WRF near RealTime HighResolution Forecast Using Bluesky

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WRF (near) Real-Time High-Resolution Forecast
Using Bluesky

• Wei Wang
• May 19, 2005
• CISL User Forum

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Outline

• A brief introduction of WRF
• Purposes of doing high-resolution WRF real-time
  forecasting
• Forecast experiments on bluesky
• Forecast examples BAMEX, RT2004, RT2005, and
  hurricanes
• Benefits of these forecast experiments
• Future

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WRF

• WRF stands for Weather Research and Forecasting
  model. It has been in development in the past few
  years.
• It supports a variety of weather research and
  forecasting capabilities, with a strong emphasis
  on the 1 10 km grid spacing range.
• The current release is WRF Version 2.

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Purposes

• Evaluate and test the model on daily basis for
  the following
• Ability to predict convective weather, its
  initiation, evolution and, to some extend,
  severity.
• Ability to forecast intensity of hurricanes.
• Evaluate if there are any values to the
  forecasting community.

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WRF Forecasts

• 2003 May 15 July 10, 4 km
• In support of field program BAMEX
• 2004 Spring/Summer, Apr 25 July 31, 4 km
• 2005 Spring/Summer, Apr 15 July 31, 4 km
• Partially in support NOAA/SPC Spring Program
• 2003 2004 Hurricane season 4 major hurricanes
  Isabel (03), Frances, Ivan and Jeanne (04), 4 km
• 2004 2005 Winter (DWFE) Dec 1 Mar 31, 5 km

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Computing Resources

• IBM bluesky
• 128 256 processors, up to 6 wallclock hours per
  day
• MSS
• up to 70 Gb per day

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Forecast Domains
4km forecast domain, 2005
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Convection Forecast Example
Reflectivity, valid 5/30/03 23Z
Composite NEXRAD Radar
23 h Reflectivity Forecast
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Convection Forecast Example
Reflectivity, valid 6/23/03 06Z
Composite NEXRAD Radar
30 h Reflectivity Forecast
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Convection Forecast Example
Reflectivity, valid 5/25/03 06Z
30 h Reflectivity Forecast
Composite NEXRAD Radar
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Example Radar reflectivity,24 h fcst vs obs,
valid 0000 UTC May 13, 2005
WRF 4km
NMM 4.5km
WRF 2km
observed
http// www.spc.noaa.gov/exper/Spring_2005
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Values to Forecasting Community

• For many forecasters, 2003 BAMEX data were the
  first convection-permitting forecasts in
  real-time they had used.
• The success of the forecasts showed the
  operational community that there were definite
  values added by using these high-resolution
  forecasts.

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Values to Forecasting Community

• Some forecasters statements
• .. This 4km WRF data has been very very useful
  to our operational forecasts, convective
  planning, and situation awareness.
• Overall, I found the 4km WRF output very
  valuable, especially the "dbz graphics. I more
  or less used it as a "quick look" for potential
  hazardous weather in my CWA. More often than not,
  the WRF outperformed the ETA20 and RUC with
  location and intensity of high plains
  thunderstorm activity.
• I would like to have the 4-km WRF running all
  year.

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WRF Hurricane Forecasts

• Evaluate models ability to do tropical storm
  (TC) and hurricane forecast.
• For example, tracks from 5-day forecasts
• Can the use of high-resolution model improve the
  intensity forecast?

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A Typical TC Forecast Domain
12 km
4 km
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WRF Hurricane Forecasts

• Hurricane Ivan (2004) best track

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Ivan at landfall 0800 UTC, 16 Sep 2004
32 h forecast from 4 km WRF
Mobile Radar
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WRF Hurricane Forecasts

• Hurricane Isabel (2003) best track

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Isabel at landfall 1700 UTC Sept 18, 2003
WRF
Obs
17 hr
WRF
WRF
41 hr
29 hr
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Values to Developers

• Strength and weakness of the model in any
  systematic way
• Robustness of the model when doing various
  applications

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Future

• Larger grid, finer resolutions, and longer
  forecast
• WRF 2 km, 30 h produced by OU and done at the
  PSC, using 1100 processors
• Can we do it here?

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In the near Future

• TCSP (Tropical Cloud Systems and Processes), July
  2005 to look at tropical storm genesis over
  Eastern Pacific
• August / September, 2005 hurricane forecast
• MIRAGE (Megacity Impacts on Regional and Global
  Environments) Spring 2006
• Multiple domains with the finest one at 3 4 km

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Acknowledgement

• Ginger Caldwell
• George Fuentes
• Marc Genty
• Siddhartha Ghosh
• Dick Valent

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Relevant web pages

• WRF model
• wrf-model.org
• Current WRF 4 km forecast
• www.mmm.ucar.edu/projects/wrf_spring/
• Current SPC Spring Program
• www.spc.noaa.gov/exper/Spring_2005/