Discussion: Except for rain in northern California the Christmas Week starts quiet and presents excellent conditions for Holiday travel. However, major changes are on the way. Beginning Wednesday a large rain storm emerges in the Great Plains to Texas (Fig. 1). The heaviest rain is Thursday through the Dallas area where severe thunderstorms are possible. Severe storms could affect Houston. The heavy rain moves east across Southeast U.S. THU/FRI with up to 5 in. of rain possible in some areas. Severe thunderstorms will affect the Gulf Coast from Louisiana to the Florida Panhandle.
Snowfall also emerges with this storm with 3-9 in. of snow for Nebraska/South Dakota WED and 6-10 in. Upper Midwest WED night into THU (Fig. 2). A major snowstorm is likely in Ontario THU/FRI featuring high wind and incoming arctic air. Blizzard conditions are likely to emerge with up to 18 in. of snow.
Arctic air from Canada works its way south and east into the Great Lakes region the night of Dec. 30 (Fig. 3). On New Year’s Eve a snowstorm emerges as the arctic air combined with moisture from the Great Lakes pushes 3-15 in. of snow from the Great Lakes region to New England. A storm forms off Nantucket, MA on New Year’s Eve pulling the snow into New England. High wind with this storm.
Another surge of snow across the southern Plains to the Mid-Atlantic States is expected Jan. 1-2. Plenty of cold across the East follows this second storm. The second storm brings more heavy rain to the Southeast (Fig. 4).
Fig. 1: This week’s rainfall forecast indicates heavy rain in the Great Plains and Southeast U.S.
Fig. 2: This week’s snowfall forecast depicts an evolving northern U.S./southeast Canada storm.
Fig. 3: The U.S. snowfall forecast for days 6-11 ahead features 2 storms.
Fig. 4: Heavy rains on the Gulf Coast Jan. 1-2, 2019.