PROGNOSTIC DISCUSSION FOR UPDATED MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EST TUESDAY JAN 31 2006
         .         .         .         .         .         .         .         .
30-DAY OUTLOOK DISCUSSION FOR FEBRUARY 2006

THE OCEANIC AND ATMOSPHERIC INDICATORS FOR THE TROPICAL PACIFIC OCEAN ARE 
CONSISTENT WITH A WEAK LA NINA.  THE AREA OF BELOW NORMAL SSTS ALONG THE 
EQUATOR IN THE PACIFIC HAS EXTENDED WESTWARD TO AS FAR AS 10 DEGREES WEST 
OF THE DATE LINE... WITH MOST OF THIS AREA AT LEAST 0.5 DEG C BELOW NORMAL.  
SIGNIFICANTLY ABOVE NORMAL SSTS ARE CONFINED TO THE AREA WEST OF 160E.  SOME 
NEAR NORMAL SSTS HAVE DEVELOPED NEAR THE SOUTH AMERICAN COAST... BUT AT DEPTH 
THERE IS A LARGE VOLUME OF COLDER THAN NORMAL WATER IN THE EASTERN EQUATORIAL 
PACIFIC... SO SSTS IN THE EASTERN PACIFIC ARE EXPECTED TO REMAIN NEAR OR BELOW 
NORMAL AT LEAST FEBRUARY.  THE GRADIENT OF SSTS IN THE PACIFIC ALONG THE 
EQUATOR... BELOW NORMAL IN THE EAST AND CENTRAL PACIFIC AND ABOVE NORMAL OVER 
THE FAR WESTERN PACIFIC... IS EXPECTED TO HELP MAINTAIN STRONGER THAN AVERAGE 
LOW LEVEL EASTERLIES IN THE CENTRAL EQUATORIAL PACIFIC.  THERE ARE SOME HINTS 
THAT AN MJO WAVE MAY BE DEVELOPING OVER THE INDIAN OCEAN - INDONESIA AREA... 
BUT IF THIS IS SO... IT WOULD STILL TAKE A FEW WEEKS FOR IT TO MOVE INTO THE 
CENTRAL PACIFIC WHERE IT COULD AFFECT THE CRICULATION AT MIDDLE LATITUDES.

THE DISTRIBUTION OF ANOMALOUS CONVECTION IN THE TROPICS HAS RESEMBLED A LA 
NINA FOR THE PAST FEW WEEKS... WITH HEAVY CONVECTIVE RAINFALL OVER INDONESIA 
AND VICINITY... AND THIS IS EXPECTED TO CONTINUE FOR AT LEAST THE NEXT WEEK 
OR TWO.  DRY CONDITIONS ARE PREDICTED TO CONTINUE OVER THE CENTRAL EQUATORIAL 
PACIFIC... SO ANY FORCING FROM THE TROPICS IS EXPECTED TO BE OF THE LA NINA 
VARIETY.  HOWEVER... THIS WINTER HAS SEEN A LOT OF STRONG INTERNAL VARIABILITY 
AT MIDDLE AND HIGH LATITUDES AND PRESENT INDICATIONS ARE FOR THIS TO CONTINUE.  
DURING LATE DECEMBER AND EARLY JANUARY THE EXTRATROPICAL PATTERN MORE CLOSELY 
RESEMBLED THAT WHICH USUALLY ACCOMPANIES EL NINO... AND THEN FOR THE LATTER 
PART OF JANUARY IT LOOKED MORE TYPICAL OF WHAT ACCOMPANIES LA NINA.  HOWEVER... 
RETROGRESSION OF THE PATTERN AT HIGH AND MIDDLE LATITUDES THAT HAS BEEN 
CONSISTENTLY PREDICTED BY THE MODELS FOR THE PAST WEEK OR SO WILL ALLOW A FULL 
LATITUDE RIDGE TO BUILD NEAR THE WEST COAST WHILE RETORGRESSION OF THE BLOCKING 
OVER THE NORTH ATLANTIC WILL SUPPRESS THE WESTERLIES OVER THE EASTERN CONUS.... 
RESULTING IN A POSITIVE PHASE OF THE PNA AND SIMILAR TNH PATTERNS OVER NORTH 
AMERICA AND VICINITY.  THE RESULT WILL BE A PATTERN CHANGE DURING THE FIRST 
WEEK OF FEBRUARY.

