PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT WED MAY 31 2017

30-DAY OUTLOOK DISCUSSION FOR JUNE 2017

THE UPDATED MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR JUNE 2017 ARE 
BASED ON THE LATEST FORECASTS FOR DAYS 1-7 (FROM WPC), DAYS 6-10, WEEK-2, WEEK 
3-4, THE GFS, CFS, AND ECMWF DYNAMICAL MODEL RUNS, SOIL MOISTURE 
CONSIDERATIONS, COASTAL SEA-SURFACE TEMPERATURES (SSTS), AND CLIMATOLOGY. 
THOUGH SOME OF THE PREDICTED ANOMALY AREAS REMAIN UNCHANGED FROM THE 0.5-MONTH 
LEAD OUTLOOK (ISSUED 18 MAY), THERE ARE OTHER AREAS THAT HAVE CHANGED 
SIGNIFICANTLY.

THE UPDATED MONTHLY TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL MEAN TEMPERATURES 
OVER WESTERN ALASKA, MUCH OF THE FAR WESTERN AND FAR SOUTHERN CONUS, AND NEW 
ENGLAND. HOWEVER, THE ABOVE-NORMAL TEMPERATURES THAT WERE PREDICTED OVER THE 
REMAINDER OF THE ATLANTIC SEABOARD REGION IN THE 0.5-MONTH LEAD OUTLOOK NO 
LONGER HAVE THE SUPPORT OF MOST MODELS. RELATIVELY WARM COASTAL SSTS ALSO PLAY 
SOME ROLE IN THE TEMPERATURE OUTLOOK FOR WESTERN ALASKA. ANOTHER SIGNIFICANT 
CHANGE FROM THE TEMPERATURE OUTLOOK RELEASED 18 MAY IS THE PLACEMENT AND 
COVERAGE OF PROBABILITIES FAVORING BELOW-NORMAL TEMPERATURES. THE UPDATED 
OUTLOOK DEPICTS A SOMEWHAT LARGER, AND EASTWARD DISPLACED, AREA OF FAVORED 
BELOW-NORMAL TEMPERATURES, WHICH NOW FOCUSES ON THE CENTRAL PLAINS, THE CENTRAL 
THIRD OF THE MISSISSIPPI VALLEY, THE SOUTHWESTERN OHIO VALLEY, THE TENNESSEE 
VALLEY, AND INTERIOR PORTIONS OF THE SOUTHEAST. THIS AREA IS INDICATED BY 
DYNAMICAL MODEL FORECASTS AND IS ALSO WELL SUPPORTED BY THE 6-10 DAY AND WEEK-2 
TEMPERATURE OUTLOOKS, AND HAS SOME SUPPORT FROM RECENT SOIL MOISTURE 
OBSERVATIONS. ELSEWHERE, IN AREAS WHERE CLIMATE SIGNALS ARE EITHER CONFLICTING 
OR OF VERY MODEST MAGNITUDE, EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND 
ABOVE-NORMAL MEAN TEMPERATURES ARE INDICATED.

THE UPDATED MONTHLY PRECIPITATION OUTLOOK HAS DRAMATICALLY CHANGED FROM THE 
0.5-MONTH LEAD PRECIPITATION OUTLOOK. ABOVE-MEDIAN PRECIPITATION IS FAVORED 
FROM THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS SOUTHEASTWARD ACROSS 
PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS, AND THEN EASTWARD AND 
NORTHEASTWARD ACROSS MOST OF THE SOUTHERN HALF OF THE MISSISSIPPI VALLEY, THE 
OHIO AND TENNESSEE VALLEYS, THE MID-ATLANTIC, AND MOST OF THE SOUTHEAST, WITH 
THE EXCEPTION OF FLORIDA. IN A BROAD SENSE, THIS AREA HAS THE SUPPORT OF RECENT 
CFS RUNS, AND PRECIPITATION FORECASTS ON ALL TIME-SCALES OUT TO ONE MONTH IN 
ADVANCE. FOR THE NORTHERN ROCKIES, AND THE NORTHERN AND CENTRAL HIGH PLAINS, 
MUCH OF THE EXPECTED PRECIPITATION FOR JUNE MAY COME WITHIN THE FIRST WEEK OF 
THE MONTH, ESPECIALLY IN AREAS WHERE THE CLIMATOLOGY IS RELATIVELY DRY. THERE 
ARE ELEVATED ODDS FOR BELOW-MEDIAN PRECIPITATION OVER MUCH OF WASHINGTON, 
OREGON, AND NORTHERN CALIFORNIA, AND ALSO OVER NORTHWESTERN ALASKA. THESE 
ANOMALY AREAS INDICATE WHERE THERE IS A GENERAL CONSENSUS BETWEEN THE VARIOUS 
PRECIPITATION OUTLOOKS AND MODEL RUNS NOTED EARLIER. ELSEWHERE, IN AREAS WHERE 
CLIMATE SIGNALS ARE EITHER CONFLICTING OR OF VERY MODEST MAGNITUDE, EQUAL 
CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-MEDIAN PRECIPITATION ARE INDICATED.

