMA
cutoff time (33 minutes past the top of the hour),
using these
QPEs will allow
RTMA to benefit from local expertise as well as
at least some human oversight at RFCs.
- For 6-hourly
precipitation URMA: coverage inside of an RFC’s
domain proper will only come from that RFC (at
present, if an
RFC’s input is
late or missing, coverage from neighboring RFCs
is used). The WGRFC domain will be expanded to
cover its area of
responsibility in Mexico. Areas outside of the RFC domains
(except for Gulf of Mexico and the Atlantic) will be set to
no
data/missing. Coverage for the Great Lakes will
come from
specific RFCs assigned to each Lake (at present the
average of
all available coverage from nearby RFCs is used
for the Great
Lakes). By only using data from specific RFCs
responsible for
each given grid point in the mosaic, NCEP can ensure
data
contributing to the mosaic are properly
quality-controlled. The
only exception is for areas in the Gulf of Mexico
and off the
Atlantic Coast,
which are filled in with data from the
neighboring RFCs as before; these data are provided
mainly for
visual interest (e.g., when there is a tropical
cyclone passing
through), even though the coverage would not be of
the same
quality as the areas that are within RFCs’ domains
of
responsibility.
2) Addition of
Variables
Files will be available
on the NCEP ftp, http and NOMADS servers
via the following URLs (YYYYMMDD is the year,
month, day):
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/urma/prod/urma2p5.YYYY
MMDD
http://www.ftp.ncep.noaa.gov/data/nccf/com/urma/prod/urma2p5.YYY
YMMDD
www.nomads.ncep.noaa.gov/pub/data/nccf/com/urma/prod/urma2p5.YYY
YMMDD
-
Daytime maximum temperature (TMAX) analysis, and overnight
minimum temperature (TMIN) analysis, along with the
corresponding fields of the analysis uncertainty to the
URMA-
CONUS
GRIB2. The new fields
have a nominal spatial resolution of
2.5 km and are
produced once a day. The current day 8Z analysis
creates the TMAX analysis for the previous day,
while the
current day 20Z analysis creates the TMIN analysis
for the
current day.
- Maximum
Temperature (TMAX) analysis will be added to:
urma2p5.t08z.2dvaranl_ndfd.grb2
urma2p5.t08z.2dvaranl_nwrfc.grb2
- Maximum
Temperature (TMAX) analysis uncertainty will be added
to:
urma2p5.t08z.2dvarerr_ndfd.grb2
urma2p5.t08z.2dvarerr_nwrfc.grb2
- Minimum
Temperature (TMIN) analysis will be added to:
urma2p5.t20z.2dvaranl_ndfd.grb2
urma2p5.t20z.2dvaranl_nwrfc.grb2
- Minimum
Temperature (TMIN) analysis uncertainty will be added
to:
urma2p5.t20z.2dvarerr_ndfd.grb2
urma2p5.t20z.2dvarerr_nwrfc.grb2
NCEP is adding
the following 3.0 km resolution analysis fields
and corresponding analysis uncertainty fields
from the new URMA-
Alaska system:
- 2-m
temperature,
- 2-m specific
humidity
- 2-m dew point
- 10-m wind speed
- 10-m wind
direction
- 10-m wind gust
- surface pressure
- surface visibility
- maximum temperature (TMAX)
- minimum temperature (TMIN)
These fields are
produced hourly for 00z, 01Z, 02Z, ... , and
23Z, except for TMAX and
TMIN, which are produced once a day
each. The current day 8Z analysis creates the
TMAX analysis for
the previous day, while the current day 20Z
analysis creates the
TMIN
analysis for the current day.
The URMA-Alaska
GRIB2 files containing these fields will be
available on the NCEP ftp, http and NOMADS servers as
follows:
akurma.tCCz.2dvaranl_ndfd_3p0.grb2 (for
analysis)
akurma.tCCz.2dvarerr_ndfd_3p0.grb2 (for
analysis uncertainty)
3) Product output
changes
The radius of the
Earth used for the GRIB2 encoding of the
RTMA and URMA
output files is changing from 6,371,229.0 m to
6.371,200.0 m, which is the value used by the National Digital
Forecast
Database and AWIPS.
4) Additional
airport temperature data
RTMA temperature
data will be interpolated at an additional
141 airports (all
in Alaska) to serve as a real-time observation
where an observation is unavailable. This action
will change the
order of text. Use of the RTMA is expected to help
mitigate the
problem of flight delays, diversions, and
cancellations caused
by the lack of a temperature report.
Interpolated temperature
data at airports across CONUS, Hawaii, Puerto
Rico and Guam will
continue to be available. Users can download the
hourly text
product, alphabetized by the airport 3 or 4
character code, on
the NCEP server at:
http://nomads.ncep.noaa.gov/pub/data/nccf/com/rtma/prod/airport_temps
5) Sample
Parallel Data will be available on the NCEP HTTP
server in early-November. The parallel data will be
available
via the following URLs:
http://para.nomads.ncep.noaa.gov/pub/data/nccf/com/rtma/para/
http://para.nomads.ncep.noaa.gov/pub/data/nccf/com/urma/para/
Information about
the precipitation RTMA/URMA, with links to
parallel run data directories if available at:
http://www.emc.ncep.noaa.gov/mmb/ylin/pcpanl/
For questions
regarding these changes, please contact:
Geoff DiMego
NCEP/EMC
Mesoscale Modeling Branch
College Park,
Maryland
301-683-3764
For questions
regarding the data flow aspects of these data
sets, please contact:
Carissa Klemmer
NCEP/NCO Dataflow
Team
College Park,
Maryland
301-683-0567
ncep.list.pmb-dataflow@noaa.gov
NWS National
Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
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