PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT THU JUL 17 2003

30-DAY OUTLOOK DISCUSSION FOR AUGUST 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 NINO34 SST ANOMALIES HAS SLOWED OR REVERSED AND NEAR NORMAL
CONDITIONS ARE EXPECTED THROUGH AUGUST.

SOIL MOISTURE INDICATIONS PLAY A ROLE IN THE FORECAST - AS DO
FORECASTS FROM CCA - OCN AND DYNAMICAL MODELS - AND PERSISTENT SST ANOMALIES 
IN SOME COASTAL AREAS. IN SOME CASES TOOLS ARE USED TO OFFSET EACH OTHER.
FOR INSTANCE THE SOIL MOISTURE CONSTRUCTED ANALOG TOOL GIVES INDICATIONS 
FOR BELOW NORMAL TEMPERATURES IN THE SOUTHEAST OVER EXTREMELY WET SOIL BUT
THIS IS OFFSET BY TRENDS FOR WARMER THAN NORMAL CONDITIONS. HENCE THE EC
FORECAST IN MUCH OF THE SOUTHEAST. ONLY SOUTHERN FLORIDA HAS DOMINANT TRENDS
FOR WARM. IN THE INTERIOR WEST MANY TOOLS GIVE INDICATIONS FOR ABOVE NORMAL
TEMEPRATURES BUT TOOLS ARE IN MORE DISAGREEMENT ALONG THE PACIFIC COAST. 
FOR SOUTHWESTERN COASTAL CA THE IMPACT OF BELOW NORMAL LOCAL SST WILL KEEP 
TEMPERATURES BELOW NORMAL.

THE PREDICTED PATTERN FOR TEMPERATURE FOR AUGUST OVER THE US IS IN REASONABLE
AGREEMENT WITH SHORTER RANGE FORECASTS FOR WEEK 1 AND WEEK 2 AND WITH THE 
PATTERN SO FAR IN JULY. WE ARE THUS LOOKING FOR PERSISTENCE OF THE ANOMALY
PATTERNS AND INDEED JULY TO AUGUST HAS A MAXIMUM IN MONTH-TO-MONTH PERSISTENCE. 

INDICATIONS FOR PRECIPITATION ARE WEAK AND CONFLICTING AND WITH LOW A-PRIORI 
SKILL. HENCE WE OPTED FOR EC EVERYWHERE. ONE MIGHT EXPECT THE 0.5 MONTH LEAD 
FORECAST FOR JAS - ISSUED LAST MONTH - TO HAVE SIMILARITIES TO THE CURRENT 
AUGUST FORECAST. THE REASON FOR EC EVERYWHERE IS INTRASEASONAL VARIABILITY
LEADING TO LOWER SIGNIFICANCE OF THE VERY SAME SIGNALS WHEN VERIFIED 
AS A MONTHLY FORECAST. 
  
FORECASTER: H. M. VAN DEN DOOL  

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 AUGUST 21 2003.
  
NOTE - THE NEW 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE 
WITH THE MAY 17 2001 FORECAST RELEASE.


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