PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830AM EDT THURSDAY JUN 21 2012

30-DAY OUTLOOK DISCUSSION FOR JULY 2012

ENSO NEUTRAL CONDITIONS CONTINUED INTO JUNE. SST ANOMALIES ARE SMALL ACROSS 
MUCH OF THE WESTERN AND CENTRAL PACIFIC WHERE DEPARTURES FROM NORMAL ARE WITHIN 
0.5 C. POSITIVE ANOMALIES OF 1-2 DEGREES C REMAIN OVER PORTIONS OF THE 
EQUATORIAL EASTERN PACIFIC. ANY REMAINING BELOW NORMAL SSTS ARE CENTERED NEAR 
THE DATE LINE. AT DEPTH, OCEAN TEMPERATURES ARE GENERALLY ABOVE AVERAGE WITH 
THE LARGEST POSITIVE ANOMALIES CENTERED AT 160E AT 150 METERS DEPTH WITH THE 
ONLY REMAINING BELOW-NORMAL OCEAN TEMPERATURES JUST BELOW THE SURFACE FROM 160E 
TO 160W. THE LATEST DYNAMIC AND STATISTICAL SST FORECASTS FOR THE NINO3.4 
REGION INDICATE CONTINUED SLIGHTLY POSITIVE DEPARTURES FROM NORMAL DURING THE 
MONTH OF JULY AND ENSO NEUTRAL CONDITIONS ARE EXPECTED TO REMAIN IN PLACE 
THROUGHOUT THE OUTLOOK PERIOD.     

THE JULY TEMPERATURE OUTLOOK DEPICTS ENHANCED ODDS FOR ABOVE-NORMAL MEAN 
TEMPERATURES FOR A REGION FROM THE INTERMOUNTAIN WEST AND SOUTHWEST EASTWARD TO 
INCLUDE MUCH OF THE ROCKIES, GREAT PLAINS, MISSISSIPPI VALLEY, AND PORTIONS OF 
THE SOUTHWEST GREAT LAKES AND WESTERN OHIO VALLEY. THE PRIMARY DRIVERS FOR THIS 
FORECAST ARE CONSISTENT SIGNATURES FROM DYNAMICAL MODEL FORECASTS (CFSV2 AND 
NMME) AND LOW SOIL MOISTURE CONDITIONS ACROSS MUCH OF THIS REGION. LONG TERM 
TRENDS ARE STRONG THIS TIME OF YEAR ACROSS THE SOUTHWEST AND SOUTHERN ROCKIES 
AND THIS CONTRIBUTES TO THE FORECAST IN THOSE REGIONS. THE LARGEST 
PROBABILITIES ARE INDICATED WHERE LONG-TERM TRENDS AND DYNAMICAL MODEL OUTPUT 
CORRESPOND AND ARE LOCATED ACROSS PARTS OF NEVADA, CALIFORNIA AND ARIZONA. 
BELOW-NORMAL JULY MEAN TEMPERATURES ARE FAVORED FOR AN AREA GENERALLY ALONG THE 
COAST FROM SOUTHWEST ALASKA TO THE EXTREME PACIFIC NORTHWEST DUE TO A 
COMBINATION OF BELOW-NORMAL COASTAL SSTS, FORECASTS FROM THE NMME AND TO A 
LESSER EXTENT THE CFSV2. ELSEWHERE THERE ARE CONFLICTING SIGNALS AMONG TOOLS, 
AND SO EQUAL CHANCES FOR ABOVE-, BELOW- OR NEAR-NORMAL JULY MEAN TEMPERATURES 
ARE INDICATED.

THE JULY PRECIPITATION OUTLOOK FAVORS ABOVE-MEDIAN PRECIPITATION FOR PARTS OF 
THE SOUTHWEST U.S. WHERE THERE IS INCREASING SUPPORT FROM THE FORECAST TOOLS, 
INCLUDING THE CFSV2 AND SOME MEMBERS OF THE NMME, THAT THE EARLY STAGES OF 
SUMMER MONSOON RAINFALL MAY BE ABOVE-MEDIAN. IN ADDITION TO THE DYNAMICAL MODEL 
FORECASTS, THE CONSTRUCTED ANALOG STATISTICAL TOOL BASED ON SOIL MOISTURE ALSO 
HINTS AT ABOVE-MEDIAN PRECIPITATION IN THIS REGION DURING THE MONTH OF JULY. 
TROPICAL SUBSEASONAL VARIABILITY HAS BEEN ACTIVE ACROSS THE WESTERN HEMISPHERE 
AND HAS ENHANCED CONVECTION IN THE TROPICS AND SUBTROPICS. THIS SIGNAL MAY 
PERSIST OVER THE NEXT 1-2 WEEKS AND MAY ALSO CONTRIBUTE MOISTURE TO THE 
DEVELOPING MONSOON CIRCULATION DURING EARLY JULY. THE ODDS FOR BELOW MEDIAN 
PRECIPITATION ARE ELEVATED FOR THE NORTHWEST U.S. AND ARE SUPPORTED BY THE 
CFSV2, LONG-TERM TRENDS AND TO A LESSER EXTENT BY SOME MEMBERS OF THE NMME. A 
COMBINATION OF FORECASTS FROM THE NMME AND CFSV2 AS WELL AS RAPIDLY WORSENING 
DROUGHT CONDITIONS FAVOR BELOW-MEDIAN PRECIPITATION FOR A REGION STRETCHING 
FROM THE NORTH-CENTRAL GREAT PLAINS TO PARTS OF THE OHIO VALLEY. ELSEWHERE 
THERE ARE CONFLICTING SIGNALS AMONG TOOLS SO EQUAL CHANCES FOR ABOVE-, BELOW- 
AND NEAR-MEDIAN PRECIPITATION ARE FORECAST FOR JULY TOTAL PRECIPITATION.

