Climate Prediction Center - Seasonal Outlook

Prognostic Discussion for Long-Lead Hawaiian Outlooks 
NWS Climate Prediction Center College Park MD 
830AM EDT Thu Jun 17 2021 
 
MONTHLY FORECAST DISCUSSION VALID JULY 2021 
 
Sea surface temperature (SST) anomalies from negative one-half degree Celsius to positive one-half degree Celsius were observed over the Hawaiian islands during the previous week. 
 
For January through May 2021, rainfall total accumulations were: 
 
- Lihue Airport 19.68 inches (124 percent of normal) 
- Honolulu Airport 9.45 inches (125 percent of normal) 
- Kahului Airport 14.80 Inches (156 percent of normal) 
- Hilo Airport 69.56 Inches (134 percent of normal) 
 
The NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) predict above normal monthly mean air temperatures over the northwestern Hawaiian Islands (Honolulu and Lihue) and equal chances (EC) for above, near, or below normal temperatures for the southeastern Hawaiian islands (Hilo and Kahului) in July 2021. Below normal precipitation is predicted by most dynamical and statistical models for the Hawaiian Islands during July 2021. 
 
 
 





  TEMPERATURE   PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 Hilo   EC  76.2  0.4  B45  7.1  9.5  11.4
 Kahului   EC  79.2  0.4  B45  0.2  0.4  0.5
 Honolulu  A45  81.4  0.5  B40  0.2  0.4  0.5
 Lihue  A55  79.2  0.4  B40  1.5  1.7  1.9
 
 
SEASONAL FORECAST DISCUSSION VALID JAS 2021 - JAS 2022 
 
Refer to the prognostic discussion of the long-lead seasonal outlooks for the CONUS and Alaska for a description of the ENSO outlook and other climate conditions relevant to the seasonal outlook. ENSO-neutral conditions are present across the Pacific Ocean, with near-to-below average sea surface temperatures (SSTs) over the east-central and eastern equatorial Pacific Ocean. Subsurface temperature anomalies remained positive in the western Pacific and closer to the surface in the eastern Pacific Ocean, but decreased slightly in magnitude, while negative subsurface temperature anomalies remain in a small region of the central Pacific Ocean. Low-level easterly wind anomalies were observed over the central and eastern equatorial Pacific Ocean, while upper-level westerly wind anomalies were observed over the central and eastern equatorial Pacific Ocean. ENSO-neutral persisted and is likely to continue through the Northern Hemisphere summer with a 66 percent probability for July-September 2021. 
 
Enhanced probabilities for below normal temperatures are indicated over Hilo from JAS 2021 to SON 2021, while equal chances (EC) for above, near, or below normal temperatures are forecast over Kahului and Honolulu, during this period. Above normal temperatures are forecast for Lihue beginning in ASO 2021 and continuing for several seasons. Above normal temperatures are likely for northwestern Hawaiian Islands, including Lihue, Honolulu and Kahului, from OND 2021 to DJF 2022. The predicted pattern of advancing above normal temperatures across the northwestern Hawaiian Islands and near to below normal temperatures for southeastern islands is supported by most dynamical and statistical forecast tools, including dynamical models  of the NMME and the constructed analog statistical model. 
 
Enhanced probabilities for below normal precipitation are likely over the Hawaiian Islands from summer (JAS) 2021 to OND 2021, consistent with most dynamical model forecasts. Due to considerable uncertainty in the precipitation forecasts from dynamical and statistical models over the Hawaiian Islands in NDJ 2021 and longer leads, equal chances (EC) for above, near or below normal precipitation are indicated. Drier conditions across the Hawaiian Islands in early leads are consistent with near to below normal SSTs in the central and eastern equatorial Pacific, current ENSO-neutral conditions and increasing chances of La Nina conditions by winter. 
 
