920 FXUS07 KWBC 301900 PMD30D PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EDT TUE SEP 30 2008 30-DAY OUTLOOK DISCUSSION FOR OCTOBER 2008 ENSO-NEUTRAL CONDITIONS CONTINUED DURING SEPTEMBER 2008, AS SEA SURFACE TEMPERATURES (SSTS) IN THE EAST-CENTRAL EQUATORIAL PACIFIC OCEAN (NINO 3.4 REGION) GENERALLY REMAINED NEAR-AVERAGE. SSTS IN THE EASTERN PACIFIC ARE STILL ABOVE AVERAGE, BUT ABOVE NORMAL OCEAN TEMPERATURES ARE CONFINED TO A SHALLOW LAYER NEAR THE SURFACE. RECENT FORECASTS FROM THE CFS INDICATE ENSO-NEUTRAL CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE NEXT FEW MONTHS AT LEAST, THEREFORE, ENSO IMPACTS WERE NOT CONSIDERED FOR THIS OCTOBER MONTHLY FORECAST. THE OCTOBER 2008 TEMPERATURE FORECAST CALLS FOR BELOW AVERAGE MEAN TEMPERATURES ALONG THE PACIFIC COAST OF NORTH AMERICA FROM WASHINGTON TO SOUTHCENTRAL ALASKA. THIS IS LARGELY DUE TO BELOW NORMAL SSTS IN ADJACENT COASTAL WATERS. SHORT TERM FORECASTS INDICATE AN UPPER LEVEL TROUGH OVER THE GULF OF ALASKA IN THE EARLY PART OF THE MONTH, WHICH SLIGHTLY INCREASES THE CONFIDENCE AND EXTENT OF THE BELOW NORMAL TEMPERATURES SHOWN IN THE OUTLOOK ISSUED IN MID SEPTEMBER. AN ENHANCED PROBABILITY OF ABOVE NORMAL TEMPERATURES IS FORECAST FOR THE SOUTHWESTERN U.S. INCLUDING SOUTHERN CALIFORNIA. THIS IS DUE MOSTLY TO EARLY AUTUMN TEMPERATURE TRENDS IN THESE REGIONS AS INDICATED IN THE CCA AND OCN TOOLS. THE ANOMALOUS WARMTH EXPECTED ALONG THE SOUTHERN CALIFORNIA COAST IS ATTRIBUTED TO THE RECENT DEVELOPMENT OF POSITIVE SST ANOMALIES IN THIS AREA. RECENT TEMPERATURE TRENDS ARE RESPONSIBLE FOR THE ABOVE AVERAGE AIR TEMPERATURES PREDICTED ACROSS NEW ENGLAND FOR OCTOBER, THIS AREA IS EXPANDED SLIGHTLY IN SPITE OF AN ANTICIPATED COLD START OF THE MONTH BECAUSE OF INDICATIONS FOR ABOVE NORMAL TEMPERATURES IN THE SECOND WEEK OF OCTOBER OVER PARTS OF THE NORTHEASTERN CONUS. ABOVE AVERAGE MEAN TEMPERATURES ARE ALSO INDICATED FOR WESTERN AND NORTHERN PORTIONS OF COASTAL ALASKA, DUE TO RECENT TRENDS AND ALSO AN UNUSUAL LARGE EXTENT OF OPEN WATER FOR THIS TIME OF YEAR IN THE ARCTIC OCEAN NORTH OF ALASKA. ELSEWHERE, EQUAL CHANCES OF ABOVE-, NEAR-, AND BELOW AVERAGE TEMPERATURES ARE PREDICTED. AN ANTICIPATED UPPER LEVEL TROUGH OVER THE GULF OF ALASKA SHOULD ENHANCE THE PACIFIC JET STREAM AND BRING SOME SIGNIFICANT PRECIPITATION TO THE WEST COAST EARLY IN THE MONTH FROM NORTHERN CALIFORNIA TO THE PACIFIC NORTHWEST, ENHANCING CHANCES OF ABOVE MEDIAN MONTHLY TOTALS IN THAT AREA. THERE ARE NO MAJOR TROPICAL SYSTEMS THREATENING THE CONUS IN THE FIRST WEEK OF OCTOBER, SO THE AREA OF ABOVE MEDIAN PRECIPITATION ALONG THE GULF COAST HAS BEEN REDUCED SOMEWHAT, SINCE THIS IS DUE PARTIALLY TO ANTICIPITATED TROPICAL STORM ACTIVITY. LITTLE DEFINITIVE GUIDANCE IS PROVIDED BY THE TRADITIONAL STATISTICAL TOOLS FOR THE OCTOBER PRECIPITATION FORECAST IN THE REMAINDER OF THE COUNTRY, AND THERE ARE NO SUBSTANTIAL SHORT TERM SIGNALS OUTSIDE OF THE PACIFIC NORTH WEST SUGGESTING SUBSTANTIALLY ALTERED CHANCES OF ABOVE- NEAR- OR BELOW MEDIAN PRECIPITATION AMOUNTS FROM THEIR CLIMATOLOGICAL EXPECTATIONS. FORECASTER: DAVID UNGER NOTES: AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED AS EC (EQUAL CHANCES). THE NEXT MONTHLY OUTLOOK...FOR NOVEMBER 2008...WILL BE ISSUED ON THU OCT 16 2008 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD. $$