PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOK CLIMATE PREDICTION CENTER NCEP NATIONAL WEATHER SERVICE WASHINGTON DC 3 PM EDT THURSDAY MAY 13 1999 ' PROGNOSTIC DISCUSSION OF HAWAIIAN OUTLOOKS MONTHLY OUTLOOK DISCUSSION - JUNE 1999 SSTS NEAR HAWAII RANGE FROM ABOUT ONE-HALF DEGREE C BELOW NORMAL NEAR THE BIG ISLAND OF HAWAII TO SLIGHTLY ABOVE NORMAL NEAR THE NORTHWESTERN ISLANDS. FOR A DISCUSSION OF THE SSTS IN THE EQUA- TORIAL PACIFIC REFER TO THE 90 DAY MESSAGE. CCA MIXED WITH LOCAL PERSISTENCE - WHICH IS SUPPORTED BY THE CMP FORECASTS - INDICATES GENERALLY BELOW NORMAL TEMPERATURES OVER THE ISLANDS - WITH STRONGEST PROBABILITIES FOR COLD OVER THE BIG ISLAND AND WEAKEST FOR THE NORTHWESTERN ISLANDS WHERE NEAR NORMAL MIGHT BE THE MOST LIKELY OUTCOME BY A SMALL MARGIN - CONSISTENT WITH THE GRADIENT IN SST ANOMALIES. NEITHER CCA NOR THE CMP SHOW ANY TILT OF THE ODDS FOR PRECIPITATION - SO CL IS ASSIGNED EVERYWHERE. TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV HILO B15 75.2 0.5 CL 4.6 5.7 7.0 KAHULUI B8 77.4 0.6 CL 0.0 0.3 0.2 HONOLULU B4 79.4 0.5 CL 0.1 0.3 0.5 LIHUE N2 77.8 0.4 CL 1.1 1.5 1.9 ' SEASONAL OUTLOOK DISCUSSION -JUN-JUL-AUG 1999 TO JUN-JUL-AUG 2000 REFER TO THE 90 DAY DISCUSSION FOR FORECASTS FOR THE EQUATORIAL PACIFIC SSTS. THE CURRENT LA NINA CONDITIONS ARE ONE CONSIDER- ATION FOR THE HAWAIIAN FORECASTS AND ALSO THE POSSIBILITY OF A CONTINUED COLD EVENT THROUGH NEXT WINTER. COMPOSITES OF TEMPERATURE AND PRECIPITATION FOR THECOLD PHASE OF ENSO SHOW FAIRLY WEAK RESULTS FOR HAWAII DURING THE WARM HALF OF THE YEAR. THE CCA TOOL - WHICH INCLUDES ENSO IMPACTS - IS THE PRINCIPAL TOOL USED - ALONG WITH WHATEVER SIGNALS WERE AVAILABLE FROM THE CMP. LOCAL PERSISTENCE FOR THE SHORT LEADS FOR TEMPERATURE IS ALSO USED - REFLECTING A GRADUAL DYING AWAY OF THE INITIAL SST ANOMALY GRADIENT IN THE VICINITY OF THE ISLANDS. CCA INDICATES A SLIGHT TENDENCY TOWARDS WARMTH AT SEVERAL ISLANDS FROM JJA THROUGH OND AND THEN FOR DJF THROUGH MJJ 2000 IT FAVORS A TILT TOWARDS COLD - CONSISTENT WITH THE EXPECTATION THAT THE COLD EVENT WILL CONTINUE THROUGH AT LEAST NEXT WINTER. THIS FOLLOWS THE TENDENCY FOR HAWAII TO EXPERIENCE A 1-YEAR DELAY IN WINTER TEMPERATURE ANOMALY FOLLOWING THE ENSO EVENT OF THE SAME SIGN THE PREVIOUS WINTER. THIS IS RELATED TO THE APPEARANCE OF THE ENSO-RELATED EQUATORIAL SST ANOMALY OF THE PREVIOUS WINTER AT SUBTROPICAL (INCLUDING HAWAII) LATITUDES THE FOLLOWING WINTER. THERE WERE NO SIGNALS FOR PRECIPITATION ANOMALIES FROM ANY TOOL AFTER JAS 1999. CLARIFICATION: CL INDICATES CLIMATOLOGICAL PROBABILITIES - WHICH MEANS THAT NO PARTICULAR TILT OF THE ODDS TOWARD ABOVE - NEAR - OR BELOW NORMAL CONDITIONS IS FORECAST. A5 (EXAMPLE) MEANS