PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300PM EST MONDAY FEB 28 2011 30-DAY OUTLOOK DISCUSSION FOR MARCH 2011 LA NINA CONDITIONS ARE PRESENT ACROSS THE TROPICAL PACIFIC OCEAN. THOUGH SEA SURFACE TEMPERATURES (SSTS) NEAR THE EQUATOR IN THE EASTERN AND CENTRAL PACIFIC OCEAN HAVE BEEN AT LEAST 1 DEGREE C BELOW NORMAL FROM ABOUT 160 E TO 120W IN FEBRUARY, SSTS FROM THE CENTRAL PACIFIC TO THE SOUTH AMERICAN COAST HAVE WARMED DURING THE LAST MONTH. SSTS ARE NOW SLIGHTLY ABOVE NORMAL IN THE FAR EASTERN PACIFIC. THE SUBSURFACE OCEAN HEAT CONTENT FROM NEAR-EQUATORIAL AVERAGE TEMPERATURES IN THE UPPER OCEAN IS BELOW NORMAL WITHIN A SHALLOW LAYER TO ABOUT 100 METERS DEPTH EAST OF THE DATELINE AND AT GREATER DEPTH EAST OF 120 W, WHILE ABOVE NORMAL ANOMALIES IN THE WEST PACIFIC HAVE CONTINUED TO EXPAND EASTWARD AT DEPTH TO ABOUT 140 W AT THE END OF FEBRUARY. THE LARGE SCALE ATMOSPHERIC CIRCULATION OVER THE TROPICAL PACIFIC OCEAN IS CONSISTENT WITH LA NINA CONDITIONS. CONVECTION IS ENHANCED OVER PARTS OF THE MARITIME CONTINENT AND SUPPRESSED OVER THE WESTERN AND CENTRAL EQUATORIAL PACIFIC OCEAN. LOW LEVEL EASTERLY TRADE WINDS ARE ENHANCED OVER THE WESTERN AND CENTRAL PACIFIC. WESTERLY WIND ANOMALIES AT UPPER LEVELS ARE ENHANCED OVER THE CENTRAL AND EAST-CENTRAL PACIFIC WITH ANOMALOUS OFF-EQUATORIAL CYCLONIC CIRCULATIONS IN THE SUBTROPICS OF BOTH HEMISPHERES. STATISTICAL AND DYNAMICAL ENSO FORECAST MODELS MAINTAIN LA NINA CONDITIONS THROUGH MARCH INTO BOREAL SPRING. MJO ACTIVITY INTO MARCH IS UNCERTAIN AT THIS TIME WITH BACKGROUND LA NINA CONDITIONS EXPECTED TO DOMINATE THE PATTERN OF TROPICAL CONVECTION. THE ARCTIC OSCILATION (AO) WHICH HAD BEEN PERSISTENTLY NEGATIVE FROM MID-NOVEMBER INTO THE THIRD WEEK OF JANUARY, INFLUENCING THE ATMOSPHERIC CIRCULATION, HAS BEEN POSITIVE IN THE LAST HALF OF FEBRUARY. DYNAMICAL MODEL FORECASTS PREDICT THE AO TO EITHER REMAIN POSITIVE OR NEAR NEUTRAL IN THE BEGINNING OF MARCH. DUE TO UNCERTAINTY IN THE FORECAST, THE AO DOES NOT INFLUENCE THE UPDATED MARCH OUTLOOK. SST ANOMALIES IN THE NINO 3.4 REGION ARE FORECAST BY THE CPC SST CONSOLIDATION TO BE NEAR -1 C THROUGH THE FMA SEASON, SUGGESTING MODERATE LA NINA CONDITIONS FOR MARCH 2011. THE MARCH 2011 TEMPERATURE AND PRECIPITATION OUTLOOKS WERE BASED LARGELY ON LA NINA COMPOSITES, WITH ADJUSTMENTS MADE USING THE CFS DYNAMICAL FORECASTS, AND CONSIDERATION OF THE OBSERVED ATMOSPHERIC STATE, AS WELL AS CPC STATISTICAL TOOLS, INCLUDING DECADAL TRENDS RELATED TO CHANGES IN THE LONG TERM CLIMATE STATE. THE COVERAGE OF ABOVE AND BELOW NORMAL FORECAST AREAS IS HIGH FOR A MONTHLY FORECAST, DUE