Hawaii 30 & 90 Day Narrative

408 
FXHW40 KWBC 201230
PMDHCO
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THU APR 20 2017
MONTHLY FORECAST DISCUSSION VALID MAY 2017
SEA SURFACE TEMPERATURE (SST) ANOMALIES SURROUNDING THE HAWAIIAN ISLANDS ARE 
CURRENTLY FROM POSITIVE ONE-HALF DEGREE TO TWO DEGREES. THIS IS WARMER THAN 
LAST MONTH.
FOR JANUARY 2017 THROUGH THE END OF MARCH 2017, RAINFALL TOTAL ACCUMULATIONS 
WERE:
- LIHUE AIRPORT 10.73 INCHES (93 PERCENT OF NORMAL)
- HONOLULU AIRPORT 10.08 INCHES (159 PERCENT OF NORMAL)
- KAHULUI AIRPORT 6.62 INCHES (92 PERCENT OF NORMAL)
- HILO AIRPORT 21.89 INCHES (68 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 NEAR TO ABOVE NORMAL 
SSTS AROUND THE HAWAIIAN ISLANDS. THIS ELEVATES THE CHANCES OF ABOVE-NORMAL 
MONTHLY MEAN AIR TEMPERATURES FOR THE HAWAIIAN ISLANDS IN MAY 2017. EQUAL 
CHANCES (EC) FOR ABOVE, NEAR, OR BELOW MEDIAN PRECIPITATION ARE ALSO INDICATED 
BY MOST DYNAMICAL MODEL FORECASTS FOR HAWAII DURING MAY 2017. 
           TEMPERATURE           PRECIPITATION
          FCST   AVE    LIM  FCST  BLW  MEDIAN  ABV
HILO       A55   74.0   0.5   EC   4.1   7.4   8.7
KAHULUI    A55   75.8   0.6   EC   0.2   0.5   0.8
HONOLULU   A55   78.0   0.6   EC   0.2   0.4   0.8
LIHUE      A55   75.8   0.6   EC   1.3   1.5   2.3
SEASONAL FORECAST DISCUSSION VALID MJJ 2017 - MJJ 2018
REFER TO THE PROGNOSTIC DISCUSSION ON LONG-LEAD SEASONAL OUTLOOKS FOR THE CONUS 
AND ALASKA, AND DISCUSSION OF THE FORECASTS OF EQUATORIAL PACIFIC SSTS, 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 NEAR AVERAGE IN THE CENTRAL PACIFIC OCEAN, WHILE ABOVE 
AVERAGE SSTS ARE PRESENT IN THE EASTERN PACIFIC OCEAN AND ALONG 20N IN THE 
PACIFIC BASIN. SUBSURFACE (DOWN TO 150 METERS) TEMPERATURES HAVE DECREASED IN 
THE EAST-CENTRAL PACIFIC DURING RECENT WEEKS, WHILE INCREASING NEAR THE DATE 
LINE AND THE COAST OF SOUTH AMERICA. CONVECTION REMAINED ENHANCED OVER MOST OF 
THE MARITIME CONTINENT WHILE BEING SUPPRESSED OVER THE CENTRAL TROPICAL PACIFIC 
AND MUCH OF THE OFF-EQUATORIAL NORTHERN PACIFIC THAT LIES EAST OF THE DATE 
LINE. ENSO-NEUTRAL CONDITIONS ARE FAVORED TO CONTINUE THROUGH AT LEAST THE 
NORTHERN HEMISPHERE SPRING 2017, WITH INCREASING CHANCES FOR EL NINO 
DEVELOPMENT BY LATE SUMMER AND FALL. 
ENHANCED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR HAWAII 
FROM MJJ 2017 TO ASO 2017 DUE TO PREDICTED ANOMALOUSLY ABOVE-NORMAL SEA SURFACE 
TEMPERATURES ACROSS THE REGION. THE CPC CONSTRUCTED ANALOG (CA) TOOL ALSO 
FAVORS NEAR TO ABOVE NORMAL TEMPERATURES, WITH ODDS INCREASING FROM SOUTH TO 
NORTH, AND ANOMALIES RATHER SMALL IN MAGNITUDE. EQUAL CHANCES (EC) FOR ABOVE, 
NEAR, OR BELOW NORMAL TEMPERATURES ARE ANTICIPATED AT ALL LOCATIONS FOR SON 
2017 AND BEYOND.
THE NMME FAVORS ABOVE MEDIAN PRECIPITATION FOR MUCH THE BOREAL SUMMER. THE CPC 
CONSTRUCTED ANALOG (CA) TOOL FAVORS BELOW MEDIAN RAINFALL FOR EACH OF THE NEXT 
12 SEASONS. THE OUTLOOK FAVORS THE DYNAMICAL GUIDANCE FOR THE FIRST LEAD, IN 
THE REGIONS WHERE THE SIGNAL IS STRONGEST. SOME DYNAMICAL MODELS PREDICT A WARM 
EVENT (EL NINO) BY THE NORTHERN HEMISPHERE AUTUMN, CONTINUING INTO WINTER 
2017-18. IF CORRECT, HISTORICAL EL NINO COMPOSITES FAVOR INCREASED ODDS FOR DRY 
CONDITIONS FOR HAWAII IN WINTER, WHICH IS CONSISTENT WITH THE FORECAST FROM THE 
CA TOOL. THE MIDDLE LEADS REFLECT THE UNCERTAINTY IMPLIED BY THE DISAGREEMENT 
IN THE DYNAMICAL MODELS AND THE CA TOOL. THE LATTER PORTIONS OF THE OUTLOOK 
REFLECT THE CONSISTENCY AMONG THE CA AND IMPLICATIONS OF DYNAMICAL MODEL 
OUTLOOKS FAVORING EL NINO. 
