PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EST THU NOV 15 2018 MONTHLY FORECAST DISCUSSION VALID DECEMBER 2018 SEA SURFACE TEMPERATURE (SST) ANOMALIES ARE CURRENTLY AROUND POSITIVE ONE-HALF DEGREE TO POSITIVE ONE DEGREE C OVER KAUAI, OAHU AND MAUI, AND ABOUT POSITIVE ONE DEGREE TO POSITIVE TWO DEGREES C OVER THE BIG ISLAND. FOR JANUARY 2018 THROUGH THE END OF OCTOBER 2018, RAINFALL TOTAL ACCUMULATIONS WERE: - LIHUE AIRPORT 44.18 INCHES (161 PERCENT OF NORMAL) - HONOLULU AIRPORT 15.99 INCHES (140 PERCENT OF NORMAL) - KAHULUI AIRPORT 19.70 INCHES (160 PERCENT OF NORMAL) - HILO AIRPORT 153.55 INCHES (154 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 DECEMBER 2018. THIS INCREASES THE CHANCES OF ABOVE NORMAL MONTHLY MEAN AIR TEMPERATURES FOR HAWAII IN DECEMBER 2018. MOST DYNAMICAL MODELS PREDICT BELOW NORMAL PRECIPITATION OVER AREAS NEAR THE NORTHWESTERN HAWAIIAN ISLANDS WITH GREATER UNCERTAINTY AMONG FORECASTS FOR MOST OTHER AREAS OF THE HAWAIIAN ISLANDS DURING DECEMBER 2018. TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV HILO A65 72.5 0.4 EC 6.8 10.2 13.6 KAHULUI A65 73.5 0.5 EC 1.9 2.7 3.4 HONOLULU A60 74.9 0.6 B45 0.8 1.3 3.8 LIHUE A60 73.3 0.5 B45 1.8 3.2 5.5 SEASONAL FORECAST DISCUSSION VALID DJF 2018 - DJF 2019 REFER TO THE PROGNOSTIC DISCUSSION ON LONG-LEAD SEASONAL OUTLOOKS FOR THE CONUS AND ALASKA FOR A DISCUSSION OF THE ENSO FORECAST AND CLIMATE CONDITIONS RELEVANT TO THE SEASONAL OUTLOOK, INCLUDING DETAILS ON THE CURRENT STATE OF THE ATMOSPHERE AND OCEAN. ENSO-NEUTRAL CONDITIONS CURRENTLY ARE PRESENT ACROSS THE EQUATORIAL PACIFIC OCEAN. EQUATORIAL SEA SURFACE TEMPERATURES (SSTS) ARE ABOVE AVERAGE ACROSS THE PACIFIC OCEAN. POSITIVE SUBSURFACE TEMPERATURE ANOMALIES HAVE STRENGTHENED AND EXPANDED INTO THE EASTERN PACIFIC OCEAN. CONVECTION IS ANOMALOUSLY BELOW AVERAGE OVER THE DATE LINE. LOW-LEVEL WESTERLY WIND ANOMALIES ARE OBSERVED OVER THE EASTERN PACIFIC, WHILE WEAK UPPER-LEVEL WESTERLY WIND ANOMALIES ARE PRESENT OVER THE FAR WESTERN PACIFIC. THE OFFICIAL CONSENSUS ENSO FORECAST INDICATES ABOUT 80% PROBABILITY OF EL NINO ONSET THROUGH THE NORTHERN HEMISPHERE WINTER 2018, AND ABOUT 55-60% CHANCE INTO SPRING 2019. ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED FOR HAWAII FROM DJF 2019 TO MJJ 2019 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 OF THE HAWAII FORECAST FOR JJA 2019 AND BEYOND, DUE TO INCREASING UNCERTAINTY IN CLIMATE CONDITIONS AT LONGER LEAD TIMES. MOST ENSO FORECAST MODELS PREDICT A WARM EVENT, OR EL NINO, DEVELOPING IN THE NORTHERN HEMISPHERE AUTUMN OR WINTER 2018-19. HISTORICAL EL NINO IMPACTS INDICATE STRONG CORRELATIONS BETWEEN EL NINO AND INCREASED PROBABILITIES OF BELOW NORMAL PRECIPITATION FOR HAWAII IN WINTER AND SPRING, CONSISTENT WITH NMME DYNAMICAL MODEL FORECASTS AND STATISTICAL TOOLS, INCLUDING THE CONSTRUCTED ANALOG AND THE ENSO-OCN TOOL, INDICATING THE COMBINED IMPACT OF EL NINO AND DECADAL CLIMATE VARIABILITY. INCREASED PROBABILITIES OF BELOW NORMAL PRECIPITATION ARE FAVORED FOR THE HAWAIIAN ISLANDS FROM DJF TO MJJ 2019. THERE IS CONSIDERABLE UNCERTAINTY ACROSS THE HAWAIIAN ISLANDS IN THE PRECIPITATION FORECAST AMONG AVAILABLE FORECAST TOOLS