TO THE PRESENCE OF AN ONGOING MODERATE LA NINA. AN UPDATE TO THE MARCH OUTLOOK HAS BEEN MADE AT THE END OF FEBRUARY CONSIDERING THE LATEST NUMERICAL WEATHER PREDICTION MODEL FORECASTS AND THE STATE OF THE ATMOSPHERE AND OCEAN. LA NINA CONDITIONS CHANGED ONLY MODERATELY FROM THE HALF MONTH TO END OF MONTH OUTLOOKS. SLIGHT ADJUSTMENTS TO THE TEMPERATURE AND PRECIPITATION OUTLOOKS WERE BASED PRIMARLIY ON ATMOSPHERIC MODEL FORECASTS OF THE FIRST TWO WEEKS OF MARCH, UTILIZING THE BIAS-CORRECTED NORTH AMERICA ENSEMBLE FORECAST SYSTEM, AND THE LATEST ZERO-LEAD CFS COUPLED OCEAN-ATMOSPHERE MODEL FORECASTS. THE TEMPERATURE OUTLOOK FOR MARCH 2011 INDICATES INCREASED CHANCES OF BELOW AVERAGE MEAN TEMPERATURES ALONG THE WEST COAST, IN THE PACIFIC NORTHWEST, AND ACROSS THE NORTHERN TIER OF STATES TO THE WESTERN GREAT LAKES REGION. THERE ARE ENHANCED ODDS OF BELOW NORMAL MEAN TEMPERATURES ALSO OVER MOST OF ALASKA. ENHANCED CHANCES FOR BELOW NORMAL TEMPERATURES IN NORTHERN ALASKA WAS CHANGED IN THE UPDATED OUTLOOK TO EQUAL CHANCES WITH A FORECAST OF ABOVE NORMAL TEMPERATURES IN THE REGION IN THE FIRST HALF OF MARCH. INCREASED CHANCES FOR ABOVE NORMAL TEMPERATURES ARE PREDICTED FROM THE SOUTHWEST THROUGH THE SOUTHERN PLAINS TO THE GULF COAST AND FLORIDA PANHANDLE, WITH THE GREATEST PROBABILITIES FOR MUCH OF ARIZONA AND TEXAS. THE PRECIPITATION OUTLOOK FOR MARCH 2011 INDICATES INCREASED CHANCES OF ABOVE MEDIAN PRECIPITATION IN NORTHERN CALIFORNIA, FROM THE PACIFIC NORTHWEST INTO THE NORTHERN PLAINS, AND FROM THE CENTRAL GREAT LAKES SOUTHWARD TO THE OHIO AND TENNESSEE VALLEYS. BELOW MEDIAN PRECIPITATION IS PREDICTED TO BE MOST LIKELY ACROSS MUCH OF THE SOUTHERN U.S. FROM SOUTHERN CALIFORNIA TO THE SOUTHERN PLAINS, ACROSS THE GULF COAST INTO FLORIDA, AND INCLUDING THE SOUTHERN ATLANTIC COAST. BELOW MEDIAN PRECIPITATION EXTENDING FROM SOUTHEAST COLORADO TO THE CENTRAL PLAINS AND IN PARTS OF THE GULF COAST REGION IN THE HALF MONTH LEAD ARE LESS LIKELY CONSIDERING THE CURRENT MODEL PRECIPITATION FORECASTS. THE SOUTHERN COAST OF ALASKA AND THE ALASKAN PANHANDLE ARE ALSO INDICATED TO HAVE INCREASED CHANCES OF BELOW MEDIAN PRECIPITATION. WHERE THERE ARE NO CLEAR CLIMATE SIGNALS FOR THE MARCH 2011 FORECAST PERIOD, EQUAL CHANCES (EC) OF BELOW, NEAR, AND ABOVE NORMAL FOR TEMPERATURE AND BELOW, NEAR, AND ABOVE MEDIAN FOR PRECIPITATION ARE INDICATED. FORECASTER: DAN COLLINS NOTES: AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED AS EC (EQUAL CHANCES). THE NEXT MONTHLY OUTLOOK...FOR APR ... WILL BE ISSUED ON THU MAR 17 2011 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD. $$