PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830AM EDT THURSDAY JUN 17 2010

30-DAY OUTLOOK DISCUSSION FOR JULY 2010

SEA SURFACE TEMPERATURE (SST) ANOMALIES NEAR THE EQUATOR IN THE EAST CENTRAL 
PACIFIC OCEAN HAVE DECREASED OVERALL IN THE LAST MONTH, CONTINUING THE TENDENCY 
OF THE PREVIOUS MONTH. SST ANOMALIES ARE NOW BELOW NORMAL ALONG THE EQUATOR 
FROM THE SOUTH AMERICAN COAST TO ABOUT 170W LONGITUDE. EQUATORIAL SST ANOMALIES 
ARE NOW GENERALLY BELOW NEGATIVE 1 DEGREE C FROM ABOUT 90W TO 150W LONGITUDE. 
THE CPC CONSOLIDATION SST FORECAST BASED ON THE CFS AND THREE STATISTICAL 
MODELS SUGGESTS THAT THE AVERAGE SST IN THE NINO 3.4 REGION (BETWEEN 5N AND 5S, 
170W AND 120W) WILL REMAIN BELOW NORMAL THROUGH NEXT WINTER. 
 
CURRENT ATMOSPHERIC CONDITIONS ARE CONSISTENT WITH THE END OF LAST WINTER'S EL 
NINO AND THE RETURN OF ENSO-NEUTRAL CONDITIONS. CONVECTION IN THE CENTRAL 
PACIFIC OCEAN, ASSOCIATED WITH THE PREVIOUS EL NINO, CONTINUED TO WEAKEN OVER 
THE LAST MONTH OVER AN EXPANDING AREA. LOW LEVEL EASTERLY TRADE WIND ANOMALIES 
WERE RECENTLY OBSERVED OVER THE WESTERN AND CENTRAL EQUATORIAL PACIFIC AND 
WESTERLY WIND ANOMALIES PERSISTED AT UPPER LEVELS OVER THE EAST CENTRAL 
EQUATORIAL PACIFIC. 
 
THE JULY 2010 MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED 
PRIMARILY ON TEMPERATURE AND PRECIPITATION FORECASTS FROM THE NCEP CLIMATE 
FORECAST SYSTEM (CFS) COUPLED OCEAN-ATMOSPHERE DYNAMICAL MODEL AND COMPOSITES 
OF JULY TEMPERATURES AND PRECIPITATION FOR ANALOGS TO THE CURRENT YEAR AND 
FORECASTS OF LIKELY FUTURE ENSO CONDITIONS. COMPOSITES WERE CREATED BASED ON 
THE NINO 3.4 REGION TEMPERATURE ANOMALIES FOR PAST YEARS TRANSITIONING FROM AN 
EL NINO EVENT DURING THE PREVIOUS WINTER AND SPRING INTO AN ENSO-NEUTRAL OR LA 
NINA EVENT. YEARS WHERE EL NINO EVENTS RECURRED IN A SECOND YEAR WERE NOT USED, 
AS THIS SCENARIO IS CONSIDERED UNLIKELY FOR THE CURRENT YEAR, BASED ON THE CPC 
NINO 3.4 SST CONSOLIDATION FORECAST. THESE COMPOSITES INDICATE AN INCREASED 
LIKELIHOOD OF ABOVE NORMAL TEMPERATURES FOR JULY ACROSS MUCH OF THE U.S., 
PARTICULARLY IN THE SOUTHWEST, NORTHERN ROCKIES AND NORTHEAST. COMPOSITES 
INDICATE ABOVE MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHWEST MONSOON REGION 
AND FROM THE CENTRAL PLAINS INTO THE CENTRAL MISSISSIPPI VALLEY. BELOW MEDIAN 
PRECIPITATION IS INDICATED BY THESE COMPOSITES FOR THE WESTERN GREAT LAKES 
REGION. IN ADDITION, STATISTICAL FORECASTS FROM THE CCA, OCN AND SMLR WERE 
CONSIDERED. 
 
