PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT THU JULY 17 2003

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     SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS

THE SEASONAL OUTLOOK REFLECTS THE PRESENCE OF LONG TERM TRENDS ON U.S. 
TEMPERATURE AND PRECIPITATION...STATISTICAL FORECAST TOOLS ...WITH SOME INPUT 
FROM NUMERICAL MODELS DURING THE FIRST SEVERAL SEASONS AND - FINALLY - 
THE POSSIBILITY A LA NINA WILL DEVELOP SOMETIME WITHIN THE NEXT SEVERAL  MONTHS 
 - AlTHOUGH THE TIMING AND EVEN THE EXISTENCE OF THIS TRANSITION IS NOW MUCH 
MORE UNCERTAIN THAN IT WAS LAST MONTH DUE TO CONTINUED INCREASES IN THE HEAT 
CONTENT OF THE EASTERN TROPICAL PACIFIC OCEAN.   

THE RAPID TRANSITION AWAY FROM EL NINO TOWARD LA NINA EARLIER THIS YEAR - 
FOLLOWED - IN THE PAST THREE MONTHS - BY AN APPARENT SLOWING - AND NOW EVEN 
A REVERSAL - OF THE TRANSITION INCREASES THE UNCERTAINTY ASSOCIATED WITH 
THIS SET OF FORECASTS .  THEREFORE - EXCEPT FOR AREAS WITH STRONG TRENDS - 
BOTH PROBABILITIES AND AREA COVERED BY NON-EC PROBABILITIES WILL BE RELATIVELY 
LOW IN THIS SET OF FORECASTS.  THE FORECASTS FOR SEASONS THROUGH EARLY NEXT 
SPRING REFLECT A STATE OF THE PACIFIC ENSO 3.4 REGION THAT IS SOMETHING 
APPROXIMATING AN AVERAGE OF WEAK LA NINA CONDITIONS AND ENSO-NEUTRAL
CONDITIONS.  ENSO CONTRIBUTIONS CEASE AFTER FMA - AFTER WHICH MAINLY TREND 
IS USED FOR THE FORECASTS.  

THE OUTLOOK FOR AUGUST THROUGH OCTOBER 2003 CALLS FOR ABOVE NORMAL TEMPERATURES 
OVER MUCH OF THE WEST AND SOUTHERN FLORIDA.  ASO PRECIPITATION IS EXPECTED TO 
BE BELOW AVERAGE OVER CALIFORNIA AND MUCH OF THE GREAT BASIN AND ABOVE AVERAGE 
OVER MUCH OF THE SOUTHEAST.  
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     BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOK

NOTE:  FOR GRAPHICAL DISPLAYS OF THE FORECAST TOOLS DISCUSSED BELOW SEE: 

http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing

     CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS

EASTERLY WINDS - WHICH WERE STRONGER THAN NORMAL OVER THE CENTRAL AND WEST-
CENTRAL EQUATORICAL PACIFIC DURING MARCH AND APRIL - SUBSEQUENTLY GAVE WAY
TO MODEST WESTERLY ANOMALIES OVER MUCH OF THE PACIFIC - WITH AN AREA OF 
ANOMALOUS SOUTHWESTERLY FLOW ACROSS THE EQUATOR OVER THE EASTERN PACIFIC DURING 
MUCH OF THE SECOND HALF OF JUNE AND EARLY JULY.  THIS APPEARS TO BE WEAKENING 
CURRENTLY AS STRONGER THAN NORMAL EASTERLIES ARE REDEVELOPING NEAR THE DATELINE 
WITHIN THE PAST WEEK.  THE TRADITIONAL TAHITI-MINUS-DARWIN-BASED SOI WAS -0.6 
IN MAY AND HAD DECLINED FURTHER TO -1.1 IN JUNE.  DURING THE FIRST WEEK OF JULY 
EQUATORIAL PACIFIC SEA SURFACE TEMPERATURES HAD INCREASED TO 0.5 C ABOVE NORMAL 
AS FAR EAST AS 120W.  TEMPERATURES WERE BETWEEN 0.5 TO 1 DEGREE ABOVE NORMAL 
OVER THE ENTIRE EQUATORIAL PACIFIC WEST OF THAT LOCATION.  SUB-SURFACE WATERS 
HAVE ALSO WARMED IN RESPONSE TO A STRONG INTRASEASONAL OSCILLATION WHICH IS 
PASSING THROUGH THE EASTERN TROPICAL PACIFIC NOW.  HEAT CONTENT OF THE WATERS 
OVER BOTH THE CENTRAL AND EASTERN PAICIFC HAS RISEN - BRINGING INTO QUESTION 
THE STRENGTH - TIMING OF ONSET - AND DURATION OF ANY LA NINA WHICH MAY DEVELOP.  

ON THE OTHER HAND IN A NUMBER OF REGIONS THE ATMOSPHERE IS DISPLAYING BEHAVIOR 
WHICH IS CONSISTENT WITH A COLD EVENT.  FOR EXAMPLE - THE MONSOON HAS BEEN 
ENHANCED OVER MEXICO AND HAS FINALLY MADE A DELAYED APPEARANCE OVER ARIZONA.  
ALSO - SIGNS OF ENHANCEMENT OF THE CENTRAL AMERICAN MONSOON HAVE APPEARED 
IN LOW-LEVEL WINDS IN THE EASTERN TROPICAL AND SUBTROPICAL PACIFIC.  THIS 
TREND IS EXPECTED TO CONTINUE THROUGH THE SUMMER AND NOW THAT IT IS FINALLY 
BECOMING ESTABLISHED - THE MONSOON SEEMS LIKELY TO BE AT LEAST SLIGHTLY 
ENHANCED IN THE SOUTHWEST US.  UNCERTAINTY IN THE EXACT LOCATION OF THE MAIN 
MOISTURE PLUME HOWEVER PRECLUDES MAKING A FORECAST OF THE EXACT LOCATION OF THE 
ABOVE MEDIAN PRECIPITATION. THERE HAVE ALSO ALREADY BEEN FOUR NAMED TROPICAL 
STORMS OVER THE ATLANTIC/CARIBBEAN BASIN - ALTHOUGH THIS CAN ALSO BE DUE TO 
OTHER FACTORS SUCH AS ABOVE NORMAL SSTS AND AN ACTIVE WEST AFRICAN SUMMER RAINY 
SEASON.  FINALLY - 200 HPA HEIGHTS HAVE FALLEN TO SLIGHTLY BELOW NORMAL OVER 
THE TROPICAL PACIFIC BASIN - SHOWING COOLING IN THE REGION - ANOTHER FEATURE 
CONSISTENT WITH LA NINA.     
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     PROGNOSTIC DISCUSSION OF SST FORECASTS

FORECASTS FROM MULTIPLE MODELS GIVE A RANGE OF POSSIBLE FUTURE SST PATTERNS 
IN THE TROPICAL PACIFIC - INDICATING CONSIDERABLE UNCERTAINTY - ALTHOUGH MOST 
PROJECTIONS FALL WITHIN THE WEAK LA NINA OR ENSO-NEUTRAL RANGE.  AN AVERAGE OVER 
ALL MODELS INDICATES VERY WEAK LA NINA CONDITIONS DEVELOPING DURING THE SUMMER 
WITH LARGEST NEGATIVE SST ANOMALIES PEAKING ASSOCIATED WITH THE EVENT 
DEVELOPING DURING LATE FALL AND EARLY WINTER.  TO SEE THESE FORECASTS GO TO:

http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing/plume.gif 

A CONSOLIDATION FORECAST OF IN-HOUSE TOOLS THAT SHOW TEMPERATURE ANOMALIES IN
THE NINO 3.4 SST REGION PREDICTS THE DEVELOPMENT OF VERY WEAK LA NINA CONDITIONS 
BY LATE SUMMER.  NINO 3.4 SST ANOMALIES ARE PREDICTED TO STRENGTHEN TO ONLY 
ABOUT -0.5 C BY OND AND NDJ - BUT EVEN THIS IS LESS THAN ONE-HALF A STANDARD 
DEVIATION BELOW NORMAL.  CONFIDENCE IN THE FORECAST DROPS AFTER EARLY WINTER 
WHILE THE SST ANOMALY ALSO WEAKENS REACHING A TENTATIVE ZERO CROSSING DURING 
NEXT SPRING IN THE CONSOLIDATION.  SSTA FORECASTS BY MODELS RUN IN OTHER CENTERS 
RANGE FROM WEAK EL NINO TO MODERATE LA NINA CONDTIONS WITH AN AVERAGE SIMILAR 
TO THE CONSENSUS OF CPC - WEAK LA NINA TO NEUTRAL CONDITIONS.

     PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOK

THE STATISTICAL TOOLS - CCA - OCN - SMLR - WERE CONSULTED AT ALL LEAD TIMES.
DYNAMICAL MODEL FORECASTS FROM NCEP AND OTHER FORECAST CENTERS WERE EXAMINED
FOR THE PERIOD ASO 2003 - NDJ 2003. IN ASO WE ALSO PAY ATTENTION TO THE SOIL 
MOISTURE TOOL CAS.  INITIAL SOIL MOISTURE ANOMALIES CONTINUE TO BE UNUSUALLY 
WET IN THE SOUTHEAST AND THE MIDDLE ATLANTIC STATES AND DRY IN SECTIONS OF THE 
CENTRAL GREAT PLAINS - THE SOUTHWEST AND THE ROCKIES.  CAS AND OCN TEMPERATURE 
FORECASTS WERE CONSIDERED TOGETHER AS A CONSOLIDATION OF THESE TWO TOOLS AND 
WERE USED FOR THOSE AREAS AND PROJECTION TIMES WHERE THEY HAD USEFUL 
STATISTICAL SIGNIFICANCE. 
  
THE DYNAMICAL MODELS ARE CONSISTENT IN PREDICTING ABNORMAL WARMTH OVER MUCH
OF THE WESTERN U.S. BUT MOSTLY BELOW NORMAL TEMPERATURES IN AREAS EAST OF THE 
CONTINENTAL DIVIDE - AS WELL AS ABNORMAL COLD AND WETNESS OVER ALASKA.  
FORECASTS FROM THESE TOOLS REPRESENT A CONSISTENT RESPONSE TO A PREDICTED 
CONTINUED EVOLUTION TOWARD COLD EVENT CONDITIONS.  HOWEVER SINCE MODEL INITIAL 
CONDITIONS ARE USUALLY NOT CAUGHT UP TO THE CURRENT STATUS - AND RECENT CHANGES 
IN THE HEAT CONTENT OF THE EASTERN TROPICAL PACIFIC OCEAN HAVE REDUCED THE 
LIKELIHOOD LA NINA WILL DEVELOP WITH THE STRENGTH AND PERSISTENCE ANTICIPATED 
EARLIER - THE DYNAMICAL MODEL FORECASTS ARE DE-EMPHASIZED IN THIS SET OF 
FORECASTS.  
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     PROGNOSTIC DISCUSSION OF OUTLOOKS - ASO 2003 TO ASO 2004

TEMPERATURE:

THE TEMPERATURE FORECAST FOR ASO IS BASED PRIMARILY UPON INDICATIONS FROM 
CCA - OCN AND A COMPOSITE OF PAST CASES FOR THIS SEASON WEIGHTED ABOUT EQUALLY 
FOR LA NINA AND NEUTRAL CONDITONS.  OVER THE CONUS THE TREND REQUIRES 
WARM ANOMALIES CENTERED OVER THE SOUTHWEST AND FLORIDA - AND IN MANY AREAS 
THE INDICATIONS FOR WARMTH ARE SUPPORTED BY CCA.  IN OTHER AREAS THE SOIL 
MOISTURE TOOL FORECASTS AREAS OF ABNORMALLY COOL CONDITIONS IN LOCATIONS WHERE 
TRENDS WERE FOR WARMTH - SO EC WAS ASSIGNED IN AREAS WITH CONFLICTS AMONG 
TOOLS AS WELL AS WHERE THE SIGNALS WERE WEAK OR NON-EXISTENT.  

MOST OF THE STATISTICAL MODELS INDICATE ABOVE MEDIAN TEMPERATURES OVER MUCH OF 
ALASKA - ESPECIALLY THE WESTERN PART - DURING THE WINTER AND SPRING SEASONS.  
WARMTH IS SUPPORTED DURING ASO BY WELL ABOVE NORMAL SSTS IN THE BERING SEA THAT 
ARE NOT LIKELY TO GO AWAY SOON.  HOWEVER - THE DYNAMICAL MODELS AND CCA LEAN 
TOWARDS BELOW NORMAL TEMPERATURES OVER PARTS OF EASTERN AND CENTRAL INTERIOR 
ALASKA - AND RECENT OBSERVATIONS HAVE SHOWN OCCASIONAL COOL PERIODS IN THAT 
PART OF THE STATE.  THEREFORE ABOVE NORMAL TEMPERATURES HAVE BEEN FORECAST FOR 
MUCH OF THE STATE FOR THE UPCOMING WINTER AND SPRING SEASONS - WITH THE HIGHEST 
PROBABILITES GENERALLY IN THE SOUTH AND WEST.

FOR ASO - WARM ANOMALIES IN THE SOUTHWEST ARE TEMPERED SOMEWHAT BY THE 
POSSIBILITY OF ENHANCED MONSOON CONDITIONS ESPECIALLY IN ARIZONA AND THE 
EASTERN GREAT BASIN.  THIS IS INDICATED BY LOWER PROBABILITY ANOMALIES IN THE 
REGION THAN WHAT WOULD OTHERWISE BE INDICATED BY TREND CONSIDERATIONS ALONE.  
DURING OND THE TREND SIGNAL ITSELF IS AT ITS WEAKEST IN THE SOUTHWEST U.S. 

FROM OND THROUGH MAM TEMPERATURE FORECASTS ARE BASED PRIMARILY UPON COMPOSITES 
CONDITIONAL UPON ENSO-NEUTRAL TO WEAK LA NINA CONDITIONS ALONG WITH INDICATIONS 
FROM CCA AND TREND.  WARMER THAN NORMAL TEMPERATURES ARE PREDICTED IN ALASKA
THROUGHOUT THIS PERIOD DUE TO OCN AND EXPECTED WARM OCEANS NEAR ALASKA.  OVER 
THE CONUS - THE CURRENT SET OF FORECASTS EMPHASIZES ONLY THE STRONGEST - MOST 
CONFIDENT INDICATIONS FROM THAT TOOL.  THOSE ARE FOUND MAINLY IN THE SOUTH AND 
SOUTHWEST DURING WINTER AND IN THE SOUTHWEST IN SPRING AND SUMMER.  TRENDS 
ALONE - AS WELL AS CCA - WOULD FAVOR MUCH OF THE EASTERN HALF OF THE NATION TO 
HAVE ABOVE NORMAL TEMPERATURES DURING THE WINTER SEASONS- BUT THE WEAK LA 
NINA-ENSO NEUTRAL COMPOSITES SUGGEST THAT SCATTERED AREAS OF NEAR OR BELOW 
NORMAL ARE JUST AS LIKELY - SO THE NORTHEAST AND MIDWEST WERE LEFT WITH EC. 
IN ADDITION - THE AO AND NAO - WHICH CAN NOT CURRENTLY BE PREDICTED BEYOND A 
COUPLE OF WEEKS IN ADVANCE - HAVE NOT BEEN AS CONSISTENLTY POSITIVE IN RECENT 
WINTERS AS THEY WERE IN THE EARLIER PART OF THE PAST DECADE - THEREFORE MAKING 
MILD WINTERS LESS OF A SURE THING SINCE THE MID 90S.

