PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830 AM EDT THU MAY 18 2006 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS WHICH USUALLY INFLUENCE SEASONAL CLIMATE INCLUDE 1) EL NINO AND LA NINA - WHICH TOGETHER MAKE UP EL NINO/SOUTHERN OSCILLATION OR ENSO - 2) TRENDS - THE DIFFERENCE BETWEEN THE MOST RECENT 10-YEAR MEAN OF TEMPERATURE OR 15-YEAR MEAN OF PRECIPITATION FOR A GIVEN LOCATION AND TIME OF YEAR AND THE 30-YEAR CLIMATOLOGY PERIOD (CURRENTLY 1971-2000) - 3) TROPICAL 30-60-DAY OSCILLATION- WHICH MAY AFFECT CLIMATE VARIABILITY WITHIN A SEASON - 4) THE NORTH ATLANTIC OSCILLATION - OR NAO - AND 5) PERSISTENTLY DRY OR WET SOILS IN THE SUMMER AND SNOW AND ICE COVER ANOMALIES IN THE WINTER. 6) AN OBJECTIVE CONSOLIDATION (CALLED CON IN THE TEXT) OF THE OCN, CCA, SMLR AND CFS FORECASTS IS USED AS A FIRST-GUESS IN PREPARING THE FORECAST MAPS. SST ANOMALIES ACROSS MUCH OF THE CENTRAL AND EASTERN EQUATORIAL PACIFIC HAVE DECREASED TO NEAR-NORMAL BY MID-MAY. ALTHOUGH THERE IS STILL SOME INDICATION OF LA NINA REMAINING IN THE ATMOSPHERIC CIRCULATION IN THE WESTERN TROPICAL PACIFIC, THESE ARE THE LAST REMAINING VESTIGES, AND ARE EXPECTED TO CONTINUE TO DECLINE IN STRENGTH. NO ENSO-RELATED IMPACTS ARE ANTICIPATED THIS SUMMER. THE TEMPERATURE OUTLOOK FOR JUN-JUL-AUG (JJA) 2006 CALLS FOR WARMER THAN NORMAL CONDITIONS ACROSS THE WESTERN AND SOUTHERN U.S., FROM THE PACIFIC COAST STATES AND ROCKIES TO THE GULF COAST STATES AND CAROLINAS, AND ALSO OVER WESTERN AND SOUTHERN ALASKA. ELSEWHERE THERE ARE EQUAL CHANCES OF WARMER-THAN ... COOLER-THAN... OR NEAR-NORMAL TEMPERATURES DURING JJA, INCLUDING A SMALL SECTION OF THE INTERIOR NORTHWEST. THE PRECIPITATION OUTLOOK FOR JUN-JUL-AUG (JJA) 2006 CALLS FOR THE INTERIOR PACIFIC NORTHWEST. ELSEWHERE THERE ARE EQUAL CHANCES OF PRECIPITATION BEING WETTER-THAN... DRIER-THAN... OR NEAR-MEDIAN DURING JJA, WHICH ALSO INCLUDES ALL OF ALASKA. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOK NOTE: FOR GRAPHICAL DISPLAYS OF THE FORECAST TOOLS DISCUSSED BELOW SEE: HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/TOOLS/BRIEFING CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS THE CURRENT PATTERNS OF ANOMALOUS OCEAN TEMPERATURES ARE CONSISTENT IN INDICATING A RETURN TO ENSO-NEUTRAL CONDITIONS IN THE TROPICAL PACIFIC. DURING APRIL SSTS WERE CLOSE TO AVERAGE AT MOST LOCATIONS BETWEEN INDONESIA AND 90W, WHICH IS REFLECTED IN THE NEAR ZERO DEPARTURES OBSERVED IN ALL OF THE NINO REGIONS, EXCEPT FOR NINO 1+2. DURING THE MONTH, NEGATIVE SST DEPARTURES DEVELOPED IN THE EXTREME EASTERN EQUATORIAL PACIFIC, WHICH IS A REVERSAL FROM CONDITIONS OBSERVED DURING FEBRUARY-MARCH. DURING APRIL ABOVE-AVERAGE PRECIPITATION (NEGATIVE OLR ANOMALIES, WAS OBSERVED OVER PORTIONS OF INDONESIA AND NORTHERN AUSTRALIA, WHILE BELOW-AVERAGE PRECIPITATION (POSITIVE OLR ANOMALIES) WAS OBSERVED OVER THE CENTRAL EQUATORIAL PACIFIC AND THE EASTERN TROPICAL PACIFIC BETWEEN THE EQUATOR AND 20N. SLIGHTLY STRONGER-THAN-AVERAGE LOW-LEVEL (850 HPA) EASTERLY WINDS PERSISTED OVER THE CENTRAL EQUATORIAL PACIFIC, AND ANOMALOUS UPPER-LEVEL (200-HPA) CYCLONIC CIRCULATION CENTERS WERE OBSERVED IN BOTH HEMISPHERES. ALTHOUGH THESE ATMOSPHERIC FEATURES ARE LINGERING EFFECTS OF LA NINA, THEY ARE WEAKER THAN IN PREVIOUS MONTHS. SINCE FEBRUARY THE BASIN-WIDE UPPER OCEAN HEAT CONTENT HAS INCREASED, BECOMING SLIGHTLY POSITIVE IN APRIL. COLLECTIVELY, THESE ATMOSPHERIC AND OCEANIC FEATURES SIGNAL THE DEMISE OF LA NINA AND A RETURN TO ENSO-NEUTRAL CONDITIONS. MOST OF THE STATISTICAL AND COUPLED MODELS PREDICT ENSO-NEUTRAL CONDITIONS IN THE TROPICAL PACIFIC THROUGH THE END OF 2006. HOWEVER, THE SPREAD OF THESE FORECASTS (WEAK LA NIņA TO WEAK EL NINO) INDICATES CONSIDERABLE UNCERTAINTY IN THE OUTLOOK FOR THE LAST HALF OF THE YEAR. PROGNOSTIC DISCUSSION OF SST FORECASTS MOST OF THE STATISTICAL AND COUPLED MODELS PREDICT ENSO-NEUTRAL CONDITIONS IN THE TROPICAL PACIFIC THROUGH THE END OF 2006. HOWEVER, THE SPREAD OF THESE FORECASTS (WEAK LA NINA TO WEAK EL NINO) INDICATES CONSIDERABLE UNCERTAINTY IN THE OUTLOOK FOR THE LAST HALF OF THE YEAR. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE OUTLOOK FOR JJA 2006 THROUGH JJA 2007 IS BASED ON THE CFS, THE MULTI-MODEL ENSEMBLE FROM IRI AND THE CDC-CCA RENDERING OF THE MOST LIKELY CONSENSUS FORECAST OF SEVERAL DYNAMICAL MODEL FORECASTS, AS WELL AS CCA, ECCA, SMLR, AND OCN. FORECASTS FROM JJA THROUGH NDJ 2006 PRIMARILY REFLECT THE CONSOLIDATED TEMPERATURE AND PRECIPITATION PRODUCTS (A SKILL WEIGHTED OBJECTIVE BLEND OF CFS, CCA, SMLR, AND OCN), AS WELL AS THE CFS. THE OUTLOOKS FOR DJF 2006 THROUGH JJA 2007 ARE BASED LARGELY ON A CONSOLIDATION OF CCA... SMLR... AND OCN (CFS IS NOT AVAILABLE AFTER LEAD 6)... AS WELL AS LONG-TERM TRENDS. PROGNOSTIC DISCUSSION OF OUTLOOKS - JJA 2006 TO JJA 2007 TEMPERATURE: TEMPERATURE PROBABILITIES FOR JJA 2006 ARE LITTLE-CHANGED FROM LAST MONTH. THE JAS FORECAST FEATURES A NEW ABOVE NORMAL AREA FROM NORTH DAKOTA EASTWARD TO NORTHERN SECTIONS OF THE GREAT LAKES, BETTER REFLECTING THE CONSOLIDATION FORECAST. ALSO, A REGION OF EQUAL CHANCES HAS BEEN ADDED TO THE INTERIOR NORTHWEST, BASED ON INDICATIONS FROM THE CONSOLIDATION. REMAINING FORECASTS ALSO SHOW SMALL CHANGES TO REFLECT BETTER CONFORMITY TO THE CONSOLIDATION FORECAST. MAJOR CONTRIBUTORS TO THE FORECAST ARE THE OCN, THE CCA AND THE SMLR, WITH THE CFS MAKING ITS GREATEST CONTRIBUTIONS IN LEADS 1-4. HOWVER, THOSE CONTRIBUTIONS ARE SMALL IN THIS FORECAST, DUE TO A RELATIVELY LOW EXPECTED SKILL LEVEL, BASED ON 20 YEARS OF HINDCASTS. PRECIPITATION: THE MAJOR PRECIPITATION FEATURES FROM LAST MONTHS FORECAST HAVE CHANGED LITTLE. THE MAIN FEATURES IN LEAD 1-4 ARE ABNORMAL DRYNESS IN THE NORTHWEST IN LEADS 1-3, AND ABNORMAL WETNESS IN THE SOUTHEAST IN LEADS 1-4. THE DRYNESS IS FROM GOOD CONSENSUS AMONG STATISTICAL TOOLS. THE SOUTHEAST WETNESS IS CONSISTENT WITH CONTINUED LIKELIHOOD OF AN ENHANCED ATLANTIC TROPICAL STORM SEASON. REMAINING FORECASTS ARE LITTLE-CHANGED FROM LAST MONTH, WITH THE EXCEPTION OF DJF AND JFM, IN WHICH PRIOR INDICATIONS OF ABOVE-MEDIAN PRECIPITATION IN THE SOUTH-CENTRAL U.S. HAVE BEEN CHANGED TO EC. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: EDWARD OLENIC STARTING WITH THE SEASONAL OUTLOOK RELEASED IN FEBRUARY, 2006, THE GLOSSARY OF TERMS WILL NO LONGER APPEAR WITH THIS MESSAGE. INSTEAD, TERMS THAT ARE IN THE GLOSSARY WILL BE LINKED TO THEIR DEFINITION. FOR A DESCRIPTION OF THE STANDARD FORECAST TOOLS - THEIR SKILL - AND THE FORECAST FORMAT PLEASE SEE OUR WEB PAGE AT HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/DISC.HTML (USE LOWER CASE LETTERS) INFORMATION ON THE FORMULATION AND SKILL OF THE CAS FORECASTS MAY BE FOUND AT: HTTP://WWW.CPC.NCEP.NOAA.GOV/SOILMST/FORECASTS.HTML (USE LOWERCASE LETTERS) NOTES - THESE CLIMATE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR VALID PERIOD. WITHIN ANY GIVEN VALID PERIOD OBSERVATIONS AND SHORT AND MEDIUM RANGE FORECASTS SHOULD BE CONSULTED. THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCE OF THE NEW SET NEXT MONTH ON THU JUN 15 2006. 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE $$