Mesoscale & Microscale Meteorological Division / ESSL / NCAR WRF (near) Real-Time High-Resolution...

Mesoscale & Microscale Meteorological Division / ESSL / NCAR

WRF (near) Real-Time High-Resolution Forecast

Using BlueskyWei Wang

May 19, 2005

CISL User Forum


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


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.


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.


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


Computing Resources

• IBM bluesky: – 128 – 256 processors, up to 6 wallclock

hours per day

• MSS: – up to 70 Gb per day


Forecast Domains

4km forecast domain, 2005


Convection Forecast Example

Reflectivity, valid 5/30/03 23Z

23 h Reflectivity Forecast Composite NEXRAD Radar


Example: Radar reflectivity,24 h fcst vs obs, valid 0000 UTC May 13, 2005

WRF 4km

WRF 2km

NMM 4.5km

observed

http:// www.spc.noaa.gov/exper/Spring_2005


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.


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.”


WRF Hurricane Forecasts

• Evaluate model’s 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?


A Typical TC Forecast Domain

12 km

4 km



Hurricane Ivan (2004): best track


Ivan at landfall: 0800 UTC, 16 Sep 2004

Mobile Radar

32 h forecast from 4 km WRF



Hurricane Isabel (2003): best track


41 hr29 hr

17 hr

Obs

WRF

WRF

WRF

Isabel at landfall: 1700 UTC Sept 18, 2003


Values to Developers

• Strength and weakness of the model in any systematic way

• Robustness of the model when doing various applications


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?


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


Acknowledgement

Ginger Caldwell

George Fuentes

Marc Genty

Siddhartha Ghosh

Dick Valent


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/

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