FORECASTS BEGINNING WITH JFM ARE BASED LARGELY ON TREND-ADJUSTED ENSO-NEUTRAL 
COMPOSITES - OCN AND CCA - WITH INCREASING EMPHASIS ON THE LATTER TWO WITH 
INCREASING TIME DUE TO GROWING UNCERTAINTY IN THE STATUS OF ENSO AFTER THE 
SPRING BARRIER.  THE TREND-ADJUSTED COMPOSITES AND THE TREND ITSELF HAD GOOD 
AGREEMENT FOR AN AREA OF BELOW NORMAL TEMPERATURES OVER THE HIGH PLAINS 
BEGINNING IN FMA THAT EXPANDED AND SHIFTED NORTHEASTWARD TOWARDS THE UPPER 
MISSISSIPPI VALLEY BY MJJ.  FORECASTS FOR THE SUMMER 2004 SEASONS INDICATE 
WARMTH OVER THE SOUTHWEST AND SOUTHEAST FROM OCN WITH SOME SUPPORT FROM CCA.                                              
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PRECIPITATION:

ABOVE MEDIAN PRECIPITATION WAS FORECAST FOR ASO AND SON ONLY IN THE SOUTHEAST 
WHERE INDICATIONS FROM CCA WERE SUPPORTED  BY CONSIDERATIONS OF WET GROUND AND 
THE POSSIBILITY OF AN ENHANCED ATLANTIC TROPICAL STORM SEASON.  ALSO - TREND-
ADJUSTED ENSO COMPOSITES AND DYNAMICAL MODELS ALL INDICATE ABOVE NORMAL 
PRECIPITATION IN FLORIDA.  SURPRISINGLY - THE SOIL MOISTURE MODELS ELIMINATED 
MOST OF THE WETNESS OVER THE SOUTHEAST - EVEN AS SOON AS SEPTEMBER - WHICH 
MADE THE FORECAST FOR ASO BASED ON THIS TOOL LOOK TOO DRY.  PERHAPS EVEN MORE 
INEXPLICABLY THIS TOOL DEVELOPED A LOT OF DRYNESS OVER THE NORTHEAST AND THE 
MIDWEST.  AS A RESULT THESE WERE LARGELY DISCOUNTED AND EC WAS FORECAST.  
SEVERAL OF THE STATISTICAL FORECASTS - INCLUDING NCEP - CCA AND CONSTRUCTED 
ANALOG FOR SOIL MOISTURE (CAS) HAVE INDICATIONS FOR BELOW MEDIAN PRECIPITATION 
ACROSS MUCH OF THE INTERIOR WEST AND NORTHERN PLAINS.  HOWEVER RECENT RAINS 
EAST OF THE CONTINENTAL DIVIDE SUGGEST THAT IN THAT AREA THESE FORECASTS SHOULD 
BE DISREGARDED - AND SO EC IS FORECAST THERE.  THE INDICATIONS FOR BELOW 
MEDIAN PRECIPITATION OVER MUCH OF THE GREAT BASIN AND INTERIOR SOUTHWEST WERE 
CONSIDERED REASONABLE WITH SUPPORT FROM TREND-ADJUSTED ENSO COMPOSITES AND THUS 
WERE RETAINED FOR THE FOUR FORECASTS THROUGH NDJ - WITH THE AREA OF FORECAST 
RELATIVE DRYNESS SHRINKING TO THE SOUTH WITH TIME.

THE EXPECTED DEVELOPMENT OF LA NINA CONDITIONS WOULD FAVOR AN ACTIVE MONSOON IN 
THE SOUTHWESTERN U.S. AND SOUTHERN ROCKIES - BUT SINCE THE EARLY INDICATIONS 
FOR A DEVELOPING LA NINA ARE CURRENTLY WEAKENING - THE MONSOON HAS STARTED 
LATE - AND ABOVE MEDIAN PRECIPITATION YIELDS ARE MORE LIKELY TO SHOW UP DURING 
LA NINA IN MEXICO THAN IN THE SOUTHWESTERN U.S. - THAT AREA WAS LEFT WITH EC.
   
TREND COMPOSITES WITH SOME SUPPORT FROM THE STATISTICAL TOOLS GAVE THE 
FORECASTS FOR WET CONDITIONS IN THE NORTHWEST U.S. FOR OND - WHICH EVOLVED 
INTO A WET ANOMALY OVER THE NORTHERN AND CENTRAL ROCKIES AND ADJACENT HIGH 
PLAINS FOR NDJ THROUGH MAM.  THIS IS CLIMATOLOGICALLY CONSISTENT WITH THE 
FORECASTS OF BELOW NORMAL TEMPERATURE IN THE SAME GENERAL AREA FOR SOME OF 
THE SAME SEASONS.  THE AREA OF ABOVE MEDIAN PRECIPITATION FORECAST FROM 
NORTHEASTERN TEXAS BEGINNING WITH OND THAT EXPANDS AS FAR AS THE CENTRAL 
APPALACHIANS  DURING JFM WAS INDICATED BY OCN AND THE TREND COMPOSITES FOR 
WEAK LA NINA AND ENSO-NEUTRAL CONDITIONS - AS IS THE AREA OF RELATIVE 
DRYNESS PREDICTED OVER FLORIDA DURING DJF AND JFM.  

NO RELIABLE FORECAST SIGNALS COULD BE SEEN FOR AMJ THROUGH JJA 2004  - WHILE 
TREND-ADJUSTED ENSO-NEUTRAL COMPOSITES WITH SOME SUPPORT FROM OCN AND CCA 
GAVE CONSISTENT INDICATIONS FOR DRYNESS IN THE GREAT BASIN AND WET CONDITIONS 
OVER PORTIONS OF THE CENTRAL HIGH PLAINS AND CENTRAL ROCKIES FOR THE JAS 
AND ASO 2004 FORECASTS.
  
FORECAST INDICATIONS FOR PRECIPITATION ARE UNCERTAIN IN MOST OF ALASKA - AND 
WITH THE EXCEPTION OF STRONGLY-FORCED STABLE COLD-SEASON PATTERNS DURING EL 
NINO EVENTS - USUALLY HAVE RATHER LOW SKILL - ESPECIALLY IN THE WARM SEASONS.  
THEREFORE THE ENTIRE STATE WAS LEFT EC FOR PRECIPITATION AT ALL LEADS. 
  
NOTE -  AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL
PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES).
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GLOSSARY AND DEFINITIONS:

ANALOG (NATURAL ANALOG) - A WEATHER MAP THAT RESEMBLES ANOTHER WEATHER MAP - 
USUALLY FROM DIFFERENT YEARS BUT THE SAME SEASON IN THE HISTORICAL RECORD.  THE 
CRITERION FOR SELECTING AN ANALOG IS OFTEN THE PATTERN CORRELATION BETWEEN THE 
MAPS.  TWO MAPS WILL JUST BEGIN TO RESEMBLE EACH OTHER TO THE HUMAN EYE AT A 
PATTERN CORRELATION OF ABOUT 40%.  TO BE USEFUL - ANALOGS NEED TO HAVE MUCH
HIGHER CORRELATIONS TO THE ORIGINAL MAP THAN THAT - 80% OR MORE.  ANALOGS ARE 
INCREASINGLY DIFFICULT TO FIND AS THE GEOGRAPHIC REGION BEING COMPARED 
INCREASES IN SIZE.  PERFECT ANALOGS TO THE ENTIRE NORTHERN HEMISPHERE SIMPLY 
DO NOT EXIST - FOR PRACTICAL PURPOSES.  THIS IS WHY SIMPLE ANALOG FORECAST 
METHODS DO NOT WORK VERY WELL.  

ANNUAL CYCLE - AT MOST LOCATIONS THE CLIMATE STATE VARIABLES - T - P - SST-
WIND - AND OTHERS DISPLAY A REGULAR VARIATION WHICH FOLLOWS THAT OF THE
ELEVATION OF THE SUN IN THE SKY.  A GRAPH OF THE 30 YEAR AVERAGE OF A 
VARIABLE FOR EACH DAY OF THE YEAR VERSUS DATE SHOWS A WAVE-FORM WHICH -
FOR T AT DES MOINES FOR EXAMPLE - RANGES SMOOTHLY FROM LOWEST VALUES IN THE 
WINTER TO HIGHEST VALUES IN THE SUMMER.

