NUMERICAL WEATHER PREDICTION IN VERY SHORT TERM WIND FORECASTING

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Zoltan Toth

Global Systems DivisionNOAA/OAR/ESRL

Acknowledgements:Forecast Applications Branch

HISTORICAL OVERVIEW & STATUS

• T-LAPS – Terminal Local Analysis & Prediction System– Fine scale (5 km?) analysis of 3D winds around 40

terminals since early 1990s - ITWS– Revolutionary solution at the time– Still used in operations today (20-year old system)– Statistical nowcasting tools have limitations

• NWS operational systems today (NAM, RAP) – ~ 12 km resolution

• Analysis has insufficient detail• Forecast does not resolve features of interest

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WHAT HAS CHANGED• User needs - Demand for analyses and forecasts that are

– More accurate– More detailed– 3D gridded– Supporting specific decision tool

• Scientific readiness – Advances in– Data assimilation - 4DVAR, hybrid, multiscale methods– Numerical modeling – Boundary layer, microphysics, etc– Ensembles to quantify uncertainty for decision making

• Observing systems – New instruments / platforms– Various profilers, radiometrics

• Computing– Massively parallel architectures, Graphical Processing Units, Fine

Grain computing, etc

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TRADITIONAL 3DVAR, LAPS, & VAR-LAPSLAPS

VAR-LAPS

TRUTH

3DVAR withsmall-scalecovariance

3DVAR withlarge-scalecovariance

3DVARMedium-

scale

NEW REVOLUTION FOR 0-3 HOUR FORECASTS?

NWP-based very short term forecasting possible

•Paradigm shifts due to major advances in 4 areas– From statistically based nowcasting tools & subjective methods to

• Statistically enhanced NWP guidance– From disjoint efforts focusing on different AIVs to

• Holistic approach based on gridded NWP guidance– Same core system with specific end user applications serving multiple users

•Vision– 1 km resolution national NWP-based system

• Analysis with 5-min update frequency• Forecast for 0-3 hours, with 15-min frequency• Statistical processor to reduce systematic errors and blend with latest obs

WARN ON FORECASTING (WOF) – ARE WE GETTING THERE?

• On occasion, variational LAPS superior to advection and persistence

Variational LAPS

WHAT’S NEEDED?

NWP-based very short term forecasting

•Observations – Use all existing observations– Asses additional needs – Observing System Simulation

Experiments– Deploy systems near terminals – focus on lower atmosphere

•NWP data assimilation– Focus on fine scales – multiscale methods– 4-DVAR– Dynamical & physical balances for forecast initialization

•Numerical forecasting– Boundary layer & microphysics parameterizations– Variable resolution models for enhancements near terminals– Ensembles to quantify forecast uncertainty

TO MAKE & COMPLETE THE FORECAST

• Computing– GPU or other fine grain solutions

• Statistical postprocessing– Modify / reconfigure existing nowcasting tools to use NWP

guidance– Bayesian methods to fuse predictive information from

• NWP guidance• Latest observations• Conditional climatology

• User applications – Aviation– Wind compression– Runway wind shifts– Visibility– Icing– Turbulence– Precipitation incl type– Lightning– Convection

Cloud / Reflectivity / Precip Type (1km analysis) - Loop

DIA

Obstructions to visibility along approach paths

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APPLICATIONS / NEEDS - NWS

• High quality digital TAF – WFOs

• Wind compression / approach decisions – CWSUs

• Automated frontal analysis – NCEP/HPC

• Severe weather initiation – NCEP/SPC

• Fire Weather – WFOs

• Marine forecasting - WFOs

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Variational LAPS, Mar. 23, 2011 1230ZFront analysis for the case of

Divergence field

FIRE WEATHER APPLICATIONIncident reportIncident report

Regional scale dataRegional scale data

Downscaling Downscaling

Fine Scale Forecast Fine Scale Forecast

Fill in detailsFill in details

Variational LAPSVariational LAPS

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Example of Downscaling: Four Mile Canyon Fire

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Initial input at 8km res

Surface U wind (colors)

NO

RT

H-S

OU

TH

EAST – WEST (km)0 100 200

363330272421181512 9 6 3 0 -3 -6

Contour lines: topography

Downscaled output at 1km resolution

Finer details in wind in response to high resolution terrain

EAST – WEST (km)0 100 200

APPLICATIONS / NEEDS – DoD & DHS

• Dispersion forecasting – DHS

• Precision drops – US Army

• Toxic air alerts for rocket launches – USAF – RSA

• Nuclear pollution tracking – USAF – AFTAC

• Dispersion – toxic plume prediction – DHS – GTAS

• Theater forecasts

LAPS Applications:High Resolution LAPS is used to initialize WRF model runs and other systems around the globePersonnel:Linda Wharton, Isidora Jankov, Steve Albers, Dan Birkenheuer - FAB

LAPS

RSA (Range Standardization

And Automation System)

AFTAC (Air Force Technical

Applications Center)

DFW SEA NYC KSC

WRF WRF WRF WRF

Ensemble

WRF WRF WRF WRF WRF WRF

PADS

AWIPS II

RSA - Range Standardization and Automation Weather Support System

… to support dispersion models predicting where toxic plumes from rocket launches will go.

… to provide high resolution weather data to help with launch decisions.

http://esrl.noaa.gov/gsd/fab

OAR/ESRL/GSD/Forecast Applications Branch

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PADS - Precision Air-Drop System

Geo-Targeted Alerting System

Provides air dispersion and toxic plume information along with NOAA meteorological and environmental data to state and local emergency management agencies.

AFTAC - Air Force Technical Applications Center

Provides nuclear treaty monitoring, nuclearevent detection and analyzes disturbing events for nuclear identification.

BACKGROUND

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LAPS USER BASE

• NOAA– ~120 WFOs (via AWIPS), ARL, NESDIS

• Other US Agencies– DHS, DoD, FAA, CA DWR, GA Air Qual.

• Academia– Univ of HI, Athens, Arizona, CIRA, UND,

McGill

• Private Sector– Weather Decision Tech., Hydro Meteo,– Precision Wind, Vaisala, Telvent

• International agencies (10+ countries)– KMA, CMA, CWB, Finland (FMI), Italy, Spain, – BoM (Australia), Canary Islands, HKO, – Greece, Serbia, Nanjing Inst. of Met.

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LAPS SCIENTIFIC IMPACT – REFEREED PAPERS

• 30 refereed publications by GSD/NOAA• 1-2 refereed papers per year

• 391 citations in refereed papers• ~ 40 / year recently

LAPS NOAA, local analysis and prediction system– Query period: 1989 - 2012-10-11

•432 Papers

•4163 Citations

– Cites/year: 181.00– Cites/paper: 9.64/0.0/0 (mean/median/mode)– Cites/author: 1975.61– Papers/author: 221.50

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LAPS SCIENTIFIC IMPACT – ALL PUBLICATIONS