Climate Prediction Center - Seasonal Outlook

Prognostic Discussion for Long-Lead Hawaiian Outlooks 
NWS Climate Prediction Center College Park MD 
830AM EDT Thu May 21 2020 
 
MONTHLY FORECAST DISCUSSION VALID JUNE 2020 
 
Positive sea surface temperature (SST) anomalies from about positive one half to one degree Celsius are surrounding the Hawaiian Islands during the previous week. 
 
For January through April 2020, rainfall total accumulations were: 
 
- Lihue Airport 21.57 inches (157 percent of normal) 
- Honolulu Airport 8.33 inches (120 percent of normal) 
- Kahului Airport 9.38 Inches (107 percent of normal) 
- Hilo Airport 57.21 Inches (131 percent of normal) 
 
The NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) predict above normal SSTs around the Hawaiian Islands for June 2020. This elevates the chances of above normal monthly mean air temperatures for Hawaii in June 2020. Most dynamical models  from the NMME indicate Equal Chances (EC) for above, near or below normal precipitation over the Hawaiian Islands during June 2020. 
 
 
 





  TEMPERATURE   PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 Hilo  A60  75.4  0.4   EC  5.3  6.3  8.7
 Kahului  A65  78.0  0.5   EC  0.1  0.1  0.2
 Honolulu  A70  80.3  0.4   EC  0.1  0.2  0.3
 Lihue  A70  78.1  0.4   EC  1.1  1.3  1.6
 
 
SEASONAL FORECAST DISCUSSION VALID JJA 2020 - JJA 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. ENSO-neutral conditions currently are present across the equatorial Pacific Ocean. Equatorial sea surface temperatures (SSTs) are above average across most of the western Pacific Ocean and near average across most of the eastern Pacific Ocean. Negative subsurface temperature anomalies strengthened and have shifted from the western to eastern Pacific Ocean, while positive subsurface temperatures anomalies have mostly dissipated. Tropical convection is suppressed over the Date Line and around Indonesia. Low-level wind anomalies were easterly in the east-central Pacific, and upper-level wind anomalies were westerly over the central and eastern portions of the basin. The tropical atmospheric circulation is generally consistent with ENSO-neutral. ENSO-neutral is likely to continue through Northern Hemisphere summer 2020 with probabilities about 65 percent and through autumn 2020 with probabilities about 45 to 50 percent. 
 
Enhanced probabilities for above normal temperatures are indicated across the Hawaiian Islands in the outlook from JJA 2020 to OND 2020, due to predicted persistence of above normal sea surface temperatures in the NMME dynamical model forecasts, and supported by statistical models including the Constructed Analog (CA) and Optimal Climate Normals (OCN) through NDJ 2020. The signal weakens at longer leads, therefore Equal Chances (EC) for above, near or below normal temperatures are indicated for Hawaii in DJF 2021 and thereafter. 
 
Now Hawaii is into a dry season. The NMME and the consolidation of dynamical and statistical tools also favor below normal precipitation from JJA 2020 through SON 2020 over all Hawaiian Islands, though some statistical tools such as the CA indicate above normal is more likely for Hawaii during this period. There is considerable uncertainty in the precipitation forecasts among available dynamical and statistical tools over the Hawaiian Islands in OND 2020 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
 JJA 2020  A65  75.2  0.4  B60  19.4  27.2  31.4
 JAS 2020  A60  76.1  0.4  B50  25.2  28.6  33.4
 ASO 2020  A55  76.4  0.4  B45  26.1  28.8  33.3
 SON 2020  A50  76.2  0.4  B40  24.3  30.2  40.8
 OND 2020  A45  75.5  0.4   EC  28.3  34.5  42.0
 NDJ 2020  A40  74.2  0.4   EC  26.4  36.6  43.0
 DJF 2021   EC  72.8  0.4   EC  19.6  30.2  33.3
 JFM 2021   EC  71.8  0.4   EC  22.0  32.0  44.5
 FMA 2021   EC  71.7  0.4   EC  24.6  34.1  45.5
 MAM 2021   EC  72.0  0.5   EC  22.5  28.4  34.0
 AMJ 2021   EC  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
 

















 Kahului
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JJA 2020  A65  77.7  0.4  B60  0.7  1.1  1.5 
 JAS 2020  A60  79.0  0.4  B50  0.8  1.1  1.6 
 ASO 2020  A55  79.4  0.4  B45  0.8  1.6  2.5 
 SON 2020  A50  79.1  0.4  B40  2.1  3.3  4.8 
 OND 2020  A45  77.8  0.4   EC  4.2  5.3  8.1 
 NDJ 2020  A40  75.9  0.4   EC  5.2  7.6  9.5 
 DJF 2021   EC  73.8  0.4   EC  4.6  6.9  8.7 
 JFM 2021   EC  72.5  0.4   EC  4.2  6.2  8.2 
 FMA 2021   EC  72.3  0.4   EC  3.2  4.1  6.4 
 MAM 2021   EC  73.0  0.4   EC  2.5  3.5  4.6 
 AMJ 2021   EC  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 
 

















 Honolulu
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JJA 2020  A65  79.9  0.4  B60  0.7  0.8  1.3 
 JAS 2020  A60  81.3  0.4  B50  1.0  1.4  1.7 
 ASO 2020  A55  81.7  0.4  B45  1.6  2.4  3.1 
 SON 2020  A50  81.4  0.4  B40  2.5  4.0  5.6 
 OND 2020  A45  80.0  0.4   EC  4.4  6.4  8.5 
 NDJ 2020  A40  77.7  0.5   EC  3.9  5.6  8.8 
 DJF 2021   EC  75.3  0.5   EC  3.7  5.6  8.6 
 JFM 2021   EC  73.9  0.4   EC  2.1  4.6  7.8 
 FMA 2021   EC  73.8  0.4   EC  1.9  3.2  4.7 
 MAM 2021   EC  74.8  0.4   EC  1.8  2.6  3.0 
 AMJ 2021   EC  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 
 

















 Lihue
  TEMPERATURE  PRECIPITATION
    FCST  AVE  LIM  FCST  BLW  MEDIAN  ABV
 JJA 2020  A65  77.7  0.4  B60  4.4  5.3  6.9 
 JAS 2020  A60  79.0  0.3  B50  5.3  6.1  7.8 
 ASO 2020  A55  79.4  0.3  B45  6.2  7.9  8.4 
 SON 2020  A50  79.1  0.3  B40  9.2  10.0  11.2
 OND 2020  A45  77.8  0.3   EC  9.2  11.7  15.6
 NDJ 2020  A40  75.7  0.3   EC  8.6  12.1  16.9
 DJF 2021   EC  73.6  0.4   EC  7.5  8.4  14.0
 JFM 2021   EC  72.2  0.4   EC  6.5  8.8  13.8
 FMA 2021   EC  72.1  0.5   EC  5.8  8.4  9.9 
 MAM 2021   EC  72.8  0.5   EC  5.3  6.6  8.0 
 AMJ 2021   EC  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 
 

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 Jun 18, 2020.
 
 
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