An extended heat wave began across the U.P. on June 10, 1956. A record high of 95 was observed in Ironwood, with 93 reported in Iron Mountain. Temperatures of 90 degrees or above were then recorded the next three days. In Marquette, a sweltering record of 98 was set on the 12th and 99 on the 13th. These readings were the warmest in the Queen City in almost eight years.
The hot weather developed in time-honored fashion as the main band of westerlies or jet stream retreated north into Canada. That allowed an upper-level ridge to form over the central U.S., paving the way for the influx of heat into the Upper Peninsula (Image 1). The ridge hung tough for several days peaking at the time Marquette sizzled in the upper 90s (Image 2). Finally, the hot ridge was flattened by a cool front dropping in out of south-central Canada. The hot spell lasted just a little over a week. The rest of the month ran predominately below average. June 1956 ended a modest 2.5 degrees above average despite the extended heat wave.
So far, June 2014 is now running a little over two degrees above average after a warm start. The last couple of days have been cool??especially at night. Our observer on North Camp Road north of Ishpeming hit 32 this morning after a low of 31 yesterday. Both mornings frost was observed on roof tops. The official low at the National Weather Service near Negaunee was 40 degrees.
No heat waves are in the immediate future. In fact, it appears that temperatures will briefly fall well below average Friday as a significant low-pressure system drives a strong cool front through the region Thursday.