Summer 2012 Seasonal Forecast

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1 Summer 2012 Seasonal Forecast The 7th Annual Earth Networks Energy Weather Seminar: Summer/Hurricane Outlook 2012 Thursday, April 12 Houston, TX Anthony Artusa Climate Prediction Center Photo:

2 Contents Significant factors in this Summer s Outlook (ENSO-Neutral Conditions, Soil Moisture, reduced Wind Shear) Numerical Tools Used (experimental NMME) Seasonal Outlook maps (Temp/Prcp) plus some Correlation and Composite maps Past Performance Statistics (Heidke Skill Score) West Gulf Hurricane Strikes ( )

3 Forecast Models/Tools * Statistical and Dynamical Models used to predict Seasonal Temperature and Precipitation CON: Consolidation CFSv2: Climate Forecast System (version 2) NMME: National Multi-Model Ensemble CAS: Constructed Analog on Soil moisture ENSO Composites: historical El Nino/Southern Oscillation information SMLR: Screening Multiple Linear Regression CCA: Canonical Correlation Analysis ECCA: Ensemble CCA OCN: Optimal Climate Normals (recent trends) IRI: International Research Institute for Climate & Society * More detailed information can be found in glossary at end of presentation

4 CFSv1 CFSv2 GFDL Experimental National Multi-Model Ensemble (NMME) (monthly and seasonal) ECHAM(F) ECHAM(A) NCAR NASA

5 IRI

6 IRI

7 IRI

8 IRI

9 Soil Moisture / Drought Monitor: Outlook:

10 Arctic Oscillation (Northern Annular Mode) Summer Temperature Summer Precipitation + + NEUTRAL NEUTRAL - -

Seasonal Correlation between Surface air Temperature and the AO (1950-2011) JJA +0.6 +0.4 +0.2 JAS +0.6 +0.4 +0.2 0-0.

11 Seasonal Correlation between Surface air Temperature and the AO ( ) JJA JAS ESRL NCEP/NCAR REANALYSIS

Seasonal Correlation between Precipitation rate and the AO (1950-2011) JJA +0.6 +0.4 JAS +0.6 +0.4 +0.

12 Seasonal Correlation between Precipitation rate and the AO ( ) JJA JAS ESRL NCEP/NCAR REANALYSIS

13 Percent of ENSO-Neutral events in each Temperature Tercile at (29N, 95W)

14 Percent of ENSO-Neutral events in each Precipitation Tercile at (29N, 95W)

15 Heidke Skill Score (HSS) (for categorical forecasts) C - ϵ HSS = * (100) T - ϵ C: number of Correctly forecast stations T: Total number of stations ϵ: number of stations expected correct by random chance = 1/

16 N N W C C C N W N W N N N N W C N

17 N N W C C C N W N W N N N N W C N %-Cov

18 Season Number (1-203)

19 Season Number (1-203)

20 Houston, we ve got a problem!!

21 Total Number of Hurricane Strikes ( )

22 Total Number of Major Hurricane Strikes ( )

23 A brief stroll down Memory Lane.. Famous Tropical Cyclones that affected the Houston/Galveston area since 1900 * Hurricane IKE * Houston Yacht Club - All remaining photos (web locations) are referenced at the end of the presentation

24 Great Galveston Hurricane (1900) Galveston Hurricane (1915)

25 Hurricane Carla (1961) Hurricane Alicia (1983)

26 Tropical Storm Allison (2001) Hurricane Ike (2008)

27 THE END Hurricane Ike (2008) Copyright: 2008 KTRK Houston

28 Photo Sources: Great Galveston Hurricane of Galveston Hurricane of Hurricane Carla (1961) Hurricane Alicia (1983) Tropical Storm Allison (2001) Hurricane Ike (2008)

