WINTER ANALOGS FOR 2005-2006 WINTER
BOTH OCTOBER AND NOVEMBER WILL BE WARMER THAN NORMAL (IN THE WARMEST THIRD OF EACH PRESPECTIVE MONTHS). HISTORICALLY SPEAKING THEIR HAVE BEEN 16 INSTANCES OF THIS OCCURRING IN THE 133 YEARS OF RECORD IN PHL AND A DOZEN OF THE ENSUING WINTERS HAVE BEEN WARMER THAN THE LONG TERM MEDIAN OF 34.5 DEGREES. NINE OF THESE COUPLETS HAVE OCCURRED IN ENSO NEUTRAL WINTERS WHICH IS THE CURRENT AND EXPECTED ENSO STATE FOR THE UPCOMING WINTER. THE FOLLOWING ARE THE NINE ENSO WINTERS THAT FOLLOWED BOTH AN UNSEASONABLY WARM OCTOBER AND NOVEMBER. WE HAVE STAR(ED) (*) THE AUTUMNS IN WHICH THE PDO (PACIFIC DECADAL OSCILLATION) WAS ALSO NEGATIVE IN OCTOBER AND NOVEMBER. THIS INDEX NORMALLY "FAVORS" A MILDER WINTER IN THE EAST IF IT REMAINS NEGATIVE. NO METEOROLOGICAL AGENCY THAT WE ARE AWARE OF ISSUES A PDO FORECAST. THE UKMET DOES ISSUE A NAO OUTLOOK (NEGATIVE NAO TO PREVAIL) WHICH IN AN ENSO NEUTRAL WINTER WILL HAVE A BIG SAY ON THE UPCOMING WINTER TEMPERATURES.

THIS IS FOR PHILADLEPHIA.

            ENSUING    ENSUING   ENSUING  WINTER   SEASONAL SNOW

            DEC        JAN       FEB      MEAN
1900-1      36.6       33.1      27.2     32.3          10.6 
1912-3      40.3       42.2      34.4     39.0           9.5 
1927-8*     38.9       35.6      35.1     36.5          15.5 
1928-9      40.8       34.2      35.2     36.7          11.9      
1931-2      44.2       46.2      39.6     43.3           7.7 
1946-7*     38.0       38.3      28.4     34.9          23.7 
1985-6      33.3       32.8      32.1     32.7          16.4 
1990-1*     42.1       35.2      40.0     39.1          14.6 
2001-2*     43.7       39.2      41.1     41.1           4.0     

AVG OF ALL

ANALOGS     39.8       37.4      34.8     37.3          12.7   

CURRENT       
1971-2000   37.4       32.3      34.8     34.8          19.3
NMLS             
BUT...........................(AND THERE ALWAYS IS A BUT) MOST OF THOSE ANALOG OCTOBERS/NOVEMBERS WERE QUITE DRY. OCTOBER WAS THE WETTEST OCTOBER ON RECORD FOR MANY PLACES. THE LAST COUPLE OF WINTERS THE EVENTUAL OUTCOME HAS COME CLOSER BY MATCHING BOTH OCTOBER AND NOVEMBER TEMPERATURE AND PRECIPITATION THAN JUST PURE TEMPERATURES. THIS IS THE SHORT LIST BELOW WHICH INCLUDED ONLY THOSE THAT HAD A NEGATIVE PDO INDEX AND HAD A SIMILAR PRECIPITATION/TEMPERATURE PATTERN FOR OCTOBER AND NOVEMBER. ENSO STATE WAS NOT A DECIDING FACTOR. GIVEN THE WAY DECEMBER IS STARTING, THIS SECOND SET OF ANALOGS IS LOOKING BETTER ALL THE TIME.
            ENSUING  ENSUING   ENSUING  WINTER  SEASONAL SNOW

            DEC      JAN       FEB      MEAN
1927-28*    38.9     35.6      35.1     36.5        15.5
1922-23#    36.1     34.4      30.0     33.5        19.5
1970-71^    35.8     27.8      36.1     33.2        18.3 

AVG OF      36.9     32.6      33.7     34.4        17.8  
ANALOGS 

CURRENT     37.4     32.3      34.8     34.8        19.3  
1971-2000    
NMLS        

* WAS AN ENSO NEUTRAL WINTER
# WAS BARELY A WEAK LA NINA WINTER
^ WAS A MODERATE LA NINA WINTER 

FOR MORE CLIMATOLOGICAL INSIGHTS USING CPC/S FIGURES HERE IS THE BREAKDOWN OF AVERAGE SEASONAL SNOWFALL SINCE THE 1949-50 WINTER BASED ON ENSO STATE. THAT 55 YEAR AVERAGE FOR PHILADELPHIA WAS 21.6 INCHES.
STRONG LA NINA.........14.2 INCHES
MODERATE LA NINA.......18.7 INCHES
WEAK LA NINA...........22.7 INCHES
LA NADA................21.7 INCHES (OUR EXPECTED STATE)
WEAK EL NINO...........28.1 INCHES
MODERATE EL NINO.......27.7 INCHES
STRONG EL NINO.........10.4 INCHES

THE CURRENT CPC OUTLOOK FOR THE WINTER FOR PHILADELPHIA IS FOR EQUAL CHANCES FOR EITHER A WARMER/WETTER OR COLDER/DRIER THAN NORMAL WINTER WITH RESPECT TO BOTH TEMPERATURES AND PRECIPITATION.

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