PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EST FRI FEB 29 2008

30-DAY OUTLOOK DISCUSSION FOR MARCH 2008

STRONG LA NINA CONDITIONS CONTINUE THROUGHOUT THE TROPICAL PACIFIC AND WILL 
CONTINUE TO FORM THE UNDERLYING BASIS FOR THIS UPDATED MONTHLY FORECAST.  WELL 
BELOW AVERAGE SEA SURFACE TEMPERATURES (SSTS) ARE OBSERVED ACROSS THE CENTRAL 
AND EASTERN EQUATORIAL PACIFIC.  SSTS MORE THAN 2 DEG CELSIUS BELOW AVERAGE 
WERE OBSERVED BETWEEN 175E AND 120W AND THE NINO 3.4 REGION INDEX VALUE HAS 
BEEN NEAR -2.0 FOR THE PAST MONTH.  IN ADDITION THE LOW LEVEL EQUATORIAL 
EASTERLY WINDS HAVE BEEN STRONGER THAN AVERAGE ACROSS THE CENTRAL EQUATORIAL 
PACIFIC... STRONGER THAN AVERAGE UPPER LEVEL WESTERLY WINDS HAVE BEEN 
OBSERVED... AND CONVECTION HAS BEEN SUPPRESSED OVER THE CENTRAL PACIFIC.  
COLLECTIVELY, THESE ATMOSPHERIC AND OCEANIC CONDITIONS ARE CONSISTENT WITH 
STRONG LA NINA CONDITIONS.  SST FORECASTS FROM THE CFS AND A SUITE OF OTHER 
STATISTICAL AND DYNAMICAL MODELS INDICATE THAT LA NINA SHOULD REMAIN STRONG OR 
MODERATE THROUGH MARCH AND INTO THE SPRING. THEREFORE, THE MARCH TEMPERATURE 
AND PRECIPITATION FORECASTS ARE BASED STRONGLY ON LA NINA COMPOSITES FOR THE 
FEBRUARY - APRIL SEASON.  

INTRASEASONAL (MJO) ACTIVITY HAS BEEN RATHER PERSISTENT SINCE MID-NOVEMBER, AND 
HAS MODULATED LA NINA IMPACTS ACROSS THE CONUS AT VARIOUS TIMES DURING THE 
WINTER.  DURING MIDDLE TO LATE FEBRUARY THE MJO PROPAGATED THROUGH THE WESTERN 
PACIFIC INTO THE WESTERN HEMISPHERE BEFORE STALLING AND WEAKENING.  VARIOUS 
MODEL FORECASTS ARE GENERALLY INDICATING THAT THE CURRENT MJO WILL STRENGTHEN 
AND BEGIN PROPAGATING DURING EARLY MARCH, POTENTIALLY REACHING A LOCATION THAT 
WOULD HELP TO REINFORCE THE EXPECTED LA NINA SIGNAL.  THEREFORE THE UPDATED 
MARCH FORECAST IS LARGELY CONSISTENT WITH THE HALF MONTH LEAD... DESPITE 
INDICATIONS OF A DIFFERENT PATTERN IN THE SHORT TERM. 

THE TEMPERATURE OUTLOOK FOR MARCH FAVORS ABOVE AVERAGE TEMPERATURES ACROSS MOST 
OF THE SOUTH FROM NEW MEXICO EASTWARD... ACROSS THE SOUTHERN AND CENTRAL 
PLAINS... AND ALONG THE EASTERN SEABOARD FROM FLORIDA NORTHWARD THROUGH THE 
NORTHERN MID-ATLANTIC. BELOW-AVERAGE TEMPERATURES ARE MOST LIKELY IN THE 
PACIFIC NORTHWEST AND IN SOUTHERN CALIFORNIA AND ALSO IN SOUTHERN ALASKA AND 
THE ALASKAN PANHANDLE. THE OBSERVED BELOW-AVERAGE SSTS ALONG THE CALIFORNIA 
COAST FAVOR A CONTINUATION OF BELOW AVERAGE TEMPERATURES IN SOUTHERN 
CALIFORNIA.  THE TEMPERATURE FORECAST OVER THE REST OF THE CONUS AND ALASKA IS 
CONSISTENT WITH OBSERVATIONS FROM PREVIOUS STRONG LA NINA EPISODES.  THE 
TEMPERATURE FORECAST IN THESE REGIONS IS ALSO SUPPORTED BY THE SMLR AND THE 
CCA, AS WELL AS UPDATED FORECASTS FROM THE CFS.     

THE PRECIPITATION FORECAST FOR MARCH USED FEBRUARY - APRIL LA NINA COMPOSITES 
AS THE STARTING POINT, WHICH INDICATES MEAN DRY CONDITIONS ACROSS THE ENTIRE 
SOUTHERN U.S. AND WETTER THAN AVERAGE CONDITIONS IN THE PACIFIC NORTHWEST AND 
IN THE OHIO AND TENNESSEE VALLEYS. INDICATIONS IN THE SHORT TERM FAVORED 
EXPANDING THE REGION IN THE OHIO AND TENNESSEE VALLEYS INTO PARTS OF THE 
NORTHEAST... AND SCALING BACK SOME OF THE DRY IN THE SOUTHEAST.  DRIER THAN 
AVERAGE CONDITIONS ARE ALSO FAVORED IN SOUTHERN ALASKA... AS INDICATED BY THE 
CFS AND THE CCA.



FORECASTER: MIKE HALPERT

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

THE NEXT MONTHLY OUTLOOK...FOR APRIL 2008...WILL BE ISSUED ON THU MAR 20 2008

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

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