A 5% HIGHER THAN NORMAL CHANCE THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE ABOVE CLASS. B3 (EXAMPLE) MEANS A 3% HIGHER THAN NORMAL PROBABILITY THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE BELOW CLASS. N2 (EXAMPLE) MEANS A 2% HIGHER THAN NORMAL PROBABILITY THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE NEAR NORMAL CLASS. NOTE -- THE HAWAIIAN FORECAST IS BASED ON THE CCA TOOL AND ENSO CONSIDERATIONS ONLY HILO TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV JJA 1999 B8 75.8 0.4 A4 19.7 23.8 28.5 JAS 1999 CL 76.1 0.4 A3 22.0 26.2 30.9 ASO 1999 CL 76.0 0.4 CL 23.3 26.6 30.3 SON 1999 B2 75.3 0.4 CL 25.7 31.2 37.4 OND 1999 B2 74.1 0.4 CL 27.1 33.9 41.7 NDJ 1999 B3 72.7 0.4 CL 27.0 34.0 42.2 DJF 1999 B4 71.9 0.5 CL 19.8 27.1 36.1 JFM 2000 B2 71.8 0.5 CL 22.8 30.2 39.1 FMA 2000 CL 72.1 0.5 CL 30.5 37.2 44.7 MAM 2000 CL 72.8 0.5 CL 30.4 36.8 44.1 AMJ 2000 CL 73.9 0.5 CL 24.2 29.4 35.4 MJJ 2000 CL 75.0 0.5 CL 20.5 24.5 29.0 JJA 2000 CL 75.8 0.4 CL 19.7 23.8 28.5 KAHULUI TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV JJA 1999 CL 78.5 0.5 CL 0.6 0.9 1.3 JAS 1999 A2 78.9 0.5 A3 0.8 1.1 1.4 ASO 1999 A3 78.6 0.5 CL 1.2 1.7 2.4 SON 1999 A3 77.4 0.5 CL 2.4 3.4 4.8 OND 1999 A2 75.5 0.5 CL 4.8 6.3 8.1 NDJ 1999 CL 73.5 0.4 CL 6.7 8.8 11.4 DJF 1999 B2 72.2 0.5 CL 6.9 9.0 11.5 JFM 2000 CL 72.1 0.5 CL 6.7 8.7 11.1 FMA 2000 CL 72.9 0.5 CL 4.7 6.4 8.5 MAM 2000 B3 74.2 0.5 CL 3.0 4.4 6.1 AMJ 2000 B2 75.7 0.5 CL 1.1 1.9 3.1 MJJ 2000 B4 77.3 0.6 CL 0.6 1.0 1.6 JJA 2000 CL 78.5 0.5 CL 0.6 0.9 1.3 HONOLULU TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV JJA 1999 CL 80.4 0.5 CL 0.9 1.3 1.8 JAS 1999 A2 81.0 0.5 A3 1.3 1.7 2.1 ASO 1999 A2 80.7 0.5 CL 1.8 2.8 4.0 SON 1999 CL 79.3 0.5 CL 3.6 5.1 6.9 OND 1999 N2 77.0 0.5 CL 6.0 8.0 10.4 NDJ 1999 CL 74.7 0.4 CL 6.7 9.0 11.4 DJF 1999 CL 73.3 0.4 CL 6.2 8.3 10.9 JFM 2000 B2 73.4 0.5 CL 5.0 6.9 9.1 FMA 2000 B4 74.4 0.5 CL 3.7 5.1 6.8 MAM 2000 B4 75.9 0.5 CL 2.5 3.8 5.5 AMJ 2000 B5 77.6 0.5 CL 1.5 2.4 3.6 MJJ 2000 B3 79.1 0.5 CL 1.1 1.7 2.5 JJA 2000 CL 80.4 0.5 CL 0.9 1.3 1.8 LIHUE TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV JJA 1999 N2 78.7 0.4 A4 4.5 5.3 6.2 JAS 1999 CL 79.2 0.4 A2 4.9 5.9 7.0 ASO 1999 CL 78.7 0.4 CL 6.2 7.8 9.7 SON 1999 A2 77.4 0.4 CL 9.3 11.4 13.8 OND 1999 A2 75.3 0.4 CL 10.8 13.7 17.1 NDJ 1999 CL 73.3 0.4 CL 12.1 15.2 18.7 DJF 1999 CL 72.0 0.5 CL 10.5 13.3 16.6 JFM 2000 B2 72.0 0.6 CL 9.1 11.9 15.3 FMA 2000 B3 72.8 0.6 CL 7.8 10.0 12.6 MAM 2000 B3 74.1 0.6 CL 7.7 9.9 12.3 AMJ 2000 B2 75.8 0.5 CL 5.8 7.5 9.5 MJJ 2000 B2 77.5 0.4 CL 4.9 6.3 8.0 JJA 2000 CL 78.7 0.4 CL 4.5 5.3 6.2 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 THURSDAY JUNE 17 1999. NNNN NNNN