PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830 AM EST THU JAN 17 2008 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS WHICH USUALLY INFLUENCE THE SEASONAL CLIMATE OUTLOOK INCLUDE: 1) EL NINO AND LA NINA - WHICH COMPRISE EL NINO/SOUTHERN OSCILLATION OR ENSO. 2) TRENDS - APPROXIMATED BY 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). THE OCN TOOL REPRESENTS THE TREND. 3) THE TROPICAL 30-60 DAY OSCILLATION - SOMETIMES CALLED MADDEN JULIAN OSCILLATION (MJO) - AFFECTS CLIMATE VARIABILITY WITHIN SEASONS. 4) THE NORTH ATLANTIC OSCILLATION (NAO) AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE ANOMALY PATTERN ESPECIALLY DURING THE COLD SEASONS. THESE PHENOMENA ARE CURRENTLY KNOWN TO BE PREDICTABLE ONLY OVER A WEEK OR SO. 5) PERSISTENTLY DRY OR WET SOILS IN THE SUMMER AND SNOW AND ICE COVER ANOMALIES IN THE WINTER. THESE FACTORS TEND TO PERSIST FOR LONG PERIODS AND ACT AS A KIND OF MEMORY IN THE CLIMATE SYSTEM. 6) STATISTICAL FORECAST TOOLS - CANONICAL CORRELATION ANALYSIS (CCA)... AND SCREENING MULTIPLE LINEAR REGRESSION (SMLR). 7) DYNAMICAL FORECAST MODELS... INCLUDING THE NCEP CLIMATE FORECAST SYSTEM (CFS). 8) AN OBJECTIVE CONSOLIDATION (ABBREVIATED CON IN THE TEXT) OF THE OCN... CCA... SMLR 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. A RATHER STRONG COLD EVENT (LA NINA) CONTINUES ACROSS THE PACIFIC BASIN. SEA SURFACE TEMPERATURES (SSTS) ARE WITH THE EXCEPTION OF WESTPAC BELOW AVERAGE THROUGHOUT THE ENTIRE EQUATORIAL PACIFIC OCEAN. SSTS IN THE NINO 3.4 REGION (FROM 5N TO 5S AND 170W TO 120W) ARE A GOOD INDICATOR OF THE STRENGTH OF A LA NINA. SSTS IN THE NINO 3.4 REGION AVERAGED 1.5 DEGREES C BELOW NORMAL DURING DECEMBER, WHERE A VALUE OF 1.0 TO 1.5 DEGREES BELOW NORMAL INDICATES THE EXISTENCE OF MODERATE LA NINA CONDITIONS. SO FAR THERE IS NO SIGN OF WEAKENING. FORECASTS AND OBSERVATIONS SUPPORT A PREDICTION OF STRONG LA NINA CONDITIONS FOR FMA 2008, FOLLOWED BY WEAKER LA NINA CONDITIONS THEREAFTER. THE CONSENSUS OF MODEL FORECASTS FOR NINO 3.4 SSTS INDICATE THAT THE CURRENT SST ANOMALIES OF BETWEEN 1 AND 2+ DEGREES C BELOW NORMAL WILL GRADUALLY DIMINISH DURING FMA AND MAM (SPRING) 2008. MOST OF THE NATION, INCLUDING NORTHWEST ALASKA, IS LIKELY TO EXPERIENCE ABOVE AVERAGE TEMPERATURES, BASED ON A COMBINATION OF TREND AND LA NINA INFLUENCES. ELSEWHERE... THE FORECAST CALLS FOR EQUAL CHANCES (EC) OF ABOVE-, NEAR-, AND BELOW AVERAGE TEMPERATURES. THE PRECIPITATION OUTLOOK FOR FMA 2008 FAVORS ABOVE AVERAGE PRECIPITATION AMOUNTS IN THE PACIFIC NORTHWEST AND NORTHERN ROCKIES, AND FROM THE CENTRAL MISSISSIPPI VALLEY NORTHEASTWARD TO THE CENTRAL GREAT LAKES. BELOW AVERAGE PRECIPITATION AMOUNTS ARE EXPECTED IN THE SOUTHWEST... THE SOUTHERN AND CENTRAL PLAINS... ALONG THE GULF COAST AND THROUGHOUT MUCH OF THE SOUTHEASTERN U.S. INCLUDING FLORIDA, THE MIDDLE ATLANTIC COAST STATES AND COASTAL SECTIONS FROM THE DELMARVA PENINSULA TO FAR EASTERN SECTIONS OF NEW ENGLAND. ELSEWHERE... THE FORECAST CALLS FOR EQUAL CHANCES (EC) OF ABOVE-, NEAR-, AND BELOW AVERAGE PRECIPITATION. THESE PRECIPITATION SIGNALS ARE THE EXPECTED RESPONSE TO A LA NINA, ALONG WITH A RELATIVELY SMALL INFLUENCE FROM TRENDS. