Climate Prediction Center - Seasonal Outlook

Prognostic Discussion for Long-Lead Hawaiian Outlooks 
NWS Climate Prediction Center College Park MD 
830AM EDT Thu Sep 16 2021 
 
MONTHLY FORECAST DISCUSSION VALID OCTOBER 2021 
 
Sea surface temperature (SST) anomalies from negative one-half degree Celsius to zero degrees Celsius were observed in the region of the Hawaiian Islands during the previous week. 
 
For January through August 2021, rainfall total accumulations were: 
 
- Lihue Airport 23.85 inches (108 percent of normal) 
- Honolulu Airport 9.88 inches (103 percent of normal) 
- Kahului Airport 15.46 Inches (150 percent of normal) 
- Hilo Airport 88.68 Inches (118 percent of normal) 
 
The NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) favor below normal temperatures for Hilo, and equal chances (EC) for above, near, or below normal temperatures for Lihue, Honolulu and Kahului in October 2021. Below normal precipitation is favored by most dynamical and statistical models for the Hawaiian Islands during October 2021. 
 
 
 





  TEMPERATURE   PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 Hilo  B40  75.7  0.5  B60  7.8  8.6  12.1
 Kahului   EC  78.2  0.4  B60  0.3  0.6  1.1
 Honolulu   EC  80.2  0.5  B60  0.5  1.3  1.9
 Lihue   EC  78.1  0.3  B60  2.5  3.3  4.2
 
 
SEASONAL FORECAST DISCUSSION VALID OND 2021 - OND 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) across most of the Pacific Ocean. Positive subsurface temperature anomalies remain at depth in the western Pacific Ocean and weakened near the Date Line, while negative subsurface anomalies have persisted across most of the east-central and eastern Pacific Ocean. Low-level easterly wind anomalies were observed over the western equatorial Pacific Ocean, while upper-level westerly wind anomalies were observed over the western and east-central equatorial Pacific Ocean. A transition from ENSO-neutral to La Nina is likely during the next couple of months, with winter a 70-80 % chance of La Nina during the Northern Hemisphere winter 2021-22. 
 
Equal chances (EC) for above, near, or below normal temperatures are forecast over Hilo from OND to NDJ 2021, while enhanced probabilities for above normal temperatures are indicated over Hilo from DJF 2022 to MAM 2022. Equal chances (EC) for above, near, or below normal temperatures are also forecast over Kahului, Honolulu and Lihue in OND 2021, while above normal temperatures are favored for Kahului, Honolulu, and Lihue from NDJ 2021 to Spring (MAM 2022), consistent with trend and most dynamical and statistical forecast tools, including dynamical models  of the NMME. The signal weakens at longer leads, therefore Equal Chances (EC) for above, near or below normal temperatures are indicated for Hawaii beginning in AMJ 2022 and thereafter. 
 
Enhanced probabilities for above normal precipitation are forecast over the Hawaiian Islands from NDJ 2021 to MAM 2022, consistent with most dynamical model forecasts and trend. Wet conditions across the Hawaiian Islands at these lead times are also consistent with increasing chances of La Nina conditions by late fall and winter. Due to considerable uncertainty in the precipitation forecasts from dynamical and statistical models over the Hawaiian Islands in OND 2021 and in AMJ 2022 and longer leads, equal chances (EC) for above, near or below normal precipitation are indicated. 
 
 
















 Hilo
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 OND 2021   EC  75.5  0.4   EC  28.3  34.5  42.0
 NDJ 2021   EC  74.2  0.4  A40  26.4  36.6  43.0
 DJF 2022  A40  72.8  0.4  A50  19.6  30.2  33.3
 JFM 2022  A40  71.8  0.4  A60  22.0  32.0  44.5
 FMA 2022  A45  71.7  0.4  A50  24.6  34.1  45.5
 MAM 2022  A40  72.0  0.5  A40  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
 ASO 2022   EC  76.4  0.4   EC  26.1  28.8  33.3
 SON 2022   EC  76.2  0.4   EC  24.3  30.2  40.8
 OND 2022   EC  75.5  0.4   EC  28.3  34.5  42.0
 

















 Kahului
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 OND 2021   EC  77.8  0.4   EC  4.2  5.3  8.1 
 NDJ 2021  A40  75.9  0.4  A40  5.2  7.6  9.5 
 DJF 2022  A40  73.8  0.4  A50  4.6  6.9  8.7 
 JFM 2022  A50  72.5  0.4  A60  4.2  6.2  8.2 
 FMA 2022  A45  72.3  0.4  A50  3.2  4.1  6.4 
 MAM 2022  A40  73.0  0.4  A40  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 
 ASO 2022   EC  79.4  0.4   EC  0.8  1.6  2.5 
 SON 2022   EC  79.1  0.4   EC  2.1  3.3  4.8 
 OND 2022   EC  77.8  0.4   EC  4.2  5.3  8.1 
 

















 Honolulu
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 OND 2021   EC  80.0  0.4   EC  4.4  6.4  8.5 
 NDJ 2021  A40  77.7  0.5  A40  3.9  5.6  8.8 
 DJF 2022  A50  75.3  0.5  A50  3.7  5.6  8.6 
 JFM 2022  A55  73.9  0.4  A60  2.1  4.6  7.8 
 FMA 2022  A45  73.8  0.4  A50  1.9  3.2  4.7 
 MAM 2022  A40  74.8  0.4  A40  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 
 ASO 2022   EC  81.7  0.4   EC  1.6  2.4  3.1 
 SON 2022   EC  81.4  0.4   EC  2.5  4.0  5.6 
 OND 2022   EC  80.0  0.4   EC  4.4  6.4  8.5 
 

















 Lihue
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 OND 2021   EC  77.8  0.3   EC  9.2  11.7  15.6
 NDJ 2021  A40  75.7  0.3  A40  8.6  12.1  16.9
 DJF 2022  A50  73.6  0.4  A50  7.5  8.4  14.0
 JFM 2022  A55  72.2  0.4  A60  6.5  8.8  13.8
 FMA 2022  A50  72.1  0.5  A50  5.8  8.4  9.9 
 MAM 2022  A40  72.8  0.5  A40  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 
 ASO 2022   EC  79.4  0.3   EC  6.2  7.9  8.4 
 SON 2022   EC  79.1  0.3   EC  9.2  10.0  11.2
 OND 2022   EC  77.8  0.3   EC  9.2  11.7  15.6
 

FORECASTER: Luke He 
 
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 Oct 21, 2021.
 
 
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