PROGNOSTIC DISCUSSION FOR LONG-LEAD OUTLOOKS CLIMATE PREDICTION CENTER NCEP NATIONAL WEATHER SERVICE WASHINGTON DC 3 PM EST THURSDAY MARCH 14 2002 BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOK . . . . . . . . THIS OUTLOOK REFLECTS THE EXPECTED U.S. CLIMATE ANOMALIES BASED ON THE LONG-TERM TREND AS ESTIMATED BY OCN - AND STATISTICALLY BASED RELATIONSHIPS BETWEEN RECENT OCEANIC AND ATMOSPHERIC CONDITIONS AND U.S. TEMPERATURE AND PRECIPITATION. DYNAMICAL FORECASTS FROM GENERAL CIRCULATION MODELS WERE ALSO CONSIDERED FOR THE FIRST FOUR SEASONS. THE EXPECTED TRANSITION TO EL NINO CONDITIONS INFLUENCES THE OUTLOOK BEGINNING WITH THE OND 2002 FORECAST. THE OUTLOOK FOR OND 2002 UNTIL MAM 2003 ARE HEAVILY INFLUENCED BY THE ANTICIPATION OF AN EL NINO EVENT FOR NEXT WINTER. CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS PACIFIC SSTS ARE NOW ABOUT 1 DEG C ABOVE NORMAL ALONG THE EQUATOR FROM THE INTERNATIONAL DATE LINE TO ABOUT 170E AND WEST OF THE SOUTH AMERICAN COAST FROM 85W TO 105W - AND SSTS ALONG THE EQUATOR ARE GENERALLY NEAR OR ABOVE NORMAL ACROSS THE PACIFIC. SUB-SURFACE PACIFIC OCEAN TEMPERATURES ALONG THE EQUATOR ARE SUBSTANTIALLY WARMER THAN NORMAL DOWN TO A 150 METER DEPTH IN MOST PLACES - AND THEIR RECENT EVOLUTION SUGGESTS THAT A WARM EVENT MAY BE UNDERWAY. THE DEPTH OF THE OCEANIC THERMOCLINE HAS INCREASED MARKEDLY IN THE EAST-CENTRAL PACIFIC IN RECENT WEEKS AND THAT WARM WATER HAS RECENTLY BEGUN COMING TO THE SURFACE ALONG THE EQUATORIAL SOUTH AMERICAN COAST. HOWEVER ATMOSPHERIC INDICIES CONTINUE TO REFLECT NEUTRAL ENSO CONDITIONS THUS FAR. THE EXTRATROPICAL NORTH PACIFIC SSTS CONTINUE TO BE BELOW NORMAL OVER A LARGE AREA NORTH OF 40N LATITUDE AS WELL AS EXTENDING FROM 150W LONGITUDE TO THE NORTH AMERICAN COAST. . . . . . . . . PROGNOSTIC DISCUSSION OF SST FORECASTS STATISTICAL AND DYNAMICAL PREDICTIONS OF NINO 3.4 SSTS ARE IN POOR AGREEMENT ON THE ENSO OUTLOOK FOR THE NEXT SEVERAL MONTHS TO YEAR. TWO OF THE THREE MAIN TOOLS RUN AT NCEP FORECAST WEAK TO MODERATE WARM EPISODE (EL NINO) CONDITIONS TO DEVELOP BY SUMMER (CCA AND THE NCEP NUMERICAL MODEL) - WHILE THE CONSTRUCTED ANALOG (CA) METHOD KEEPS TEMPERATURES NEAR NORMAL THROUGH THE REMAINDER OF 2002. THE CA PREDICTION DOES NOT ACCOUNT FOR THE SUB-SURFACE OBSERVATIONS WHICH HAVE CHANGED DRAMATICALLY IN THE LAST FEW MONTH - WHICH MAY EXPLAIN ITS LACK OF RESPONSE TO RECENT CHANGES. THE MOST RECENT OBSERVATIONS OF SSTS IN THE CENTRAL PACIFIC - ALONG WITH THE SUB SURFACE STRUCTURE SUPPORTS THE ENSO PREDICTION TOOLS THAT FAVOR WARMER SSTS - HENCE THE OFFICIAL FORECAST IS FOR A WARM ENSO EVENT TO DEVELOP WITHIN THE NEXT FEW MONTHS. THUS THIS MONTH OUTLOOK WILL FOLLOW THE FORECAST FROM THE NCEP MODEL AND CCA AND NOT THE CA OR THE REGRESSION CONSOLIDATION FORECAST. ABOVE NORMAL CENTRAL EQUATORIAL PACIFIC SSTS ARE ALSO SUPPORTED BY SOME - BUT NOT ALL - MODELS RUN AT OTHER CLIMATE CENTERS. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOK THE STATISTICAL TOOLS ...CCA - OCN - SMLR... WERE CONSULTED AT ALL LEAD TIMES. DYNAMICAL MODEL FORECASTS FROM NCEP AND OTHER FORECAST CENTERS WERE CONSULTED FOR THE PERIOD AMJ - JAS 2002. THE LARGE SCALE CIRCULATION PATTERNS ARE ANTICIPATED TO REFLECT WARM ENSO CONDITIONS BY LATE SUMMER AND INTO THE NEXT COOL SEASON - SO WARM EVENT COMPOSITES WERE CONSULTED FOR SEASONS UNTIL MAM 2003. . . . . . . . . PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2002 TO AMJ 2003 TEMPERATURE: THERE IS A GENERAL CONSENSUS FOR ABOVE NORMAL TEMPERATURES ACROSS MUCH OF THE WESTERN AND SOUTHERN STATES AMONG THE DYNAMICAL MODELS AND THE STATISTICAL TOOLS FOR AMJ 2002. THE NCEP MODEL CONTINUES TO PREDICT BELOW NORMAL TEMPERATURES OVER MUCH OF THE U.S. - AS IT HAS FOR THE PAST FEW SEASONS - AND WILL BE DISCOUNTED BECAUSE IT WAS NOT CONSISTENT WITH THE SOLUTIONS FROM NUMERICAL MODELS RUN AT OTHER CENTERS AND CONFLICTED WITH THE FORECASTS FROM THE STATISTI- CAL TOOLS. CCA INDICATES TEMPERATURES ACROSS MUCH OF THE WEST WILL BE BELOW THE MEAN OF THE LAST DECADE BUT SINCE THERE IS A STRONG WARMING TREND THERE TEMPERA- TURES ABOVE THE 1971-2000 MEAN ARE STILL SLIGHTLY FAVORED. IN ADDITION THE ONLY LOCATIONS IN THE WEST THAT THE CCA SHOWS SKILL AT DURING AMJ ARE WHERE IT AGREES WITH THE OCN IN FORECASTING WARMER THAN NORMAL. DRY INITIAL SOIL MOISTURE CONDITIONS AND - IN SOME REGIONS - LOW SNOW COVER ARE A REAL CONCERN ACROSS LARGE PORTIONS OF THE NATION. THIS WILL RESULT IN ANOMALOUSLY HIGH PORTION OF SOLAR ENERGY BEING CONVERTED TO SURFACE HEATING INSTEAD OF CAUSING EVAPORATION. THUS ABOVE NORMAL TEMPERATURES HAVE BEEN PUT INTO THE CAROLINAS AND PORTIONS OF ADJACENT STATES FOR AMJ BASED ON DRY INITIAL CONDITIONS AND A FORECAST OF BELOW MEDIAN PRECIPITATION FOR AMJ. BELOW NORMAL SSTS IN THE EASTERN NORTH PACIFIC WILL COUNTERACT THE RECENT WARMING TRENDS ALONG THE IMMEDIATE WEST COAST FROM ALASKA TO CALIFORNIA AND ARE ANTICIPATED TO BRING CONDITIONS THERE MORE IN LINE WITH THE 1971-2000 CLIMATOLOGY THAN TRENDS INDICATE. CCA PREDICTS BELOW NORMAL TEMPERATURES FOR INTERIOR ALASKA FOR AMJ THROUGH JJA WHICH CONFLICTS WITH RECENT TRENDS THERE - SUGGESTING THE ALASKAN TEMPERATURES WILL REFLECT THE LONG TERM NORMALS. ONLY MINOR CHANGES WERE MADE FROM THE PREVIOUS SET OF FORECASTS BEYOND THE LATE SPRING - EARLY SUMMER. THE AREA OF ABOVE NORMAL TEMPERATURES FORECAST FOR JJA AND JAS 2002 WAS EXPANDED SLIGHTLY INTO THE MONTANA AND WYOMING AREA DUE TO SIGNALS FROM CCA WITH SOME SUPPORT FROM SMLR. OCN - WITH VARYING AMOUNTS OF SUPPORT FROM CCA AND SMLR - INDICATES WARMER THAN NORMAL TEMPERATURES FOR MOST SEASONS FROM AMJ 2002 THROUGH AMJ 2003 IN THE SOUTHWEST U.S. HOWEVER THE OCN WARM SIGNAL IN THE SOUTHWEST FOR OND - WHICH HAS BEEN THE WEAKEST SEASON FOR THIS SIGNAL - HAS BEEN REDUCED TO A SINGLE STATION WITH SIGNIFICANT SKILL AND THUS WAS LEFT OUT OF THE OND TEMPERATURE OUTLOOK SINCE CCA AND SMLR ALSO EACH HAD ONE OR TWO STATIONS FORECASTING WARMER THAN NORMAL WITH SOME SKILL - BUT NONE OF THESE STATIONS FROM ANY OF THESE TOOLS WERE THE SAME. TEMPERATURES FOR OND 2002 THROUGH MAM 2003 REFLECT THE INFLUENCE OF TRENDS AND AN ANTICIPATED MATURE