509
FXUS07 KWBC 191249
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EDT THU JUN 19 2008
30-DAY OUTLOOK DISCUSSION FOR JULY 2008
SEA SURFACE TEMPERATURE (SST) ANOMALIES ALONG THE EQUATORIAL PACIFIC REMAIN
BELOW NORMAL OVER THE CENTRAL PACIFIC, BUT THE MAGNITUDE AND EASTWARD EXTENT OF
THE ANOMALIES HAS BEEN DIMINISHING IN RECENT WEEKS AS ABOVE NORMAL SST
ANOMALIES INCREASE IN THE EASTERN PACIFIC. BELOW NORMAL SST ANOMALIES IN THE
NORTH PACIFIC MAKE A TYPICAL LA NINA HORSESHOE PATTERN EXTENDING FROM ALONG THE
EQUATOR NEAR THE DATELINE NORTHEASTWARD TO THE CALIFORNIA COAST, THEN FOLLOWING
THE PACIFIC COAST OF NORTH AMERICA INTO THE GULF OF ALASKA. SSTS IN THE NINO
3.4 REGION (BETWEEN 5 N AND 5 S, AND 170 W AND 120 W) HAD WARMED TO ABOUT 0.4
DEGREES CELSIUS BELOW NORMAL AS OF THE END OF MAY. THE ATMOSPHERIC CIRCULATION
THROUGHOUT THE TROPICAL PACIFIC OCEAN REFLECTS WEAKENED LA NINA CONDITIONS,
WITH WEAKER THOUGH STILL GREATER THAN NORMAL LOW LEVEL EASTERLIES ALONG THE
EQUATOR, SUPPRESSED CONVECTION IN THE CENTRAL EQUATORIAL PACIFIC, AND ENHANCED
CONVECTION OVER THE WESTERN EQUATORIAL PACIFIC. THE CONSOLIDATION OF NUMERICAL
AND STATISTICAL NINO 3.4 FORECASTS INDICATES ENSO NEUTRAL CONDITIONS THROUGH
THE NEXT COUPLE MONTHS. THE MOST RECENT CFS MODEL FORECASTS INDICATE RAPID
WARMING OF THE EQUATORIAL PACIFIC SSTS DURING THIS PERIOD. THE MONTHLY MEAN
SST ANOMALY IN THE NINO 3.4 REGION IS EXPECTED TO BE NEAR-NORMAL (LESS THAN
HALF A DEGREE CELSIUS) IN JUNE AND JULY. ANY RESIDUAL ATMOSPHERIC EFFECTS OF
THE RECENT LA NINA ARE EXPECTED TO HAVE SMALL IMPACTS ON U.S. TEMPERATURES AND
PRECIPITATION IN JULY.
BELOW NORMAL SST ANOMALIES ALONG THE PACIFIC COAST OF NORTH AMERICA ARE
EXPECTED TO FAVOR BELOW NORMAL AIR TEMPERATURES FOR IMMEDIATE COASTAL AREAS
FROM THE SOUTHERN COAST OF ALASKA TO SOUTHERN CALIFORNIA. THERE IS AN ENHANCED
PROBABILITY OF ABOVE NORMAL TEMPERATURES IN THE SOUTHWESTERN U.S. AND THE GREAT
BASIN DUE TO LARGE SUMMER TEMPERATURE TRENDS IN THESE REGIONS AS INDICATED IN
THE CCA AND OCN TOOLS. MUCH ABOVE NORMAL SOIL MOISTURE ANOMALIES AND INCREASED
EVAPORATIVE COOLING, ALONG WITH EXPECTED BELOW NORMAL MEAN UPPER LEVEL HEIGHTS
OVER THE EASTERN U.S. INDICATED BY THE CFS FORECAST, LEADS TO AN ENHANCED
PROBABILITY FOR BELOW NORMAL TEMPERATURES OVER PORTIONS OF THE U.S. MIDWEST
INCLUDING THE CENTRAL MISSISSIPPI AND WESTERN OHIO VALLEYS. ABOVE NORMAL
TEMPERATURES ARE MOST LIKELY FROM TEXAS EASTWARD THROUGH THE GULF COAST STATES
AS INDICATED BY THE CFS AND CAS, DUE IN PART TO DRY CONDITIONS.
LOCAL SOIL MOISTURE CONDITIONS ARE ASSOCIATED WITH AN INCREASED PROBABILITY OF
ABOVE MEDIAN RAINFALL FOR THE CENTRAL MISSISSIPPI VALLEY NORTHWARD INTO THE
GREAT LAKES REGION. DRY CONDITIONS ARE FORECAST FOR COASTAL REGIONS OF THE
PACIFIC NORTHWEST BY THE CFS AND THE CAS, CONSISTENT WITH THE TRENDS. BELOW
NORMAL SOIL MOISTURE ANOMALIES LEAD TO AN ENHANCED PROBABILITY OF BELOW MEDIAN
RAINFALL FOR EAST TEXAS AND WESTERN LOUISIANA AS INDICATED BY THE CAS AND CFS.
FORECASTER: DAN COLLINS
NOTES: AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL
PROBABILITIES) ARE NOW LABELED AS EC (EQUAL CHANCES).
AN UPDATED MONTHLY OUTLOOK... FOR JUL WILL BE ISSUED ON MON JUNE 30 2008
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD.
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