PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EST THU FEB 18 2010

30-DAY OUTLOOK DISCUSSION FOR MARCH 2010

EL NINO CONDITIONS CONTINUE ACROSS THE EQUATORIAL PACIFIC OCEAN WITH SEA 
SURFACE TEMPERATURE (SST) DEPARTURES OF +1.0 DEGREE C OR GREATER ACROSS MUCH OF 
THE CENTRAL PACIFIC. THERE HAS BEEN A LESSENING IN THE POSITIVE ANOMALIES 
ACROSS THE EASTERN PORTION OF THE BASIN BUT THIS IS TYPICAL DURING THIS PART OF 
THE SEASONAL CYCLE WHEN TOTAL SST VALUES REACH THEIR MAXIMUM. OCEAN SUB-SURFACE 
TEMPERATURE ANOMALIES ALSO REMAIN POSITIVE FROM THE SURFACE TO A DEPTH OF 
APPROXIMATELY 150 M FROM 170E TO 100W ALONG THE EQUATOR ACROSS THE PACIFIC, 
THEREFORE EL NINO CONDITIONS ARE EXPECTED TO CONTINUE THROUGH MARCH 2010.

CURRENT ATMOSPHERIC CONDITIONS ARE CONSISTENT WITH EL NINO. ENHANCED TROPICAL 
CONVECTION ACROSS THE WESTERN AND CENTRAL PACIFIC OCEAN IS EVIDENT AS WELL AS 
ANOMALOUS LOW-LEVEL WESTERLY WIND ANOMALIES ACROSS PORTIONS OF THE WEST-CENTRAL 
PACIFIC DURING THE PAST 30 DAYS. IN ADDITION, UPPER-LEVEL EASTERLY WIND 
ANOMALIES ARE OBSERVED ACROSS THE CENTRAL PACIFIC WITH WELL-ESTABLISHED 
ANTICYCLONES BOTH NORTH AND SOUTH OF THE EQUATOR. BASED ON THE AFOREMENTIONED 
OCEANIC AND ATMOSPHERIC CONDITIONS, TYPICAL EL NINO WINTER U.S. IMPACTS REMAIN 
A FACTOR IN THE MARCH 2010 MONTHLY OUTLOOK. 

EL NINO COMPOSITES FOR BOTH MEAN TEMPERATURE AND TOTAL PRECIPITATION FOR THE 
FEBRUARY-MARCH-APRIL SEASON WERE CONSULTED FOR THIS OUTLOOK. EL NINO CONDITIONS 
FAVOR ENHANCED CHANCES FOR BELOW-AVERAGE TEMPERATURES ACROSS PARTS OF THE 
SOUTH-CENTRAL AND SOUTHEAST U.S. INTO THE SOUTHERN MID-ATLANTIC AND AN ENHANCED 
LIKELIHOOD FOR ABOVE-NORMAL TEMPERATURES FOR MUCH OF ALASKA, THE PACIFIC 
NORTHWEST AND PARTS OF THE GREAT LAKES. ABOVE-MEDIAN PRECIPITATION IS FAVORED 
FOR MUCH OF THE SOUTHERN TIER OF THE U.S. FROM CALIFORNIA ACROSS THE SOUTHWEST 
AND GULF COAST TO THE SOUTHEAST AND SOUTHERN MID-ATLANTIC. ELEVATED CHANCES FOR 
BELOW-MEDIAN PRECIPITATION ARE INDICATED FOR THE PACIFIC NORTHWEST AND PARTS OF 
THE SOUTHERN GREAT LAKES AND OHIO VALLEY.

