PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THU APR 19 2018 MONTHLY FORECAST DISCUSSION VALID MAY 2018 SEA SURFACE TEMPERATURE (SST) ANOMALIES ARE CURRENTLY AROUND ZERO TO POSITIVE ONE-HALF DEGREE C OVER MOST OF THE NORTHERN HAWAIIAN ISLANDS, AND ABOUT POSITIVE ONE-HALF DEGREE TO ONE DEGREE C OVER THE SOUTHEASTERN ISLANDS. FOR JANUARY 2018 THROUGH THE END OF MARCH 2018, RAINFALL TOTAL ACCUMULATIONS WERE: - LIHUE AIRPORT 18.62 INCHES (162 PERCENT OF NORMAL) - HONOLULU AIRPORT 6.75 INCHES (107 PERCENT OF NORMAL) - KAHULUI AIRPORT 8.85 INCHES (112 PERCENT OF NORMAL) - HILO AIRPORT 41.01 INCHES (127 PERCENT OF NORMAL) THE NCEP CLIMATE FORECAST SYSTEM (CFS) AND OTHER CLIMATE MODELS RUN AS A PART OF THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) PREDICT ABOVE NORMAL SSTS AROUND THE HAWAIIAN ISLANDS FOR MAY 2018. THIS ELEVATES THE CHANCES OF ABOVE NORMAL MONTHLY MEAN AIR TEMPERATURES FOR LIHUE, HONOLULU, KAHULUI, AND HILO IN MAY 2018. MOST DYNAMICAL TOOLS ALSO FAVOR ABOVE NORMAL PRECIPITATION FOR HILO, KAHULUI, HONOLULU AND LIHUE DURING MAY 2018. TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV HILO A60 74.0 0.5 A50 4.1 7.4 8.7 KAHULUI A60 75.8 0.6 A50 0.2 0.5 0.8 HONOLULU A50 78.0 0.6 A50 0.2 0.4 0.8 LIHUE A40 75.8 0.6 A50 1.3 1.5 2.3 SEASONAL FORECAST DISCUSSION VALID MJJ 2018 - MJJ 2019 REFER TO THE PROGNOSTIC DISCUSSION ON LONG-LEAD SEASONAL OUTLOOKS FOR THE CONUS AND ALASKA FOR A DISCUSSION OF THE FORECASTS OF EQUATORIAL PACIFIC SSTS, AND FOR THE GENERAL BACKGROUND FOR THE SEASONAL FORECAST, INCLUDING DETAILS ON THE CURRENT STATE OF THE ATMOSPHERE AND OCEAN. WEAK LA NINA CONDITIONS CURRENTLY ARE PRESENT ACROSS THE EQUATORIAL PACIFIC OCEAN. EQUATORIAL SEA SURFACE TEMPERATURES (SSTS) ARE BELOW AVERAGE ACROSS THE EAST-CENTRAL AND EASTERN PACIFIC OCEAN, AND ABOVE AVERAGE IN THE WESTERN PACIFIC. POSITIVE SUBSURFACE TEMPERATURE ANOMALIES AT DEPTH HAVE SHIFTED EASTWARD TO 110W, WHILE NEGATIVE ANOMALIES PERSIST CLOSER TO THE SURFACE BETWEEN 150W AND 120W. CONVECTION WAS SUPPRESSED NEAR AND EAST OF THE DATE LINE AND ENHANCED OVER THE FAR WESTERN TROPICAL PACIFIC OCEAN, WHILE LOW-LEVEL WIND ANOMALIES WERE EASTERLY OVER THE EAST-CENTRAL PACIFIC, AND WESTERLY OVER THE FAR WESTERN PACIFIC. MOST MODELS INDICATE A TRANSITION FROM LA NINA TO ENSO NEUTRAL IS MOST LIKELY (GREATER THAN 50% CHANCE) DURING THE APRIL-MAY SEASON, WITH NEUTRAL CONDITIONS LIKELY TO CONTINUE THROUGH THE NORTHERN HEMISPHERE SUMMER 2018. ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED FOR HAWAII FROM MJJ 2018 TO OND 2018 DUE TO PREDICTED ABOVE NORMAL SEA SURFACE TEMPERATURES ACROSS THE REGION. EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW NORMAL TEMPERATURES ARE INDICATED AT ALL LOCATIONS FOR NDJ 2018 AND BEYOND. DYNAMICAL TOOLS FAVOR ABOVE NORMAL PRECIPITATION FOR HAWAII IN FROM MJJ TO ASO, 2018. THE STATISTICAL TOOLS (CANONICAL CORRELATION ANALYSIS, AND ENSO-OCN) PREDICT BELOW NORMAL PRECIPITATION DURING THE SUMMER. THEREFORE THE PROBABILITIES OF ABOVE NORMAL PRECIPITATION ARE LOWERED. THERE IS CONSIDERABLE UNCERTAINTY ACROSS THE HAWAIIAN ISLANDS IN THE PRECIPITATION FORECAST AMONG AVAILABLE DYNAMICAL AND STATISTICAL TOOLS (CONSTRUCTED ANALOG, CANONICAL CORRELATION ANALYSIS, AND ENSO-OCN) IN SON AND LONGER LEADS, SO EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW NORMAL PRECIPITATION ARE INDICATED. HILO TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2018 A65 74.0 0.4 A40 20.2 27.5 29.1 JJA 2018 A60 75.2 0.4 A40 19.4 27.2 31.4 JAS 2018 A55 76.1 0.4 A40 25.2 28.6 33.4 ASO 2018 A50 76.4 0.4 A40 26.1 28.8 33.3 SON 2018 A45 76.2 0.4 EC 24.3 30.2 40.8 OND 2018 A40 75.5 0.4 EC 28.3 34.5 42.0 NDJ 2018 EC 74.2 0.4 EC 26.4 36.6 43.0 DJF 2019 EC 72.8 0.4 EC 19.6 30.2 33.3 JFM 2019 EC 71.8 0.4 EC 22.0 32.0 44.5 FMA 2019 EC 71.7 0.4 EC 24.6 34.1 45.5 MAM 2019 EC 72.0 0.5 EC 22.5 28.4 34.0 AMJ 2019 EC 72.9 0.5 EC 21.4 23.7 29.0 MJJ 2019 EC 74.0 0.4 EC 20.2 27.5 29.1 \N KAHULUI TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2018 A65 76.0 0.5 A40 0.7 1.1 1.8 JJA 2018 A60 77.7 0.4 A40 0.7 1.1 1.5 JAS 2018 A55 79.0 0.4 A40 0.8 1.1 1.6 ASO 2018 A50 79.4 0.4 A40 0.8 1.6 2.5 SON 2018 A45 79.1 0.4 EC 2.1 3.3 4.8 OND 2018 A40 77.8 0.4 EC 4.2 5.3 8.1 NDJ 2018 EC 75.9 0.4 EC 5.2 7.6 9.5 DJF 2019 EC 73.8 0.4 EC 4.6 6.9 8.7 JFM 2019 EC 72.5 0.4 EC 4.2 6.2 8.2 FMA 2019 EC 72.3 0.4 EC 3.2 4.1 6.4 MAM 2019 EC 73.0 0.4 EC 2.5 3.5 4.6 AMJ 2019 EC 74.3 0.5 EC 1.2 1.6 2.2 MJJ 2019 EC 76.0 0.5 EC 0.7 1.1 1.8 \N HONOLULU TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2018 A60 78.2 0.4 A40 0.8 1.4 1.6 JJA 2018 A55 79.9 0.4 A40 0.7 0.8 1.3 JAS 2018 A55 81.3 0.4 A40 1.0 1.4 1.7 ASO 2018 A50 81.7 0.4 A40 1.6 2.4 3.1 SON 2018 A45 81.4 0.4 EC 2.5 4.0 5.6 OND 2018 A40 80.0 0.4 EC 4.4 6.4 8.5 NDJ 2018 EC 77.7 0.5 EC 3.9 5.6 8.8 DJF 2019 EC 75.3 0.5 EC 3.7 5.6 8.6 JFM 2019 EC 73.9 0.4 EC 2.1 4.6 7.8 FMA 2019 EC 73.8 0.4 EC 1.9 3.2 4.7 MAM 2019 EC 74.8 0.4 EC 1.8 2.6 3.0 AMJ 2019 EC 76.3 0.4 EC 1.2 1.6 1.8 MJJ 2019 EC 78.2 0.4 EC 0.8 1.4 1.6 \N LIHUE TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2018 A60 76.0 0.5 A40 4.9 5.4 5.9 JJA 2018 A55 77.7 0.4 A40 4.4 5.3 6.9 JAS 2018 A55 79.0 0.3 A40 5.3 6.1 7.8 ASO 2018 A50 79.4 0.3 A40 6.2 7.9 8.4 SON 2018 A45 79.1 0.3 EC 9.2 10.0 11.2 OND 2018 A40 77.8 0.3 EC 9.2 11.7 15.6 NDJ 2018 EC 75.7 0.3 EC 8.6 12.1 16.9 DJF 2019 EC 73.6 0.4 EC 7.5 8.4 14.0 JFM 2019 EC 72.2 0.4 EC 6.5 8.8 13.8 FMA 2019 EC 72.1 0.5 EC 5.8 8.4 9.9 MAM 2019 EC 72.8 0.5 EC 5.3 6.6 8.0 AMJ 2019 EC 74.2 0.5 EC 4.7 5.5 6.0 MJJ 2019 EC 76.0 0.5 EC 4.9 5.4 5.9 \NFORECASTER: LUKE HE ANOMALIES BASED ON 1981-2010 MEANS CLARIFICATION: EC INDICATES EQUAL CHANCES THAT THE CLIMATE WILL FALL INTO ANY ONE OF THE THREE RANGES OR CATEGORIES WHOSE BOUNDARIES ARE SPECIFIED IN THE TABLES ABOVE. A FORECAST SPECIFICATION OF EC MEANS THERE IS NO PARTICULAR TILT OF THE ODDS TOWARD ABOVE-NORMAL OR BELOW-NORMAL CONDITIONS IN THE OUTLOOK. FOR EXAMPLE A40 MEANS A 40% CHANCE THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE ABOVE CLASS, B40 MEANS A 40% PROBABILITY THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE BELOW CLASS, AND N35 MEANS A 35% PROBABILITY THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE NEAR-NORMAL CLASS. WHEN EC IS SPECIFIED, ALL CATEGORIES ARE EQUALLY LIKELY. NOTE - THESE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR VALID PERIODS. WITHIN ANY VALID PERIOD OBSERVATIONS AND SHORTER RANGE FORECASTS SHOULD BE CONSULTED. ALSO - THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCE OF THE NEW SET NEXT MONTH ON THU MAY 17, 2018. $$