PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT THU JUN 19 2003

30-DAY OUTLOOK DISCUSSION FOR JULY 2003
                                                                               .
WARM EPISODE (EL NINO) CONDITIONS HAVE RAPIDLY DISSIPATED IN THE TROPICAL 
PACIFIC DURING THE BOREAL SPRING MONTHS OF 2003.  IN THE PAST MONTH THE TREND 
TOWARDS NEGATIVE SST ANOMALIES HAS SL0WED AT LEAST TEMPORARILY - PROBABLY DUE 
TO MODULATION BY MJO ACTIVITY.  SSTS REMAIN SLIGHLY ABOVE NORMAL NEAR THE 
DATELINE - BUT THE WARMEST WATER REMAINS TO THE WEST.   DURING THE PAST FEW 
MONTHS THE DEPTH OF THE OCEANIC THERMOCLINE HAS STEADILY DECREASED ACROSS THE 
CENTRAL AND EASTERN EQUATORIAL PACIFIC - CONSISTENT WITH THE APPEARANCE OF 
COLDER THAN NORMAL SURFACE AND SUBSURFACE WATER IN THE UPPER LAYERS OF THE 
EQUATORIAL PACIFIC - ALTHOUGH THIS TREND HAS ALSO TEMPORARILY PAUSED. 

THE LATEST STATISTICAL AND COUPLED MODEL FORECASTS INDICATE CONSIDERABLE
UNCERTAINTY FOR THE NEXT SEVERAL MONTHS.  WHILE SOME FORECAST THE POSSIBILITY
THAT LA NINA WILL DEVELOP DURING THE SECOND HALF OF 2003 OTHERS INDICATE A
RESURGENCE OF EL NINO CONDITIONS BY THE END OF THE YEAR.  ALL SUCH MODELS HAVE
RELATIVELY LOW SKILL DURING TRANSITION PHASES OF THE ENSO CYCLE.  HOWEVER BASED
ON CURRENT CONDITIONS AND RECENT OBSERVED TRENDS IT APPEARS LIKELY THAT AT 
LEAST WEAK COLD EPISODE (LA NINA) CONDITIONS WILL DEVELOP IN THE TROPICAL 
PACIFIC DURING THE NEXT SEVERAL MONTHS.  MIDDLE LATITUDE IMPACTS DURING THIS 
TRANSITION ARE LIKELY TO BE MINIMAL DURING JULY.

SOIL MOISTURE INDICATIONS PLAY A MAJOR ROLE IN THE FORECAST FOR JULY - AS DO
FORECASTS FROM CCA - OCN AND DYNAMICAL MODELS - AND PERSISTENT SST ANOMALIES 
IN SOME COASTAL AREAS. 

THE SOIL MOISTURE CONSTRUCTED ANALOG TOOL BASED ON DATA THROUGH MID-JUNE GAVE
INDICATIONS FOR ABOVE NORMAL TEMPERATURES IN THE SOUTHWEST AND NORTHERN GREAT 
BASIN IN JULY AS WELL AS ALONG THE MIDDLE AND NORTH ATLANTIC COASTS.  THE 
INDICATIONS FOR THE WESTERN AREAS WERE ACCEPTED - BUT ABOVE NORMAL TEMPERATURES 
WERE CONSIDERED UNLIKELY ALONG THE MIDDLE AND NORTH ATLANTIC COASTAL PLAINS 
DUE TO VERY WET GROUND (99TH PERCENTILE IN THE 70-YR PERIOD OR RECORD) AND 
PERSISTENLY BELOW NORMAL SSTS ALONG THE CONTINENTAL SHELF. ABOVE MEDIAN IN THE 
WESTERN AREAS ARE ALSO SUGGESTED BY CCA AND OCN REGRESSION - ALTHOUGH BELOW 
NORMAL WAS FORECAST FOR THE SOUTHERN CALIFORNIA COAST BECAUSE OF ABNORMALLY 
COOL COASTAL WATERS IN THAT AREA.   