TOOLS USED FOR THE LONG LEAD FEBRUARY FORECAST INCLUDING OCN - CFS - CAS AND 
CCA ARE STILL CONSIDERED IN THE BACKGROUND... BUT MOST EMPHASIS IS BEING 
PLACED ON OBJECTIVE SEPCIFICATIONS OF THE PATTERNS OF TEMPERATURE AND 
PRECIPITATION FROM RECENT GFS MODEL RUNS FOR THE FIRST TWO WEEKS OF THE 
MONTH. DURING THE FIRST WEEK OF THE MONTH A TROUGH IS PREDICTED TO DEVELOP 
OVER THE SOUTHEASTERN U.S.  WHILE A RIDGE DOMINATES THE SOUTHWEST.  STORMS AND 
RELATIVELY HEAVY RPECIPITATION ARE EXPECTED TO CONTINUE OVER THE PACIFIC 
NORTHWEST FOR THE FIRST FEW DAYS OF THE MONTH... AND A RATHER WET STORM WILL 
MOVE THROUGH THE OHIO VALLEY AND APPALACHIANS INTO THE NORTHEAST.  DURING THE 
SECOND WEEK OF THE MONTH... A STRONG TROUGH IS PREDICTED TO BECOME FIRMLY 
ESTABLISHED OVER THE EASTERN CONUS... WHILE THE RIDGE OVER THE SOUTHWEST IS 
PREDICTED TO BUILD STRONGLY NORTHWARD INTO WESTERN CANADA... COMBINING WITH 
THE BLOCKING RETROGRADING FROM THE NORTH ATLANTIC TO GIVE ABOVE NORMAL 500-HPA 
HEIGHTS OVER JUST ABOUT ALL OF CANADA.  AS THE STRONG COLD TROUGH OVER ALASKA 
IS ALSO PREDICTED TO RETROGRADE TO THE BERING SEA... THE TEMPERATURE ANOMALIES 
OVER MOST OF THE U.S. WILL REVERSE... WITH ALASKA BECOMING MILDER THAN NORMAL 
WHILE MOST OF THE SOUTHEASTERN THIRD OF THE CONUS WILL LIKELY EXPERIENCE BELOW 
NORMAL TEMPERATURES.  SINCE PATTERNS THIS STRONG USUALLY PERSIST FOR AT LEAST 
A COUPLE OF WEEKS ONCE ESTABLISHED... EVEN WHEN THERE IS A LOT OF INTERNAL 
VARIABILITY... THE TEMPERATURE ANOMALY PATTERN FOR THE MONTH IS EXPECTED TO BE 
SIMILAR TO THAT INDICATED FOR THE SECOND WEEK OF THE MONTH... WITH ALLOWANCES 
FOR THE LINGERING OPPOSING PATTERN FOR THE FIRST FEW DAYS AND UNDERLYING LA 
NINA FORCING IN AREAS WHERE THESE EFFECTS ARE LIKELY TO BE STRONGEST.  

THE PRECIPITATION FORECAST FOR THE CONUS REFLECTS RATHER STRONG INDICATIONS 
FROM CFS AND OTHER MODELS WITH SUPPORT FROM CCA FOR DRIER THAN NORMAL 
CONDITIONS OVER BOTH THE SOUTHWEST AND THE SOUTHEAST.  THE AREA OF DRYNESS 
HAS BEEN EXPANDED NORTHWARD TO SOUTHERN OREGON DUE TO THE EXPECTED END OF 
THE WET PATTERN IN THE PACIFIC NORTHWEST.  OVER THE CENTRAL AND EASTERN U.S. 
THE PATTERN DEPICTED COULD BE VIEWED AS A SOUTHWARD-DISPLACED LA NINA 
PATTERN... WITH THE OHIO VALLEY STORM TRACK TYPICAL OF LA NINA PUSHED TO 
THE SOUTH OF ITS MODAL POSITION AND EXTENDING ACROSS THE CENTRAL APPALACHIANS 
INTO THE NORTHEAST DUE TO STORMS THAT ARE HIGHLY LIKELY TO AFFECT THAT AREA 
DURING THE FIRST TWO WEEKS OF THE MONTH.  THE DRY AREAS OVER THE SOUTHEAST 
THAT USUALLY ACCOMPANY LA NINA WERE ALSO PUSHED A LITTLE TO THE SOUTH OF 
THEIR MODAL POSITIONS. 

STRONGLY ANOMALOUS SOUTHERLY FLOW EXPECTED TO DEVELOP OVER ALASKA WHEN THE 
TROUGH THAT HAS BEEN OVER THE STATE RETROGRADES WILL PROBABLY BE STRONG 
AND PERSITENT ENOUGH TO BRING WET CONDTIONS ALONG THE SOUTH COAST.

FORECASTER: A. J. WAGNER 


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

THE NEXT MONTHLY OUTLOOK... FOR MAR 2006... WILL BE RELEASED ON THU 
FEB 16 2006... ALONG WITH THE NEXT SET OF LONG-LEAD SEASONAL FORECASTS.  
  
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1971-2000 BASE PERIOD.


$$