                      HILO
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
MJJ 2017  A60  74.0   0.4    EC   20.2   27.5   29.1
JJA 2017   A0  75.2   0.4    EC   19.4   27.2   31.4
JAS 2017  A45  76.1   0.4    EC   25.2   28.6   33.4
ASO 2017  A45  76.4   0.4    EC   26.1   28.8   33.3
SON 2017   EC  76.2   0.4    EC   24.3   30.2   40.8
OND 2017   EC  75.5   0.4    EC   28.3   34.5   42.0
NDJ 2017   EC  74.2   0.4   B40   26.4   36.6   43.0
DJF 2018   EC  72.8   0.4   B40   19.6   30.2   33.3
JFM 2018   EC  71.8   0.4   B40   22.0   32.0   44.5
FMA 2018   EC  71.7   0.4   B40   24.6   34.1   45.5
MAM 2018   EC  72.0   0.5    EC   22.5   28.4   34.0
AMJ 2018   EC  72.9   0.5    EC   21.4   23.7   29.0
MJJ 2018   EC  74.0   0.4    EC   20.2   27.5   29.1
\N                      KAHULUI
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
MJJ 2017  A60  76.0   0.5    EC   0.7    1.1    1.8 
JJA 2017  A55  77.7   0.4    EC   0.7    1.1    1.5 
JAS 2017  A45  79.0   0.4    EC   0.8    1.1    1.6 
ASO 2017  A45  79.4   0.4    EC   0.8    1.6    2.5 
SON 2017   EC  79.1   0.4    EC   2.1    3.3    4.8 
OND 2017   EC  77.8   0.4    EC   4.2    5.3    8.1 
NDJ 2017   EC  75.9   0.4   B40   5.2    7.6    9.5 
DJF 2018   EC  73.8   0.4   B40   4.6    6.9    8.7 
JFM 2018   EC  72.5   0.4   B40   4.2    6.2    8.2 
FMA 2018   EC  72.3   0.4   B40   3.2    4.1    6.4 
MAM 2018   EC  73.0   0.4    EC   2.5    3.5    4.6 
AMJ 2018   EC  74.3   0.5    EC   1.2    1.6    2.2 
MJJ 2018   EC  76.0   0.5    EC   0.7    1.1    1.8 
\N                      HONOLULU
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
MJJ 2017  A60  78.2   0.4   A40   0.8    1.4    1.6 
JJA 2017  A55  79.9   0.4    EC   0.7    0.8    1.3 
JAS 2017  A50  81.3   0.4    EC   1.0    1.4    1.7 
ASO 2017  A45  81.7   0.4    EC   1.6    2.4    3.1 
SON 2017   EC  81.4   0.4    EC   2.5    4.0    5.6 
OND 2017   EC  80.0   0.4    EC   4.4    6.4    8.5 
NDJ 2017   EC  77.7   0.5   B40   3.9    5.6    8.8 
DJF 2018   EC  75.3   0.5   B40   3.7    5.6    8.6 
JFM 2018   EC  73.9   0.4   B40   2.1    4.6    7.8 
FMA 2018   EC  73.8   0.4   B40   1.9    3.2    4.7 
MAM 2018   EC  74.8   0.4    EC   1.8    2.6    3.0 
AMJ 2018   EC  76.3   0.4    EC   1.2    1.6    1.8 
MJJ 2018   EC  78.2   0.4    EC   0.8    1.4    1.6 
\N                      LIHUE
          TEMPERATURE           PRECIPITATION
         FCST   AVE   LIM  FCST   BLW  MEDIAN   ABV
MJJ 2017  A60  76.0   0.5   A40   4.9    5.4    5.9 
JJA 2017  A60  77.7   0.4    EC   4.4    5.3    6.9 
JAS 2017  A50  79.0   0.3    EC   5.3    6.1    7.8 
ASO 2017  A50  79.4   0.3    EC   6.2    7.9    8.4 
SON 2017   EC  79.1   0.3    EC   9.2    10.0   11.2
OND 2017   EC  77.8   0.3    EC   9.2    11.7   15.6
NDJ 2017   EC  75.7   0.3    B4   8.6    12.1   16.9
DJF 2018   EC  73.6   0.4   B40   7.5    8.4    14.0
JFM 2018   EC  72.2   0.4   B40   6.5    8.8    13.8
FMA 2018   EC  72.1   0.5   B40   5.8    8.4    9.9 
MAM 2018   EC  72.8   0.5    EC   5.3    6.6    8.0 
AMJ 2018   EC  74.2   0.5    EC   4.7    5.5    6.0 
MJJ 2018   EC  76.0   0.5    EC   4.9    5.4    5.9 
\NFORECASTER: MATTHEW ROSENCRANS
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 18, 2017.
$$