WMO/WWRP WorkshopUse of NWP for Nowcasting
25 October 2011
Evaluation of the 3-km High Resolution Rapid Refresh (HRRR) as Nowcast
Guidance
NOAA/ESRL/GSDCurtis Alexander, Steve Weygandt,
Stan Benjamin, David Dowell, Eric James, Patrick Hofmann,
Tanya Smirnova, Ming Hu, and John Brown
Hourly Updated NOAA NWP Models
13km Rapid Refresh
(mesoscale)
13km RUC (mesoscale)
3km HRRR (storm-scale)
RUC – current oper Model, new 18h fcst every hour
High-Resolution Rapid Refresh Experimental 3km nest inside RR, new 15-h fcst every hour
Rapid Refresh (RR) replaces RUC at NCEP in 2011 WRF, GSI with RUC features
Spring 2011 Hourly HRRR Initialization from RR
HourlyRR
LateralBoundaryConditions
Interp to 3 km grid
HourlyHRRR
15-h fcst
Initial Condition
Fields
11 z 12 z 13 z
Time (UTC)
AnalysisFields
3DVARObs
3DVARObs
Back-groundFields
18-h fcst 18-h fcst
1-hrfcst
DDFI DDFI
1-hrfcst
18-h fcst
1-hrfcst
Interp to 3 km grid
15-h fcst
Use 1-h old LBC
to reducelatency
Use most recent IC (post-DFI)
to get latest radar info
Reduced Latency:
~2h for 2011
NOAA/ESRL/GSD/AMB Models
Model Version Assimilation Radar DFI Radiation Microphysics Cum
Param PBL LSM
RUC N/A RUC-3DVAR Yes RRTM/Dudhia Thompson Grell-
DevenyiBurk-
Thompson RUC
RRWRF-ARW v3.2+
GSI-3DVAR Yes RRTM/Goddard Thompson G3 +
Shallow MYJ RUC
HRRRWRF-ARWv3.2+
None: RR I.C. No RRTM/
Goddard Thompson None MYJ RUC
Model Run at: Domain Grid Points
Grid Spacing
Vertical Levels
Vertical Coordinate
Boundary Conditions Initialized
RUC GSD, NCO CONUS 451 x
337 13 km 50 Sigma/ Isentropic NAM Hourly
(cycled)
RR GSD,EMC
North America
758 x 567 13 km 50 Sigma GFS Hourly
(cycled)
HRRR GSD CONUS 1799 x 1059 3 km 50 Sigma RR Hourly
(no-cycle)
NOAA/ESRL/GSD/AMB Models
Model Version Assimilation Radar DFI Radiation Microphysics Cum
Param PBL LSM
RUC N/A RUC-3DVAR Yes RRTM/Dudhia Thompson Grell-
DevenyiBurk-
Thompson RUC
RRWRF-ARW v3.2+
GSI-3DVAR Yes RRTM/Goddard Thompson G3 +
Shallow MYJ RUC
HRRRWRF-ARWv3.2+
YesMultiple Radar DA
ExperimentsRRTM/
Goddard Thompson None MYJ RUC
Model Run at: Domain Grid Points
Grid Spacing
Vertical Levels
Vertical Coordinate
Boundary Conditions Initialized
RUC GSD, NCO CONUS 451 x
337 13 km 50 Sigma/ Isentropic NAM Hourly
(cycled)
RR GSD,EMC
North America
758 x 567 13 km 50 Sigma GFS Hourly
(cycled)
HRRR GSD CONUS 1799 x 1059 3 km 50 Sigma RR Hourly
(no-cycle)
HRRR Milestones• Inception over northeastern US
Sept 2007• Integration into CoSPA: Aviation Users
Spring 2008• Domain expansion to eastern US
Mar 2009• HCPF time-lagged ensemble inception May
2009• HRRR WRF-ARW updated to v3.1.1
Oct 2009• Domain expansion to CONUS
Oct 2009• HRRR WRF-ARW updated to v3.2
Apr 2010• Forecast period extended to 15 hrs
Apr 2010• Real-time multi-scale reflect. verification June
2010• Parallel (shadow) retrospective system Sept
2010• Attained ~95% reliability
Jun 2010• Reduced latency to ~2 hrs
Dec 2010
HRRR (and RR) Future Milestones• Conversion of all output to GRIB2 format
Apr 2011• Transition from RUC to RR parent model
Apr 2011• DOE-funded HRRR FTP site for energy industry May
2011• Update to WRF-ARW v3.3.1
Nov 2011• Rapid Refresh operational at NCEP
Dec 2011• Reflectivity data assimilation at 3 km scale 2012• Incorporate SatCast products at 3 km scale 2012• Assimilate Radial Velocity at 3 km scale
2012• HRRR demo @ESRL improves
2012-2014• Ensemble Rapid Refresh (NARRE) at NCEP
2014• HRRR operational at NCEP
2015?• Ensemble HRRR (HRRRE) at NCEP
2016?
