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![Page 1: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/1.jpg)
Operational Application of Operational Application of Ensembles at the SPC:Ensembles at the SPC:
Fire Weather ForecastingFire Weather Forecasting
Where Americas Climate and Weather Services Begin
David BrightNOAA/NWS/Storm Prediction Center
Norman, OK
Advanced Fire Weather Forecasters CourseFire Weather Virtual Conference
April 25, 2008
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Nine NWS National Centers
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• Hail, Wind, Tornadoes
• Excessive rainfall
• Fire weather
• Winter weather
STORM PREDICTION CENTERSTORM PREDICTION CENTER HAZARDOUS PHENOMENA
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SPC Fire Weather Outlooks• To provide national fire weather guidance for use by the National
Weather Service, as well as other federal, state, and local government agencies
• The products are intended to delineate areas of the contiguous U. S. where the forecast weather conditions, combined with pre-existing fuel conditions, result in a significant threat for wildfires
• Issued once per day during the overnight hours (through 8 days)
• Critical, Extremely Critical, and Critical Dry Thunderstorm forecasts– Low RH– Moderate / strong winds– Antecedent conditions / drought (NFDRS)– Critical area for dry thunderstorms implies
widespread lightning with minimal rainfall
![Page 5: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/5.jpg)
Outline
• Motivation for Ensemble Forecasting
• SPC Ensemble Applications in Fire Weather– Medium to Short-range Case Study
(Southern California Fires Oct. 2007)
• Ensemble Calibration and Decision Support
• Summary and Future Directions
![Page 6: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/6.jpg)
Outline
• Motivation for Ensemble Forecasting
• SPC Ensemble Applications in Fire Weather– Medium to Short-range Case Study
(Southern California Fires Oct. 2007)
• Ensemble Calibration and Decision Support
• Summary and Future Directions
![Page 7: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/7.jpg)
Example: A deterministic approachExample: A deterministic approach
57h NAM Forecast valid 21 UTC 25 June 200710m Wind (> 15 mph); 2m RH (< 20%) (filled)
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Example: A deterministic approachExample: A deterministic approach
Truth: SPC OA valid 21 UTC 25 June 200710m Wind (> 15 mph); 2m RH (< 20%) (filled)
![Page 9: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/9.jpg)
57h NAM Forecast Valid: 21 UTC 25 June 2007
Verifying AnalysisObserved: 21 UTC 25 June 2007
• Does not provide direct information on forecast uncertainty• Could be misleading and oversell forecast capability• Decision making may be optimized by considering uncertainty
Example: A deterministic approachExample: A deterministic approach
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Sources of Uncertainty in NWP:Sources of Uncertainty in NWP:
• Observations– Density– Error– Representative– QC
• Analysis• Models • LBCs, etc.
Satellite
Land
Data and Models
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Uncertainty in Initial AnalysesUncertainty in Initial Analyses
NCEP Eta Data Assimilation850 mb Initial Analysis (Hgt, Tmp, Wnd)
20 March 2006 12 UTC
NCEP WRF Data Assimilation850 mb Initial Analysis (Hgt, Tmp, Wnd)
20 March 2006 12 UTC
Two state of the art assimilation systems, and two similar but clearly different analyses (even over land).
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500 mb Hgt RMSE – Winter 2006-2007
Slope of Ens Mean (solid) is less steep
Skill is retained longer
Same results in summer
Deterministic models lose skill faster than ensemble mean
Ens Spread
Ens Mean
GFS and Ens Control
Climatology
Ens mean reduces RMSE after Day 3. Improvement increases with time and extends predictability Spread-skill
suggests ensemble is underdispersive
Error Growth with Time: GFSError Growth with Time: GFS
1.41 x Climate RMSE
(Limit of Skill)
Ensemble skill ~12-13 daysDeterministic skill ~10 days
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- Weather models...- All forecasts contain errors that
increase with time- Doubling time of small initial errors ~1
to 2 days- Maximum large-scale (synoptic to
planetary) predictability ~10 to 14 days
- Ensemble systems…- A collection of models that provide
information on the range of plausible forecasts and extend predictability
- Increasing in popularity- Principles scale (global high-res)- Requires “tools” to view the large
number of models using a slightly different approach (statistical)
Weather forecasting: It’s impossible to be deterministically correct all of the time!
