PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EST SATURDAY DEC 31 2005
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30-DAY OUTLOOK DISCUSSION FOR JANUARY 2005

THE OCEANIC AND ATMOSPHERIC INDICATORS FOR THE TROPICAL PACIFIC OCEAN CURRENTLY
FAVOR A NEUTRAL ENSO CLASSIFICATION...BUT HAVE MOVED CLOSER TO A WEAK LA NINA. 
SSTS ALONG THE EQUATOR IN THE EASTERN PACIFIC ARE MORE THAN .5 DEG C BELOW 
NORMAL FROM ABOUT 170W TO NEAR THE SOUTH AMERICAN COAST... WITH SOME REGIONS 
1.0 DEG C BELOW NORMAL. SSTS ALONG THE EQUATOR WEST OF THE DATELINE AVERAGE 
JUST OVER .5 DEG C ABOVE NORMAL.  
BELOW NORMAL OCEAN TEMPERATURES IN THE EASTERN PACIFIC EXTEND FROM THE SURFACE 
TO OVER 150 METERS DEPTH... SO SSTS IN THE EASTERN EQUATORIAL PACIFIC ARE 
LIKELY TO REMAIN BELOW NORMAL THROUGH THE END OF JANUARY. THE GRADIENT OF 
SSTS IN THE PACIFIC ALONG THE EQUATOR... BELOW NORMAL SSTS IN THE EAST AND NEAR 
TO ABOVE NORMAL SSTS IN THE CENTRAL AND WESTERN PACIFIC... IS EXPECTED TO HELP 
MAINTAIN STRONGER THAN AVERAGE LOW LEVEL EASTERLIES IN THE CENTRAL EQUATORIAL 
PACIFIC.

THE DISTRIBUTION OF ANOMALOUS CONVECTION IN THE TROPICS DOES RESEMBLE A LA NINA.
BUT THE MIDLATITUDE CIRCULATION OVER THE PACIFIC AND NORTH AMERICA DOES NOT. 
IN FACT WE HAVE HAD PNA AND TNH LIKE PATTERNS THAT WOULD NORMALLY BE ASSOCIATED 
WITH AN EL NINO. THERE ARE NO DEFINITIVE INDICATIONS THAT THE CURRENT
PATTERN WILL CHANGE DRASTICALLY.

TOOLS USED FOR THE LONG LEAD JANUARY FORECAST INCLUDED OCN - CFS AND CCA. THESE
TOOLS HAVE CHANGED LITTLE BY THE TIME THIS UPDATE WAS MADE. THE UPDATE USES THE 
WEEK1 AND WEEK2 INPUT FROM THE GFS AND EC MODELS. THE PATTERN OF THE LAST 10 
DAYS IS VERY CONSISTENT WITH THE LONG LEAD JANUARY FORECAST AND SO ARE THE 
WEEK 1 AND WEEK 2 PREDICTIONS. BASICALLY WARM IN THE WESTERN TWO THIRDS OF THE 
NATION AND NEAR NORMAL IN THE EAST. HENCE CHANGES TO THE JANUARY LONG LEAD 
PREDICTION ARE LIMITED.
WE EXPANDED THE WARMTH IN THE CENTER OF THE NATION TO THE CANADIAN BORDER. WE 
ALSO EXPANDED WARMTH TO INCLUDE THE CALIFORNIA COAST. WE MOVED THE ABOVE NORMAL 
ISOLINES A BIT WESTWARD IN THE SOUTHEAST TO ACCOMODATE THE POSSIBILITY OF A 
COLD AIR OUTBREAK IN THE WEEK 2 PERIOD. THE POSITIVE SNOW ANOMALIES IN EASTERN
OREGON AND ADJACENT AREAS APPEAR TO BE WEAKENING SO WE NO LONGER REDUCED THE 
CHANCES FOR ABOVE NORMAL TEMPERATURE IN THOSE AREAS. GENERALLY SNOW WATER 
EQUIVALENT APPEAR BELOW MEDIAN IN MUCH OF THE WEST. 

TOOLS FOR AK ARE INCONCLUSIVE HENCE EC IS SHOWN EVERYWHERE FOR TEMPERATURE.

BECAUSE OF MINOR LA NINA CONDITIONS WE PREDICTED AT LONG LEAD BELOW MEDIAN 
PRECIPITATION OVER FLORIDA AND IN A SMALL AREA IN THE INTERIOR SW. 
WE EXPANDED THE FORECAST FOR BELOW MEDIAN PRECIPITATION TO COVER MUCH OF THE 
SOUTH. HEAVY RAINS ARE EXPECTED IN THE SHORT RANGE ALONG THE WEST COAST. 
THIS IS ENOUGH TO TILT PROBABILITIES FOT THE MONTH TO ABOVE MEDIAN FOR MUCH
OF CALIFORNIA. ELSEWHERE - INCLUDING ALASKA WE PREDICT EQUAL CHANCES.

A MAJOR CIRCULATION BREAK IS NOT UNCOMMON IN THE FIRST HALF OF JANUARY. IF A LA 
NINA PATTERN WERE TO DEVELOP PRECIPITATION WOULD BE EXPECTED IN THE CURRENTLY 
DRY AREAS FROM NE TEXAS TO THE GREAT LAKES. NO SHORT TERM INDICATIONS EXIST THAT 
THIS WILL INDEED HAPPEN. PLEASE CONSULT 6-10 DAY AND WEEK 2 FORECAST FOR ANY
NEAR-FUTURE CHANGES. 
 

 


FORECASTER: H. VAN DEN DOOL 


NOTES -  AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL
PROBABILTIES) ARE NOW LABELED EC (EQUAL CHANCES).

THE NEXT MONTHLY OUTLOOK... FOR FEB 2006... WILL BE RELEASED ON THU 
JAN 19 2006. 
  
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD.


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