An El Nino Modoki-based Climate Outlook through winter 2018-19 Executive Summary: The Climate Impact Company season 1-3 ahead forecast is revised due to the likelihood of an emerging El Nino Modoki. The favored climate pattern is cool pattern change for later summer in the Great Plains, wet weather evolving in both autumn and winter across the southern states and a sneaky cold regime in the East for winter 2018-19. Climate discussion: A somewhat recent discovery of an infrequent version of an El Nino episode known as El Nino Modoki is becoming a more likely scenario for the next 1-3 to as many as 9 months ahead according to the Japan Agency for Marine-Earth Science and Technology (Fig. 1) and various global SSTA forecast models governing the most likely climate patterns around the globe. Fig. 1: El Nino-Modoki Index forecast by the Japan Agency for Marine-Earth Science and Technology indicates a weak Modoki ahead for 2018-19. To estimate a historical precedent of El Nino Modoki regimes on global climate analog years are chosen. El Nino Modoki occurred in 2002-03, 2004-05 and 2009-10 (Fig. 2). There are other El Nino Modoki episodes prior to the 3 listed however they occurred when another important mode of climate variability, the Atlantic multi-decadal oscillation (AMO) was in the cool phase (Fig. 3). Fig. 2: Analog years comparing cool Nino12 SSTA and warm Nino34 characteristic of El Nino Modoki and the last 3 months of 2018. Fig. 3: Analog years are chosen from the past 20 years when the Atlantic multi-decadal oscillation has been in the warm phase. Outlooks: A simple El Nino Modoki analog forecast of temperature and precipitation anomalies is indicated for JUL/AUG, SEP/OCT/NOV and DEC/JAN/FEB 2018-19. The outlooks are a confident first estimate of what to expect in each sector of the globe as to general climate conditions inspired by this unique El Nino scenario. Regional influences such as soil moisture during the warm season and snow cover during the cold season plus regional SSTA regimes outside of the tropics can modify the El Nino Modoki climate. July/August 2018: An interesting forecast very much away from the warmer-than-normal persistence of spring and early summer. However, if El Nino Modoki unfolds as expected a U.S. pattern change is likely for the second half of summer possibly most focused on August considering current operational forecasts extending well into July. The pattern change is much cooler in the Central U.S. The anomalous warmth dominant during early summer 2018 shifts to the West Coast mid-to-late summer. The southern Plains to the Delta is wetter than normal while the Mid-Atlantic is also wet. The Gulf of Mexico is drier than normal as evolving El Nino-inspired upper shear thwarts tropical cyclone development. The central/east-central tropical Pacific Ocean is very wet with frequent tropical events. Fig. 4-5: An El Nino Modoki climate pattern featuring temperature and precipitation anomalies for North America for JUL/AUG 2018. SEP/OCT/NOV 2018: Typical of an El Nino climate the Modoki version of warm ENSO causes a wet regime across the southern U.S., wettest as mid-to-late autumn arrives. Much of the U.S. is temperate while Canada into the northern U.S. is warmer than normal. Fig. 6-7: An El Nino Modoki climate pattern featuring temperature and precipitation anomalies for North America for SEP/OCT/NOV 2018. DEC/JAN/FEB 2018-19: El Nino Modoki during North America winter causes a colder-than-normal climate in the East/Southeast U.S. The southern and eastern tier of the U.S. is wetter than normal. The pattern opens the door for extreme cold risk given a persistent blocking pattern over Greenland (i.e. negative North Atlantic oscillation). Southern U.S. drought should fade this winter season. Historically, El Nino means a mild pattern in the high demand energy East U.S. but this winter a cold risk is favored. Fig. 8-9: An El Nino Modoki climate pattern featuring temperature and precipitation anomalies for North America for DEC/JAN/FEB 2018-19.