Our very slow march to the warm season continues this week. Over the weekend, a huge area of high pressure near Hudson Bay dominated our weather with dry, cool conditions. It was still influencing our weather from its position just east of Hudson Bay this morning (Image 1 above). To the southwest, low pressure over Nebraska was holding relatively stationary. This low is still expected to wobble up to the western Great Lakes and control Upper Michiganâ??s weather through the end of the week.
Rain over Wisconsin will gradually spread northward, impeded in its progress by the dry easterly flow off the high. However, a strong disturbance on the southeastern flank of the Plains low will lift north-northwestward and finally bring a slug of moisture into our area. Rain should develop over the far south during the night and then spread slowly northward. There may be some snow or sleet mixed in with the rain over parts of the northwestern and north-central highlands, but no travel problems are expected as temperatures should be a little above freezing.
Disturbances will continue to pin-wheel around the low eventually dragging the system into the Great Lakes (Image 2). Once it gets here, it will be very slow to leave. Cloudy, wet and chilly weather should be the result. At this point, it appears the best rains will occur on Tuesday, with only scattered rain, some drizzle and even fog likely after that.Looking ahead, the prospects for long-lasting warmth look dim. On Wednesday, the big low will be spinning close by (Image 3). By the end of the work week, it should be breaking down and lifting to the northeast. However upstream, the pattern that we saw repeated throughout this historic winter is forecast to develop again (Image 4). That means a big ridge along the West Coast to Alaska and a deep, cold trough downstream over central North America. This argues for chilly weather well into next week.