29 Tools Glossary CFS - AN ENSEMBLE MEAN FORECAST FROM A FULLY-COUPLED - ONE-TIER OCEAN- ATMOSPHERE DYNAMICAL MODEL WITH NO OCEAN-ATMOSPHERE FLUX ADJUSTMENTS DONE IN POST-PROCESSING. OCEAN INITIAL CONDITIONS ARE FROM THE GLOBAL OCEAN DATA ASSIMILATION SYSTEM (GODAS). FORECASTERS USE AN ENSEMBLE MEAN OF 40 FORECAST MEMBERS. ALL ANOMALIES ARE WITH RESPECT TO A HINDCAST CLIMATOLOGY - EXCEPT FOR NINO SSTS - FOR WHICH A BIAS CORRECTION WITH THE AVERAGE IS FIRST APPLIED. THE OBSERVED NINO CLIMATOLOGY FOR IS THEN USED TO DEFINE THE NINO ANOMALIES. CCA - CANONICAL CORRELATION ANALYSIS LINEARLY PREDICTS THE EVOLUTION OF PATTERNS OF TEMPERATURE AND PRECIPITATION BASED UPON PATTERNS OF GLOBAL SST - 700MB HEIGHT - AND U.S. SURFACE TEMPERATURE AND PRECIPITATION FROM THE PAST YEAR FOR THE MOST RECENT FOUR NON-OVERLAPPING SEASONS. CCA EMPHASIZES ENSO EFFECTS - BUT ONLY IN A LINEAR WAY AND CAN ALSO ACCOUNT FOR TRENDS - LOW FREQUENCY ATMOSPHERIC MODES SUCH AS THE NORTH ATLANTIC OSCILLATION (NAO) AND OTHER LAGGED TELECONNECTIONS IN THE OCEAN-ATMOSPHERE SYSTEM. CCA FORECASTS ARE AVAILABLE FOR ALL 13 FORE- CAST PERIODS FOR THE LOWER 48 STATES - HAWAII - AND ALASKA. ECCA - UTILIZES THE CCA (CANONICAL CORRELATION ANALYSIS) METHOD OF PROJECTING LOADING PATTERNS ONTO PREDICTOR FIELDS TO MAKE A LINEAR PREDICTION OF TEMPERATURE AND PRECIPITATION. THESE LOADING PATTERNS ARE STATISTICALLY DETERMINED BY MAXIMIZING THE CORRELATION BETWEEN THE PREDICTORS AND PREDICTANDS (FORECAST FIELDS) USING DATA GOING BACK TO THE ENSEMBLE IS CREATED BY MAKING FORECASTS USING VARIOUS PREDICTOR VARIABLES TO MAKE FORECASTS, THEN AVERAGING THE FORECASTS WITH EQUAL WEIGHTS. THE POOL OF POSSIBLE PREDICTORS USED ARE 200MB GLOBAL VELOCITY POTENTIAL, GLOBAL SEA SURFACE TEMPERATURES, SEA LEVEL PRESSURE (NORTH OF 40N), AND US SOIL MOISTURE ENSO COMPOSITES - AVERAGES OF OBSERVATIONAL DATA STRATIFIED BY EL NINO - LA NINA OR ENSO-NEUTRAL CONDITIONS PROVIDE GUIDANCE FOR U.S. EL NINO AND LA NINA EFFECTS BY SUPPLYING HISTORICAL FREQUENCIES OF THE THREE FORECAST CLASSES IN PAST YEARS WHEN (FOR THE PARTICULAR FORECAST SEASON) THE CENTRAL EQUATORIAL PACIFIC WAS CHARACTERIZED BY MODERATE OR STRONG LA NINA OR EL NINO CONDITIONS. REGIONS INFLUENCED BY ENSO ARE DEFINED BY HISTORICAL FREQUENCIES THAT DIFFER SIGNIFICANTLY FROM CLIMATOLOGY. PROBABILITY ANOMALIES ARE ESTIMATED BY THE USE OF HISTOR- ICAL FREQUENCIES TEMPERED BY THE DEGREE OF CONFIDENCE THAT EITHER WARM OR COLD ENSO CONDITIONS WILL BE IN PLACE IN A GIVEN TARGET SEASON. VERSIONS OF THE MAPS OF THE HISTORICAL FREQUENCIES USED TO MAKE THE FORECASTS CAN BE VIEWED UNDER "U.S. EL NINO/LA NINA IMPACTS" ON THE CPC WEBSITE LOCATED AT OCN - THE OPTIMAL CLIMATE NORMALS METHOD PREDICTS T AND P ON THE BASIS OF YEAR-TO-YEAR PERSISTENCE OF THE OBSERVED AVERAGE ANOMALIES FOR A GIVEN SEASON DURING THE LAST 10 YEARS FOR T - AND THE LAST 15 YEARS FOR P. OCN EMPHASIZES LONG-TERM TRENDS AND MULTI-YEAR REGIME EFFECTS. OCN FORECASTS ARE AVAILABLE FOR ALL 13 FORECAST PERIODS - BUT ARE NOT YET AVAILABLE FOR HAWAII.

30 Tools Glossary (cont.) CAS - CONSTRUCTED ANALOG ON SOIL MOISTURE IS BASED ON EMPIRICAL ORTHOGONAL FUNCTIONS (EOF) FROM DATA OVER THE LOWER 48 STATES BEGINNING IN THIS TOOL CONSTRUCTS A SOIL MOISTURE ANALOG FROM A WEIGHTED MEAN OF PAST YEARS. THE WEIGHTS ARE DETERMINED FROM THE SIMILARITY OF SOIL MOISTURE CONDITIONS IN PRIOR YEARS TO A COMBINATION OF RECENTLY SOIL MOISTURE OBSERVATIONS AND A MEDIUM RANGE FORECAST OF SOIL MOISTURE OUT TO 14 DAYS BASED ON MRF TEMPERATURE AND PRECIPITATION FORECASTS. THEN THE TEMPERATURE AND PRECIPITATION OBSERVED IN SUBSEQUENT SEASONS IN THOSE PAST YEARS ARE WEIGHTED IN THE SAME PROPORTION TO PRODUCE A FORECAST THAT IS CONSISTENT WITH CURRENT SOIL MOISTURE CONDITIONS. ALTHOUGH AVAILABLE THROUGHOUT THE YEAR - THE CAS IS USED ONLY DURING THE WARM HALF OF THE YEAR FROM APRIL TO SEPTEMBER AND FOR THE SHORTER LEADS WHEN THEIR EFFECTS ARE THE MOST PRONOUNCED AND SKILLFUL. SMLR - SCREENING MULTIPLE LINEAR REGRESSION TOOL IS USED TO EXTRACT INFORMATION FROM A VARIETY OF SOURCES TO PRODUCE A FORECAST FOR SEASONAL AND MONTHLY TEMPERATURE AND PRECIPITATION. SMLR USES THE SAME PREDICTOR FIELDS AS FOR CCA BUT IS APPLIED TO SINGLE STATIONS RATHER THAN MULTI-STATION ANOMALY PATTERNS AS IS DONE IN CCA. ADDITIONALLY - SMLR USES THE TWO WEEK MRF-BASED SOIL MOISTURE FORECAST AS A PREDICTOR. CON (CONSOLIDATION) - AN OBJECTIVE, SKILL WEIGHTED (AND CALIBRATED) COMBINATION OF THE OCN, CCA, SMLR, ECCA, AND CFS FORECASTS IS USED AS A FIRST GUESS IN PREPARING THE FORECAST MAPS. THIS TECHNIQUE MAKES OPTIMUM USE OF THE KNOWN SKILL OF OUR FORECAST TOOLS. IRI A MODEL THAT IS INDEPENDENTLY GENERATED BY THE INTERNATIONAL RESEARCH INSTITUTE FOR CLIMATE AND SOCIETY (IRI) WHICH USES SSTS (SEA SURFACE TEMPERATURES) AND IN SOME CASES, PERSISTENCE, TO CONSTRUCT SEASONAL OUTLOOKS OF SURFACE TEMPERATURE AND PRECIPITATION FOR VARIOUS REGIONS INCLUDING THE U.S. (PLEASE REFER TO SOURCE #3 FOR MORE INFORMATION. NMME NATIONAL MULTI-MODEL ENSEMBLE. THIS EXPERIMENTAL PRODUCT BECAME AVAILABLE FOR CONSIDERATION IN CPC S SEASONAL OUTLOOKS AROUND SEPTEMBER 2011, AND USES A VARIETY OF INPUTS WHICH CURRENTLY (AS OF LATE MARCH 2012) INCLUDE: CFSV1, CFSV2, ECHAMA, ECHAMF, NCAR, NASA, AND GFDL MODELS. (PLEASE REFER TO SOURCE #4 FOR MORE INFORMATION). Sources: (Item #26)

NLDAS Drought Forecast Analysis The system developed by Princeton University and University of Washington was transitioned to NCEP/EMC in July 2008, and now it is run as the EMC experimental forecast

31 NLDAS Drought Forecast Analysis The system developed by Princeton University and University of Washington was transitioned to NCEP/EMC in July 2008, and now it is run as the EMC experimental forecast system. ** Drought Forecast using Initial Condition ** Experimental Drought Forecast based on CFS Forecast (probability of total soil moisture < 20 th %-ile) Experimental Drought Forecast based on CFS Forecast (probability of total soil moisture < 20 th %-ile) JUNE 2012 JULY

32 Seasonal Correlation of Summer (JJA) Temp/Prcp with the Pacific Decadal Oscillation (PDO) ( ) JJA Temperature JJA Precipitation

33 Starting with a La Nina winter/early spring (drought already initiated in the south): Lingering La Nina Impacts ENSO- Neutral Conditions Southeast U.S. more likely to receive breaks in drought Southeast U.S. more likely to see continuing drought Relationships between ENSO and drought over the southeastern United States (Kingtse C. Mo and Jae E. Schemm, 2008)

34 IRI

35 IRI

36 Seasonal Correlation between Surface air Temperature and the AO ( ) 1. MJJ JJA JAS ESRL NCEP/NCAR REANALYSIS

37 Seasonal Correlation between Precipitation rate and the AO ( ) 1. MJJ 2. JJA 3. JAS

ENSO Cycle: Recent Evolution, Current Status and Predictions. Update prepared by Climate Prediction Center / NCEP 9 May 2011

ENSO Cycle: Recent Evolution, Current Status and Predictions Update prepared by Climate Prediction Center / NCEP 9 May 2011 Outline Overview Recent Evolution and Current Conditions Oceanic Niño Index (ONI)