PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT WED JUN 30 2010

30-DAY OUTLOOK DISCUSSION FOR JULY 2010

SEA SURFACE TEMPERATURES (SST'S) NEAR THE EQUATOR IN THE EASTERN AND CENTRAL 
PACIFIC OCEAN DECREASED SLIGHTLY THIS MONTH, CONTINUING THE TENDENCY FROM MAY. 
SST ANOMALIES ARE NOW NEGATIVE ALONG THE EQUATOR FROM THE SOUTH AMERICAN COAST 
TO AROUND THE DATE LINE. EQUATORIAL SST ANOMALIES ARE NOW 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 
ANOMALY IN THE NINO 3.4 REGION (BETWEEN 5N AND 5S, 170W AND 120W) WILL REMAIN 
BELOW NORMAL THROUGH NEXT WINTER. 

CURRENT ATMOSPHERIC CONDITIONS REMAIN CONSISTENT WITH ENSO-NEUTRAL CONDITIONS. 
CONVECTION IN THE WESTERN AND CENTRAL PACIFIC OCEAN CONTINUED TO BE SUPPRESSED 
DURING JUNE, WHILE LOW LEVEL EASTERLY TRADE WIND ANOMALIES HAVE PERSISTED OVER 
THE CENTRAL EQUATORIAL PACIFIC. 

THE UPDATED JULY 2010 MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS 
INCORPORATE INFORMATION FROM THE LATEST DYNAMICAL WEATHER PREDICTION MODELS AS 
WELL AS MONTHLY TEMPERATURE AND PRECIPITATION FORECASTS FROM THE NCEP CLIMATE 
FORECAST SYSTEM (CFS) COUPLED OCEAN-ATMOSPHERE DYNAMICAL MODEL. COMPOSITES OF 
JULY TEMPERATURES AND PRECIPITATION FOR ANALOGS TO THE CURRENT YEAR AND 
FORECASTS OF LIKELY FUTURE ENSO CONDITIONS WERE CONSIDERED IN THE ORIGINAL 
HALF-MONTH LEAD OUTLOOKS AND THE UPDATED OUTLOOKS. 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 UPDATED JULY 2010 TEMPERATURE OUTLOOK IS GENERALLY SIMILAR TO THE 
HALF-MONTH LEAD OUTLOOK, INDICATING 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. PROBABILITIES OVER TEXAS WERE DECREASED SLIGHTLY 
WHERE EXPECTED PRECIPITATION AND CLOUD COVER EARLY IN THE MONTH MAY DECREASE 
TEMPERATURES. THERE IS AN INCREASED LIKELIHOOD OF BELOW NORMAL TEMPERATURES FOR 
NORTHERN CALIFORNIA, OREGON AND WASHINGTON, WHERE SST'S ARE CURRENTLY BELOW 
NORMAL AND THE CFS FORECAST INDICATES BELOW NORMAL TEMPERATURES UNDER A 
PERSISTENT TROUGH DURING THE MONTH OF JULY. THERE IS ALSO A SLIGHTLY ENHANCED 
CHANCE OF BELOW NORMAL JULY MEAN TEMPERATURES FOR THE CENTRAL MISSISSIPPI 
VALLEY REGION, WHERE SOIL MOISTURE CONTINUES TO BE SIGNIFICANTLY ABOVE NORMAL 
AND PRECIPITATION IS ALSO EXPECTED TO BE ENHANCED BY THE LARGE SCALE FLOW 
PATTERN. THERE IS AN ENHANCED CHANCE OF BELOW NORMAL TEMPERATURES FOR THE 
SOUTHWEST ALASKAN COAST AND ALEUTIAN ISLANDS SUPPORTED BY THE CFS AND DYNAMICAL 
MODEL FORECASTS AND WHERE SEA SURFACE TEMPERATURES ARE ANOMALOUSLY LOW. AN 
ENHANCED CHANCE OF ABOVE NORMAL TEMPERATURES FOR EASTERN ALASKA IS ASSOCIATED 
IN PART WITH DECADAL TEMPERATURE TRENDS AND SUPPORTED BY SOME SHORT RANGE 
DYNAMICAL MODEL FORECASTS. 

THE UPDATED JULY 2010 PRECIPITATION OUTLOOK INDICATES AN ENHANCED PROBABILITY 
OF ABOVE MEDIAN PRECIPITATION FOR WESTERN AREAS OF OREGON AND WASHINGTON WHERE 
CFS FORECASTS PREDICT A TROUGH OVER THE PACIFIC COAST DURING JULY. AN AREA OF 
ENHANCED PROBABILITY FOR ABOVE MEDIAN PRECIPITATION IS ALSO FORECAST FROM THE 
CENTRAL MISSISSIPPI VALLEY INTO THE SOUTHERN GREAT LAKES REGION, WHERE SHORT 
RANGE PREDICTIONS INDICATE INCREASED PRECIPITATION AMOUNTS WITH AN INFLUX OF 
MOISTURE FROM THE GULF OF MEXICO. AN AREA OF ENHANCED PROBABILITY FOR ABOVE 
MEDIAN PRECIPITATION HAS BEEN ADDED IN THE MONTHLY UPDATE TO TEXAS AND THE 
WESTERN GULF COAST DUE TO INCREASED PRECIPITATION AMOUNTS NORTH OF HURRICANE 
ALEX, AS INDICATED IN SHORT RANGE DYNAMICAL WEATHER PREDICTIONS. THIS FORECAST 
IS SUPPORTED TO SOME EXTENT BY CFS JULY PRECIPITATION FORECASTS 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).

THE NEXT MONTHLY OUTLOOK...FOR AUGUST 2010...WILL BE ISSUED ON THU JUL 15 2010

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

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