IN JJA 2019 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 DJF 2019 A65 72.8 0.4 B65 19.6 30.2 33.3 JFM 2019 A60 71.8 0.4 B70 22.0 32.0 44.5 FMA 2019 A60 71.7 0.4 B65 24.6 34.1 45.5 MAM 2019 A55 72.0 0.5 B65 22.5 28.4 34.0 AMJ 2019 A45 72.9 0.5 B60 21.4 23.7 29.0 MJJ 2019 A40 74.0 0.4 B50 20.2 27.5 29.1 JJA 2019 EC 75.2 0.4 EC 19.4 27.2 31.4 JAS 2019 EC 76.1 0.4 EC 25.2 28.6 33.4 ASO 2019 EC 76.4 0.4 EC 26.1 28.8 33.3 SON 2019 EC 76.2 0.4 EC 24.3 30.2 40.8 OND 2019 EC 75.5 0.4 EC 28.3 34.5 42.0 NDJ 2019 EC 74.2 0.4 EC 26.4 36.6 43.0 DJF 2020 EC 72.8 0.4 EC 19.6 30.2 33.3 KAHULUI TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV DJF 2019 A65 73.8 0.4 B65 4.6 6.9 8.7 JFM 2019 A60 72.5 0.4 B70 4.2 6.2 8.2 FMA 2019 A60 72.3 0.4 B65 3.2 4.1 6.4 MAM 2019 A55 73.0 0.4 B65 2.5 3.5 4.6 AMJ 2019 A45 74.3 0.5 B60 1.2 1.6 2.2 MJJ 2019 A40 76.0 0.5 B50 0.7 1.1 1.8 JJA 2019 EC 77.7 0.4 EC 0.7 1.1 1.5 JAS 2019 EC 79.0 0.4 EC 0.8 1.1 1.6 ASO 2019 EC 79.4 0.4 EC 0.8 1.6 2.5 SON 2019 EC 79.1 0.4 EC 2.1 3.3 4.8 OND 2019 EC 77.8 0.4 EC 4.2 5.3 8.1 NDJ 2019 EC 75.9 0.4 EC 5.2 7.6 9.5 DJF 2020 EC 73.8 0.4 EC 4.6 6.9 8.7 HONOLULU TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV DJF 2019 A60 75.3 0.5 B65 3.7 5.6 8.6 JFM 2019 A55 73.9 0.4 B70 2.1 4.6 7.8 FMA 2019 A55 73.8 0.4 B65 1.9 3.2 4.7 MAM 2019 A50 74.8 0.4 B65 1.8 2.6 3.0 AMJ 2019 A45 76.3 0.4 B60 1.2 1.6 1.8 MJJ 2019 A40 78.2 0.4 B50 0.8 1.4 1.6 JJA 2019 EC 79.9 0.4 EC 0.7 0.8 1.3 JAS 2019 EC 81.3 0.4 EC 1.0 1.4 1.7 ASO 2019 EC 81.7 0.4 EC 1.6 2.4 3.1 SON 2019 EC 81.4 0.4 EC 2.5 4.0 5.6 OND 2019 EC 80.0 0.4 EC 4.4 6.4 8.5 NDJ 2019 EC 77.7 0.5 EC 3.9 5.6 8.8 DJF 2020 EC 75.3 0.5 EC 3.7 5.6 8.6 LIHUE TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV DJF 2019 A55 73.6 0.4 B65 7.5 8.4 14.0 JFM 2019 A50 72.2 0.4 B70 6.5 8.8 13.8 FMA 2019 A50 72.1 0.5 B65 5.8 8.4 9.9 MAM 2019 A45 72.8 0.5 B65 5.3 6.6 8.0 AMJ 2019 A40 74.2 0.5 B60 4.7 5.5 6.0 MJJ 2019 A40 76.0 0.5 B50 4.9 5.4 5.9 JJA 2019 EC 77.7 0.4 EC 4.4 5.3 6.9 JAS 2019 EC 79.0 0.3 EC 5.3 6.1 7.8 ASO 2019 EC 79.4 0.3 EC 6.2 7.9 8.4 SON 2019 EC 79.1 0.3 EC 9.2 10.0 11.2 OND 2019 EC 77.8 0.3 EC 9.2 11.7 15.6 NDJ 2019 EC 75.7 0.3 EC 8.6 12.1 16.9 DJF 2020 EC 73.6 0.4 EC 7.5 8.4 14.0 FORECASTER: LUKE HE ANOMALIES ARE BASED ON THE 1981-2010 MEANS. CLARIFICATION: EC INDICATED EQUAL CHANCES THAT THE PREDICTED PARAMETER WILL FALL INTO ANY ONE OF THE THREE CATEGORIES, WHOSE BOUNDARIES ARE SPECIFIC IN THE TABLES ABOVE. A FORECAST SPECIFICATION OF EC MEANS THERE IS NO PARTICULATE TILT OF THE ODDS TOWARD ABOVE NORMAL OR BELOW NORMAL CONDITIONS IN THE OUTLOOK. FOR EXAMPLE A40 MEANS A 40% CHANCE THAT THE AVERAGE TEMPERATURE OR TOTAL PRECIPITATION WILL BE IN THE ABOVE NORMAL CLASS, B40 MEANS A 40% CHANCE THAT THE AVERAGE TEMPERATURE OR TOTAL PRECIPITATION WILL BE IN THE BELOW NORMAL CLASS, AND N35 MEANS A 35% PROBABILITY THAT THE AVERAGE TEMPERATURE OR TOTAL 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 THE VALID PERIODS. WITHIN ANY VALID PERIOD, OBSERVATIONS AND SHORTER RANGE FORECASTS SHOULD BE CONSULTED. ALSO, THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCES OF THE NEW SET NET MONTH, ON THU DEC 20, 2018. $$