ANOMALY - THE ARITHMETIC DIFFERENCE BETWEEN THE VALUE OF A VARIABLE AT A GIVEN
PLACE AND TIME AND THE LONG-TERM AVERAGE (USUALLY 30 YEARS) FOR THE LOCATION
AND TIME OF YEAR.

CA - CONSTRUCTED ANALOG - A LINEAR COMBINATION OF PAST OBSERVED ANOMALY 
PATTERNS SUCH THAT THE COMBINATION IS AS CLOSE AS DESIRED TO THE INITIAL
STATE.  A FORECAST IS OBTAINED BY PERSISTING THE WEIGHTS ASSIGNED TO EACH
YEAR IN THE HISTORICAL RECORD AND LINEARLY COMBINING THE STATES FOLLOWING
THE INITIAL TIME IN THE HISTORICAL YEARS.

CAS - CONSTRUCTED ANALOG SOIL MOISTURE PREDICTION TECHNIQUE. 

CCA - CANONICAL CORRELATION ANALYSIS - A TECHNIQUE WHICH PREDICTS THE STATUS OF 
U.S. T AND P FOR SOME FUTURE TARGET SEASON USING THE MOST RECENT 4 NON-
OVERLAPPING SEASONAL OBSERVATIONS OF TROPICAL PACIFIC SST - CIRCULATION AND 
U.S. T OR P TO CHARACTERIZE THE RECENT BEHAVIOR OF THE CLIMATE - AND PAST 
OBSERVATIONS TO PLACE RECENT BEHAVIOR INTO A HISTORICAL CONTEXT. 

CLIMATOLOGY - THE 30-YEAR AVERAGE OF A VARIABLE - LIKE TEMPERATURE - AT A 
GIVEN LOCATION AND TIME OF YEAR.
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CONUS - CONTERMINOUS UNITED STATES

DYNAMICAL MODEL - A PREDICTION METHOD WHICH USES EQUATIONS DESCRIBING THE
PHYSICAL BEHAVIOR OF A SYSTEM AND A COMPREHENSIVE SET OF CURRENT OBSERVATIONS
OF THE VALUES OF THE VARIABLES DESCRIBING THE CURRENT STATE OF THE SYSTEM 
(INITIAL CONDITIONS) TO PREDICT THE VALUES OF THOSE VARIABLES A SHORT TIME-STEP 
IN THE FUTURE.  THOSE VALUES ARE - IN TURN - USED AS THE INITIAL CONDITIONS FOR 
A SUBSEQUENT PREDICTION - AND SO ON - UNTIL THE DESIRED FUTURE PREDICTION TIME 
IS REACHED.     

EASTERLY WIND - WIND BLOWING FROM EAST TO WEST.

EC - EQUAL CHANCES - THE PROBABILITY OF THE MOST LIKELY CATEGORY CANNOT BE
DETERMINED AND THE EXPECTED LIKELIHOODS OF ABOVE - NORMAL AND BELOW DO NOT 
DIFFER FROM THEIR CLIMATOLOGICAL ODDS OF 33 1/3% EACH.  EC REPLACES CL.

EL NINO - THE WARM PHASE OF THE ENSO CYCLE

ENSO - ACRONYM FOR EL NINO/SOUTHERN OSCILLATION

GCM - GENERAL CIRCULATION MODEL - A GENERIC TERM APPLIED TO GLOBAL DYNAMICAL 
MODELS.

LA NINA - THE COLD PHASE OF THE ENSO CYCLE

MJO - MADDEN-JULIAN OSCILLATION - ALSO CALLED TROPICAL INTRA-SEASONAL OSCILLA-
TION - A DISTURBANCE IN TROPICAL CONVECTION - PRECIPITATION - WIND AND 
PRESSURE.  MJO PRECIPITATION AND CLOUDINESS ARE ENHANCED ONLY IN REGIONS WHERE
SSTS ARE VERY WARM - E.G. INDIAN OCEAN AND WEST PACIFIC.  THE PRESSURE AND WIND 
DISTURBANCE ASSOCIATED WITH MJO IS OBSERVED TO MOVE FROM WEST TO EAST 
COMPLETELY AROUND THE GLOBAL TROPICS IN ABOUT 30 TO 60 DAYS.

