“Supercells with tornadoes (some long-tracked and significant at EF2+ damage levels)”

Weather

Sat. Late AM Update: The words above are from the Forecast Discussion of the Storm Prediction Center.

Storm chasers will be converging on northern Illinois this PM. There is a Moderate Risk Area (in red) for parts of Illinois. Surrounding that, there is an Enhanced Risk Area (in orange) that comes up to Lake Michigan. The Slight Risk Area (in yellow) comes up into S. Lower Michigan – generally south of a line from Holland to Toledo. The Marginal Risk Area (in dark green) now covers areas south of a line from Manistee to Houghton Lake.

SPC says:

 A severe-weather outbreak weather is expected for portions of the Midwest
   this afternoon and evening.  A few long-tracked, significant
   tornadoes are possible, along with large, damaging hail and severe
   gusts.

…SPC says: “A potentially potent severe weather setup as ingredients needed for this are appearing to favorably align on Saturday… Storms may continue well into the evening across parts of the OH Valley/southern Great Lakes posing a severe risk.”

We’re only in the Slight and Marginal Risk Areas here in W. Michigan. The best chance of severe weather Saturday will be southwest of Michigan. We haven’t had severe weather in a long time (not much last year), so it’s time to think about a severe weather plan. This year, with the coronavirus sheltering, you’ll have to think about not just where, but who you will be sheltering with.

If you’re in a big box store or supermarket, there may be a designated area where shoppers and store employees go during a tornado warning. However, putting dozens of shoppers and store staff in a relatively small shelter has the added risk of virus transmission right now. The best plan is for you not to be there in the first place. Stay home during a tornado watch if you have a suitable shelter. If you’re home does not have a suitable shelter, think about moving to a place where there is a suitable shelter before the storm. The underground parking areas in the city are very good tornado shelters (stay away from the entrances/exits). Idea: Make the underground parking areas free during a tornado watch – events have been canceled this year – there would be no wait to exchange money or to put credit cards into a machine. Tornado watches are rare. Most of West Michigan didn’t get a tornado watch all last year (Berrien and Cass Counties had one tornado watch).

Severe Weather Outlook map with cities for Sat. Mar. 28 2020

I think we’ll have a more active severe weather season this year in both Michigan and the U.S. This outlook area will be updated later today and again Saturday AM and (if I’m up), I’ll update this blog thread when that happens. I’ve set up shop in my basement, and my house actually has a real tornado shelter (with a foot of concrete on top of it), so I should be able to blog and do facebook and twitter during a storm (as long as my internet connection is good).

Probabilty of a tornado within 25 miles of a given point.

This map shows the probability of a tornado within 25 miles of a given point…it’s over 15% in the red area in Illinois. The 5% risk runs essentially south of I-94 and the 2% risk is south of a line from Saugatuck to Detroit. So, the chance of a tornado within 25 miles is less than 2% for Holland, Grand Rapids, Lansing and points to the north.

Probability of a hail report within 25 miles of a given point Sat. PM/night

This is the probability of a severe hail report within 25 miles of a given point. Note it’s a relatively high 30% all the way up through the Chicago area. The 15% severe hail probability comes up to Benton Harbor, Kalamazoo, Battle Creek and Hillsdale.

Severe Hail Reports from Friday

Here’s the Storm Reports from Friday…there were 95 reports of severe hail – 27 of them were hail from 2- 3.5″ in diameter. If you look at the map, there were two supercell hail-producing storms that moved SW to NE across OK and MO. There were no reported tornadoes and no reports of wind damage…just two gigantic thunderstorms that produced long swaths of hail damage.

Again, we’re only in the Slight and Marginal Risk Areas Sat. PM in southern Lower Michigan. The threat is greater across N. Illinois, but it certainly bears watching. Here’s radar:

Central Great Lakes sector loop

Go to: Most Recent Image

ALSO: Bear sighting in Walker at the Blueberry Valley Condo Complex, off Walker NW north of Richmond NW. Snow falling in the mountains just east of San Diego. Snowing as I write this on the webcam at Julian CA. Hail up to dime-size at Vista CA. Lightning at El Cajon CA. Record heat in the South. Funnel clouds were spotted near San Clemente CA.

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