Strong Winds – Lakeshore Flooding – Possible Power Outages Wednesday

Bill’s Blog

Posted: Jun 7, 2020 / 02:01 AM EDT Updated: Jun 7, 2020 / 02:01 AM EDT

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Unfortunately, this could be a significant weather event. The remains of Tropical Storm Cristobal and a strong cold front coming in from the west will combine to produce strong winds over the Great Lakes late Tuesday night into Wednesday. Models suggest gusts to over 50 mph are possible. While thunderstorms are possible along a sharp cold front late Tuesday night (possibly strong storms), it’s the general circulation around a deep low pressure system that generate the fast winds. The strongest winds may persist for 12 hours or more.

The water level of Lake Michigan is very high right now. A strong west wind for 12 hours is likely to produce a “standing seiche“. The west wind will push the water toward the Michigan shore, causing the water level to drop on the Wisconsin shore and rise on the Michigan shore. It’s possible that the higher water level will cause the flow of rivers that flow into the lake to reverse and the water to rise in the river channels and the lakes that rise and fall with the water level of Lake Michigan (Lake Macatawa, Muskegon Lake, Mona Lake, White Lake, Pentwater Lake, etc.).

Another problem is that the leaves are out now, providing more surface area for the winds to hit. Look for downed branches and possibly whole trees and power outages. Here’s the path of Tropical Storm Cristobal:

cone graphic

* The storm comes onshore today (Sun.) as a Tropical Storm. There will be heavy rain and a moderate storm surge to the right of where the eye of the storm crosses land. It’ll diminish to a Depression as it moves into Arkansas, but the moisture will flow north and the pressure gradient will increase as it moves into Wisconsin and it interacts with the cold frontal system. Here’s expected rainfall from Cristobal:

[Image of WPC QPF U.S. rainfall potential]

Even though we’re not in the direct path of the remains of Cristobal, the combination of humid air and the cold front will mean rain and a possible thunderstorm for West Michigan. Some 6″ rainfall totals are possible in LA/MS and N. Florida. Here’s Southern regional radar:

Southern Mississippi Valley sector loop
Go to: Most Recent Image

This is what the G.R. NWS said Sat. evening about the midweek storm:

"AFTER LOOKING AT BOTH THE GFS AND ECMWF AND THE ENSEMBLES OF BOTH MODELS, I AM BECOMING VERY CONCERNED ABOUT TUESDAY NIGHT AND WEDNESDAY FOR AN EXTREME WIND EVENT (FOR JUNE). THE ECMWF ENSEMBLE MEAN IS GIVING ALL OF OUR COASTAL LOCATIONS WIND GUSTS IN THE 50 TO 55 MPH RANGE FROM MIDNIGHT TILL AROUND 6 PM WEDNESDAY. THE GFS HAS SIMILAR WIND SPEEDS. THE MODELS HAVE BEEN VERY CONSISTENT ON THE TRACK OF THIS STORM. GIVEN TREES ARE LEAFED OUT, GETTING SYNOPTIC SCALE WIND GUSTS IN THE 40 TO 50 MPH RANGE FOR OVER 12 HOURS WOULD BE A REAL ISSUE FOR US. IT'S EARLY YET BUT IT SEEMS MORE THAN REASONABLE TO PUT THIS IN OUR GRIDS AND FORECAST PRODUCTS. SO IN COORDINATION WITH MKX I UPDATED OUR WIND FORECAST FOR WEDNESDAY." 

At this point, it’s likely that we’ll have a Lakeshore Flood Warning, Gale Warnings, a Beach Hazard Statement and perhaps a Wind Advisory for late Tuesday night into Wednesday. Stay with us for later forecast updates.