PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT MON JUL 31 2006

30-DAY OUTLOOK DISCUSSION FOR AUGUST 2006

SEA SURFACE TEMPERATURES ALONG THE EQUATOR IN THE EASTERN AND CENTRAL PACIFIC 
OCEAN AVERAGE SLIGHTLY ABOVE NORMAL, RANGING FROM ABOUT NORMAL TO AS MUCH AS 
ONE DEGREE C ABOVE NORMAL IN THE MOST RECENT WEEK. EVEN THOUGH ALMOST ENTIRELY 
ABOVE NORMAL, THIS PATTERN IS IN THE POSITIVE HALF OF NEUTRAL ENSO CONDITIONS, 
ALTHOUGH NOT FAR FROM THE THRESHOLD OF A WEAK EL NINO.  NEVERTHELESS, THE 
OVERALL PATTERN SHOWS A RELATIVE MINIMUM IN THE SST FIELD ON THE EQUATOR, WHICH 
IS NOT WHAT ONE EXPECTS WITH A SIGNIFICANT EL NINO.  RECENT DEVELOPMENTS  
CONTINUE A SLOW WARMING TREND THAT HAS EXISTED SINCE FEBRUARY IN BOTH SSTS AND 
THE UPPER LAYERS OF THE PACIFIC BASIN AS A WHOLE.  CONSIDERING ALL OF THESE 
FACTORS, ENSO IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT ON THE CLIMATIC 
CONDITIONS OVER THE U.S. DURING AUGUST. 

THE UPDATED TEMPERATURE AND PRECIPITATION OUTLOOKS FOR AUGUST ARE BASED ON 
INDICATIONS FROM VARIOUS STATISTICAL TOOLS AND TRENDS AVAILABLE AT THE TIME OF 
THE FORECAST MADE IN MID-JULY, PLUS INDICATIONS FROM THE NUMERICAL MODELS USED 
FOR SHORT- AND METIUM-RANGE FORECASTING, AND THE LATEST AVAILABLE CONSTRUCTED 
ANALOG FROM SOIL MOISTURE (CAS) STATISTICAL FORECAST.

FOR THE MOST PART THE AREA OF BOVE NORMAL TEMPERATURES PREDICTED FOR MOST OF 
THE SOUTHERN... CENTRAL... AND SOUTHEASTERN PARTS OF THE CONUS WAS EXPANDED A 
LITTLE, ESPECIALLY OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. 
CONFIDENCE AS SHOWN BY THE PROBABILITY CONTOURS WAS ALSO INCREASED, AS NEARLY 
ALL THE TOOLS WERE IN AGREEMENT FOR THE WARMTH, ESPECIALLY IN THE SOUTH-CENTRAL 
STATES, WHERE CAS WAS GIVING AN EXCEPTIONALLY STRONG SIGNAL.  AREAS TO THE EAST 
OF THE SOUTHERN APPALACHINS WERE REDUCED TO EC DUE TO WEAKENED INDICATIONS FOR 
CONTINUED OR CONSISTENT WARMTH THERE.  THE MAJOR CHANGE FROM THE PRELIMINARY 
FORECAST MADE IN MID-JULY IS OVER THE INTERIOR SOUTHWEST, WHERE AN AREA THAT 
HAD BEEN PREDICTED TO BE WARM NOW LOOKS LIKE A MIX OF NEAR NORMAL AND BELOW 
NORMAL, WITH THE LATTER BEING MOST LIKELY OVER EASTERN ARIZONA AND WESTERN NEW 
MEXICO NORTHWARD THROUGH THE FOUR CORNERS AREA, WHERE THE SOUTHWEST MONSOON IS 
EXPECTED TO BE MOST ACTIVE, ESPECIALLY WITHIN THE SHORT AND MEDIUM RANGE.  
SINCE THE MONSOON CLOUDINESS AND MOISTURE IS NOT EXPECTED TO BE IN CALIFORNIA 
EXCEPT IN A VERY TRANSIENT WAY, AND THE PREDICTED PATTERN OF A TROUGH JUST OFF 
THE COAST DOES NOT FAVOR UPWELLING OF COOLER WATER, ABOVE NORMAL TEMPERATURES 
ARE EXPECTED TO CONTINUE OVER BOTH INTERIOR AND COASTAL SOUTHERN CALIFORNIA, 
WHERE CURRENT SST ANOMALIES ARE THE WARMEST.  OVER ALASKA... THE WAMRTH 
FORECAST ALONG THE SOUTH COAST IN THE PRELIMINARY FORECAST WAS TRIMMED BACK, 
AND A SMALL AMOUNT OF BELOW NORMAL WITH A VERY WEAK PROBABILITY WAS PLACED FROM 
THE SOUTHERN ALASKA PANHANDLE DOWN TO THE PACIFIC NORTHWEST COAST, WHILE THE 
SMALL AREA OF BELOW NORMAL TEMPERATURES INDICATED OVER THE NORTHWESTERN PART OF 
THE STATE BASED ON STRONG SIGNALS FROM THE CFS MODEL WITH NO OPPOSING SIGNALS 
FROM THE STATISTICAL TOOLS WAS ENLARGED SLIGHTLY AS RECENT CFS MODEL FORECASTS 
ARE SIMILAR TO THE PREVIOUS ONES.  MANY OF THE FORECAST TOOLS BASED ON THE 
CURRENT DYNAMICAL MODELS INDICATED A LOT MORE BELOW NORMAL OVER THE WESTERN AND 
NORTHWESTERN PORTIONS OF THE CONUS THAN WHAT IS SHOWN IN THE OFFICIAL FORECAST 
FOR AUGUST, BUT EC WAS PREFERRED THERE SINCE RECENT MODEL ERRORS HAVE SHOWN A 
CONSISTEN BIAS FOR HEIGHTS TO BE FORECAST TOO LOW.

THE AREA OF BELOW MEDIAN PRECIPITATION CENTERED OVER THE SOUTH-CENTRAL STATES 
CONTINUES TO BE STRONGLY INDICATED BY THE CAS TOOL... WITH NO SIGNIFICANT 
OPPOSITION FROM THE OTHER STATISTICAL TOOLS OR THE CFS MODEL.  SHORT- AND 
MEDIUM-TERM INDICATIONS FROM DYNAMICAL MODELS GAVE STRONG INDICATIONS FOR AN 
ACTIVE MONSOON, SO AN AREA OF ABOVE MEDIAN PRECIPIATAION WAS FORECAST FOR THE 
INTERIOR SOUTHWESST.  EC WAS INDICATED FOR THE REMAINDER OF THE CONUS, EXCEPT 
FOR A WEAK PROBABILITY FOR ABOVE MEDIAN ALONG THE PACIFIC NORTHWEST COAST DUE 
TO THE TROUGH EXPECTED TO BE THERE FOR AT LEAST THE FIRST WEEK OR TWO OF THE 
MONTH.   THERE WERE NO RELIABLE FORECAST INDICATIONS FOR ALASKA EXCEPT FOR SOME 
HINTS FOR ABOVE MEDIAN IN THE SOUTHERN PANHANDLE... SO ALL BUT THAT PART OF THE 
STATE WAS LEFT WITH EC.

 

FORECASTER: A. J. WAGNER

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

THE NEXT MONTHLY OUTLOOK... FOR SEPTEMBER 2006... WILL BE ISSUED ON THU AUG 17 
2006

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

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