PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EST WED JAN 31 2007 30-DAY OUTLOOK DISCUSSION FOR FEBRUARY 2007 THE LATEST EL NINO/SOUTHERN OSCILLATION BULLETIN ISSUED BY THE CLIMATE PREDICTION CENTER ON 11 JAN 2006 STATES THAT EL NINO CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE MARCH-MAY 2007 SEASON. ALTHOUGH THE MONTHLY MEAN EQUATORIAL SST ANOMALIES ARE SLIGHTLY GREATER THAN 1 DEG C IN MOST PLACES FROM 170E TO THE SOUTH AMERICAN COAST AT THE TIME THIS BULLETIN WAS ISSUED... THE PEAK MAGNITUDE OF THE ANOMALIES APPEARS TO HAVE CLEARLY PASSED AND THE MOST RECENT WEEKLY ANOMALY MAP SHOWS ONLY TWO GREATLY DIMINISHED AREAS WITH POSITIVE SST ANOMALIES GREATER THAN 1 DEG C - ONE JUST WEST OF THE DATE LINE NEAR 170E AND THE OTHER BETWEEN 110W AND 120W. SINCE NORMAL SSTS ARE RISING AT THIS TIME OF YEAR, THEY ARE WARM ENOUGH TO SUPPORT NEAR-EQUATORIAL CONVECTION, EVEN THOUGH THE ANOMALIES ARE WEAKENING. THE LATEST CONSENSUS FORECAST FROM CPC FOR SST ANOMALIES IN THE NINO 3.4 REGION MADE IN MID-JANUARY SHOWED A SLIGHTLY EARLIER WEAKENING OF EL NINO CONDITIONS THAN WAS FORECAST IN DECEMBER. THE LATEST DATA FROM THE TAO ARRAY OF BOUYS SHOWS THAT TEMPERATURES AT DEPTH NEAR THE EQUATOR HAVE COOLED CONSIDERABLY... WITH A VERY WEAK OCEANIC KELVIN WAVE LOCATED NEAR 175W THAT HAD MAXIMUM POSITIVE ANOMALIES OF ONLY 2 DEG C BETWEEN 125M AND 150M DEPTH. THIS IS MUCH WEAKER THAN THE PREVIOUS KELVIN WAVE, THE REMANTS OF WHICH ARE CURRENTLY SHOALING NEAR THE COAST OF SOUTH AMERICA. THIS LAST KELVIN WAVE IS NOT EXPECTED TO SIGNIFICANTLY EXTEND THE LIFE OF THE WEAEKNING EL NINO. THE TOTAL HEAT CONTENT OF THE NEAR-SURFACE EQUATORIAL PACIFIC HAS NOTICABLY DECREASED WITHIN THE PAST FEW WEEKS. IN ANY CASE... THE WEAEKENING EL NINO IS EXPECTED TO STILL BE SOMEWHAT OF A FACTOR FOR BOTH THE TEMPERATURE AND PRECIPITATION FORECASTS OVER NORTH AMERICA DURING THE MONTH OF FEBRUARY... SINCE EVEN WITH THE CURRENT AND PROJECTED WEAKENING... ITS EFFECTS ON THE ATMOSPHERE ARE CLIMATOLOGICALLY STRONGER AND MORE RELIABLE IN LATE WINTER THAN AT ANY OTHER TIME OF YEAR. RECENT TEMPERATURE AND PRECIPITATION ANOMALIES OVER NORTH AMERICA HAVE BECOME SOMEWHAT MORE SIMILAR TO COMPOSITES OF PAST WEEK AND MODERATE EL NINOS, ALTHOUGH THE MOST RECENT PATTERNS ARE ALSO CONSIDERABLY INFLUENCED BY A STRONGLY NEGATIVE VALUE OF THE NAO... AND THE SHORT-RANGE FORECASTS FOR THE FIRST FEW DAYS OF FEBRUARY DISPLAY A STRONG PROJECTION ON A POSITIVE PNA PATTERN. THEREFORE... THE UPDATED FORECAST FOR FEBRUARY HAS BEEN MODIFIED USING FORECAST ANOMALIES SHOWN BY THE MOST RECENT AVAILABLE CFS MODEL INTEGRATION FOR FEBRUARY... KLEIN AND NEURAL NET SPECIFICATIONS FROM THE CIRCULATION FORECASTS FOR THE FIRST TWO WEEKS OF FEBRUARY... SPECIFICATIONS FROM PAST OBSERVED PATTERNS THAT HAVE GONE WITH THE STRONGEST AND MOST STABLE PROJECTED MEAN POSITIVE AND NEGATIVE 500-HPA CENTERS... AND WEIGHTED COMPOSITES OF OBSERVED MONTHLY TEMPERATURE AND PRECIPITATION ANOMALIES FOR FEBRUARIES FOLLOWING