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Model Res Levels Mems Cld Physics ConvectionGFS T126* (~ 105 km) 28 20** GFS physics Simple A-S
* Same as the operational GFS in 1998** 20 statistically independent perturbations (using Ensemble Kalman filter method)
NWS/NCEP Global Ensemble Forecast System (GEFS; the
ensemble formerly known as MREF)
Ensembles Available at the SPC: GEFS
Four times per day: 00, 06, 12, 18 UTC
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Model Res Levels Mems Cld Physics ConvectionGEM ~100 km 28 20 Sundqvist (mixed) Mixed
North American Ensemble Forecast System (NAEFS)
Model Res Levels Mems Cld Physics ConvectionGFS T126* (~ 105 km) 28 20 GFS physics Simple A-S
NAEFS was launched in 2004 as a joint experimental project between the U.S. National Weather Service, Meteorological Service of Canada, and the
National Meteorological Service of Mexico.
Advantages to combining two state-of-the-art ensemble systems:• Increase spread through more members and inclusion of model uncertainty• Provides seamless forecast guidance across national borders• Allows for cost sharing of research, development, and maintenance costs
http://www.weatheroffice.gc.ca/ensemble/index_naefs_e.html
Ensembles Available at the SPC: NAEFS
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NWS/NCEP Short Range Ensemble Forecast (SREF)
• EMC SREF system (21 members)– 87 hr forecasts four times daily (03, 09, 15, 21 UTC)
– North American domain
– Model grid lengths 32-45 km
– Multi-model: Eta, RSM, WRF-NMM, WRF-ARW
– Multi-analysis: NAM, GFS initial and boundary conds.
– IC perturbations and physics diversity
Ensembles Available at the SPC: SREF
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Ensemble Guidance at the SPCEnsemble Guidance at the SPC
• Develop specialized guidance for the specific application (severe weather, fire weather, winter weather)
• Design guidance that…– Helps blend deterministic and ensemble approaches– Facilitates transition toward probabilistic forecasts– Considerable diagnostic parameter evaluation in probability
space– Aids in decision support of high impact
weather• Gauge confidence • Alert for potentially significant
events
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Outline
• Motivation for Ensemble Forecasting
• SPC Ensemble Applications in Fire Weather– Medium to Short-range Case Study
(Southern California Fires Oct. 2007) Focus on Sunday afternoon: 00Z 22 Oct 2007
• Ensemble Calibration and Decision Support
• Summary and Future Directions
![Page 19: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/19.jpg)
Day -8 (Sunday Oct, 14 2007)
Harris Fire burns on Mount San Miguel the morning of October 23, 2007
Key Points: Examine the large-scale synoptic weather pattern A couple of members indicate the potential of an offshore wind event
Ensemble 00Z 14 October 2007 (Forecast hour = 192)
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GEFS Ensemble Mean: 500 mb Height and Vorticity
192h Forecast Valid 00 UTC 22 Oct 2007
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GEFS Ensemble Spaghetti: 500 mb Height (Single contour at 5760 m)
192h Forecast Valid 00 UTC 22 Oct 2007
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192h Forecast Valid 00 UTC 22 Oct 2007
GEM Ensemble Spaghetti: 500 mb Height (Single contour at 5700 m)
Verifying analysis
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GEM
GFS
NCEPE015
GEMEN009 Control
Control
http://www.weatheroffice.gc.ca/ensemble/cartes_e.html#
NAEFS Postage Stamp (Subset!) 500 mb Height
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192h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 500 mb Height and its Departure from Normal (# of SD)
Ens Mean – ClimatologyClimate Spread
Departure =
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192h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: PMSL; 1000-500 mb Thickness; 10m Wind (mph)
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192h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 2m RH (%) and its Standard Deviation
Breezy, dry airmass
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...DISCUSSION... A BROAD UPPER TROUGH WILL DEEPEN FROM DAY 3 INTO DAY 5 AS IT
DEVELOPS OVER THE FOUR CORNERS AREA AND MOVES INTO THE PLAINS...RESULTING IN STORMY WEATHER. THE TROUGH PASSAGE WILL LIKELY RESULT IN STRONG WLY WINDS AND MODERATELY LOW RH ACROSS NM AND W TX ON DAY 5 10/18...BUT CRITICAL CONDITIONS ARE NOT EXPECTED.
PREDICTABILITY THEN DECREASES AFTER ABOUT DAY 4 AS MODELS DIFFER IN SPEED OF UPPER LOW/TROUGH THAT DEVELOPS OVER THE CNTRL U.S. DEGREE OF RIDGING BEHIND THIS TROUGH WILL DETERMINE HOW MUCH POTENTIAL THERE IS FOR OFFSHORE FLOW INTO SRN CA/AZ...MOST LIKELY TO OCCUR IN THE 10/19-10/20 TIME FRAME.
