Hydrometeorological Prediction Center

HPC Medium Range Grid ImprovementsHPC Medium Range Grid Improvements

Mike Schichtel, Chris Bailey, Keith Brill, and David Novak

Hydrometeorological Prediction Center

•Staffed 1030-1930 UTC by two forecasters -Temperatures/Pop Desk

Max/MinT and PoP Grids

-Pressure/Fronts DeskWinds Grids

Medium Range DeskMedium Range Desk

•Preliminary grids issued by 1415 UTC (15 UTC deadline)-including 00 UTC ECMWF ensemble

•Final grids usually issued by 18 UTC (20 UTC deadline)-incorporating 12 UTC guidance suite without ECMWF

Temps/PoP

Pressure/Fronts•Sky, Dewpoint, and Wx derived

Hydrometeorological Prediction Center

HPCGuide Medium Range 5 km Grids

DEWPOINTS CLOUD COVER WEATHER TYPE

MIN TEMPS MAX TEMPS WINDS 12 HOUR POPS

Hydrometeorological Prediction Center

Day 7 Skill 2008 = Day 5 Skill 2001!

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Hydrometeorological Prediction Center

Anomaly correlation die-off scores of Model and Ensemble Mean Forecasts

Hydrometeorological Prediction Center

Model Cycle (UTC) Run Duration (Days)

Members per Day

ECMWF 00, 12 10 2

DGEX 06, 18 8 2

ECMWF Ens. 00, 12 10 102

GFS 00, 06, 12, 18 16 4

GEM Global 00, 12 10 2

UKMET 00, 12 6 2

NOGAPS 00, 06, 12, 18 8 4NAEFS 00, 12 16 40

FNMOC Ens. 00 10 10

GFS Ens. 00, 06, 12, 18 16 80

GEM Ens. 00, 12 16 40

Primary Medium Range Models/Ensembles at HPC

Hydrometeorological Prediction Center

Full International

Guidance Suite

including ECMWF

deterministic and ensemble

and bias-corrected

NAEFS

Medium Range DataMedium Range Data

GEFS Member

ECMWF Member

CMC Member

ECMWF Mean

NAEFS Mean

GEFS Mean

GFS

ECMWF

90 Ensemble members

Hydrometeorological Prediction Center

Maximum Temps vs. GFS MOS

HPC Continuity

NDFD Continuity

HPC ICTDGEX

GFS ECMWF MSC

ECMWF Ens

• Forecaster compares an international guidance suite, GFS MOS, climatology, and HPC and NDFD (NWS) continuity

• Forecaster chooses blends and weights

Forecast ProcessForecast Process

Blender

Final Product

Hydrometeorological Prediction Center

Improvements MadeImprovements MadeTd and SkyTd and Sky

• April 15, 2010: Methods to derive Dew Point and Sky Changed. MAE improved up to 20%.

•Sky: Model guidance weighted according to forecaster’s PoP blends. No downscaling.

•Dew Point: Model guidance weighted according to forecaster’s Max/MinT blends. Downscaled by using a GDAS-RTMA difference accumulated by applying a decaying weight through time.

Testing June 09 – Jan 2010 (green = new)

Testing Feb 2010 (green = new)

Better in Cool Season

Hydrometeorological Prediction Center

Improvements MadeImprovements Made Td Comparison BeforeTd Comparison Before

• MDL Verification Comparison of April-Sept (00 UTC cycle)

HPC (green) highest medium range MAE

Hydrometeorological Prediction Center

Improvements MadeImprovements Made Td Comparison After ChangeTd Comparison After Change

• MDL Verification Comparison April-Sept (00 UTC cycle)

HPC (green) now lowest

MAE

Given longer history verification shown in slide #9, HPC skill should be better during cool season

Hydrometeorological Prediction Center

Latest ImprovementsLatest ImprovementsOperational as of November 2: Increased use of model

guidance downscaled using RTMA instead of PRISM.

New Day 7 skill equals = Old method Day 5.5

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This new HPC DS_FNL score does not yet reflect additional benefits from bias corrections and forecaster modifications

Hydrometeorological Prediction Center

New Day 7 skill equals = Old method Day 5.5

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This new HPC DS_FNL score does not yet reflect additional benefits from bias corrections and forecaster modifications

Hydrometeorological Prediction Center

Other ElementsOther ElementsWind SpeedWind Speed

Jul ‘09 – Jul ‘10

HPC similar to NDFD

Hydrometeorological Prediction Center

Other ElementsOther Elements12 h PoP12 h PoP

Jul ‘09 – Jul ‘10HPC better than

MOS and

similar to

NDFD

Hydrometeorological Prediction Center

Improvements PrototypedImprovements Prototyped 6 h6 h Floating PopFloating Pop

• Real-time prototyped images available at: http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody_newparms.html

• Which can be compared to the operational suite at: http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html

•6 h statistical PoPs generated from international model suite

•The 6 h period with the higher PoP is set to the HPC 12 h PoP (consistent with floating PoP principles)

•The remaining 6 h period is assigned the statistical 6 h PoP value

•Renamed “Precipitation Likelihood Index” to avoid public confusion.

Hydrometeorological Prediction Center

Improvements PrototypedImprovements Prototyped Weather Grid EnhancementsWeather Grid Enhancements

• Real-time prototyped images available at: http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody_newparms.html

• Which can be compared to the operational suite at: http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html

•Time resolution increased from 12 h to 6 hourly

•Precipitation Type Algorithm improved (top-down approach)

•Slight chance, chance, and likely qualifiers added (based on HPC PoP)

Hydrometeorological Prediction Center

CollaborationCollaboration

• Academia / Publications

• Conferences (like NROW)

• CSTAR» Rossby Wave Packets etc.

• EMC / THORPEX- Adaptive Observations

» Targeting Observation Program

• WFOs/RFCs- 12Planet Chatroom and coordination calls

Hydrometeorological Prediction Center

•HPC uses full suite of international model guidance

•Given limited forecaster resources, increasingly relying on forecaster blending input coupled with post processing

•Improvements to Td and Sky have been made

•Improvements to PoP and Wx grids prototyped

•Improvements to Max/MinTemps November 2010 (now!)

•Open to suggestions for improvement

SummarySummary