Climate Prediction Center - Seasonal Outlook

Prognostic Discussion for Long-Lead Hawaiian Outlooks 
NWS Climate Prediction Center College Park MD 
830AM EDT Thu Oct 15 2020 
 
MONTHLY FORECAST DISCUSSION VALID NOVEMBER 2020 
 
Positive sea surface temperature (SST) anomalies from less than positive one-half degree to near one degree Celsius were observed in the vicinity of the Hawaiian Islands during the last several weeks. 
 
For January through September 2020, rainfall total accumulations were: 
 
- Lihue Airport 31.64 inches (134 percent of normal) 
- Honolulu Airport 9.95 inches (104 percent of normal) 
- Kahului Airport 10.71 Inches (97 percent of normal) 
- Hilo Airport 83.43 Inches (93 percent of normal) 
 
The NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) predict above average SSTs around the Hawaiian Islands through November 2020. This elevates the chances of above normal monthly mean air temperatures for Hawaii in November 2020. Most dynamical models  indicate an increased chance of above normal precipitation over the Hawaiian Islands during November 2020. 
 
 
 





  TEMPERATURE   PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 Hilo  A60  74.4  0.4  A50  8.7  11.4  17.1
 Kahului  A65  76.0  0.6  A50  1.2  1.8  2.6
 Honolulu  A70  77.8  0.6  A50  0.9  1.4  2.1
 Lihue  A70  75.8  0.5  A50  2.6  3.5  5.5
 
 
SEASONAL FORECAST DISCUSSION VALID NDJ 2020 - NDJ 2021 
 
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, including details on the current state of the atmosphere and ocean. The observed tropical Pacific atmosphere and ocean conditions currently are consistent with La Nina, with below average sea surface temperatures (SSTs) across the east-central and the eastern equatorial Pacific Ocean and above average SSTs in the far western equatorial Pacific. Negative subsurface temperature anomalies have persisted in the eastern Pacific Ocean and positive subsurface temperature anomalies have continued in the western Pacific Ocean and at depth near the Date Line. Tropical convection is suppressed from the west-central Pacific to the Date Line, and a slight enhancement of convection emerged over Indonesia. Low-level easterly wind anomalies were evident from the western to the east-central Pacific Ocean, while upper-level westerly wind anomalies were apparent over the east-central Pacific. The tropical atmosphere and ocean state is consistent overall with La Nina. La Nina conditions are likely to continue through Northern Hemisphere winter 2020-21, with a probability of about 85 percent. and into spring 2021 (about 60 percent chance during February-April) 
 
Enhanced probabilities for above normal temperatures are indicated across the Hawaiian Islands in the outlook from NDJ 2020 to AMJ 2021, due to predicted persistence of above normal sea surface temperatures in the NMME dynamical model forecasts through MAM 2021, and supported by statistical models including the Constructed Analog (CA) and Optimum Climate Normals (OCN) through AMJ 2021. The signal weakens at longer leads, therefore Equal Chances (EC) for above, near or below normal temperatures are indicated for Hawaii in MJJ 2021 and thereafter. 
 
Most dynamical models  and a statistical forecast combining the impacts of the ENSO state and decadal trends  predict likely above normal precipitation from NDJ 2020 through MAM 2021, consistent with negative SST anomalies across the eastern equatorial Pacific Ocean and continuing La Nina conditions through the winter. Due to considerable uncertainty in the precipitation forecasts among available dynamical and statistical tools over the Hawaiian Islands in AMJ 2021 and longer leads, equal chances (EC) for above, near or below normal precipitation are indicated in these seasons. 
 
