Looking Down to Dixie

This bright morning sun streaming through the sliding door of my balcony is blinding. At quarter-to-ten on the day before Thanksgiving, it shines low over the southeast horizon directly onto my face, forcing me to write with my left eye shut. That is not an altogether satisfying modus operandi, but I don't feel like closing the blinds or wearing a ... well, what the hell, why not wear a hat? I've just put on my trusty Tilley. Problem solved, though Lisa will probably look at me oddly when she steps into the room. Here in West Michigan, we're moving into high pressure and a warming trend through the holiday. But "warm" is a relative word which in this case means not terribly cold--rather nice, really--but don't plan on wearing a T-shirt. Hundreds of miles to my south, though, warm means warm. Warm enough to get the job done for convective weather. From now through April, Dixie Alley once again becomes the star of the show. The trough moving in for the weekend offers a good example of why. It's a deep trough, and a surface low up in the Great Lakes looks to wick up enough moisture into the Southeast to stoke the storm machine. I've included a couple of the latest 00Z Euro/GFS comparisons plus Euro 850 mb relative humidity to give you a sense of what's shaping up for 96 hours (click on images to enlarge them). The GFS is predictably faster than the ECMWF, but both are pointing to the same overall scenario, with the trough eventually pinching off into a closed low. Cloud cover presently looks like it will be rampant, minimizing instability. Still, given some ripping bulk shear, this system is something to keep an eye on as it evolves, particularly if you live in Dixie Alley. That's all for now. The sun has moved and is no longer blinding me. Time to get on with the rest of this day. May you and yours enjoy a happy and blessed Thanksgiving!

Great Lakes Waterspout Season Is at Hand

Now is the time of year when waterspouts start putting in an appearance on the Great Lakes. I had largely forgotten about spouts until a few days ago when my friend and fellow weather weenie Mike Kovalchick mentioned them in an email. Bing! A light blinked on in my head: That's right! Waterspouts! I've never seen a waterspout. But then, until last year about this time with my buddy Kurt Hulst, I'd never made a point of going out after them. Kurt and I busted that day, but maybe this year I'll get lucky, provided I increase my chances by taking more opportunities to chase spouts. I have zero experience forecasting waterspouts. Thankfully, there's a snappy little graph called the Waterspout Nomogram that simplifies the process. Developed by Wade Szilagyi of the Meteorological Service of Canada, the Waterspout Nomogram provides a quick visual aid for determining when certain critical parameters are in place for four different classifications of waterspout: tornadic, upper low, land breeze, and winter. The tornadic variety is self-explanatory, and any storm chaser with some experience making his or her own forecasts should have a good feel for when that kind of waterspout is likely. Mike favors the 500 mb cold-core, closed low setup, which to my thinking may be a variant of the first in producing low-top supercells. The remaining two, land breeze and winter, seem to involve different dynamics. For all the waterspout categories, one of the constraints is that for spouts to occur, winds at 850 mbs have to be less than 40 knots, something I find particularly interesting in the case of supercell-based waterspouts. In any event, I'm hoping that this year is my year to finally witness a spout or two. Michigan chasers and weather weenies, it's time to pay attention to the marine forecasts. The "second season" can include action right along the lakeshore even when nothing's popping anywhere else. Make sure you bring your shotgun just in case a waterspout gets too close for comfort (written with a wink and a grin).