BOTH STATISTICAL AND DYNAMICAL FORECAST TOOLS WERE ALSO CONSIDERED FOR THE 
TEMPERATURE OUTLOOK. THE CCA ALSO INDICATES A FORECAST TEMPERATURE PATTERN 
CONSISTENT WITH EL NINO CONDITIONS AND DEPICTS ENHANCED CHANCES FOR WARMER THAN 
NORMAL TEMPERATURES FOR ALASKA, THE PACIFIC NORTHWEST AND THE GREAT LAKES AND 
ENHANCED CHANCES FOR COLDER THAN NORMAL TEMPERATURES FOR PARTS OF THE SOUTHERN 
U.S.. ALTHOUGH EL NINO CONDITIONS FAVOR BELOW NORMAL TEMPERATURES FOR THE 
SOUTHWEST U.S., STRONG POSITIVE TEMPERATURE TRENDS IN THIS REGION OPPOSE THIS 
SIGNAL AS INDICATED BY THE SMLR AND OCN FORECAST TOOLS. SO EQUAL PROBABILITIES 
FOR ABOVE-, NEAR-, OR BELOW-NORMAL TEMPERATURES ARE INDICATED FOR CALIFORNIA 
AND PORTIONS OF THE SOUTHWEST AND CENTRAL INTERMOUNTAIN WEST. THE CFS ALSO 
INDICATES A STRONG EL NINO PATTERN THAT IS QUITE CONSISTENT WITH EL NINO 
COMPOSITES.   

ABOVE-AVERAGE SNOWFALL OCCURRED IN MANY AREAS OF THE EASTERN U.S. DURING 
JANUARY AND THE FIRST HALF OF FEBRUARY. SOME AREAS IN THE MID-ATLANTIC HAVE 
ALREADY SEEN THEIR GREATEST SNOWFALL EVER RECORDED AND REPEATED SNOWFALLS HAVE 
OCCURRED ACROSS PORTIONS OF THE LOWER MISSISSIPPI, TENNESSEE AND OHIO VALLEYS, 
AND THE SOUTHEAST. THE FORECAST AREA FOR BELOW-NORMAL TEMPERATURES IS LARGER 
AND EXPANDED NORTHWARD THAN WHAT WOULD NORMALLY BE EXPECTED FOR EL NINO 
CONDITIONS ALONE DUE TO THE POTENTIAL IMPACT ON THESE AREAS OF ANOMALOUS SNOW 
COVER AND SUBSEQUENT HIGHER SOIL MOISTURE. EXTENDED RANGE FORECASTS INDICATE A 
CONTINUED NEGATIVE PHASE OF THE AO AND BELOW NORMAL TEMPERATURES FOR MUCH OF 
THE EASTERN U.S., WHICH MAY ALLOW SNOW COVER TO PERSIST IN MANY AREAS INTO THE 
EARLY PORTION OF MARCH.     

THE DESIGNATED AREA FOR ENHANCED CHANCES OF ABOVE-NORMAL TEMPERATURES TYPICALLY 
OBSERVED ACROSS THE NORTHERN PLAINS AND GREAT LAKES DURING EL NINO WINTER IS 
QUITE SMALL AND IS LIMITED TO PARTS OF MINNESOTA, WISCONSIN AND MICHIGAN. THE 
CONFIDENCE FOR ABOVE-AVERAGE TEMPERATURES ASSOCIATED WITH EL NINO WINTERS 
ACROSS THE NORTHERN PLAINS AND GREAT LAKES BEGINS TO WANE IN MARCH. ALSO, HIGH 
SNOW DEPTHS AND UNCERTAINTY IN THE PHASE OF THE AO (WHICH HAS BEEN PERSISTENTLY 
STRONGLY NEGATIVE THIS WINTER TO DATE) WOULD ACT TO OPPOSE ANY EL NINO WARM 
SIGNAL. THE HIGHLIGHTED AREA IS LIMITED TO THE REGION THAT HAS SEEN 
ABOVE-NORMAL TEMPERATURES DURING THE FIRST HALF OF FEBRUARY DESPITE LARGE SNOW 
DEPTHS AND THE NEGATIVE PHASE OF THE AO.
   
FOR PRECIPITATION, EL NINO COMPOSITES WERE FOLLOWED QUITE CLOSELY AND WERE 
SUPPORTED IN MANY AREAS BY THE SMLR AND CCA STATISTICAL FORECASTS AS WELL AS 
THE CFS DYNAMICAL FORECAST.

FORECASTER: JON GOTTSCHALCK

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

AN UPDATED MONTHLY OUTLOOK... FOR MAR WILL BE ISSUED ON SUN FEBRUARY 28 2010

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

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