Turning the corner, in a small way

Tommorrow morning we will welcome the daybreak with a gain of one minute of sunshine. Since December 12th we have bee slowing adding to the daylight in the afternoon, so that sunset in the Twin Cities today will be at 448PM. On the 12th of December the sunset was 431PM.

We know that there is a lag time both diurnally and seasonally with temperatures. It is not until late January until we see the thirty year average temperatures begin to climb slowly.

Yesterday between 8AM and 9AM the thermometer bottomed out at 34 below zero at International Falls. This tied the record low for the 5th of January set in 2005. Sunrise at the Falls is at 805AM. It is not uncommon for the temperature to continue to fall on a clear, calm winter morning, especially with fresh snow cover, after sunrise.

There is little warmth generated by the sun until it is well above the horizon. The surface of the earth is sitll radiating heat back into the atmosphere. As the daylight increases there actually could be some mixing of the air in the lower levels. Thus the very chilly air, within inches of the snow pack, can mix up to the thermometer level at five feet.

Lesson learned, don't put the overnight low in the record book until well after sunrise on a clear, calm winter morning.

CE

naturesmessenger.com