WEATHER BLOG: Blast Of Chilly Air

Today is getting off to a frosty cold start, but we're expecting some sweeping changes this week eventhough some locations outside of the larger cities will start off today in the 20s, many temperatures are expected to reach the lower or middle 70s during midweek.

With a brisk northwest wind yesterday, scattered showers occurred in the Northeast and mid-Atlantic states. But in addition to rain, some of these consisted of wet snowflakes. Temperatures yesterday afternoon were mostly in the 40s or the lower 50s, but what prompted the wet snow was some much colder air above the boundary layer.

The axis of a deep upper-level trough, which has supplied the region with the very chilly air, will be lifting out to the north and east today. In its place, a strong ridge of high pressure is expected to build into the Eastern Region with the next 48 hours. As the core of high pressure on the surface weather charts moves into a position over the Carolinas and then spreads eastward into the Atlantic, the flow both at the surface and aloft will be out of the west and southwest -- which will be promoting our anticipated big warm-up.

Under a clear to partly cloudy sky tonight, most temperatures will be in the upper 30s in the typically colder spots and the 40s elsewhere. So, it will not be nearly as cold as it is early today, and that change will provide us with a 'springboard' for tomorrow. With a good deal of sunshine tomorrow, high temperatures should reach the mid and upper 60s.