PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EDT THU MAY 20 2010

30-DAY OUTLOOK DISCUSSION FOR JUNE 2010

SEA SURFACE TEMPERATURE (SST) ANOMALIES NEAR THE EQUATOR IN THE EAST CENTRAL 
PACIFIC OCEAN HAVE DECREASED MARKEDLY IN THE PAST FEW WEEKS.  SSTS ARE NOW 
SLIGHTLY BELOW NORMAL ALONG THE EQUATOR BETWEEN ABOUT 100 AND 160W LONGITUDE, 
SUGGESTING AN END TO THE EL NINO CONDITIONS PRESENT FOR THE PAST YEAR OR SO.  
SEVERAL OF THE SST FORECASTING TOOLS PREDICTED THE END OF EL NINO CONDITIONS BY 
MID-YEAR IN FORECASTS ISSUED AS EARLY AS MARCH, NOTABLY THE NCEP CFS MODEL AND 
CONSTRUCTED ANALOG TOOLS.  A CONSOLIDATION FORECAST BASED ON THESE AND OTHER 
TOOLS SUGGESTS THAT SSTS IN THE NINO 3.4 REGION (BETWEEN 5N AND 5S, 170W AND 
120W) WILL REMAIN NEAR OR POSSIBLY BELOW NORMAL THROUGH THE SUMMER.   

CURRENT ATMOSPHERIC CONDITIONS CONSISTENT WITH A WEAKENING EL NINO IN THE 
TROPICS HAVE BEEN OBSERVED IN THE EARLY PART OF MAY.  CONVECTION IN THE CENTRAL 
PACIFIC OCEAN, NORMALLY ASSOCIATED WITH EL NINO, WEAKENED CONSIDERABLY IN THE 
PAST MONTH OR SO.  THE LOW LEVEL EQUATORIAL TRADE WINDS ARE NEAR-AVERAGE VALUES 
AND WESTERLY WIND ANOMALIES ARE OBSERVED AT UPPER LEVELS.  THESE INDICATORS 
SUGGEST THAT RESIDUAL ATMOSPHERIC EFFECTS OF THE PAST WINTER'S EL NINO WILL BE 
NEGLIGIBLE IN JUNE. 

WITH NEUTRAL ENSO CONDITIONS EXPECTED, CLIMATIC ANOMALIES FOR TEMPERATURE AND 
PRECIPITATION EXPECTED FOR JUNE 2010 ARE MAINLY DUE TO LONG TERM TRENDS, THE 
INFLUENCE OF COASTAL SST ANOMALIES ON ADJACENT LAND AREAS, AND ON THE SOIL 
MOISTURE ANOMALIES.  THE CHANCES OF BELOW NORMAL TEMPERATURES ARE ELEVATED IN 
PARTS OF TEXAS AND THE SOUTHERN AND CENTRAL GREAT PLAINS DUE TO THE INFLUENCE 
OF INITIALLY HIGH VALUES OF SOIL MOISTURE.  WET SOIL CONDITIONS HELP LOWER 
TEMPERATURES AND PROVIDE MOISTURE FOR CONVECTIVE SYSTEMS.  LOCAL SSTS ARE BELOW 
NORMAL IN THE GULF OF MEXICO, COUNTERACTING RECENT TRENDS FOR ABOVE NORMAL 
TEMPERATURES IN PARTS OF THE SOUTHEAST, SO EQUAL CHANCES FOR ABOVE, NEAR, AND 
BELOW NORMAL TEMPERATURES ARE INDICATED IN THE SOUTHEAST CONUS.  THE CFS MODEL 
INDICATES THAT AN UPPER LEVEL TROUGH MAY HAVE AN INFLUENCE LOWERING 
TEMPERATURES IN THE WESTERN CONUS EARLY IN JUNE, HOWEVER TRENDS FAVORING ABOVE 
NORMAL TEMPERATURES ARE STRONG ENOUGH IN MUCH OF THE WEST TO MINIMALLY ENHANCE 
THE CHANCES FOR ABOVE NORMAL TEMPERATURES IN JUNE.  ALL TOOLS FAVOR ABOVE 
NORMAL TEMPERATURES FOR INTERIOR PORTIONS OF ALASKA, HOWEVER BELOW NORMAL SSTS 
INCREASE CHANCES FOR BELOW NORMAL TEMPERATURES IN THE ALEUTIANS AND COASTAL 
AREAS OF SOUTHWESTERN ALASKA.  
  
   THERE ARE NO SIGNIFICANT INDICATORS FOR PRECIPITATION ANOMALIES FOR THE 
CONUS AND ALASKA, EXCEPT NEAR TEXAS AND THE SOUTH-CENTRAL GREAT PLAINS.  
FAVORABLE INITIAL SOIL MOISTURE CONDITIONS ENHANCE THE CHANCES FOR ABOVE MEDIAN 
PRECIPITATION AMOUNTS FROM NORTHERN TEXAS TO MISSOURI AND SOUTHERN IOWA.    

FORECASTER: DAVID UNGER

NOTES: AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL 
PROBABILITIES) ARE NOW LABELED AS EC (EQUAL CHANCES).

AN UPDATED MONTHLY OUTLOOK... FOR JUN WILL BE ISSUED ON MON MAY 31 2010

THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD.

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