THE SOIL MOISTURE TOOL ALSO FORECAST A LARGE AREA OF ABNORMALLY COOL CONDITIONS 
OVER MUCH OF THE MIDWEST - SOUTHEAST - AND MIDDLE ATLANTIC AREAS - ALONG WITH 
WET CONDITIONS EXCEPT ALONG THE EASTERN SEABOARD AS NOTED ABOVE.  THEREFORE -
ONLY WEAK PROBABILITIES WERE FORECAST DUE TO THE NEAR-RECORD HIGH SOIL MOISTURE 
AT MANHY LOCATIONS.  THE DYNAMICAL MODELS ALSO SUPPORTED A FORECAST OF ABOVE 
MEDIAN PRECIPITATION IN PARTS OF THE SOUTHEAST - UPPER MIDWEST - AND CENTRAL 
MISSISSIPPI VALLEY.

SEVERAL OF THE STATISTICAL FORECASTS - INCLUDING NCEP - CCA AND CONSTRUCTED 
ANALOG FOR SOIL MOISTURE (CAS) HAVE INDICATIONS FOR BELOW MEDIAN PRECIPITATION 
ACROSS MUCH OF THE INTERIOR WEST AND NORTHERN PLAINS.  HOWEVER RECENT RAINS 
EAST OF THE CONTINENTAL DIVIDE SUGGEST THAT IN THAT AREA THESE FORECASTS SHOULD 
BE DISREGARDED - AND SO EC IS FORECAST THERE - BUT THE INDICATIONS FOR BELOW 
MEDIAN PRECIPITATION OVER THE NORTHERN GREAT BASIN WERE CONSIDERED REASONABLE.

THE EXPECTED DEVELOPMENT OF LA NINA CONDITIONS FAVORS AN ACTIVE MONSOON IN 
THE SOUTHWESTERN U.S. - BUT RESIDUAL LOW-LATITUDE TROPICAL JETS AND/OR 
MODULATION BY MJO ACTIVITY COULD DELAY THE MONSOON ONSET FROM ITS USUAL EARLY 
JULY DATE.  MOREOVER - SINCE ABOVE MEDIAN PRECIPITATION YIELDS ARE MORE LIKELY 
TO SHOW UP IN MEXICO DURING LA NINA THAN IN THE SOUTHWESTERN U.S. - THE 
SOUTHWESTERN U.S. WAS LEFT WITH EC.

MOST OF THE STATISTICAL MODELS INDICATE ABOVE MEDIAN TEMPERATURES OVER MUCH OF
WESTERN ALASKA - AND THIS IS SUPPORTED BY WELL ABOVE NORMAL SSTS IN THE BERING 
SEA.  HOWEVER - THE DYNAMICAL MODELS AND CCA LEAN TOWARDS BELOW NORMAL 
TEMPERATURES OVER PARTS OF EASTERN AND CENTRAL INTERIOR ALASKA - AND RECENT 
OBSERVATIONS HAVE SHOWN OCCASIONAL COOL PERIODS IN THAT PART OF THE STATE . 
FORECAST INDICATIONS FOR PRECIPITATION ARE UNCERTAIN IN MOST OF ALASKA AND 
USUALLY HAVE RATHER LOW SKILL - ESPECIALLY IN THE WARM SEASONS - SO THE 
ENTIRE STATE WAS LEFT EC FOR PRECIPITATION.


FORECASTER: A. J. WAGNER  

NOTE - THIS CLIMATE OUTLOOK IS INTENDED FOR USE ONLY PRIOR TO THE START OF THE 
VALID PERIOD.  WITHIN THE VALID PERIOD OBSERVATIONS AND SHORT AND MEDIUM RANGE 
FORECASTS SHOULD BE CONSULTED.

NOTE -  AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL
PROBABILTIES) WILL HENCEFORTH BE LABELED EC (EQUAL CHANCES).  
  
NOTE - THE NEXT 0.5 MONTH LEAD-TIME MONTHLY OUTLOOK WILL BE ISSUED 
THURSDAY JULY 17 2003.
  
NOTE - THE NEW 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE 
WITH THE MAY 17 2001 FORECAST RELEASE.


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