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Day -6 (Tuesday Oct, 16 2007)
NASA satellite image of southern California on the afternoon of October 21, 2007
Key Points: Ensemble trend for strong western ridge continues Offshore flow pattern well established in the mean
Ensemble 00Z 16 October 2007 (Forecast hour = 144)
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144h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: 500 mb Height and Vorticity
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144h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Spaghetti: 500 mb Height (Single contour at 5760 m)
![Page 31: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/31.jpg)
144h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 500 mb Height and its Departure from Normal (# of SD)
![Page 32: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/32.jpg)
144h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: PMSL; 1000-500 mb Thickness; 10m Wind (mph)
![Page 33: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/33.jpg)
144h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 2m RH (%) and its Standard Deviation
Windy, dry airmass
![Page 34: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/34.jpg)
Day -5 (Wednesday Oct, 17 2007)
Satellite image on October 24, 2007
Key Points: Relatively high confidence in western ridge and offshore / Santa Ana wind event
Ensemble 00Z 17 October 2007 (Forecast hour = 120)
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120h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: 500 mb Height and Vorticity
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120h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Spaghetti: 500 mb Height (Single contour at 5760 m)
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120h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 500 mb Height and its Departure from Normal (# of SD)
![Page 38: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/38.jpg)
120h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: PMSL; 1000-500 mb Thickness; 10m Wind (mph)
![Page 39: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/39.jpg)
120h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 2m RH (%) and its Standard Deviation
Windy, very dry airmass
![Page 40: Operational Application of Ensembles at the SPC: Fire Weather Forecasting Where Americas Climate and Weather Services Begin David Bright NOAA/NWS/Storm.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56649ef15503460f94c025f9/html5/thumbnails/40.jpg)
...DISCUSSION... LATEST MEDIUM RANGE DETERMINISTIC MODELS/ENSEMBLES SUGGEST THE
NEXT IN A SERIES OF UPPER TROUGHS WILL LIKELY CROSS THE WESTERN STATES THIS WEEKEND. MODEL CONCENSUS SUGGESTS THIS UPPER TROUGH MAY ULTIMATELY BECOME CUT-OFF OVER THE SOUTHWEST STATES...ALTHOUGH CONSIDERABLE DISCREPANCY EXISTS IN THE PLACEMENT DETAILS. REGARDLESS...IN THIS WAKE OF THIS SYSTEM...IT APPEARS AN OFFSHORE/SANTA ANA WIND EVENT MAY BECOME ESTABLISHED ACROSS SOUTHERN CA BY LATE DAY 4/SATURDAY AND DAY 5/SUNDAY INTO DAY 6/MONDAY. AS SUCH...THE POTENTIAL WOULD EXIST FOR NOCTURNALLY-ENHANCED GUSTY WINDS ACROSS SOUTHERN CA...ALONG WITH WARMER TEMPERATURES AND LOWER RH VALUES.
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Day -4 (Thursday Oct, 18 2007)
A helicopter scoops water from a golf course in Valencia, CaliforniaAP Photo/Kevork Djansezian
Key Points: Strong western ridge (ensemble mean +2 SD)Uncertainty in location/strength of trough, but mdt-stg Santa Ana likely
Ensemble 00Z 18 October 2007 (Forecast hour = 96)
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096h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: 500 mb Height and Vorticity
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096h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Spaghetti: 500 mb Height (Single contour at 5760 m)
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096h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 500 mb Height (m) and its climatologically normalized SD
Ensemble SpreadClimate Spread
Normalized Spread =
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096h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 500 mb Height and its Departure from Normal (# of SD)
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096h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble Mean: PMSL; 1000-500 mb Thickness; 10m Wind (mph)
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096h Forecast Valid 00 UTC 22 Oct 2007
GEFS Ensemble: Mean 2m RH (%) and its Standard Deviation
Very windy, very dry airmass
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...DISCUSSION... LATEST MEDIUM RANGE DETERMINISTIC MODELS/ENSEMBLES SUGGEST THE NEXT IN A
SERIES OF UPPER TROUGHS WILL LIKELY CROSS THE WESTERN STATES THIS WEEKEND. CONSIDERABLE MODEL DISCREPANCY EXISTS IN REGARDS TO THE PROGRESSION OF THIS SYSTEM...WITH THE 00Z EUROPEAN SUGGESTING THE TROUGH COULD BECOME CUT-OFF OVER THE SOUTHERN ROCKIES.