NAO - NORTH ATLANTIC OSCILLATION TELECONNECTION PATTERN.  NOTE THAT THE STATUS 
OF THE AO/NAO AND OTHER SLOWLY VARYING CIRCULATION MODES - WHILE VERY IMPORTANT 
IN DETERMINING THE TEMPERATURE AND PRECIPITATION REGIMES OVER THE US - ARE 
UNPREDICTABLE BY CURRENT TECHNOLOGY AND ARE NOT EXPLICITLY INCLUDED IN OUR 
FORECAST PROCESS.

NORTHERLY WIND - WIND BLOWING FROM NORTH TO SOUTH.

OCN - OPTIMAL CLIMATE NORMALS - A FORECAST BASED ON  PERSISTING THE AVERAGE
OF THE LAST 10 YEARS FOR TEMPERATURE AND THE LAST 15 YEARS FOR PRECIPITATION.

PNA - PACIFIC NORTH AMERICAN TELECONNECTION PATTERN.

QBO - QUASI-BIENNIAL OSCILLATION - AN OSCILLATION OF THE WIND IN THE LOWER
STRATOSPHERE BETWEEN EASTERLY AND WESTERLY WHICH REVERSES ON A NEARLY-
2 YEAR TIME SCALE.  QBO IS ONE OF THE MOST REGULAR OSCILLATIONS KNOWN.

SMLR - SCREENING MULTIPLE LINEAR REGRESSION - A TECHNIQUE WHICH SELECTS THE BEST 
SET OF PREDICTORS - FITTING THEM TO THE OBSERVATIONS TO CREATE EQUATIONS WHICH 
CAN BE USED TO MAKE PREDICTIONS.

SOUTHERLY WIND - WIND BLOWING FROM SOUTH TO NORTH.

STATISTICAL PREDICTIONS - PREDICTIONS BASED MAINLY ON LARGE OBSERVATIONAL DATA
SETS.  CCA - OCN - SMLR - CAS - CA ARE EXAMPLES OF THESE.

TELECONNECTIONS - THESE GIVE THE HISTORICAL RELATIONSHIP BETWEEN A GIVEN POINT 
AND ALL OTHER POINTS OVER A LARGE AREA - LIKE THE NORTHERN HEMISPHERE - FOR A 
GIVEN TIME OF THE YEAR.  THE POINTS ON THE MAP USUALLY CONSIST OF A SET OF
MORE OR LESS EVENLY SPACED LOCATIONS CALLED GRID POINTS.

TREND - AT A GIVEN LOCATION AND TIME OF YEAR - THE DIFFERENCE BETWEEN THE 
AVERAGE OF THE MOST RECENT 10 (15) YEARS OF OBSERVATIONS OF T (P) AND THE 
CLIMATOLOGY.

WESTERLY WIND - WIND BLOWING FROM WEST TO EAST.

ZONAL FLOW PATTERN - OCCURS WHEN 500-HPA CONTOURS LIE IN AN EAST-WEST DIRECTION
PARALLEL TO LATITUDE CIRCLES WITH NEARLY PURE WEST-TO-EAST FLOW.
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FORECASTER: A. J. WAGNER
  
FOR A DESCRIPTION OF THE STANDARD FORECAST TOOLS - THEIR SKILL - AND THE
FORECAST FORMAT PLEASE SEE OUR WEB PAGE AT: 
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/DISC.HTML
(USE LOWER CASE LETTERS)

INFORMATION ON THE FORMULATION AND SKILL OF THE CAS FORECASTS MAY BE FOUND AT:
HTTP://WWW.CPC.NCEP.NOAA.GOV/SOILMST/FORECASTS.HTML  (USE LOWER CASE LETTERS)

NOTES - THESE CLIMATE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF
THEIR VALID PERIODS. WITHIN ANY GIVEN VALID PERIOD OBSERVATIONS AND SHORT
AND MEDIUM RANGE FORECASTS SHOULD BE CONSULTED.  

THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCE OF THE NEW SET NEXT
MONTH ON AUG 21 2003.

1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17 2001
FORECAST RELEASE.

$$