Some HRRR users and applicationsAviation Weather Center (AWC): 2-D gridsFederal Aviation Administration (FAA) Command CenterNational Center for Atmospheric Research (NCAR): 2-D, 3-D, 15-min grids
Operational evaluation in CoSPAStorm Prediction Center (SPC): 2-D grids
Operational severe weather forecasting and evaluationNational Severe Storms Laboratory (NSSL): 2-D, 3-D and 15-min grids
Mesoscale analysis, Short-term precipitation forecastsNational Centers for Environmental Prediction (NCEP): 15-min grids
Real Time Mesoscale Analysis (RTMA)Bonneville Power Administration (BPA): 3-D grids
Real-time forecasts of turbine-level wind and solar irradianceColorado State University (CSU/CIRA): 2-D grids
Verification of solar irradiance forecasts at SURFRAD sitesNumerous private sector companiesAir Resources Laboratory (ARL): Tiled 3-D HRRR grids
Dispersion forecasts, Local wind forecasts in complex terrainNational Weather Service (NWS): 2-D and 3-D grids
Operational weather forecastingUnited States Air Force (USAF): 2-D grids
Operational weather forecasting
Severe Weather
Aviation
Renewable Energy
Forecasting
Model Configurations
HRRRPrimary
CoSPA
NCEPESRL/GSD
RRDev
RUCDev
RUCBackup
RRPrimary
HRRRDev
RUCOper
RREMC
RRDev2
Blending Radar Nowcasts and HRRR Forecasts for AviationCoSPA: Collaborative effort: ESRL/GSD, NCAR/RAL, MIT/LL
Provide 0-8 hr thunderstorm intensity and echo top guidance to aviation community
HRRR 15 UTC 08 July 20116 hr forecast valid 21 UTC
VIL
Echo
Top
CoSPA 17 UTC 08 July 20114 hr forecast valid 21 UTC
ObservationValid 21 UTC 08 July 2011
Blend with CIWS
Blending Radar Nowcasts and HRRR Forecasts for AviationCoSPA: Collaborative effort: ESRL/GSD, NCAR/RAL, MIT/LL
Provide 0-8 hr thunderstorm intensity and echo top guidance to aviation community
HRRR 15 UTC 08 July 20116 hr forecast valid 21 UTC
VIL
Echo
Top
CoSPA 17 UTC 08 July 20114 hr forecast valid 21 UTC
VerificationValid 21 UTC 08 July 2011
Blend with CIWS
CSI 0.20Bias 1.30
Eastern US30 dBZ threshold40 km grid
Verification of RUC/RR (parent) vs HRRRCold Season (1 Jan 2011 – 14 April 2011)
RUC vs HRRRLeadTime Clouds Precip
(13 km)Reflectivity
(40 km) Upper-Air Surface
Ceiling < 500 ft
Vis < 0.5 mile
> 0.1 inch
> 1.0 inch 25 dBZ 35 dBZ Temp RH Wind Temp Dewpt Wind
1-hr HRRR HRRRN/A N/A
Equal HRRR HRRR Equal HRRR HRRR RUC HRRR3-hr HRRR HRRR Equal HRRR HRRR RUC Equal N/A N/A N/A6-hr HRRR HRRR HRRR HRRR HRRR RUC Equal HRRR RUC HRRR
Warm Season (15 April 2011 – 25 October 2011)RR vs HRRR
LeadTime Clouds Precip
(13 km)Reflectivity
(40 km) Upper-Air Surface
Ceiling < 500 ft
Vis < 0.5 mile
> 0.1 inch
> 1.0 inch 25 dBZ 35 dBZ Temp RH Wind Temp Dewpt Wind
1-hr HRRR RRHRRR Equal
HRRR HRRR HRRR HRRR HRRR RR RR HRRR3-hr HRRR HRRR HRRR HRRR HRRR HRRR RR Equal RR Equal6-hr HRRR HRRR HRRR HRRR HRRR HRRR RR HRRR Equal Equal
HRRR Verification < 500 ft ceiling, 6-hr forecasts
TSS (3 day averages)
HRRR consistently beats the RUC(cold season)
HRRRRUCHRRR-RUC
HRRRRRHRRR-RR
HRRR consistently beats the RR(warm season)
HRRRbetterRUC/RRbetter
HRRR Verification < 0.5 mi visibility, 6-hr forecasts
TSS (7 day averages)
HRRR consistently beats the RUC(cold season)
HRRRRUCHRRR-RUC
HRRRRRHRRR-RR
HRRR consistently beats the RR(warm season)
HRRR betterRUC/RRbetter
HRRR Verification 10 m wind, 6-hr forecasts
