Daily Summary for 19 January 2007

A storm system passed over southern Ontario today and brought with it multiple layers of cloud. Lake effect snow showers were prevalent near the lakes, with some nice looking altocumulus clouds above. The CARE ground site experienced two lake effect bands (~noon & 9 PM LT), the second of which dumped 2 inches of snow on Barrie in little more than an hour. The situation near Ottawa was different, however and all the good clouds had dissipated by the time of the flight.

Today there was a planned overpass flight targeting the ~13:30 LT Ottawa overpass. Unfortunately all the interesting clouds were near CARE. From Adam on the plane:

What started out as a promising flight quickly turned disappointing as most of the mid-level cloud deck eroded away leaving only a low layer of mixed phase clouds that was unreachable for us (due to minimum flight altitude restrictions). The cloud field was so poor that C3VP flew an extra 80 miles north of their intended target to find something a bit more juicy for CloudSat to sample. We did manage to fly through some deeper portions of the lower mixed phase cloud deck on the way back to Ottawa.

As a result of the dissapointing clouds near Ottawa and the Snow Squall Warnings over CARE, a second flight took place between 17:00 and 20:00 LT targeting the lake effect snows near CARE that CLEX did not participate in. You might have already guessed that the lake effect snow bands over CARE in the early afternoon had moved on, and the early evening snow bands avoided CARE as if they just wanted to be left alone. So it was mostly clear skies at CARE during the second flight, which targeted heavy snow bands just to the north. As soon as the plane turned back to Ottawa and all the CARE folks had shut down their instruments, the snow band shifted south and hit CARE with a vengeance. (5 cm of snow in 65 min and 30 cm total!) Overall, there were good observations of lake effect clouds and snow from both CARE and the plane - just not at the same time.

Below is the CloudSat swath and MODIS IR image during the Ottawa flight.