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      11-5-2012_Powerful Slow-moving Storm

      The Saturday forecast off the GFS model shows a deep, cold trough over the western U.S. This will mean a warm up for the U.P.

      My first winter in the U.P. was beginning in the fall of 1988. I was excited by the weather pattern that set in on Halloween. A disturbance dove in from the northwest the evening of Halloween. It developed low pressure that moved just south of Upper Michigan. The air was just cold enough for rain to change to wet snow. A total of 5.9 inches of snow fell at the National Weather Service (NWS) near Negaunee. It was an â??elevationâ?? snow, typical for this time of year. In Marquette at lake-level, there was just rain mixed with some flakes. This was just a preview of what was to come a few days later.

      After this early snow, it warmed up a bit, while a system developed off to our southwest. Pacific energy dove from the northwestern states into the southern Plains on Friday, November 4, 1988. This energy induced the development of low pressure over Iowa. An expanding area of rain formed around the low and headed northeast into Upper Michigan. Rain poured down all night into the next morning as the low deepened while drifting northeast. By early Saturday morning, the system was situated just off the shoreline near Manistee in the Lower Peninsula.

      Under normal circumstances the low would continue northeastward and system precipitation would wind down and, if the air was cold enough, lake-effect rain and snow showers would occur. In this case, the storm barely moved over the next 24 hours as it continued to wind up. On Sunday morning, the low was over northern Lake Michigan not far off shore from Traverse City. The central pressure of the storm fell to 976 millibars or 28.82 inches of mercuryâ??an impressive November gale.

      Its position just east of the western and central U.P. allowed just enough cold air to wrap in from the north to change rain to a soggy, wet snow in the higher elevations. A foot-and-a-half of snow fell in the Negaunee/Ishpeming area, while up to three feet of snow came down in the Porcupine Mountains of the far western U.P. Near the Lake Superior shore, most of the precipitation fell as rain. An observer near Marquette reported five inches of rain and a little melted snow during this weekend storm.

      November 1988 was wet, stormy and snowy. The month ended with over 8 inches of precipitation, while the NWS had an impressive 42 inches of snow. Overall, the month turned out to be relatively mild. A warm spell around Thanksgiving helped to boost the mean temperature for the month to 1.7 degrees above average.

      A warm up is in store for Upper Michigan as the week wears on (Image 1 above). The big high thatâ??s been dominating our weather is drifting eastward. A huge trough is forecast to develop out west late this week, which will help to push warmer air into the Great Lakes, especially this weekend.