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Metro Detroit weather: Weekend forecast, rain chances changing

Weekend still looking uncertain

A look at the June 8, 2018 radar. (WDIV)
A look at the June 8, 2018 radar. (WDIV)

DETROIT – We’ve explained for a couple of days now how challenging this weekend’s forecast is, and we really thought we’d start getting some clarity out of the computer models today. However, not only is this not the case, but we’re even less confident about certain aspects of the forecast than we were yesterday.

Basically, there’s a stationary front draped across northern Indiana and Ohio (it’s called a stationary front because it isn’t moving much…and you thought all meteorology was hard).  This front is nothing more than the dividing line between a warmer and more humid air mass to our south, and a relatively cooler and drier air mass over us and to our north.  Meanwhile, about 20,000 feet aloft, weak little disturbances are moving across the Great Lakes, and each one can cause that front to buckle northward and trigger a batch of showers and thunderstorms.  The problem is that our computer models are notoriously poor at getting a handle on these weak disturbances, and since their exact placement is critical in terms of batches of rain as well as the front’s placement, this forecast is admittedly a struggle.

 Adding to the forecast challenge is the placement of a Canadian high pressure area north of the Great Lakes which, yesterday, looked as if it would drop far enough south to push our front south on Sunday and, thus, give us a nice day.  So, having spent a considerable amount of time this afternoon diving into every model available to us, here’s how we think the weekend will play out:

Friday night

Although some showers and thunderstorms developed this afternoon across parts of northern Indiana and northwest Ohio, all high-resolution models indicate that most of that activity will fizzle before getting here (and that’s what radar is showing as the time this article was posted).  The best chance for a widely scattered shower this evening (and not everybody will even get one) is in Lenawee, Monroe and Washtenaw Counties, with lower chances elsewhere.  That’s good news for many of us with outdoor early evening plans.  A better coverage of showers and storms should approach late tonight.  Lows in the low 60s (17 degrees Celsius), with either calm or light and variable wind.

Saturday

Scattered showers and thunderstorms appear possible through the day Saturday, but this doesn’t appear to be a continuous wall of water…there will probably be breaks in the rain.  If you have outdoor plans, such as the Tigers game or the Royal Oak Art Fair, you’ll definitely want to keep a close eye on the radar in our Local4Casters app…if you don’t have it, downloading it is easy and free:  just search under WDIV in the app store.  Also follow us on Twitter at @PGLocal4 and @Local4Casters for periodic personalized updates.  The clouds should hold highs in the mid 70s (25 degrees Celsius).  East wind at 5 to 10 mph.

Saturday’s sunrise is at 5:57 a.m., and Saturday’s sunset is at 9:09 p.m.  

Saturday night

There could be a lull in the rain activity Saturday night as we’ll be in between two of those upper level disturbances, but we still can’t rule out some showers.  Lows will be in the low 60s (17 degrees Celsius).  

Sunday

Forecast challenges continue on Sunday, as the models are now pushing that Canadian high discussed earlier farther east than south.  This is a change from yesterday, and means that the stationary front will remain close enough to give us another chance of showers and thunderstorms, although it appears that chances drop off considerably as you head north of M-59.  Highs Sunday, as long as the clouds hold tough, will once again top out in the mid 70s (25 degrees Celsius).

Next Week

Most of next week still looks like a great week of summer weather.  An approaching cold front could give us a few showers and thunderstorms later Tuesday into Tuesday night, and another could give us a thunderstorm on Thursday, but the rest of the week into the weekend appears dry with plenty of sunshine.  Highs should range from the low to mid 80s (27 to 29 degrees Celsius), and there’s some suggestion in the long range models that temps will keep going up next weekend…perhaps into the upper 80s (31 degrees Celsius) by Sunday.


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