--------- THE PREVIOUS MESSAGE, ISSUED 18 MAY, IS SHOWN BELOW ---------

ENSO-NEUTRAL CONDITIONS PERSISTED DURING APRIL, WITH NEAR-AVERAGE SEA SURFACE 
TEMPERATURES (SSTS) OBSERVED ACROSS THE CENTRAL EQUATORIAL PACIFIC, AND 
ABOVE-AVERAGE SSTS IN THE FAR EASTERN PACIFIC. A RESERVOIR OF SUBSURFACE WARMTH 
CONTINUES TO BE OBSERVED NEAR THE DATE LINE, CENTERED AT A DEPTH OF ABOUT 150 
METERS. MAXIMUM TEMPERATURE ANOMALIES RANGE FROM ABOUT 3-5 DEGREES C 
ABOVE-AVERAGE. LOW-LEVEL (850-HPA) WIND ANOMALIES AVERAGED CLOSE TO NORMAL 
DURING THE PAST 30-DAYS. FOR THE SAME TIME PERIOD, THE OUTGOING LONGWAVE 
RADIATION (OLR) PATTERN (WHICH SERVES AS A PROXY FOR CONVECTIVE ANOMALIES 
ACROSS THE TROPICAL PACIFIC) DEPICTED AN AREA OF ENHANCED CONVECTION SOUTH OF 
THE EQUATOR FROM ABOUT 160E TO 125W, OR FROM ABOUT THE SOLOMON ISLANDS EASTWARD 
ACROSS THE SOUTH PACIFIC TO THE PITCAIRN ISLANDS. SUPPRESSED CONVECTION WAS 
NOTED ROUGHLY WITHIN THE SAME LONGITUDE BAND, THOUGH NORTH OF THE EQUATOR. THIS 
OLR FIELD IS NOT REPRESENTATIVE OF EITHER AN EL NINO OR A LA NINA. 

THE MADDEN-JULIAN OSCILLATION (MJO) WAS ACTIVE SINCE LATE APRIL, WITH THE 
ENHANCED CONVECTIVE PHASE CURRENTLY OVER THE INDIAN OCEAN. DURING THE NEXT TWO 
WEEKS, THE MJO IS FORECAST TO EXHIBIT EASTWARD PROPAGATION ACROSS THE INDIAN 
OCEAN AND MARITIME CONTINENT, BUT WITH VERY LOW AMPLITUDE. THEREFORE, THE MJO 
IS NOT LIKELY TO PLAY A SIGNIFICANT ROLE IN THE MONTHLY VARIABILITY OVER NORTH 
AMERICA DURING JUNE. ANTECEDENT SOIL MOISTURE WAS ALSO CONSIDERED FOR THE JUNE 
TEMPERATURE AND PRECIPITATION OUTLOOKS. SOIL MOISTURE IS ANOMALOUSLY HIGH OVER 
PORTIONS OF THE MIDWEST, AND SOUTH-CENTRAL PARTS OF BOTH THE MISSISSIPPI VALLEY 
AND GREAT PLAIN REGIONS. AT THIS TIME OF YEAR, THERE IS A SIGNIFICANT NEGATIVE 
CORRELATION BETWEEN SURFACE TEMPERATURE AND PRECIPITATION IN THIS GENERAL AREA; 
THAT IS, RELATIVELY COOL AND WET CONDITIONS OFTEN GO HAND-IN-HAND.

