Excessive rainfall with flood risk is forecast for today southwest of San Antonio and in Arkansas. Excessive rainfall with flood risk returns to Texas and the southeast Great Plains SUN/MON. The NBM 10-day rainfall forecast indicates 5-7 in. of rain just north of Dallas.

Stratospheric warming is developing on the North America side of the North Pole now, strengthening in the 6-10-day period, and peaking across northwest continent during the 11-15-day period. The attendant colder temperature trend at ground level causes a surge in U.S. gas population weight HDD for the week ending December 4th.

At day-16, the 12Z GFS shifts stratospheric warming from northwest continent indicated by all models during previous model runs, to Northern Canada. In this position, the model creates cold air quickly thrusted into the U.S. in the 11-15-day period), a dramatic cooler change.

The upper air pattern projected across Europe during the next 1-2 weeks features a deep upper-level low-pressure trough causing chilly weather for the next 10 days (at least) and excessive rainfall capable of producing flooding in parts of central, south, and southeast portions of Europe. Heavy snows are likely in the South-central Europe mountain areas, and the wet regime extends eastward to include Ukraine.