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS 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 SEA SURFACE TEMPERATURES (SSTS) ARE SUBSTANTIALLY BELOW AVERAGE IN THE EQUATORIAL PACIFIC FROM THE SOUTH AMERICAN COAST TO FAR WEST OF THE DATE LINE. SST ANOMALIES ARE BETTER THAN -2 C FROM 110W TO THE DATELINE. OCEAN TEMPERATURES IN THE UPPERMOST 200 METERS IN THE EAST PACIFIC HAVE REMAINED WELL BELOW NORMAL, WITH LARGEST DEPARTURES OF -3 C BETWEEN 130W AND 110W. IN THE WESTPAC THE SUBSURFACE SHOWS AN EXTENSIVE POSITIVE ANOMALY OF 3.5 C OR A DEEP THERMOCLINE. ANOMALIES IN OUTGOING LONGWAVE RADIATION SHOW SUPRESSED CONVECTION (POSITIVE ANOMALIES) OVER MUCH OF THE EQUATORIAL PACIFIC... ESPECIALLY NEAR AND JUST WEST OF THE DATE LINE. LOW LEVEL EASTERLY WINDS ARE STRONGER THAN NORMAL OVER THE CENTRAL TROPICAL PACIFIC. THESE ATMOSPHERIC CIRCULATION ANOMALIES ARE CONSISTENT WITH LA NINA CONDITIONS. AN MJO EVENT HAS BEEN MODULATING THE LA NINA CONDITIONS FOR THE LAST 2 MONTHS AND AFTER A COMPLETE TOUR AROUND THE EARTH THE MJO'S ENHANCED CONVECTION IS NOW HESITATING TO RE-ENTER THE PACIFIC. PROGNOSTIC DISCUSSION OF SST FORECASTS THE STATISTICAL TOOLS... THE MARKOV MODEL... CCA... AND CONSTRUCTED ANALOG PREDICT SST ANOMALIES OF BETWEEN -0.5 AND -1.3 C FOR FMA. BUT THE CFS REACHES -2.5 IN FMA BEFORE RELAXING. A CONSOLIDATION FORECAST BASED ON CCA, CONSTRUCTED ANALOG (CA), MARKOV AND CFS MODELS PREDICTS GREATEST ANOMALIES OF ABOUT -1.0 C IN FMA 2008, -0.9 C IN MAM 2008, AND CONTINUES TO STEADILY RISE TO NEAR -0.5 C BY AMJ 2008. BEYOND THIS TIME, ENSO NEUTRAL CONDITIONS ARE PREDICTED BY THE CONSOLIDATION TOOL AT LEAST THROUGH SON 2008. IT IS TOO EARLY TO SPECULATE ABOUT NEXT WINTER ALTHOUGH WE NOTE THAT SOME TOOLS OR AT LEAST SOME OF THEIR ENSEMBLE MEMBERS INDICATE THE POSSIBILITY OF NINO3.4 BEING THE ENTIRE YEAR 2008 ON THE COLD SIDE. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE TEMPERATURE OUTLOOKS FOR ALL LEAD TIMES ARE BASED ON THE CONSOLIDATION (CON) TOOL... WHICH IS A SKILL-AND SPREAD-WEIGHTED OBJECTIVE BLEND OF THE CFS... CCA... SMLR AND OCN FORECAST TOOLS. IN ADDITION, COMPOSITES OF MODERATE (WEAK) LA NINA EVENTS FROM 1950-2006 WERE USED FOR FMA AND MAM 2008. PRECIPITATION OUTLOOKS FOR FMA AND MAM 2008 ARE DERIVED ALMOST ENTIRELY FROM COMPOSITES OF LA NINAS... WITH PROBABILITIES ADJUSTED TO REFLECT THE EXPECTED INTENSITY OF THE CURRENT LA NINA CONDITIONS. THE CON IS NOT AVAILABLE FOR ALASKA... SO THE FORECAST THERE IS BASED LARGELY ON ANALYSIS OF THE