INITIALLY ON DAY 3/SATURDAY...STRONG GUSTY WINDS ASSOCIATED WITH THE UPPER TROUGH/STRONG JET COULD YIELD AT LEAST NEAR-CRITICAL CONDITIONS ACROSS THE SOUTH CENTRAL HIGH PLAINS. THEREAFTER...IN THE WAKE OF THE UPPER TROUGH...CONFIDENCE CONTINUES TO INCREASE THAT A MODERATE-STRONG OFFSHORE/SANTA ANA WIND EVENT MAY BECOME ESTABLISHED ACROSS SOUTHERN CA BY LATE DAY 3/SATURDAY AND DAY 4/SUNDAY THROUGH DAY 6/TUESDAY. AS SUCH...THE POTENTIAL WOULD EXIST FOR NOCTURNALLY-ENHANCED GUSTY WINDS ACROSS SOUTHERN CA...ALONG WITH WARMER TEMPERATURES AND LOWER RH VALUES INTO EARLY NEXT WEEK.
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Day -3 (Friday Oct, 19 2007)
A back fire on a hillside in Jamul, CaliforniaAP Photo/Kevork Djansezian
Key Points: Shift focus to the Short Range Ensemble Forecast (SREF) Begin to examine mesoscale details and diagnostics
AP Photo/Rick Bowmer
SREF Ensemble 21Z 18 October 2007 (Forecast hour = 75)
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SREF Products Available on the SPC WebsiteSREF Products Available on the SPC Websitehttp://www.spc.noaa.gov/exper/sref/
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SREF 500 mb Mean Height, Wind, Temp
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SREF 500 mb Height (Spaghetti = 5700 m)
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SREF Mean PMSL, 10m Wind, Thickness
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SREF 10 meter Maximum Wind (any member)
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SREF Pr[WSPD > 20 mph] and Mean WSPD = 20 mph (dash)
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SREF 700 mb Mean Wind (kts)
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SREF Mean 2m Dew Point Temperature
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SREF Pr[RH < 15%] and Mean RH = 15% (dash)
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SREF Pr[RH < 10%] and Mean RH = 10% (dash)
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Pr [P12I < 0.01”] XPr [RH < 15%] XPr [WSPD > 20 mph] XPr [TMPF > 60F]
SREF Combined or Joint Probability
Critical Conditions
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SREF Combined or Joint Probability
Pr [P12I < 0.01”] XPr [RH < 15%] XPr [WSPD > 30 mph] XPr [TMPF > 60F]
High-end Critical Conditions
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SREF Combined or Joint Probability
Pr [P12I < 0.01”] XPr [RH < 10%] XPr [WSPD > 30 mph] XPr [TMPF > 60F]
Extremely Critical Conditions
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SREF Median Fosberg Index + Union (red)Fosberg Fire Weather Index (FFWI)Non-linear, empirical relationship between weather and
fire behavior.
FFWI = F(Wind speed, RH, Temperature) 0 < FFWI < 100 FFWI > ~50-60 significant conditions FFWI > ~75 extreme conditions
Union: At least one member > 50
Median
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SREF Pr[Fosberg Index > 70] and Mean FFWI = 70
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SREF Maximum Fosberg Index (any member)
Extreme values
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Examine the Individual Member Forecasts (Plumes)http://www.spc.nssl.noaa.gov/exper/sref/plume
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2m Relative Humidity Plumes
Clustering by modelGood agreement RH ~5-10%
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10m Wind Speed Plumes
Sustained winds 15-30 mph; clustered by model
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Fosberg Fire Weather Index Plumes
FFWI values from 40-80; clustered by model; well over 50% > 60
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...DISCUSSION... LATEST MEDIUM RANGE DETERMINISTIC MODELS/MREF ENSEMBLES CONTINUE TO
SUGGEST THAT THE NEXT UPPER TROUGH WILL CROSS THE WESTERN/CENTRAL STATES THROUGH DAY 3/SUNDAY...POSSIBLY BECOMING CUT-OFF/STALLING ACROSS THE SOUTHERN PLAINS EARLY NEXT WEEK. INITIALLY ON DAY 3/SUNDAY...STRONG GUSTY WINDS ASSOCIATED WITH THE UPPER TROUGH/STRONG JET COULD YIELD AT LEAST NEAR-CRITICAL CONDITIONS ACROSS THE SOUTH CENTRAL HIGH PLAINS.
AS HIGH PRESSURE PERSISTS ACROSS THE GREAT BASIN LATE THIS WEEKEND THROUGH EARLY NEXT WEEK...IT APPEARS A POTENTIALLY STRONG OFFSHORE/SANTA ANA WIND EVENT WILL OCCUR FROM EARLY DAY 3/SUNDAY INTO AT LEAST DAY 5/TUESDAY. THE POTENTIAL WILL EXIST FOR NOCTURNALLY-ENHANCED GUSTY WINDS ACROSS SOUTHERN CA...ALONG WITH WARMER TEMPERATURES AND LOWER RH VALUES THROUGH EARLY NEXT WEEK. THESE CONDITIONS...ALONG WITH EXTREME DROUGHT...SUGGEST A CONSIDERABLE FIRE DANGER WILL EXIST ACROSS SOUTHERN CA.
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Day -2 (Saturday Oct, 20 2007)
...DISCUSSION... …EXTREMELY CRITICAL FIRE WEATHER AREA - MTNS/VALLEYS OF SRN CA…
PRIMARY CONDITIONS: SUSTAINED NELY WINDS FROM 30-50 MPH WITH GUSTS OVER 75 MPH...MIN RH READINGS FROM 5-10 PERCENT...LONG TERM DROUGHT A VERY STRONG SANTA ANA/OFFSHORE WIND EVENT IS EXPECTED TO DEVELOP BEGINNING LATE ON DAY ONE AND LASTING PAST DAY 2...
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Outline
• Motivation for Ensemble Forecasting
• SPC Ensemble Applications in Fire Weather– Medium to Short-range Case Study
(Southern California Fires Oct. 2007)
• Ensemble Calibration and Decision Support
• Summary and Future Directions
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Calibrated Probability of a Thunderstorm Calibrated Probability of a Thunderstorm
15h Forecast Ending: 00 UTC 01 Sept 2004Calibrated probability: Solid/Filled
3 hr valid period: 21 UTC 31 Aug to 00 UTC 01 Sept 2004
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15h Forecast Ending: 00 UTC 01 Sept 2004Calibrated probability: Solid/Filled; NLDN CG Strikes (Yellow +)
3 hr valid period: 21 UTC 31 Aug to 00 UTC 01 Sept 2004
Calibrated Probability of a Thunderstorm Calibrated Probability of a Thunderstorm
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Perfect Forecast
No Skill
Perfect Forecast
No Skill
Calibrated ReliabilityCalibrated Reliability (5 Aug to 5 Nov 2004)(5 Aug to 5 Nov 2004)
Calibrated Thunder Probability
Climatology
Frequency[0%, 5%, …, 100%]
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SREF 3h Calibrated Probability of Thunderstorms
Thunderstorm = > 1 CG Lightning Strike in 40 km grid box
What about dry thunderstorms?
Photo from John Saltenberger
27 hour SREF Guidance Valid 21-00 UTC 15 June 2006
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SREF 3h Calibrated Probability of “Dry” Thunderstorms
Dry thunderstorms = CG Lightning with < 0.10” precipitation
27 hour SREF Guidance Valid 21-00 UTC 15 June 2006
Red indicates grid cells with “dry lightning”
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SPC SREF Web Page
Calibrated Guidance
Plume Site
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Outline
• Motivation for Ensemble Forecasting
• SPC Ensemble Applications in Fire Weather– Medium to Short-range Case Study
(Southern California Fires Oct. 2007)
• Ensemble Calibration and Decision Support
• Summary and Future Directions
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General Comments about Ensemble Approach at the SPC
• Ensembles have become a routine part of the forecast process at the SPC
• Ensemble approach to forecasting similar to the deterministic approach– Ingredients based inputs– Diagnostic and parameter evaluation– Tend to view diagnostics in probability space – particularly in short-range
• Ensembles contribute appropriate levels of confidence to the forecast process and can aid decision making (formally or informally)
• Calibration of ensemble output can remove systematic biases and improve the spread, and can be used to probabilistically downscale larger-scale environment
• Continue to enhance the short- and medium-range ensemble applications for the SPC fire weather program
– Expanded products in GEFS– Calibrated guidance– Incorporation of NAEFS– Collaboration with partners
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Potential Fire Support From Ensembles
ENSEMBLE
INPUTS
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SPC Fire Outlooks on the WEBSPC Fire Outlooks on the WEBhttp://www.spc.nssl.noaa.gov/products/fire_wx/overview.html
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SPC SREF Products on the WEBSPC SREF Products on the WEBhttp://www.spc.noaa.gov/exper/sref/
Questions/Comments…[email protected]