EL NINO EVENT. PROBABILITY ANOMALIES ARE MODEST SINCE THE STRENGTH OF THE WARM EVENT IS UNCERTAIN AT THIS TIME. IN THE ABSENCE OF TRENDS THE WINTERTIME TEMPERATURES THROUGHOUT MUCH OF THE SOUTHERN U.S. TEND TO BE BELOW NORMAL IN A WARM ENSO EVENT. HOWEVER A WARMING TREND ACROSS MUCH OF THE SOUTH MODERATES THE EL NINO SIGNAL. THE ENSO SIGNAL FOR BELOW NORMAL IS STRONG ENOUGH RELATIVE TO THE TREND TO FAVOR BELOW NORMAL TEMPERATURES OVER FLORIDA NEXT WINTER AND SPRING. A WARM EVENT IS ASSOCIATED WITH NEAR TO BELOW NORMAL TEMPERATURES ALONG THE GULF COAST AND TEXAS. HOWEVER UNCERTAINTY IN THE STRENGTH OF THE WARM EVENT PREVENTS A CLEAR DETERMINATION OF THE CATEGORICAL FORECAST THERE - LEAVING THE ODDS CLOSE TO CLIMATOLOGY IN MOST OF THE GULF COAST AND TEXAS REGION. . . . . . . . . . PRECIPITATION: ABOVE MEDIAN PRECIPITATION IS FAVORED IN THE PACIFIC NORTHWEST IN AMJ AND MJJ DUE TO LONG-TERM TRENDS. LARGE PORTIONS OF THE NATION HAVE DRY INITIAL SOIL MOISTURE CONDITIONS. THE CAROLINAS AND PORTIONS OF ADJACENT STATES HAVE VERY DRY INITIAL CONDITIONS AND ARE FORECAST TO HAVE BELOW MEDIAN PRECIPITAION FOR AMJ BASED ON THE SOIL MOISTURE TOOL AND THE SMLR - ALTHOUGH THE SOIL MOISTURE TOOL ALONE FORECASTS LARGER AREAS OF BELOW MEDIAN PRECIPITATION. OCN GIVES AN AREA OF BELOW MEDIAN PRECIPITAION OVER MUCH OF THE WESTERN U.S. FOR JAS - WHICH WAS EXPANDED SLIGHTLY TO INCLUDE PORTIONS OF WASHINGTON AND MONTANA BASED ON CCA. A WET AREA FORECAST OVER FLORIDA DURING LATE SUMMER AND EARLY FALL IS THE RESULT OF OCN INDICATIONS - WHILE FROM LATE FALL INTO WINTER THE ABOVE MEDIAN FOR FLORIDA IS FROM EL NINO COMPOSITES. OTHER WARM ENSO CONDITION CONSIDERA- TIONS INCLUDE A PREDICTION OF DRY CONDITION FOR PORTIONS OF THE MID-ATLANTIC STATES IN ASO AND SON 2002 - WHICH HAVE BEEN EXPANDED INTO THE UPPER OHIO VALLEY BASED ON OCN AND CCA INDICATIONS. THE BELOW MEDIAN PRECIPITATION FORECAST IN THE PACIFIC NORTHWEST IN OND AND THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS FROM NDJ 2002 THROUGH FMA 2003 ARE ALSO BASED ON EL NINO WITH SOME SUPPORT FROM OCN. BEGINNING IN OND 2002 AND CONTINUING THROUGH MAM 2003 EXTENSIVE AREAS OF ABOVE MEDIAN PRECIPITATION WITH MODEST PROBABILITIES ARE FORECAST ACROSS THE SOUTHERN PART OF THE NATION DUE TO EXPECTED EL NINO CONDITIONS. THE BELOW MEDIAN PRECIPITATION IN THE NORTH CENTRAL STATES AND THE OHIO VALLEY FROM JFM 2003 THROUGH MAM 2003 ARE ALSO DUE TO EXPECTED EL NINO INFLUENCES. THERE ARE NO RELIABLE FORECAST INDICATIONS FOR ALASKA PRECIPITATION TO DEPART FROM CLIMATOLOGICAL PROBABILITIES DURING ANY OF THE LEADS AT THIS TIME. FORECASTERS: R. MARTIN AND H. VAN DEN DOOL 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/MULTI-SEASON/ 13_SEASONAL_OUTLOOKS/TOOLS (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 LOWER CASE LETTERS) NOTES - THESE CLIMATE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR VALID PERIODS. 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 THURSDAY APRIL 18 2002. 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17 2001 FORECAST RELEASE. NNNN NNNN