CFS WITH CONSIDERATION OF THE OCN... CCA AND SMLR. PRECIPITATION OUTLOOKS FOR AMJ 2008 AND BEYOND REFLECT WEAK SIGNALS FROM LONG TERM TRENDS. IT WOULD HAVE BEEN POSSIBLE TO USE SOIL MOISTURE TOOLS FOR SPRING AND SUMMER BUT THE PRESENT INITIAL CONDITION ON A NATIONAL BASIS IS RATHER WEAK AND DISORGANIZED. PROGNOSTIC DISCUSSION OF OUTLOOKS - FMA 2008 TO FMA 2009 TEMPERATURE: THE TEMPERATURE OUTLOOK FOR FMA 2008 CALLS FOR ENHANCED CHANCES OF ABOVE AVERAGE TEMPERATURES FOR MOST OF THE SOUTHERN AND CENTRAL CONUS AS WELL AS NORTHWEST ALASKA. ALONG THE SOUTHERN CA COAST ENHANCED CHANCES FOR BELOW NORMAL TEMPERATURES ARE PREDICTED DUE TO COLD SST IN THE CALIFORNIA CURRENT. EQUAL CHANCES (EC) OF ABOVE-, NEAR- AND BELOW AVERAGE TEMPERATURES ARE EXPECTED ELSEWHERE. THE FMA AND MAM 2008 TEMPERATURE FORECAST IS BASED LARGELY ON TREND-ADJUSTED LA NINA COMPOSITES, AND CONSIDERATION OF THE CONSOLIDATION TOOL, THE CFS AND IRI TOOLS, AND CURRENT AND ANTICIPATED LOCATIONS OF SIGNIFICANT SNOW/ICE COVER. THE TREND DOMINATES THE TEMPERATURE CONSOLIDATION FORECAST OUTLOOKS BEYOND AMJ. FOR ALL LONGER LEADS THERE ARE AREAS FOR ABOVE NORMAL TEMPERATURE - PRIMARILY IN THE WEST FROM MJJ THROUGH ASO AND IN THE CENTRAL AND NORTHERN STATES FOR NEXT WINTER. CHANGES MADE RELATIVE TO THE SET OF FORECASTS RELEASED A MONTH AGO ARE SMALL. PRECIPITATION: THE PRECIPITATION OUTLOOK FOR FMA 2008 CALLS FOR ELEVATED CHANCES OF ABOVE MEDIAN PRECIPITATION AMOUNTS IN THE PACIFIC NORTHWEST AND FROM THE CENTRAL MISSISSIPPI VALLEY, THROUGH SECTIONS OF THE OHIO VALLEY AND TENNESSEE, TO THE CENTRAL GREAT LAKES. ELEVATED CHANCES FOR BELOW MEDIAN PRECIPITATION ARE FORECAST FOR THE SOUTHWEST, THE SOUTHERN ROCKIES, THE SOUTHERN AND CENTRAL PLAINS, THE SOUTHEAST, AND FROM VIRGINIA AND DELAWARE UP THE IMMEDIATE EAST COAST TO FAR EASTERN MASSACHUSETTS. THE FAM AND MAM FORECASTS ARE BASED PRIMARILY ON TREND-ADJUSTED LA NINA COMPOSITES AND TO A LESSER EXTENT ON THE CONSOLIDATION TOOL. FORECASTS FOR AMJ 2008 AND BEYOND ARE BASED ON LONG-TERM TRENDS AND THE CONSOLIDATION TOOL. THE LIKELIHOOD OF ABOVE AVERAGE PRECIPITATION IS INCREASED ACROSS FLORIDA FROM JAS-SON 2008, WHICH COINCIDES WITH THE EXPECTED BULK OF SEASONAL TROPICAL CYCLONE ACTIVITY. BELOW MEDIAN PRECIPITATION AMOUNTS ARE EXPECTED FOR SECTIONS OF THE WEST AND PACIFIC NORTHWEST FROM MAM THROUGH ASO 2008, AND FOR SECTIONS OF THE SOUTHEAST IN DJF 2008-09 AND JFM 2009. ABOVE MEDIAN PRECIPITATION AMOUNTS ARE EXPECTED FOR SECTIONS OF THE CENTRAL SOUTHERN STATES IN DJF2008/09 THROUGH FMA2009 - THIS IS BASED ON TREND. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: HUUG VAN DEN DOOL FOR A DESCRIPTION OF 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 FORMATION OF 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 FEB 21 2008 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE. $$