RMS (3 day averages)
HRRR consistently beats the RUC
(cold season)
HRRRRUCHRRR-RUC
HRRRRRHRRR-RR
HRRR nearly equal to RR
(warm season)
RUC/RR betterHRRR better
HRRR VerificationUpper-Air Wind, 6-hr forecasts
RMS
HRRR and RUC nearly equal(cold season)
HRRRRUCHRRR-RUC
HRRRRRHRRR-RR
RR consistently beats the HRRR(warm season)
HRRR better RUC better HRRR better RR better
HRRR VerificationPrecipitation, 24-hr (2x12) forecasts
15 April – 25 October 2011
HRRRRRRUC
HRRR consistently beats the RR/RUC(warm season)
| | | | | | | |0.01 0.10 0.25 0.50 1.00 1.50 2.00 3.00 in
Threshold
CSI13 km
BIAS13 km
Optimal
Threshold
| | | | | | | |0.01 0.10 0.25 0.50 1.00 1.50 2.00 3.00 in
HRRR VerificationReflectivity, All Forecasts
25 dBZ CSI40 km
HRRR consistently beats the RUCAt 4+ hrs (cold season)
HRRRRUCHRRR-RUC
HRRRRRHRRR-RR
HRRR consistently beats the RR(warm season)
HRRR betterRUC/RRbetter
HRRR VerificationReflectivity, All Forecasts
35 dBZ CSI
HRRR consistently beats the RUC(cold season)
HRRRRUCHRRR-RUC
HRRRRRHRRR-RR
HRRR consistently beats the RR(warm season)
HRRRbetterRUC/RRbetter
HRRR – wintertime forecast applications
IFRLIFR MVFR
Excellent skill for low ceiling / visibility
|--------VFR-------------
HRRR – wintertime forecast applications
IFRLIFR MVFR
Excellent skill for low ceiling / visibility
|--------VFR-------------
LIFRLIFR
IFR
IFRVFR
VFR
MVFR
MVFR
Very good skill for small-scale details in strongly forced
convection andprecipitation
HRRR – wintertime forecast applications
NSSL reflectivity08z Jan. 17, 2010
HRRR 8h fcst.
Surface obs08z Jan. 17, 2010
HRRR – wintertime forecast applicationsGood skill for small-scale terrain-related details
60 F60 F
HRRR Reflectivity VerificationEastern US, Reflectivity > 25 dBZ
11-20 August 2011
Reflectivity DA in RR/RUC increases HRRR forecast skillHRRR bias depends strongly on parent model
CSI 40 km
RUC->HRRR RadarRR->HRRR Radar
RR->HRRR No RadarRUC->HRRR No Radar
RR->HRRR RadarRR->HRRR No RadarRUC->HRRR RadarRUC->HRRR No Radar
BIAS 03 km
Optimal
00 hr HRRR forecasts
RR – No radar data RR – Radar data
Obs00z 12 August 2011
01 hr HRRR forecasts
ObsObs
RR – No radar data RR – Radar data
01z 12 August 2011
RR – No radar data RR – Radar data
Reflectivity00z 12 August 201100 hr forecasts
Convergence Cross-Section
RR – No radar data RR – Radar data
Convergence Cross-Section
Reflectivity01z 12 August 201101 hr forecasts
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
40-km
20-km
25 dBZ6-h fcst
3-km
Many caseAll init times
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
ConvectiveInitiation
period
40-km
20-km
25 dBZ6-h fcst
3-km
Initi
atio
n
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
ConvectiveInitiation
period
40-km
20-km
25 dBZ6-h fcst
3-km
ConvectiveDecayperiod
Initi
atio
n
Dec
ay
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
ConvectiveInitiation
period
40-km
20-km
25 dBZ6-h fcst
3-km
ConvectiveDecayperiod
Tran
sitio
n
Initi
atio
n
Dec
ay
33
Time-lagged ensembleModel InitTime Example: 15z + 2, 4, 6 hour HCPF
Forecast Valid Time (UTC)11z 12z 13z 14z 15z 16z 17z 18z 19z 20z 21z 22z 23z
13z+412z+511z+6
13z+612z+711z+8
13z+812z+911z+10
HCPF2 4 6
18z 17z 16z 15z 14z
13z12z11z
Model runs used
model has 2h latency
Spatio-temporal scale of probabilities?
Probability of convection at fixed point in space/time is very smalleven during summer afternoons in the southeastern US
Horizontal Scale Time Window Probability > 40 dBZ
O(1 km ) O(1 min)O(<< 1%)
O(10 km) O(10 min)O(1 %)
O(100 km) O(100 min)O(30%)
Spatio-temporal scale of probabilities?
Observed convection nearAtlanta, GA
22 UTC 26 October 2010
3 hr forecast valid 21 UTC 26 October 4 hr forecast valid 22 UTC 26 October
Same model runat different valid times
Spatio-temporal scale of probabilities?
Observed convection nearAtlanta, GA
22 UTC 26 October 2010
3-4 hr forecast valid 21-22 UTC 4-5 hr forecast valid 22-23 UTC
Use a 2 hr time window
Spatio-temporal scale of probabilities?
Observed convection nearAtlanta, GA
22 UTC 26 October 2010
3-4 hr forecast valid 21-22 UTC 4-5 hr forecast valid 22-23 UTC
Then applyspatial filter:90 km radiusshown here
Reliability vs Resolution/SharpnessLogistic regression using various observation time windows for calibration
Parameter choices:3 members (2 hr lag youngest member)Fixed 2 hr time windowFixed 60 km spatial filter1.0 m/s updraft velocity detection threshold
P(convection) = [1 + exp(-z)]-1
z = B0 + B1x1 + B2x2 + B3x3
where Bi are the regressed weightsand xi are the predictors (HRRR member forecasts)
Obtain reliability while preserving resolutionProbabilities constrained between 0 and 1
The HRRR and HCPF
Confidence Probabilities and Deterministic
Valid 23z 16 July 2010
The HRRR and HCPF
Confidence Probabilities and Deterministic
Valid 23z 16 July 2010
Updraft helicity fromfour consecutive HRRR runs 13-16 UTC (color coded by run)
Tornado ReportsUp to valid time(red dots)
HRRR Severe Weather Forecasts Tornado Outbreak KS/OK10 May 2010
Updraft helicity probabilityFour consecutive HRRR runs (13-16 UTC)
Time-bracket of 2-hrs45 km search radius
HRRR Severe Weather Forecasts Tornado Outbreak KS/OK10 May 2010
43
Summary• HRRR now initialized by the RR as of 14 April 2011
• Parallel (shadow) HRRR-dev will demo 2012 candidate changes in
real-time and/or retrospective runs:
- WRF v3.3.1- MYNN PBL scheme- Shallow convective param- Satcast product- Soil moisture nudging- 3-km radar radial
velocity assimilation- 3-km radar reflectivity
assimilation- Refined 13-km Radar-DFI
• HCPF development
• Research Regular HRRRat NESSC as duplicate source
Targeting improved convective initiationforecastsTargeting improved convective maintenanceforecastsTargeting confidenceof convective forecastsTargeting improved reliability of HRRR
}}}}
HRRR Precipitation ForecastTONIGHT
13UTC 25 October 2011 Run14 hr Fcst Valid 03 UTC (9 p.m.) 15 hr Fcst Valid 04 UTC (10 p.m.)
Rain in Boulder Snow in Boulder
How much? See Steve Weygandt’s Talk @ 3:30 p.m.