Ken Howard, Jian Zhang, Steve Vasiloff
National Severe Storms Laboratory
Carrie Langston, Brian Kaney, Ami Arthur
Cooperative Institute for Mesoscale Meteorological Studies,
University of Oklahoma
HydroMet Research Group
Warning R&D Division
Q2

“While tremendous progress has been made in the last quarter-century in many areas of QPE and VSTQPF, significant gaps continue to exist in both
knowledge and capabilities that are necessary to produce accurate high- resolution precipitation estimates at the
national scale for a wide spectrum of users.”
“To meet the nation's needs for the precipitation information effectively, the authors herein propose a community-wide integrated approach for precipitation information that fully capitalizes on recent advances in science and technology, and leverages the wide range of expertise and experience that exists in the research and operational
communities. “
Flash Flood Workshop
2

Q2 exists today as a scientific and community-based convergence towards accurate, very high-resolution multi-sensor precipitation estimates on a national scale.
Q2 is a continuation of NSSL's departure from a radar-centric approach to precipitation estimation towards an integration of radar, satellite, model, and surface observations.
Q2 goal is to glean the best practices and techniques from NOAA’s River
Forecast Centers, Forecast Offices, Office of Hydrology, domestic/international organizations and universities.
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Focused on the flash flood scale - high resolution in both time and space
Real-time (means real world) - Q2 R&D concepts and techniques are implemented in a ‘real time’ system
Operations centric - R&D focused on operational challenges and needs for critical decision support.
Challenges:
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1. National Basin Delineation Project and Repository
2. Radar Reflectivity Comparison Tool
3. Q2 National Mosaic and Quantitative Precipitation
Estimation System
4. Verification System – QVS
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USGS National Elevation Dataset (NED)
Objective: To create a national dataset of flash-flood-scale basins delineated from high-resolution digital elevation data to support the NWS Flash Flood Monitoring and Prediction (FFMP) program.
The high level of quality of the NED base data enabled the use of a mostly automated GIS delineation process.
 This effort has spanned the past 10 years.
 NSSL has had ongoing interaction and coordination with:

Every Weather Forecast Office

FFMP developers (MDL)

OCWWS, OHD

RFCs and other dataset users
Resulting basin boundary datasets are used in FFMP average basin rainfall calculations and displays.
 Significant accomplishments include:

Creation of a national seamless flash-flood-scale basin and stream dataset
NWS
FFMP
Publication:
Arthur, A. T., G. M. Cox, N. R. Kuhnert, D. L. Slayter, K. W. Howard, 2005:
The National Basin Delineation Project. Bulletin of the American
Meteorological Society, 86, 1443-1452.
Flash Flood Workshop
Specialized techniques were used to improve results in areas such as natural sinks.
6

Objective: A real time system to monitor the quality of base level data to determine potential calibration offsets and transmitter drift.
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Flash Flood Workshop
Q2
Real-time platform to develop, test, and assess advanced techniques in quality control, data integration and precipitation estimation and short term forecasting.
http://nmq.ou.edu
8

Radar
Quality
Control
Satellite
Rain
Gauge
3-D
Radar
Mosaic
Model
Sfc Obs &
Sounding
Mosaic
Products
QPE
Precip
Products
QPF*
(0-2h)
Verification Users
Lightning
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~140 WSR-88D
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31 Canadian 2 TDWR 1 TV station radar
10

National 3D Mosaic
(1x1 km, 21 vertical levels)
5-minute update cycle
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National Q2 QPE
(1x1 km, 5-minute update)
11

NSSL produces and disseminates a suite of 30+ high resolution product grids over North America
(1-km, 2.5 minutes) for use in model data assimilation, aviation product development and hydrometeorology.
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Flash Flood Workshop
13

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14

Flash Flood Workshop
15

Flash Flood Workshop
Q2
Precipitation
Products
And
Diagnostics
WRA
Salt River
Project
Stand Alone Q2 System
16

NSSL
Flash Flood Workshop
NSSL researchers receive feedback, comments and ideas from the operational personnel, private sector and other researchers to improve the quality and accuracy of the precipitation estimates.
17

NSSL researchers and collaborators can assess and compare the quality of the precipitation estimates using a spectrum of independent observing networks and techniques.
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Q2
Radar
Only
Q2
Gauge
Correct
Flash Flood Workshop
NWS
RFC
Stage 4
NESDIS
HydroEst
19

On a daily basis we verify 7600+ Q2/gauge pairs
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Q2 ‘best science’ infusion into NWS operations
Integration of dual polarization moments and techniques into the Q2 framework
- enhance quality control
- enhance QPE performance
Seamless integration of radar systems and radar networks - forward compatibility
Higher resolution in both space and time to address the urban FFs
Maintain and support Q2 as a national hydromet testbed for ‘real time’ technique development and product evaluation
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Flash Flood Workshop
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Products
3-D Reflectivity Mosaic
Composite Reflectivity
Storm Top (18dBZ)
Height of 0C
Severe Hail Index
Probability of Severe Hail
Max Estimated Hail Size
Vertically Integrated Liquid (VIL)
Precipitation Type
Precipitation Rate
1- and 3-h precipitation accumulation
6- and 72-h precipitation accumulation
Unit dBZ dBZ km-MSL km-MSL none
% mm kg/m2 none mm/hr mm mm
Update
Cycle
5 min
5 min
5 min
5 min
5 min
5 min
5 min
5 min
5 min
5 min
5 min
Every 1 hour
Model Data Assimilation. NWP Model verification. Aviation flight levels
Weather and severe weather monitoring
Aviation
Reanalysis
Severe weather verification
Use/Application
Aviation flash flood monitoring and prediction
Flash flood monitoring and prediction
Flood prediction, water resource management, hydrologic model calibration
Precipitation/drought climatology
NSSL produces and disseminates a suite of high resolution grids depicting the type and amount of precipitation reaching the earth’s surface over North America (1-km, 5-minutes)
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