Hawaii 30 & 90 Day Narrative

682 
FXHW40 KWBC 201231
PMDHCO
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THU SEP 20 2018
MONTHLY FORECAST DISCUSSION VALID OCTOBER 2018
SEA SURFACE TEMPERATURE (SST) ANOMALIES ARE CURRENTLY AROUND ZERO TO POSITIVE 
ONE HALF DEGREE C OVER THE NORTHWESTERN HAWAIIAN ISLANDS, AND ABOUT POSITIVE 
ONE-HALF DEGREE TO POSITIVE ONE DEGREE C OVER THE SOUTHEASTERN ISLANDS. 
FOR JANUARY 2018 THROUGH THE END OF AUGUST 2018, RAINFALL TOTAL ACCUMULATIONS 
WERE:
- LIHUE AIRPORT 33.67 INCHES (157 PERCENT OF NORMAL)
- HONOLULU AIRPORT 9.59 INCHES (112 PERCENT OF NORMAL)
- KAHULUI AIRPORT 15.91 INCHES (149 PERCENT OF NORMAL)
- HILO AIRPORT 129.81 INCHES (162 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 OCTOBER 2018. THIS ELEVATES THE CHANCES OF 
ABOVE NORMAL MONTHLY MEAN AIR TEMPERATURES FOR HAWAII IN OCTOBER 2018. MOST 
DYNAMICAL TOOLS ALSO FAVOR ABOVE NORMAL PRECIPITATION FOR THE HAWAIIAN ISLANDS 
DURING OCTOBER 2018.
           TEMPERATURE           PRECIPITATION
          FCST   AVE    LIM  FCST  BLW  MEDIAN  ABV
HILO       A65   75.7   0.5  A45   7.8   8.6   12.1
KAHULUI    A65   78.2   0.4  A45   0.3   0.6   1.1
HONOLULU   A60   80.2   0.5  A45   0.5   1.3   1.9
LIHUE      A60   78.1   0.3  A45   2.5   3.3   4.2
SEASONAL FORECAST DISCUSSION VALID OND 2018 - OND 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. ENSO-NEUTRAL CONDITIONS CURRENTLY 
ARE PRESENT ACROSS THE EQUATORIAL PACIFIC OCEAN. EQUATORIAL SEA SURFACE 
TEMPERATURES (SSTS) ARE ABOVE AVERAGE IN PARTS OF THE CENTRAL AND WESTERN 
PACIFIC OCEAN. POSITIVE SUBSURFACE TEMPERATURE ANOMALIES HAVE EXPANDED IN THE 
CENTRAL AND EAST-CENTRAL PACIFIC OCEAN, WHILE A SMALL AREA OF NEGATIVE 
SUBSURFACE TEMPERATURE ANOMALIES PERSISTS IN THE EASTERN PACIFIC OCEAN. 
CONVECTION RETURNED TO NEAR AVERAGE OVER THE DATE LINE. ANOMALOUS LOW-LEVEL 
WESTERLY WINDS WERE EVIDENT OVER THE EAST-CENTRAL AND WESTERN TROPICAL PACIFIC 
OCEAN, WHILE UPPER-LEVEL WINDS WERE WESTERLY OVER THE EASTERN PACIFIC OCEAN. 
MOST MODELS INDICATE ABOUT 50-55% CHANCE OF EL NINO ONSET DURING THE NORTHERN 
HEMISPHERE FALL 2018, INCREASING TO 65-70% DURING WINTER 2018-19.
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED FOR HAWAII 
FROM OND 2018 TO MAM 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 FOR AMJ 2019 AND BEYOND.
MOST ENSO FORECAST MODELS PREDICT A WARM EVENT (EL NINO) BY THE NORTHERN 
HEMISPHERE AUTUMN OR WINTER 2018-19. IF CORRECT, HISTORICAL EL NINO COMPOSITES 
FAVOR INCREASED ODDS FOR DRY CONDITIONS FOR HAWAII IN WINTER AND SPRING , WHICH 
IS CONSISTENT WITH THE FORECASTS FROM THE DYNAMICAL TOOLS AND THE STATISTICAL 
TOOLS (CONSTRUCTED ANALOG AND ENSO-OCN). THERE IS CONSIDERABLE UNCERTAINTY 
ACROSS THE HAWAIIAN ISLANDS IN THE PRECIPITATION FORECAST AMONG AVAILABLE 
FORECAST TOOLS IN OND 2018, AND IN MJJ 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
OND 2018  A70  75.5   0.4    EC   28.3   34.5   42.0
NDJ 2018  A65  74.2   0.4   B60   26.4   36.6   43.0
DJF 2019  A60  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  A50  71.7   0.4   B65   24.6   34.1   45.5
MAM 2019  A40  72.0   0.5   B60   22.5   28.4   34.0
AMJ 2019   EC  72.9   0.5   B50   21.4   23.7   29.0
MJJ 2019   EC  74.0   0.4    EC   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
                      KAHULUI
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
OND 2018  A70  77.8   0.4    EC   4.2    5.3    8.1 
NDJ 2018  A65  75.9   0.4   B60   5.2    7.6    9.5 
DJF 2019  A60  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  A50  72.3   0.4   B65   3.2    4.1    6.4 
MAM 2019  A40  73.0   0.4   B60   2.5    3.5    4.6 
AMJ 2019   EC  74.3   0.5   B50   1.2    1.6    2.2 
MJJ 2019   EC  76.0   0.5    EC   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 
                      HONOLULU
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
OND 2018  A65  80.0   0.4    EC   4.4    6.4    8.5 
NDJ 2018  A60  77.7   0.5   B60   3.9    5.6    8.8 
DJF 2019  A55  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  A45  73.8   0.4   B65   1.9    3.2    4.7 
MAM 2019  A40  74.8   0.4   B60   1.8    2.6    3.0 
AMJ 2019   EC  76.3   0.4   B50   1.2    1.6    1.8 
MJJ 2019   EC  78.2   0.4    EC   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 
                      LIHUE
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
OND 2018  A60  77.8   0.3    EC   9.2    11.7   15.6
NDJ 2018  A55  75.7   0.3   B60   8.6    12.1   16.9
DJF 2019  A50  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  A45  72.1   0.5   B65   5.8    8.4    9.9 
MAM 2019  A40  72.8   0.5   B60   5.3    6.6    8.0 
AMJ 2019   EC  74.2   0.5   B50   4.7    5.5    6.0 
MJJ 2019   EC  76.0   0.5    EC   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
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 OCT 18, 2018.
$$