Highlight: Slowly colder but doubting arctic air impact. Snowier! MJO supports a colder U.S. pattern in January. Stratospheric warming looms as an arctic air producer…cold burst potential. Day 1-5 Outlook (Dec. 23-27, 2018): Next major storm WED/THU Central U.S. Some light snow/rain Northeast U.S. Christmas Eve. Storm track shifts from Northwest U.S. SUN/MON to northern California MON/TUE. Organizing West-central/Central U.S. storm WED; steady and heavier snows Wyoming to Dakotas. Heavy rains/thunderstorms Mid-South THU (snow into Upper Midwest). Fig. 1-2: Climate Impact Company temperature and precipitation anomaly forecast for days 1-5 ahead. Day 6 to 10 Outlook (Dec. 28, 2018-Jan. 1, 2019): Stormy/colder. Snowstorm early period from southwest Great Plains to Upper Midwest U.S. to New England. Mid-to-late period heavy rains in the Gulf of Mexico region. Widening cold across fresh snow cover West; pieces of arctic air touching the U.S./Canada border. Fig. 3-4: Climate Impact Company temperature and precipitation anomaly forecast for days 6-10 ahead. Day 11-15 Outlook (Jan. 2-6, 2019): Colder but no arctic air. Snowy Ohio Valley to New England. Continued stormy in the Southeast; milder/drier Northwest. Fig. 5-6: Climate Impact Company temperature and precipitation anomaly forecast for days 11-15 ahead. Week 3 (Jan. 6-12) and week 4 (Jan. 13-19) outlook: Colder. Signs of MJO inspired East U.S. cold trough. Snow cover increase. Support for cold increasing. Doubting arctic air, however. Fig. 7-8: Climate Impact Company week 3/week 4 ahead temperature anomaly forecasts for the U.S. Gas population weight 4-week HDD forecast: The trend is colder for middle January and cold bias is East/Northeast. Fig. 9: CIC week 4 verification/forecast of weekly departure from normal of gas population weight HDD. Fig. 10: CIC week 4 forecast of weekly departure from normal of gas population weight HDD by U.S. region. Fig. 11: The ECMWF 30-day MJO forecast indicates a progressive nature supporting a warm U.S. pattern in December shifting toward colder support in January.