Climate Prediction Center - Seasonal Outlook

Prognostic Discussion for Long-Lead Hawaiian Outlooks 
NWS Climate Prediction Center College Park MD 
830AM EDT Thu Apr 18 2019 
 
MONTHLY FORECAST DISCUSSION VALID MAY 2019 
 
Sea surface temperature (SST) anomalies are around zero degree C to positive one degree C over Hawaiian Islands during the last week. Recent SST values are both warmer than March and warmer than average for this time of year. 
 
Through March 2019, rainfall total accumulations were: 
 
- Lihue Airport 4.64 inches (40 percent of normal) 
- Honolulu Airport 2.58 inches (41 percent of normal) 
- Kahului Airport 8.3 Inches (115 percent of normal) 
- Hilo Airport 17.17 Inches (53 percent of normal) 
 
NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) predict near to above normal SSTs around the Hawaiian Islands for May 2019, with the largest SST anomalies near the easternmost islands. Near normal SSTs are indicated in some models near the Northwestern Hawaiian Islands, west of Kauai. Most dynamical models  predict near or below normal precipitation over the Hawaiian Islands during May 2019, which is also consistent with the low-frequency state over the tropical Pacific. The signals  for below normal precipitation increase to the north and west. 
 
 
 





  TEMPERATURE   PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 Hilo  A50  74.0  0.5   EC  4.1  7.4  8.7
 Kahului  A45  75.8  0.6   EC  0.2  0.5  0.8
 Honolulu  A45  78.0  0.6   EC  0.2  0.4  0.8
 Lihue  A40  75.8  0.6  B40  1.3  1.5  2.3
 
 
SEASONAL FORECAST DISCUSSION VALID MJJ 2019 - MJJ 2020 
 
Refer to the prognostic discussion on long-lead seasonal outlooks for the CONUS and Alaska for a discussion of the ENSO outlook and other climate conditions relevant to the seasonal outlook, including details on the current state of the atmosphere and ocean. Weak EL Nino conditions currently are present across the equatorial Pacific Ocean. Equatorial sea surface temperatures (SSTs) are above average across most of the equatorial Pacific Ocean. Positive subsurface temperature anomalies have persisted across most of the equatorial Pacific Ocean, while negative subsurface temperature anomalies have appeared in pockets about 150 meters below the surface. The pockets of colder than normal ocean temperatures are located near 150E, 160W and 120W. Convection was enhanced near the Date Line, while low-level wind anomalies were westerly across the western Pacific Ocean, and upper-level winds were anomalous easterly over the western and westerly eastern Pacific with enhanced divergence implied near the highest OLR anomalies, indicating an atmospheric response to the convection. A weak El Nino is likely to continue through the Northern Hemisphere summer 2019 (65% chance) and possibly fall (50-55% chance). 
 
Enhanced probabilities for above normal temperatures are indicated for Hawaii from MMJ to SON 2019 due to predicted above normal sea surface temperatures across the region according to statistical and dynamical models . The probabilities for the early leads are slightly higher than last month with slightly higher odds for El Nino to continue through the summer. The signal is strongest to the south and east, therefore Equal chances (EC) for above, near, or below normal temperatures are indicated for Lihue beginning in SON 2019, and for all of the Hawaiian Islands for OND 2019 and beyond. 
 
With the predicted continuation of an El Nino, the precipitation forecast for Hawaii follows historical El Nino impacts that indicate strong correlations between El Nino and increased probabilities of below normal precipitation in winter and spring. The summer correlations are much weaker, with some potential impacts from enhanced tropical cyclone activity in the central Pacific during El Nino years, though the impacts to landmasses are highly uncertain at this time. The precipitation outlook is consistent with NMME dynamical model forecasts and statistical tools, including Constructed Analog, Canonical Correlation Analysis, and an ENSO-OCN tool (that combines the impacts of El Nino and decadal climate variability), indicating below normal precipitation for Hilo and Kahului from MJJ and JJA 2019 and for Honolulu and Lihue from MJJ to JAS 2019. Most tools indicate a slight tilt toward above average precipitation in ASO 2019, so that's reflected in the outlooks for Hilo and Kahului. There is considerable uncertainty across the Hawaiian Islands in the precipitation forecast among available forecast tools in SON 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
 MJJ 2019  A45  74.0  0.4  B50  20.2  27.5  29.1
 JJA 2019  A50  75.2  0.4  B40  19.4  27.2  31.4
 JAS 2019  A55  76.1  0.4   EC  25.2  28.6  33.4
 ASO 2019  A45  76.4  0.4  A40  26.1  28.8  33.3
 SON 2019  A40  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
 JFM 2020   EC  71.8  0.4   EC  22.0  32.0  44.5
 FMA 2020   EC  71.7  0.4   EC  24.6  34.1  45.5
 MAM 2020   EC  72.0  0.5   EC  22.5  28.4  34.0
 AMJ 2020   EC  72.9  0.5   EC  21.4  23.7  29.0
 MJJ 2020   EC  74.0  0.4   EC  20.2  27.5  29.1
 

















 Kahului
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 MJJ 2019  A45  76.0  0.5  B50  0.7  1.1  1.8 
 JJA 2019  A50  77.7  0.4  B40  0.7  1.1  1.5 
 JAS 2019  A55  79.0  0.4   EC  0.8  1.1  1.6 
 ASO 2019  A45  79.4  0.4  A40  0.8  1.6  2.5 
 SON 2019  A40  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 
 JFM 2020   EC  72.5  0.4   EC  4.2  6.2  8.2 
 FMA 2020   EC  72.3  0.4   EC  3.2  4.1  6.4 
 MAM 2020   EC  73.0  0.4   EC  2.5  3.5  4.6 
 AMJ 2020   EC  74.3  0.5   EC  1.2  1.6  2.2 
 MJJ 2020   EC  76.0  0.5   EC  0.7  1.1  1.8 
 

















 Honolulu
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 MJJ 2019  A45  78.2  0.4  B50  0.8  1.4  1.6 
 JJA 2019  A50  79.9  0.4  B45  0.7  0.8  1.3 
 JAS 2019  A55  81.3  0.4  B40  1.0  1.4  1.7 
 ASO 2019  A45  81.7  0.4   EC  1.6  2.4  3.1 
 SON 2019  A40  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 
 JFM 2020   EC  73.9  0.4   EC  2.1  4.6  7.8 
 FMA 2020   EC  73.8  0.4   EC  1.9  3.2  4.7 
 MAM 2020   EC  74.8  0.4   EC  1.8  2.6  3.0 
 AMJ 2020   EC  76.3  0.4   EC  1.2  1.6  1.8 
 MJJ 2020   EC  78.2  0.4   EC  0.8  1.4  1.6 
 

















 Lihue
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 MJJ 2019  A40  76.0  0.5  B50  4.9  5.4  5.9 
 JJA 2019  A45  77.7  0.4  B45  4.4  5.3  6.9 
 JAS 2019  A50  79.0  0.3  B40  5.3  6.1  7.8 
 ASO 2019  A40  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
 JFM 2020   EC  72.2  0.4   EC  6.5  8.8  13.8
 FMA 2020   EC  72.1  0.5   EC  5.8  8.4  9.9 
 MAM 2020   EC  72.8  0.5   EC  5.3  6.6  8.0 
 AMJ 2020   EC  74.2  0.5   EC  4.7  5.5  6.0 
 MJJ 2020   EC  76.0  0.5   EC  4.9  5.4  5.9 
 

FORECASTER: Matthew Rosencrans 
 
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 May 16, 2019.
 
 
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