1	Using Short Range Ensemble Model Data in National Fire Weather Outlooks
2	Overview SPC Fire Weather Program Use of short range ensemble forecasts (SREF) Case Studies July 8, 2003 Recent Santa Ana event (October 25-31, 2003) Conclusions
3	SPC Fire Weather Program Fire weather forecasts began in 1998 Purpose is to provide national fire weather guidance to NWS, federal, state and local government agencies Product will outlook areas where critical fire weather conditions combined with pre-existing fuel conditions forecast to occur
4	SPC Fire Weather Program Types of Outlooks: Critical Fire Weather Areas Extremely Critical Fire Weather Areas Dry Thunderstorm Areas Issued for widespread dry lightning
5	Critical Fire Weather Area Outlooks based on forecasts of Relative Humidity, maximum temperatures, sustained winds, and pre-existing fuels RH criteria varies by geography Temperatures must be greater than 60 F Sustained surface winds (10 meter) must be greater than 20 mph High Fire Danger Class Index, low 100/1000 hr fuel moisture, long term drought
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7	Use of SREF output What is an ensemble forecast?? Collection of different model solutions By changing the initial conditions, different forecast solutions are created SPC uses a 15 member ensemble from NCEP Consists of Eta, Eta KF, RSM models 48 km resolution
8	Use of SREF output Ensemble forecasts first applied operationally in the 1990s Studies have shown that ensembles are more skillful than using 1 single model (Wandishin et al, 2001, Bright and Mullen 2001) SPC began using SREF operationally in 2002
9	Use of SREF output At the SPC, nearly 300 SREF products are available: Relative Humidity Temperature Wind Fosberg Fire Weather Index Haines Index Convective precipitation Combinations of the above
10	Use of SREF output Statistical Fields Mean and Spread Shows the “average” of the ensemble Will smooth small scale features Probability Indicate the percentage of ensemble members which meet certain criteria Extreme values Useful in predicting “worst case” events
11	"Fosberg Fire Weather Index Mean..." Fosberg Fire Weather Index Mean and Standard Deviation Valid July 8 at 2100 UTC
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14	Case Studies/Verification SPC Fosberg Fire Weather Index is used to verify fire weather outlooks Index is calculated with local objective analysis scheme Fosberg FWI greater than 50 is a “threshold” value
15	Case Studies (July 8, 2003) Forecast valid at 18 UTC on July 8 Minimum RH with Mean Surface Wind
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18	Santa Ana Event October 2003 Statewide loss of 20 lives 2600 houses with over 725,000 acres burned Monetary loss figures for the disaster are estimated to be over two billion dollars
19	Satellite Loop
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24	Santa Ana Event October 2003 SREF showed some skill Increased resolution of model would likely create better forecasts Fosberg Fire Weather Index did not verify well for this event
25	Conclusions Short range ensemble forecasts will be used more and more in the future With increased experience and development, ensembles will likely prove to be more useful than a single deterministic model
26	Conclusions (Continued) Model resolution increases Better model physics Ongoing research in Initial Condition perturbations Increased ensemble spread Data mining tools and display
27	Acknowledgements The authors would like to thank Steve Weiss at the Storm Prediction Center for his review and Jason Levit for his assistance with case study data
28	For more information Visit the SPC Fire Weather Page: www.spc.noaa.gov/fire Page contains latest SPC fire outlooks, Eta forecasts and latest surface analysis Will include ensemble forecast guidance in the future This presentation is available online: www.spc.noaa.gov/publications/taylor/srefams.html Email: Sarah.Taylor@noaa.gov