THE JULY 2010 TEMPERATURE OUTLOOK INDICATES AN INCREASED LIKELIHOOD OF ABOVE 
NORMAL TEMPERATURES ACROSS MUCH OF THE SOUTHERN U.S. FROM THE SOUTHWEST 
NORTHWARD INTO THE CENTRAL ROCKIES AND EASTWARD THROUGH TEXAS AND ALONG THE 
GULF COAST TO FLORIDA, CONSISTENT WITH THE CFS TEMPERATURE FORECASTS, 
COMPOSITES OF ANALOG YEARS, AND THE DECADAL TRENDS. THERE IS AN INCREASED 
LIKELIHOOD OF BELOW NORMAL TEMPERATURES FOR THE PACIFIC COAST OF NORTHERN 
CALIFORNIA, WESTERN OREGON AND WASHINGTON, WHERE DYNAMICAL MODEL FORECASTS 
INDICATE A PERSISTENT UPPER LEVEL TROUGH AND ENHANCED PRECIPITATION. THERE IS 
ALSO AN ENHANCED CHANCE OF BELOW NORMAL JULY MEAN TEMPERATURES FOR REGIONS OF 
THE CENTRAL PLAINS INTO THE CENTRAL MISSISSIPPI VALLEY REGION, WHERE SOIL 
MOISTURE IS SIGNIFICANTLY ABOVE NORMAL AND PRECIPITATION IS ALSO EXPECTED TO BE 
ENHANCED BY THE LARGE SCALE FLOW PATTERN. THESE AREAS OF BELOW NORMAL 
TEMPERATURE ARE ALSO SUPPORTED BY THE CFS FORECAST. BELOW NORMAL TEMPERATURES 
SUGGESTED BY THE CFS FORECASTS FOR THE NORTHERN ROCKIES INTO THE NORTHERN 
PLAINS WERE FOUND TO BE INCONSISTENT WITH ENSO COMPOSITES AND STATISTICAL 
TOOLS, SO EQUAL CHANCES (EC) IS INDICATED IN THESE AREAS. THERE IS AN ENHANCED 
CHANCE OF BELOW NORMAL TEMPERATURES FOR THE SOUTHWEST ALASKAN COAST AND 
ALEUTIAN ISLANDS WHERE SEA SURFACE TEMPERATURES ARE ANOMALOUSLY LOW, WITH AN 
ENHANCED CHANCE OF ABOVE NORMAL TEMPERATURES FOR NORTHERN AND EASTERN ALASKA 
ASSOCIATED IN PART WITH DECADAL TEMPERATURE TRENDS OR CHANGES IN THE CLIMATE 
AND SUPPORTED BY THE CFS FORECAST. 
 
THE JULY 2010 PRECIPITATION OUTLOOK INDICATES AN ENHANCED PROBABILITY OF ABOVE 
MEDIAN PRECIPITATION FOR WESTERN AREAS OF NORTHERN CALIFORNIA, OREGON AND 
WASHINGTON WHERE THERE IS A PREDICTED PERSISTENT TROUGH OVER THE PACIFIC COAST. 
AN AREA OF ENHANCED PROBABILITY FOR ABOVE MEDIAN PRECIPITATION IS ALSO FORECAST 
FROM THE CENTRAL PLAINS INTO THE WESTERN CENTRAL MISSISSIPPI VALLEY. THIS 
FORECAST IS SUPPORTED TO SOME EXTENT BY CFS JULY PRECIPITATION FORECASTS WHICH 
INDICATE A MORE EXTENSIVE AREA OF ABOVE MEDIAN PRECIPITATION AND ALSO BY 
COMPOSITES RELATED TO A TRANSITION OF AN EL NINO TO ENSO-NEUTRAL CONDITIONS OR 
POSSIBLY A LA NINA. UNCERTAINTY IN THE PRECIPITATION OUTLOOK LEADS TO A 
FORECAST OF EQUAL CHANCES (EC) OVER OTHER REGIONS. 


FORECASTER: DAN COLLINS


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


AN UPDATED MONTHLY OUTLOOK... FOR JUL WILL BE ISSUED ON WED JUNE 30 2010


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

$$