THE CLOSEST ANALOGS TO THE 500-HPA PATTERNS FORECAST BY THE MODELS FOR THE NEXT TWO WEEKS. SOME ATTENTION HAS ALSO BEEN PAID TO EL NINO COMPOSITES FOR FEBRUARY. ALTHOUGH THE FIRST THIRD OR SO OF FEBRUARY LOOKS EXTREMELY COLD OVER THE EASTERN CONUS... THE COMPOSITE PATTERNS FOR THE ENTIRE MONTH HAD SURPRISINGLY LITTLE BELOW NORMAL TEMPERATURE... IN SPITE OF THE COLD START... AND SHOWED ABOVE NORMAL TEMPERATURES EXPANDING EASTWARD TO THE NORTHERN AND CENTRAL GREAT PLAINS. DUE TO CONSISTENT INDICATIONS FROM THE CFS MODEL THAT AT LEAST THE EASTERN THIRD OF THE CONUS MAY HAVE BELOW NORMAL TEMPERATURES DURING FEBRUARY... AND THE VERY COLD FIRST WEEK FORECAST BY ALL THE MODELS... THE WARMTH THAT HAD BEEN PREDICTED OVER THE NORTHEAST FOR JFM HAS BEEN REMOVED AND A SMALL AREA OF BELOW NORMAL HAS BEEN INTRODUCED FOR THE OHIO VALLEY AND MUCH OF THE MIDDLE ATLANTIC AND NEW ENGLAND STATES. ALTHOUGH EL NINO COMPOSITES FAVOR BELOW NORMAL TEMPERATURES OVER MUCH OF THE GULF AND SOUTH ATLANTIC STATES... SPECIFICATIONS FROM CURRENT MODEL FORECASTS FOR WEEK TWO AND THE EFFECTS OF LONG-TERM TRENDS FOR WARMTH ON THE GENERAL TENDENCY FOR EL NINOS TO BRING BELOW NORMAL TEMPERATURES TO THESE AREAS... BOTH FAVOR NEAR NORMAL RATHER THAN BELOW NORMAL TEMPERATURES FOR FEBRUARY OVER MUCH OF THE GULF AND SOUTH ATLANTIC STATES. THE SEASONAL PRECIPITATION FORECASTS FOR JFM 2007 ISSUED LAST MONTH... AND THE FORECAST ISSUED FOR FEBRUARY A COUPLE OF WEEKS AGO HAVE BEEN MODIFIED FOR THE SAME REASONS AS DISCUSSED ABOVE FOR THE TEMPERATURE FORECAST. ANALOGS TO SOME OF THE PROJECTED CIRCULATION PATTERNS HAD SUPRISINGLY GOOD AGREEMENT FOR THE ONSET OF ABOVE MEDIAN PRECIPITATION IN CALIFORNIA... ESPECIALLY THE NORTHERN HALF OF THE STATE... AND CURRENT MODEL RUNS ARE ALSO PREDICTING THE ONSET OF SIGNIFICANT PRECIPITATION IN THAT AREA. THERE ARE SIGNS THAT THE SUBTROPICAL JET STREAM HAS FINALLY BEEN ACTIVATED... SO GENERALLY ABOVE MEDIAN PRECIPITATION ACROSS THE SOUTHERN PART OF THE COUNTRY LOOKS LIKELY. AREAS SUCH AS THE NORTHEAST AND MUCH OF THE GREAT PLAINS... WHERE THE TOOLS HAD LITTLE AGREEMENT... HAD POOR A PRIORI SKILL... OR WHERE PROJECTED CIRCULATION PATTERNS WERE FORECAST TO BE UNDERGOING RAPID CHANGE WERE LEFT WITH EC. ABOVE NORMAL TEMPERATURES WERE FORECAST FOR MOST OF SOUTHERN ALASKA AND ABOVE MEDIAN PRECIPITATION WAS INDICATED FOR PART OF THE SOUTH COAST ON THE BASIS OF EL NINO CONSIDERATIONS AND SUPPORT FROM SOME OF THE STATISTICAL TOOLS. SINCE THERE WERE HINTS THAT BLOCKING AT HIGH LATITUDES OVER NORTHERN CANADA AND SOUTHEASTERN ALASKA COULD RETROGRADE WEST OF ALASKA LATER IN THE MONTH... WHICH COULD CAUSE EVENTUAL COOLING IN ALASKA... THE AREA OF PREDICTED WARMTH AND ITS CONFIDENCE WERE EXPANDED ONLY SLIGHTLY IN THE UPDATED FORECAST. FORECASTER: A J WAGNER NOTES - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). THE NEXT MONTHLY OUTLOOK... FOR MARCH 2007... WILL BE ISSUED ON THU FEB 15 2007 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD. $$