 
















 Hilo
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 NDJ 2020  A60  74.2  0.4  A45  26.4  36.6  43.0
 DJF 2021  A55  72.8  0.4  A50  19.6  30.2  33.3
 JFM 2021  A55  71.8  0.4  A60  22.0  32.0  44.5
 FMA 2021  A50  71.7  0.4  A50  24.6  34.1  45.5
 MAM 2021  A45  72.0  0.5  A40  22.5  28.4  34.0
 AMJ 2021  A40  72.9  0.5   EC  21.4  23.7  29.0
 MJJ 2021   EC  74.0  0.4   EC  20.2  27.5  29.1
 JJA 2021   EC  75.2  0.4   EC  19.4  27.2  31.4
 JAS 2021   EC  76.1  0.4   EC  25.2  28.6  33.4
 ASO 2021   EC  76.4  0.4   EC  26.1  28.8  33.3
 SON 2021   EC  76.2  0.4   EC  24.3  30.2  40.8
 OND 2021   EC  75.5  0.4   EC  28.3  34.5  42.0
 NDJ 2021   EC  74.2  0.4   EC  26.4  36.6  43.0
 

















 Kahului
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 NDJ 2020  A65  75.9  0.4  A45  5.2  7.6  9.5 
 DJF 2021  A60  73.8  0.4  A50  4.6  6.9  8.7 
 JFM 2021  A55  72.5  0.4  A60  4.2  6.2  8.2 
 FMA 2021  A50  72.3  0.4  A50  3.2  4.1  6.4 
 MAM 2021  A45  73.0  0.4  A40  2.5  3.5  4.6 
 AMJ 2021  A40  74.3  0.5   EC  1.2  1.6  2.2 
 MJJ 2021   EC  76.0  0.5   EC  0.7  1.1  1.8 
 JJA 2021   EC  77.7  0.4   EC  0.7  1.1  1.5 
 JAS 2021   EC  79.0  0.4   EC  0.8  1.1  1.6 
 ASO 2021   EC  79.4  0.4   EC  0.8  1.6  2.5 
 SON 2021   EC  79.1  0.4   EC  2.1  3.3  4.8 
 OND 2021   EC  77.8  0.4   EC  4.2  5.3  8.1 
 NDJ 2021   EC  75.9  0.4   EC  5.2  7.6  9.5 
 

















 Honolulu
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 NDJ 2020  A65  77.7  0.5  A45  3.9  5.6  8.8 
 DJF 2021  A60  75.3  0.5  A50  3.7  5.6  8.6 
 JFM 2021  A55  73.9  0.4  A60  2.1  4.6  7.8 
 FMA 2021  A50  73.8  0.4  A50  1.9  3.2  4.7 
 MAM 2021  A45  74.8  0.4  A40  1.8  2.6  3.0 
 AMJ 2021  A40  76.3  0.4   EC  1.2  1.6  1.8 
 MJJ 2021   EC  78.2  0.4   EC  0.8  1.4  1.6 
 JJA 2021   EC  79.9  0.4   EC  0.7  0.8  1.3 
 JAS 2021   EC  81.3  0.4   EC  1.0  1.4  1.7 
 ASO 2021   EC  81.7  0.4   EC  1.6  2.4  3.1 
 SON 2021   EC  81.4  0.4   EC  2.5  4.0  5.6 
 OND 2021   EC  80.0  0.4   EC  4.4  6.4  8.5 
 NDJ 2021   EC  77.7  0.5   EC  3.9  5.6  8.8 
 

















 Lihue
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 NDJ 2020  A70  75.7  0.3  A45  8.6  12.1  16.9
 DJF 2021  A65  73.6  0.4  A50  7.5  8.4  14.0
 JFM 2021  A55  72.2  0.4  A60  6.5  8.8  13.8
 FMA 2021  A50  72.1  0.5  A50  5.8  8.4  9.9 
 MAM 2021  A45  72.8  0.5  A40  5.3  6.6  8.0 
 AMJ 2021  A40  74.2  0.5   EC  4.7  5.5  6.0 
 MJJ 2021   EC  76.0  0.5   EC  4.9  5.4  5.9 
 JJA 2021   EC  77.7  0.4   EC  4.4  5.3  6.9 
 JAS 2021   EC  79.0  0.3   EC  5.3  6.1  7.8 
 ASO 2021   EC  79.4  0.3   EC  6.2  7.9  8.4 
 SON 2021   EC  79.1  0.3   EC  9.2  10.0  11.2
 OND 2021   EC  77.8  0.3   EC  9.2  11.7  15.6
 NDJ 2021   EC  75.7  0.3   EC  8.6  12.1  16.9
 

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 Nov 19, 2020.
 
 
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