An EF4 tornado near Rochelle, Illinois on April 9, 2015. (Jodi Mair via Flickr)
Tornado highlights covering the week of April 5-April 11, and a brief look ahead.
As anticipated, last week was the most active of the season so far when it comes to severe weather. While parts of the severe weather episode did not perform as expected, others did and then some.
Among the barrage of about two dozen tornadoes April 8-9, the first violent twister of the 2015 season touched down to the northwest of Chicago on April 9, killing 2.
The upcoming week shouldn’t be a total snoozer, but it seems rather unlikely to produce anything quite on the level of events we just went through.
28 convective watches were issued during the week, up 10 from the week prior. Tornado watch issuance jumped by five to nine. Tornado warnings were more than double the week prior, as were tornado reports. Main impacts were across the southern Plains into the Lower Great Lakes and Midwest.
A number of rotating storms passed through parts of the Midwest during the afternoon of April 7. Four EF1s touched down across Illinois, and two brief weak tornadoes also struck central Kentucky.
Several tornado warnings were also issued in California near the capital region of the northern Central Valley. A few funnel clouds dotted the area.
Near nightfall, a handful of supercells formed in Kansas and Missouri. One or two brief tornadoes were reported.
April 7 was expected to be “the day before the day” (in which some tornadoes occur ahead of the main event). In the end, April 8 may have ended up the day before the day.
The second moderate risk of the year, and the first for tornadoes (15% probabilities or higher), was issued by the Storm Prediction Center. Several tornadoes occurred, but it was much tamer than many expected overall. (sidenote: Mark Ellinwood was bearish enough I thought he might bust, but he did quite well with the forecast here).
Although a number of supercells formed across western Oklahoma and into Kansas late in the day, it was mostly one storm near the triple point in Kansas that did much in the way of producing tornadoes. Even then, most tornadoes were short-lived and weak, but several were quite photogenic.
Here’s some video of one of the longer-lived tornadoes near Medicine Lodge, Kansas from Skip Talbot.
It was a beautiful day for storm structure as well.
What Wednesday (Apr 8) lacked in higher-end activity, Thursday (Apr 9) easily made up for.
While the risk level remained enhanced, which was a step down compared to the day prior, there was still high odds of a tornado event, one which could include strong tornadoes.
In Illinois alone, at least eight tornadoes occurred. One was the now very well-known Rochelle/Fairdale EF4. Two people were killed by this tornado which traveled for 28.7 miles. Its wind speeds were estimated to peak at 180 to 200 mph.
Videos of the violent tornado tell quite the firsthand tale. It was a beast.
The scene afterward was difficult to see, as it always is when a powerful tornado makes contact with civilization.
This one’s barely even worth a mention, but it was an early-season weekend chase day in the High Plains. And you just have to love the High Plains!
A return to the pattern of old?
This week is starting off fairly quiet for tornado activity. Numerous severe thunderstorms did fire up across the country — focused across the Plains — on Sunday, but they were mainly wind and hail producers. More severe weather is anticipated today, again with a relatively low tornado threat.
Eyes now turn toward a slow-moving upper-level storm system slated to “cut off” over the four corners region midweek, before eventually moving out across the country toward the weekend. SPC has put up a marginal risk for Wednesday already on this system.
Systems like this, that are big and lumbering, are notoriously difficult to forecast.
Once the center of the upper low makes it to the 4 corners or east by Wednesday or Thursday (at least based on current expectations), there’s probably a daily chance of at least a little wave sparking off thunderstorms amidst at least marginally favorable wind shear.
From here, it looks like one big problem for widespread activity might be moisture availability. It seems Texas or into Oklahoma would be the favored region, though the southern High Plains more generally could face a severe or even tornado threat depending on how the system moves out.
Eventually, severe weather risks may progress east as we get into the weekend. Nothing is screaming big event at this point.
In a field historically dominated by men, Jen Walton has emerged as a transformative figure…
Jason Persoff, MD, SFHM, is recognized globally for his expertise in storm chasing. He earned…
Tornado numbers were near or above average. A chase season peak in June provided numerous…
One of the more widespread tornado outbreaks in years, from Iowa and Illinois to Arkansas.
The active start of the year could be a sign, but a mid-March pattern change…
A near average year for tornadoes across the country, with a cool season bend. We've…
