2/27 - 2/28 Winter Storm; MI

[Robert Dewey]

Okay, not exactly a sealed deal... but the 12z NAM is very close to having an all out ice storm for the Pontiac, MI area. It has been trending colder at the surface, and BUFKIT now shows temps making up to a sweltering 32.36F on E/NE wind during heaviest precip. If some of that colder air north of the boundary can undercut the warmer air being pumped in at 850mb, I think things could get interesting. Most ice storms I've seen around here have featured temps not much warmer or colder than 30F, and the last big one a few years ago was actually a "surprise" event starting out as a ZR advisory (temps expected to warm, but never did).

I know there's a lot of thermodynamics involved with melting / freezing processes. Rapidly melting snowfall in the presence of rain seems like it would help cool the surface layer in the absence of WAA... but then again, freezing releases heat.

It will be interesting to watch.

 

[Robert Dewey]

This seems like it's looking more and more likely to me. 18z NAM isn't all the way in yet, so I don't have access to the BUFKIT files... but it looks like it's slightly further south, and *might* translate into a colder surface temperature. What's interesting is that it's also kicking up more QPF, creeping up toward an inch in spots with 1.25+ south of the border. Most falling between 6z and 12z tonight / tomorrow morning.

HRRR starts things out as rain at 6z, but has been trending slightly south with the R/ZR line. You can definitely see the colder air undercutting the warm air when you loop the precip type. HRRR didn't fair so well with the tight baroclinic zone on the Feb 21st storm, which had DTW at mostly IP / ZR with a few inches of snow. DTW and even points south ended up mostly snow, picking up 10 inches. (http://www.crh.noaa.gov/images/dtx/events/snow201102211355.png)

Temps continue to hold steady at 36-38F around here... It will definitely be a race between precip and the shallow cold air dropping south.

 

[Robert Dewey]

Just looking through some historical data... The layout of the synoptic features are fairly similar, including temperatures. I believe the 2003 event was somewhat of a surprise ice storm (which dropped 1-2 inches of ice - one of the worst in SE MI history) in regards to the fact that the cold air funneled in quicker than anticipated. If I'm not mistaken, we were under a freezing rain advisory with a change over to rain expected. I don't have access to old watch/warning data, so I'm not 100% sure on that. This is, for the most part, why I think keeping an eye on this is important.

Current (0z)

April 4th, 2003 (DTW at 39F with "only" 25-30F to the north)

 

[Nick Dewhirst]

Happened to be looking through the winter weather forum and I saw your thread. I found this really interesting. I live in the northwestern Detroit suburbs and have found that freezing rain events almost always overachieve here. Somehow the cold air from Ontario can just stay locked in, especially across central Oakland county. Seen many events where a warmup was expected but never occurred. I’m currently a junior in high school, and we had 6 days off in the 2018-2019 winter. 3/6 were because of freezing rain. I’ve established a reputation for predicting our days off, and when the superintendents were going with the news channels/occasionally NWS saying it wasn’t going to be much more than a glaze, I typically went more aggressive with my forecast and it paid off.

I guess it’s just something with the topography in our area...