Hawaii 30 & 90 Day Narrative

637 
FXHW40 KWBC 191254
PMDHCO
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.
$$