DYNAMICAL MODELS FROM THE NMME SUITE GENERALLY INDICATED ABOVE-NORMAL MEAN 
TEMPERATURES FOR PORTIONS OF THE WESTERN, SOUTHERN, AND EASTERN CONUS, AND FOR 
MUCH OF WESTERN ALASKA. PROBABILISTIC AND CALIBRATED VERSIONS OF THE NMME TOOL 
WERE CONSIDERED FIRST-GUESS FIELDS FOR THE JUNE OUTLOOK. THE UNCALIBRATED NMME 
TEMPERATURE FORECAST APPEARED TO BE TOO WARM ACROSS THE MIDWESTERN STATES, 
WHERE CALCULATED SOIL MOISTURE RANKING PERCENTILES WERE EASILY IN EXCESS OF 
70-80 PERCENT. THE CFS, THE CANADIAN MODEL (CMC1 CANCM3), AND THE NASA MODEL 
PREDICTED BELOW-NORMAL TEMPERATURES OVER PORTIONS OF THE NORTHERN AND CENTRAL 
ROCKIES, AND CENTRAL AND SOUTHERN PLAINS. THE OFFICIAL TEMPERATURE OUTLOOK FOR 
JUNE INCLUDES AN AREA OF FAVORED BELOW-NORMAL TEMPERATURES OVER MUCH OF WYOMING 
AND COLORADO, ESPECIALLY IN LIGHT OF THE NEGATIVE TEMPERATURE-PRECIPITATION 
CORRELATIONS NOTED EARLIER, AND THE FACT THAT THE ONE PRECIPITATION SIGNAL THAT 
IS CONSIDERED RELIABLE IS THE AREA OF PREDICTED ABOVE-MEDIAN PRECIPITATION OVER 
THIS SAME GENERAL REGION. OTHER MODEL SOLUTIONS, SUCH AS THOSE FROM GFDL AND 
NCAR, APPEAR TO BE TOO BULLISH ON THEIR PREDICTION OF NEARLY COAST-TO-COAST 
WARMTH ACROSS THE CONUS. IN WESTERN ALASKA, MOST (BUT NOT ALL) OF THE NMME 
SUITE PREDICTS ABOVE-NORMAL TEMPERATURES. RELATIVELY WARM SSTS, AND THE 
UNUSUALLY LARGE EXPANSE OF OPEN (ICE-FREE) WATER WEST AND SOUTHWEST OF BARROW 
BY MID-MAY, FAVOR ABOVE-NORMAL TEMPERATURES FOR THE WESTERN PORTION OF THE 
NORTH SLOPE.

THE JUNE PRECIPITATION OUTLOOK ALSO USES THE PROBABILISTIC AND CALIBRATED 
VERSIONS OF THE NMME AS ITS STARTING POINT. THE ONLY SIGNAL WHICH APPEARED 
RELIABLE IS AN AREA OF EXPECTED ABOVE-MEDIAN PRECIPITATION OVER THE VICINITY OF 
THE ROCKIES, AND CENTRAL AND SOUTHERN PLAINS. THE CFS, IMME, CANADIAN MODEL 
(CMC2 CANCM4), AND TO A LESSER DEGREE THE NASA MODEL, LEND SUPPORT FOR THIS WET 
SIGNAL. IN CONTRAST, THE GFDL FLOR MODEL PREDICTS BELOW-MEDIAN PRECIPITATION 
ACROSS THIS PART OF THE CONUS, WHILE THE GFDL CM2.1 AND NCAR MODELS PREDICT 
SOMETHING IN-BETWEEN THE TWO EXTREMES. ELSEWHERE, WHICH INCLUDES A LARGE 
PORTION OF THE CONUS AND ALL OF ALASKA, PRECIPITATION SIGNALS ARE EITHER TOO 
WEAK OR TOO INCOHERENT TO BE OF MUCH USE.


FORECASTER: ANTHONY ARTUSA


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.



THE NEXT MONTHLY OUTLOOK...FOR JUL ... WILL BE ISSUED ON THU JUN 15 2017


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

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