PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EDT THU AUG 17 2006

30-DAY OUTLOOK DISCUSSION FOR SEPTEMBER 2006

EQUATORIAL SEA SURFACE TEMPERATURES IN THE EASTERN AND CENTRAL PACIFIC OCEAN 
INCREASED DURING JULY, WITH SST ANOMALIES GREATER THAN 0.5 DEGREE C OBSERVED 
ACROSS MOST OF THE PACIFIC BETWEEN 130 DEGREES E AND 140 DEGREES W.  THE 
BASIN-WIDE UPPER OCEAN HEAT CONTENT ALSO CONTINUED TO INCREASE DURING THE 
MONTH.  UPPER-OCEAN HEAT CONTENT REACHED A MINIMUM DURING FEBRUARY AND HAS 
STEADILY INCREASED, BECOMING POSITIVE IN APRIL.  POSITIVE UPPER-OCEAN HEAT 
CONTENT ANOMALIES OFTEN PRECEDE WARM EPISODES.  THE LOW-LEVEL (850-HPA) 
EASTERLY WINDS WERE WEAKER THAN NORMAL DURING JULY AND THE SOUTHERN OSCILLATION 
INDEX WAS NEGATIVE FOR THE THIRD CONSECUTIVE MONTH.  THESE INDICES, ALTHOUGH 
TRENDING TOWARD EL NINO, ARE STILL CONSISTENT WITH ENSO-NEUTRAL CONDITIONS.  
HOWEVER RECENT TRENDS HAVE INCREASED THE PROBABILITY OF A WARM EPISODE 
OCCURRING BY THE END OF THE YEAR TO NEAR 50 PERCENT.  NEVERTHELESS, ENSO IS NOT 
EXPECTED TO HAVE ANY IMPACT ON THE CLIMATIC CONDITIONS OVER THE U.S. DURING 
SEPTEMBER. 

THE LONG-LEAD TEMPERATURE AND PRECIPITATION OUTLOOKS FOR SEPTEMBER ARE BASED ON 
INDICATIONS FROM VARIOUS STATISTICAL TOOLS AND TRENDS AS WELL AS MONTHLY MODEL 
OUTPUT FROM THE CLIMATE FORECAST SYSTEM.

THE SEPTEMBER OUTLOOK FAVORS ABOVE NORMAL TEMPERATURES OVER THE NORTHEAST, 
SOUTHERN FLORIDA AND MUCH OF THE SOUTHWEST.  INDICATIONS FROM OCN PLAYED THE 
LARGEST ROLE IN THE TEMPERATURE OUTLOOK FOR ALL OF THESE REGIONS, WITH THE 
LARGEST POSITIVE TRENDS OBSERVED OVER THE SOUTHWEST IN ARIZONA.  PROBABILITIES 
FOR ABOVE NORMAL TEMPERATURES WERE ELEVATED OVER SOUTHERN CALIFORNIA DUE TO 
ABOVE NORMAL SSTS OBSERVED OFF THE CALIFORNIA COAST.  ELSEWHERE, THERE WERE NO 
STRONG INDICATIONS FOR ABOVE OR BELOW NORMAL TEMPERATURES FROM ANY OF THE TOOLS.

INDICATIONS FOR ABOVE OR BELOW NORMAL PRECIPITATION ARE WEAKER, AS IS USUALLY 
THE CASE.  THERE ARE NO STATISTICALLY SIGNIFICANT SIGNALS FROM THE CCA AND ONLY 
VERY LIMITED INDICATIONS FROM SMLR.  OCN FAVORS DRIER THAN NORMAL CONDITIONS 
OVER PARTS OF THE WEST AND WETTER THAN NORMAL CONDITIONS OVER FLORIDA.  THE 
DRIER THAN NORMAL CONDITIONS ARE ALSO SUPPORTED BY THE CFS, WHICH FAVORS DRIER 
THAN NORMAL CONDITONS IN MUCH OF THE WEST.  HAVE BACKED OFF BELOW NORMAL IN 
MUCH OF ARIZONA AND NEW MEXICO SINCE THE MONSOON HAS BEEN QUITE ACTIVE THIS 
YEAR.   



 

FORECASTER: M. HALPERT

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

AN UPDATED MONTHLY OUTLOOK... FOR SEPTEMBER 2006... WILL BE ISSUED ON THU AUG 
31 2006

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

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