Excessive heat Australia (except northeast Queensland). Very dry Argentina (wetter days 11-15). United States: Snow cover widens as a heavy snow storm brings 10-12 in. to the southern Great Plains next weekend (Fig. 1). Generally dry and mostly cold prior to this event. In the 11-15 day period a much warmer change and snow cover erosion is likely. Temperatures surge to 20+F above normal in Oklahoma/Texas the morning of Dec. 13 (Fig. 2) with more warmth to follow. Fig. 1-2: The ECMWF 48-hour snowfall forecast for next weekend (left) and temperature anomaly forecast for the morning of Dec. 13 (right). Of interest is warming and expansion of the stratosphere across northwest North America in mid-December (Fig. 3). All operational models indicate this risk. Normally, arctic air will form beneath a stratospheric warming event although models are not showing the potential extreme cold (yet). Fig. 3: The ECM ENS indicates a stratospheric warming event over northwest North America by mid-December. Canada: The Canadian Meteorological Center updated their winter forecast this past Friday. The forecast is adjusted colder as warm risk is present only in the Far Northwest and eastern Maritimes (Fig. 4). A snowy forecast is indicated along the U.S./Canada border (Fig. 5). Fig. 4-5: The Canadian Meteorological Center temperature/precipitation probability forecast for meteorological winter 2018-19. Europe/Black Sea region: A wet forecast for Western Europe reaching Central Europe concentrated in the 6-10 day period with forecasts issued late last week is less bold with the rainfall. The latest ECMWF day 1-7 forecast indicates 2-4 in. of rain centered on southern France (Fig. 6). However, a somewhat drier pattern follows days 8-14 (Fig. 7) as the storminess shifts to Southeast Europe. Some recovery in the Rhine River levels is expected (Fig. 8). Several in. of snow to more than a foot in some places is likely in Southeast Europe to the Black Sea region the next 10 days. Forecast models may be too warm in the Black Sea/southwest Russia region. Fig. 6-7: The ECMWF day 1-7 and day 8-14 total precipitation forecast for Europe and Western Russia. Fig. 8: The Rhine River level at Kaub, Germany. Australia: A Rossby Wave forms north of Australia. On either side of the equator low pressure forms and enhances a period of heavy thunderstorm activity. The ECM ENS indicates excessive rainfall north of Australia the next 1-2 weeks (Fig. 9). Countering the strong rising air currents producing the convection is heat-producing subsidence across Australia. Dangerous excessive heat is forecast across much of Australia in both the 6-10 and 11-15 day period (Fig. 10-11). Fig. 9: The ECM ENS 15-day rainfall forecast across Australia. Fig. 10-11: The 6-10 and 11-15 day temperature anomaly forecast across Australia by the GFS OP. South America: The wet pattern previously forecast across northeast Brazil remains intact for the next 7-10 days (Fig 12-13). Meanwhile Argentina to southeast Brazil are very dry the next 10 days. In the extended-range a cold front brings a wet reversal to northeast Argentina while eastern Brazil turns drier (Fig. 14). Fig. 12-14: The ECM ENS day 1-5, 6-10 and 11-15 percent of normal rainfall forecast across South America.