Weather

Actions

Heat and humidity to build this weekend

Posted at 9:30 PM, Jun 12, 2018
and last updated 2018-06-12 22:53:46-04

WEST MICHIGAN — We’ve already had temperatures earlier this season in the 90s, but that type of heat and humidity will be returning this weekend. We are expecting temperatures Saturday, Sunday and Monday in the upper 80s to low 90s!

Normal/average high temperatures for this time of year have us in the upper 70s, but we will be far exceeding that in the coming days. An area of high pressure will drift to our south/east and Michigan will end up on the return flow with southerly winds. A ridge, or buckle in our upper level jet stream (pushing well to the north) will also allow the hotter, more humid air to flow northward in to the Great Lakes.

Take a look below at one of our computer forecast models. These are temperatures about 5,000 feet above the surface, or what Meteorologists refer to the 850 millibar level. The colors represent the air masses. The warmer the tones, the hotter the surface temperatures. The image below is valid for Thursday evening. Note the yellow over Michigan. That equals about 12 degrees Celsius. That’s about 54 degrees Fahrenheit about 5,000 feet above the surface. That would yield surface temperatures in the low 80s

Now look at the same map valid for Saturday evening. Note the deeper reds over Michigan. That translates to about 20 degrees Celsius, or about 68 degrees Fahrenheit. At the surface, that will yield temperatures in the upper 80s to near 90. And the heat remains for Sunday and Monday.

The last map below is from about 30,000 feet above the surface…up around 300 millibars. This is our jet stream level…where the commercial airliners fly. Note that there is a big bubble, or high pressure ridge in our jet stream. That will allow the heat and humidity to flow into the region. If the jet stream was SOUTH of Michigan, we would likely be seeing temperatures below normal.

So get ready for some Father’s Day weekend heat and humidity. Get the complete forecast at www.fox17online.com/weather.