Discussion
Overnight observations and short term guidance gives fair to good confidence in dense fog Saturday morning throughout much of Mid Michigan including along US-127 and reaching portions of US-131. There is some potential for the fog to expand west of US-131 mainly west of Kalamazoo and Grand Rapids. Similar to a couple other fog events this week, the most widespread visibilities less than a quarter mile may occur between 8 AM and 10 AM when the winds around 500 feet relax. The fog and low clouds should mix out and evaporate between 10 AM and noon, leaving the rest of the day with some cirrus.
Global ensemble systems and recent short term guidance continues strong support for highs in the upper 60s to around 70 this weekend, with a flow of mild air on the back side of high pressure over the Northeast to Ohio valley. A light breeze and some increased coverage of high clouds can also be expected.
Ensemble spread has tightened up a little on cooler temperatures Monday and Tuesday as a cold front sinks through the area. There is still some spread in the expected highs with a range between the mid 50s and mid 60s, depending the southward progress the front makes before stalling. This cool down isn't exactly significant as it just brings temperatures closer to normal for late October. The front is also favored to come through dry.
Ensembles have a good signal for high temperatures rebounding into the 60s to near 70 on Wednesday ahead of a northern Plains low. After Wednesday, there was a significant amount of spread and lower confidence in the forecast depending on how that low would phase with the northern jet stream, and at what longitude a large scale trough within the northern stream would set up later in the week. There was a variety of solutions for late in the week with highs ranging between the 40s to near 70, however, recent cycles have increased the membership of warmer solutions. There are increasing chances for rain toward the end of the month, though confidence in that remains relatively low for now.