THE MAIN FACTORS WHICH USUALLY INFLUENCE THE MONTHLY CLIMATE OUTLOOK INCLUDE:
1) EL NINO AND LA NINA - WHICH COMPRISE ENSO. IMPACTS OF THESE EVENTS ARE 
SUMMARIZED BY SEPARATING 3-MONTH OBSERVATIONS FROM THREE OR MORE DECADES INTO 
EL NINO, NEUTRAL AND LA NINA SETS, AVERAGING EACH SEPARATELY, AND THEN 
COMPUTING ANOMALIES. THESE ARE CALLED "COMPOSITES" AND USED AT TIMES TO 
SUBJECTIVELY MODIFY THE FORECAST.
2) TRENDS - APPROXIMATED BY THE OCN TOOL AS THE DIFFERENCE BETWEEN THE MOST 
RECENT 10-YEAR MEAN OF TEMPERATURE OR 15-YEAR MEAN OF PRECIPITATION FOR A GIVEN 
LOCATION AND TIME OF YEAR AND THE 30-YEAR CLIMATOLOGY PERIOD (CURRENTLY 
1981-2010).
3) THE TROPICAL 30-60 DAY OSCILLATION - CALLED THE MADDEN JULIAN OSCILLATION 
(MJO) - AFFECTS CLIMATE VARIABILITY WITHIN SEASONS.
4) THE ARCTIC OSCILLATION (AO), THE SIMILAR NORTH ATLANTIC OSCILLATION (NAO), 
AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE 
ANOMALY PATTERN ESPECIALLY DURING BOREAL WINTER AND ARE GENERALLY CONSIDERED TO 
HAVE LOW PREDICTABILITY.
5) THE PACIFIC DECADAL OSCILLATION (PDO) - AN ENSO-LIKE PATTERN OF CLIMATE 
VARIABILITY AFFECTING THE TROPICS AND THE NORTH PACIFIC AND NORTH AMERICAN 
REGIONS, BUT WHICH VARIES ON A MUCH LONGER TIME-SCALE THAN ENSO.
6) PERSISTANTLY DRY OR WET SOILS IN THE SPRING AND SUMMER AND SNOW AND ICE 
COVER ANOMALIES IN THE WINTER. THESE FACTORS TEND TO PERSIST FOR LONG PERIODS 
AND ACT AS A KIND OF MEMORY IN THE CLIMATE SYSTEM.
7) STATISTICAL FORECAST MODELS - CANONICAL CORRELATION ANALYSIS (CCA), 
SCREENING MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOG (CA), AND 
ENSEMBLE CCA (ECCA).
8) DYNAMICAL FORECAST MODELS - INCLUDING THE NCEP CLIMATE FORECAST SYSTEM (CFS) 
AND FOR ZERO-LEAD UPDATE FORECASTS THE NCEP GLOBAL ENSEMBLE FORECAST SYSTEM 
(GEFS). THE UPGRADED VERSION OF THE CFS (CFSV2) BECAME OPERATIONAL IN LATE 
MARCH OF 2011. BOTH VERSIONS OF CFS ARE CURRENTLY RUN IN PARALLEL. AN 
EXPERIMENTAL FORECAST SYSTEM, THE NATIONAL MULTI-MODEL ENSEMBLE (NMME), 
COMPRISED OF SEVERAL DYNAMICAL MODELS IS ALSO USED.


FORECASTER: JON GOTTSCHALCK


THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1981 AND 2010, FOLLOWING
THE WORLD METEOROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3 
COMPLETE DECADES AS THE CLIMATE REFERENCE PERIOD.  THE PROBABILITY ANOMALIES
FOR TEMPERATURE AND PRECIPITATION BASED ON THESE NEW NORMALS BETTER REPRESENT
SHORTER TERM CLIMATIC ANOMALIES THAN THE FORECASTS BASED ON OLDER NORMALS.



AN UPDATED MONTHLY OUTLOOK... FOR JUL WILL BE ISSUED ON SAT JUNE 30 2012


THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD.

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