The LAPS hot start Initializing mesoscale forecast models with active cloud and precipitation proces

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The LAPS hot startInitializing mesoscale
forecast models with active cloud and
precipitation processes

• Paul Schultz
• NOAA Forecast Systems Laboratory
• Local Analysis and Prediction Branch

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Developers of the LAPS hot-start techniques

• John McGinley, branch chief, variational methods
• Paul Schultz, project manager, modeler
• Brent Shaw, modeler
• Steve Albers, cloud analysis, temp/wind analysis
• Dan Birkenheuer, humidity analysis
• John Smart, everything

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Goals

• Address NWP spin up problem
• Explicit short-range (0-6 h) QPFs and cloud
  forecasts
• Focus on a local modeling capability
• Must be computationally inexpensive
• Exploit all locally-available meteorological data
• High-resolution grids
• Robust data ingest, QC, and fusion
• Develop a flexible solution for easy technology
  transfer
• Hardware/OS independence
• Choice of mesoscale model

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LAPS II Three-Dimensional Cloud Analysis
METAR
METAR
METAR
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Cloud typing
Cumulus vertical motions
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LAPS II Dynamic Balance Adjustment
( ) b are background quantities () are
solution increments from background ( ) are
observation differences from background
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LAPS II Dynamic Balance Adjustment
FH FL
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Example first forecast hour, 5-min frames
hot start loop
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First real-time implementation

• Real-time diabatically initialized MM5 runs since
  Fall 2000
• MM5v3-4 with minor modifications
• 125 x 105 x 34 domain, 10-km grid spacing
• K-F cumulus parameterization
• Schultz explicit microphysics
• Four 24-h forecasts per day with hourly output
• Displayed on AWIPS (FSL and BOU NWS) and WWW
• http//laps.fsl.noaa.gov/cgi/laps_fcst_products.cg
  i
• Typically available 1.5 h after cycle time

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Quantitative Assessment

• Comparison of parallel model runs using three
  kinds of initialization (hot, warm, cold)
  otherwise identical
• Objective verification of model performance using
  hot start vs. other initialization methods
• Approximately 40 forecast cycles during Jan 2001
• Gridded comparisons using LAPS analysis as truth
• Computed various threat scores, RMSE, etc.

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Model Initialization Comparisons
Time-n Time
Cold start
MM5 Forecast
no LAPS analysis interpolate from larger-scale
model
Eta
Warm start
LAPS Analyses
pre-forecast nudging to a series of LAPS
analyses sometimes called dynamic initialization
MM5 Nudging
MM5 Forecast
Hot start
MM5 Forecast
diabatic initialization using the balanced LAPS
analysis
LAPS II
Dynamically balanced, Cloud-consistent LAPS
Eta LBC for all runs
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Results of Initialization Comparisons
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Results of Initialization Comparison
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Summary of first results

• Software is very reliable
• Hot start works well for winter precipitation
  systems
• Several forecast-hours of added value
• What about summertime?
• Verification not complete
• Encouraging cases
• Some known problems

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Example 21 June 2001/0600 UTC Run
MM5 00 hr Forecast, Valid 21/0600 UTC
GOES IRNOWRAD, Valid 21/0600 UTC
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Example 21 June 2001/0600 UTC Run
MM5 01 hr Forecast, Valid 21/0700 UTC
GOES IRNOWRAD, Valid 21/0700 UTC
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Example 21 June 2001/0600 UTC Run
MM5 02 hr Forecast, Valid 21/0800 UTC
GOES IRNOWRAD, Valid 21/0800 UTC
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Example 21 June 2001/0600 UTC Run
MM5 03 hr Forecast, Valid 21/0900 UTC
GOES IRNOWRAD, Valid 21/0900 UTC
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Example 21 June 2001/0600 UTC Run
MM5 04 hr Forecast, Valid 21/1000 UTC
GOES IRNOWRAD, Valid 21/1000 UTC
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Example 21 June 2001/0600 UTC Run
MM5 05 hr Forecast, Valid 21/1100 UTC
GOES IRNOWRAD, Valid 21/1100 UTC
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Convection -- the next problem

• 10-km grid is too coarse except for biggest
  storms
• too fine for conventional convective
  parameterizations
• storms start late, produce excessive precip
• subgrid-size cumuli alias to resolvable scale
• 4 km? 3 km?
• Improvements will come, QPF bias will persist
• Parameterization for subgrid cumuli probably
  required down to 250 m
• Real life get a computer, configure the model,
  solve problems as they arise

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Intriguing aspects of the D/FW TMU project

• Texas mesonet
• surface obs in every country
• wind profilers
• CRAFT project
• real-time access to full-volume, full-resolution
  WSR-88D radars
• Internet II (Abilene)
• Includes Lubbock, D/FW, but nothing south of that
  yet
• Local or remote implementation?

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Related Presentations at NWP conference

• Dynamic Balance
• WAF/NWP P1.11, McGinley and Smart
• Cloud Analysis
• WAF/NWP JP2.5A, Schultz and Albers
• Operational Evaluation/Case Studies
• WAF/NWP 3.9, Shaw et al.
• WAF/NWP P2.3, Birkenheuer et al.
• MP P4.21, Szoke and Shaw

Available in pdf format from laps.fsl.noaa.gov