As I left Denver this morning, a large storm system was centered over northeastern Colorado. A cool north breeze was flowing southward along the Front Range and an occasional pocket of drizzle coated the windshield. Further east, an upslope flow had developed on the north side of the Palmer Divide, resulting in dense fog, with visibility reduced to ten yards or so.
Once I descended to Limon, the skies cleared and remained so through western Kansas. Strong southerly winds developed east of Russell, spinning the turbines of the Smoky Hills Wind Farm and signaling that I was now east of the cold front. Since the air contained little moisture, only scattered, high clouds marred the deep blue sky; approaching Topeka, however, a band of billowing cumulus clouds appeared on the horizon, indicating that Gulf moisture was now clearly in play. Showers swept across the highway in eastern Kansas and thunderstorms, with possible tornadoes, are forecast for central Missouri this evening; so far, just light rain and gusty south winds.
As is characteristic throughout the Northern Hemisphere, winds flow counterclockwise around the center of low pressure, producing the sequence of events that accompanied my drive. A chilly north wind and wrap-around moisture produced the showers and upslope fog west of the storm while strong southerly winds, sweeping Gulf moisture into the Heartland, has set the stage for severe weather ahead of the front. In the course of an 11 hour drive, I had crossed the storm and experienced both its cold and warm sectors.