When Big and Little Combine… (Feb 7-8, 2013 Snowstorm)
February 6, 2013 2 Comments
A progressing shortwave, similar to our recent clipper systems, will cut down from Canada Wednesday and merge/phase with a longwave trough moving across the continental U.S. This interaction will ensure moisture transport from the deep south into the Great Lakes region, amplifying precipitation amounts in the area. In this way, it is different than our previous shots of snow.
This is a good example of how tricky weather can be. This past weekend, the storm was little more than a trace-3″ disturbance, now it threatens to bring triple that amount to some locations of the state. Quite interesting to see models not show agreement, and then all of a sudden snap in line with each other. Euro had this solution previously, and the GFS/NAM had come into agreement by Tuesday morning. This actually falls near a date back in 2008 when much of mid-Michigan had a 1-2 punch of snowfall:
On February 6, 2008, a snowstorm hit most of Southeast Michigan. Widespread amounts ranged from 6 inches across central Livingston, Oakland and Macomb Counties to greater than 10 inches for all of the Flint (11.3 inches at Bishop Airport), Tri Cities (12.0 inches at Tri Cities Airport)and Thumb regions. Areas across the southern Saginaw River Valley were dumped with 16 to 18 inches of snow from southwest Saginaw to Birch Run to Vassar. -Detroit/Pontiac National Weather Service
Accumulation wise, central Michigan and lower Michigan look to be in the cross-hairs for persistent snow beginning Thursday morning and continuing through to Friday morning. There is some discrepancy between the GRR(Grand Rapids) and DTX(Detroit/Pontiac) forecast offices. as to what the heaviest snow amounts will be. My experience is that GRR likes to over estimate snow accumulations, and DTX likes to hold a conservative line on accumulations. Typically with winter storms, you get little pockets of the high accumulations, but they are not as widespread as the forecast covers. These higher amounts will also depend greatly on how consistent the early snowfall is. Therefore, I believe isolated areas across mid-Michigan will receive 9″ or 10″, but most locations across mid-Michigan will see 6-8″. Along the I-94 corridor, a good swath of 3-6″ seems like a good bet as they will get high intensity snowfall, but for a shorter duration. With warmer temperatures moving into the region, this snow will have a wetter characteristic compared to lighter dry snows this past week.
Snow will begin to trickle in Thursday morning for central Michigan. Snow should then continue through the day, intensifying in the afternoon. Overnight, snow will be at the strongest. This leaves little time for morning commuters to have a clear surface, and roads will likely be covered and treacherous Further south in the state, the initial snow will not begin until the afternoon/evening on Thursday, thus lower amounts are expected. However, once the main portion of the system is over the region, heavy snows will be occurring and accumulation rates will be high enough to cause transportation issues.
The Detroit forecast office has a great briefing of timing, expectations, and other facts about the storm available to view in a PDF document online here.