Storm Chasing in Illinois on Wednesday

The formidable system that ground out large, violent tornadoes in Kansas, Oklahoma, and Texas on Tuesday will move east on Wednesday to bring another round of severe weather to southeast

Missouri, Illinois, and Indiana. And finally–finally!–I’m in a position to do some storm chasing. Financial constraints have majorly crimped my expeditions so far this season, but no way am I missing tomorrow.

Based on Tuesday morning’s NAM run, I’d been eyeballing Effingham, Illinois, as a preliminary target for trolling the I-70 corridor. The sounding for that area looked mighty pretty, as you can plainly see.

Now, however, with the 00Z runs in, I’m inclined to shift farther east near Terre Haute. Here’s another model sounding, courtesy of TwisterData, for near Oblong, Illinois. Maybe not quite as sexily backed at the surface as the Effingham sounding, but with stronger low-level winds and definitely quite functional. Maps of 500 mb winds and SBCAPE (see below) paint in a little more detail and suggest that near the Illinois/Indiana border is a good choice.

Tomorrow morning’s data will tell all. Meanwhile, it’s time for me to get my ugly-rest. I am so excited about the prospect of finally getting out and feeling the moisture, watching cumulus towers erupt and organize into glowering supercells, and hopefully videotaping some tornadoes out on the flat, wide-open Illinois prairie! A good night’s sleep and then I’m off in the morning.

Warming Trend through February

Today temperatures are forecast to be in the mid to upper 30s here in West Michigan, and by Friday they should be well into the forties. With a little luck, we may even see our first 50-degree day of the year. This warming trend has been no secret, and it’s the kind of thing that draws me out of my wintertime apathy about weather maps and whets my curiosity. The next week seems pretty well defined, but what lies beyond the horizon?

So this morning I did something I haven’t done for quite a while: I peered into the magic 8 ball of the 6Z GFS all the way out to 372 hours, to the forecast hour of 18Z Monday, February 28. My point in doing so was to get a sense of what general trend might be shaping up. What I see is the beginning of springtime incursions of warmer air. Not to say that we up here in the northwoods can don our swimsuits and head for the beach, but it looks like this week may mark the end of the long stretches of bitterly cold weather. We could see more days near or above freezing, and at times up into the forties, rather than in the 20s and teens.

In just two more weeks meteorological spring will arrive. Granted its foibles, overall the long-range GFS appears to be rolling out the carpet. We’re not there yet, friends, but today’s warmup offers a view from the hilltop and the end is in sight. We’ve almost made it through another winter.

Intense Autumn Storm System Arrives Tomorrow in the Great Lakes

I’m not going to try to be particularly clever in writing this post. Instead, I’m going to throw a bunch of weather maps and a few soundings at you and let them tell the story.

I will say that the weather system that is shaping up for late tonight on into Wednesday for the Great Lakes has the potential to be of historic proportions. In terms of sea level pressure, I’ve seen a number of comparisons to the great Armistice Day Storm of November 11, 1940. However, there are two significant differences: this storm is a bit earlier in the year, and the forecast pressure has been consistently and significantly deeper. The Armistice Day storm dropped to 979 millibars; this one may be in the 960s. In other words, we may see a record-setting barometric pressure with this system.

The bottom line is, this thing will be a wind machine like few we’ve ever seen. Here’s the current forecast discussion from the weather forecast office in Grand Rapids, Michigan.

LOW PRESSURE IN THE SOUTHERN PLAINS WILL RACE NWD AND PHASE WITH A
LOW OVER THE DAKOTAS AND RAPIDLY DEEPEN AS THE UPPER TROUGH DIGS
ACROSS THE UPPER MS VALLEY. THIS WILL LEAD TO VERY STRONG DYNAMICS
ALONG THE TRAILING COLD FRONT LATE TONIGHT. EXPECT STRONG TO SEVERE
STORMS TO DEVELOP ALONG THE FRONT AND RACE EAST. A 70KT LLJ AND
115KTS AT H5 INDICATE IT WON/T TAKE MUCH TO GET SVR WINDS WITH THIS
LINE OF STORMS LATE TONIGHT. A VERY STRONG PRESSURE COUPLET...ON THE
ORDER OF 6MB/3 HRS WILL FOLLOW THE COLD FRONT. THIS WILL LEAD TO
STRONG WINDS DEVELOPING BEHIND THE FRONT. BUFKIT WIND PROFILES SHOW
MIXING INTO THE 55-60KT LAYER AT 2K FT. IT IS LOOKING INCREASINGLY
LIKELY THAT WE/LL SEE SUSTAINED WINDS AROUND 35 MPH AND WIND GUSTS
OVER 50...AND CLOSER TO 60 ALONG THE LAKE SHORE. AS SUCH WE EXPANDED
THE HIGH WIND WATCH TO COVER THE ENTIRE CWA.

WINDS WILL DECREASE TUESDAY NIGHT AS MIXING WANES...BUT WILL
INCREASE CONSIDERABLY AGAIN WEDNESDAY. THIS IS A SLOW MOVING STORM
THAT WILL RESULT IN A PROLONGED WIND EVENT FOR THE CWA.

I’m not going to add a lot to that, but I do want to mention the possibility of tornadoes during a brief window of time. Hodographs preceding the front curve nicely, with 1 km storm-relative helicity exceeding 300 showing on this morning’s 6Z NAM sounding for Grand Rapids at 17Z tomorrow afternoon. If enough instability develops–and with winds like the ones we’re looking at, it won’t take much–then we could certainly see some spin-ups as the squall line blows through. And if there’s enough clearing to allow discrete storms to fire ahead of the front, chances for tornadoes increase all the more.

With storms rocketing along to the northeast at over 60 miles an hour, the thought of chasing them is laughable. Anyone out to intercept them will have to watch the radar, position as strategically as possible, and then hope for the best. Serendipity will be the name of the game. That game could begin as early as noon here in Michigan, and it looks to be over before 5:00 p.m.

Not the wind, though. That’ll be hanging around for a while.  Batten down the hatches, campers–we are in for one heck of a blast.

Without further ado, here are some weather maps and NAM forecast soundings from this morning’s 6Z run. Click on the images to enlarge them. Just look at that surface low! Pretty jaw-dropping, I’d say.

Forecast maps for 18Z Tuesday, October 26, 2010


Soundings

Grand Rapids, MI (forecast hour 17Z)

South Bend, IN (forecast hour 16Z)

Muncie, IN (forecast hour 17Z)

New RUC Maps on Storm Chasing Page

Storm chasers, check out the new RUC maps on my Storm Chasing page. They’re still under development, and they’re not comprehensive, but they do offer you something different. I haven’t seen F5 Data weather maps on other sites. If you’re a fan of tornado indices such as the EHI and STP, you’ll like the proprietary APRWX Tornado Index, which includes Great Lakes waterspouts.

For some strange reason, the surface dewpoint map keeps displaying surface temperatures instead. Not sure why, but obiously it needs fixin’. Everything else works as it should. I’ll welcome your comments/suggestions.