 
















 Hilo
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JAS 2021  B40  76.1  0.4  B50  25.2  28.6  33.4
 ASO 2021  B45  76.4  0.4  B60  26.1  28.8  33.3
 SON 2021  B40  76.2  0.4  B50  24.3  30.2  40.8
 OND 2021   EC  75.5  0.4  B40  28.3  34.5  42.0
 NDJ 2021   EC  74.2  0.4   EC  26.4  36.6  43.0
 DJF 2022   EC  72.8  0.4   EC  19.6  30.2  33.3
 JFM 2022   EC  71.8  0.4   EC  22.0  32.0  44.5
 FMA 2022   EC  71.7  0.4   EC  24.6  34.1  45.5
 MAM 2022   EC  72.0  0.5   EC  22.5  28.4  34.0
 AMJ 2022   EC  72.9  0.5   EC  21.4  23.7  29.0
 MJJ 2022   EC  74.0  0.4   EC  20.2  27.5  29.1
 JJA 2022   EC  75.2  0.4   EC  19.4  27.2  31.4
 JAS 2022   EC  76.1  0.4   EC  25.2  28.6  33.4
 

















 Kahului
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JAS 2021   EC  79.0  0.4  B50  0.8  1.1  1.6 
 ASO 2021   EC  79.4  0.4  B60  0.8  1.6  2.5 
 SON 2021   EC  79.1  0.4  B50  2.1  3.3  4.8 
 OND 2021  A40  77.8  0.4  B40  4.2  5.3  8.1 
 NDJ 2021  A45  75.9  0.4   EC  5.2  7.6  9.5 
 DJF 2022  A40  73.8  0.4   EC  4.6  6.9  8.7 
 JFM 2022   EC  72.5  0.4   EC  4.2  6.2  8.2 
 FMA 2022   EC  72.3  0.4   EC  3.2  4.1  6.4 
 MAM 2022   EC  73.0  0.4   EC  2.5  3.5  4.6 
 AMJ 2022   EC  74.3  0.5   EC  1.2  1.6  2.2 
 MJJ 2022   EC  76.0  0.5   EC  0.7  1.1  1.8 
 JJA 2022   EC  77.7  0.4   EC  0.7  1.1  1.5 
 JAS 2022   EC  79.0  0.4   EC  0.8  1.1  1.6 
 

















 Honolulu
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JAS 2021   EC  81.3  0.4  B50  1.0  1.4  1.7 
 ASO 2021   EC  81.7  0.4  B60  1.6  2.4  3.1 
 SON 2021   EC  81.4  0.4  B50  2.5  4.0  5.6 
 OND 2021  A45  80.0  0.4  B40  4.4  6.4  8.5 
 NDJ 2021  A50  77.7  0.5   EC  3.9  5.6  8.8 
 DJF 2022  A45  75.3  0.5   EC  3.7  5.6  8.6 
 JFM 2022   EC  73.9  0.4   EC  2.1  4.6  7.8 
 FMA 2022   EC  73.8  0.4   EC  1.9  3.2  4.7 
 MAM 2022   EC  74.8  0.4   EC  1.8  2.6  3.0 
 AMJ 2022   EC  76.3  0.4   EC  1.2  1.6  1.8 
 MJJ 2022   EC  78.2  0.4   EC  0.8  1.4  1.6 
 JJA 2022   EC  79.9  0.4   EC  0.7  0.8  1.3 
 JAS 2022   EC  81.3  0.4   EC  1.0  1.4  1.7 
 

















 Lihue
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JAS 2021   EC  79.0  0.3  B50  5.3  6.1  7.8 
 ASO 2021  A40  79.4  0.3  B60  6.2  7.9  8.4 
 SON 2021  A45  79.1  0.3  B50  9.2  10.0  11.2
 OND 2021  A50  77.8  0.3  B40  9.2  11.7  15.6
 NDJ 2021  A55  75.7  0.3   EC  8.6  12.1  16.9
 DJF 2022  A45  73.6  0.4   EC  7.5  8.4  14.0
 JFM 2022   EC  72.2  0.4   EC  6.5  8.8  13.8
 FMA 2022   EC  72.1  0.5   EC  5.8  8.4  9.9 
 MAM 2022   EC  72.8  0.5   EC  5.3  6.6  8.0 
 AMJ 2022   EC  74.2  0.5   EC  4.7  5.5  6.0 
 MJJ 2022   EC  76.0  0.5   EC  4.9  5.4  5.9 
 JJA 2022   EC  77.7  0.4   EC  4.4  5.3  6.9 
 JAS 2022   EC  79.0  0.3   EC  5.3  6.1  7.8 
 

FORECASTER: Dan Collins 
 
Anomalies are based on the 1991-2020 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 Jul 15, 2021.
 
 
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