Severe storms and heavy rains are likely in the Upper Midwest and Plains through this evening. A long duration heat wave will build across the West through next week with excessive heat watches/warnings in effect from the Southwest to Northwest. TS Josephine is forecast to pass well north of Puerto Rico and the Virgin Islands while TS Kyle is forecast to move quickly away from land this weekend. Read More >
PEAC Seasonal Rainfall OutlookThe PEAC Seasonal Rainfall Outlook is an experimental consenus forecast, produced monthly for 14 stations within Hawaii and the USAPI. The PEAC Outlook uses data from the following 7 models: UKMO, NASA GMAO, ECMWF, IRI, NCEP Constructed Analog, NCEP Coupled Model and APCC MME. The PEAC Seasonal Rainfall Outlook is a probabalistic forecast displayed in tercile form (3 categories). The three categories represent the chances of an event falling into the "Below Average", "Near Average" and "Above Average" categories, respectively. For example, a seasonal rainfall forecast of 20:30:50 should be interpreted as follows: There is a 20% chance of "Below Average" rainfall for the season; a 30% chance of "Near Average" rainfall for the season; and a 50% chance of "Above Average" rainfall for the season. For more information on terciles, click here. PEAC services is no longer providing the in house model, PEAC CCA as of January 2020.


July August September (JAS) 2020 





Forecast Discussion 

Airai: Rainfall for July August September 2020 is expected to be AvgBelow for Airai. There is a 35% chance that rainfall during the JAS season will be less than 39.25 inches; a 35% chance that rainfall will be between 39.25 inches and 50.04 inches; and a 30% chance that rainfall will be greater than 50.04 inches. Yap: Rainfall for July August September 2020 is expected to be Average for Yap. There is a 30% chance that rainfall during the JAS season will be less than 41.9 inches; a 40% chance that rainfall will be between 41.9 inches and 46.11 inches; and a 30% chance that rainfall will be greater than 46.11 inches. Chuuk: Rainfall for July August September 2020 is expected to be AvgBelow for Chuuk. There is a 35% chance that rainfall during the JAS season will be less than 34.86 inches; a 35% chance that rainfall will be between 34.86 inches and 44.29 inches; and a 30% chance that rainfall will be greater than 44.29 inches. Pohnpei: Rainfall for July August September 2020 is expected to be Average for Pohnpei. There is a 30% chance that rainfall during the JAS season will be less than 40.06 inches; a 40% chance that rainfall will be between 40.06 inches and 50.76 inches; and a 30% chance that rainfall will be greater than 50.76 inches. Kosrae: Rainfall for July August September 2020 is expected to be Average for Kosrae. There is a 30% chance that rainfall during the JAS season will be less than 41.49 inches; a 40% chance that rainfall will be between 41.49 inches and 47.32 inches; and a 30% chance that rainfall will be greater than 47.32 inches. Kwajalein: Rainfall for July August September 2020 is expected to be Average for Kwajalein. There is a 30% chance that rainfall during the JAS season will be less than 28.97 inches; a 40% chance that rainfall will be between 28.97 inches and 33.09 inches; and a 30% chance that rainfall will be greater than 33.09 inches. Majuro: Rainfall for July August September 2020 is expected to be for Average Majuro. There is a 30% chance that rainfall during the JAS season will be less than 31.17 inches; a 40% chance that rainfall will be between 31.17 inches and 38.16 inches; and a 30% chance that rainfall will be greater than 38.16 inches. Guam: Rainfall for July August September 2020 is expected to be AvgBelow for Guam. There is a 40% chance that rainfall during the JAS season will be less than 37.2 inches; a 30% chance that rainfall will be between 37.2 inches and 44.54 inches; and a 30% chance that rainfall will be greater than 44.54 inches. Saipan: Rainfall for July August September 2020 is expected to be Below for Saipan. There is a 40% chance that rainfall during the JAS season will be less than 29.48 inches; a 35% chance that rainfall will be between 29.48 inches and 35.85 inches; and a 25% chance that rainfall will be greater than 35.85 inches. Pago Pago: Rainfall for July August September 2020 is expected to be Above for Pago Pago. There is a 25% chance that rainfall during the JAS season will be less than 15.04 inches; a 35% chance that rainfall will be between 15.04 inches and 23.4 inches; and a 40% chance that rainfall will be greater than 23.4 inches. Lihue: Rainfall for July August September 2020 is expected to be AvgBelow for Lihue. There is a 35% chance that rainfall during the JAS season will be less than 5.27 inches; a 35% chance that rainfall will be between 5.27 inches and 7.79 inches; and a 30% chance that rainfall will be greater than 7.79 inches. Honolulu: Rainfall for July August September 2020 is expected to be AvgBelow for Honolulu. There is a 35% chance that rainfall during the JAS season will be less than 1.02 inches; a 35% chance that rainfall will be between 1.02 inches and 1.67 inches; and a 30% chance that rainfall will be greater than 1.67 inches. Kahului: Rainfall for July August September 2020 is expected to be AvgBelow for Kahului. There is a 35% chance that rainfall during the JAS season will be less than 0.84 inches; a 35% chance that rainfall will be between 0.84 inches and 1.64 inches; and a 30% chance that rainfall will be greater than 1.64 inches. Hilo: Rainfall for July August September 2020 is expected to be AvgBelow for Hilo. There is a 35% chance that rainfall during the JAS season will be less than 25.17 inches; a 35% chance that rainfall will be between 25.17 inches and 33.44 inches; and a 30% chance that rainfall will be greater than 33.44 inches. 

The PEAC Seasonal Rainfall Outlook is an experimental consensus forecast, produced monthly by the Pacific ENSO Applications Climate (PEAC) Service's for 14 stations within Hawaii and the USAPI. Tercile cutoffs for each location and season are based on Pacific Rainfall Climatologies (Climate Prediction Center) 19812010. (Updated 10 July 2020 at 2000 UTC PostConference) 