Tornado Digest: Tornadoes missing in April (and 2014), at least so far...

Lone Tree, Iowa tornado on April 13. (YouTube)

Looking back at the week of April 13-19.

The middle of April has historically been a rough period when it comes to big tornado events in the United States. Just three years ago, a major outbreak sequence brought North Carolina its biggest tornado day on record.

Not this year, at least not yet.

Other than April 13 which dropped a smattering of disparate tornadoes, it was a fairly quiet week across the country, with only a brief additional bout of excitement brought on by a hefty squall line.

The lack of activity gave some time to look at the tornado drought, and our prospect of ending it any time soon…

Tornado activity for the week

April 13

This was the main day of severe weather for the week — and the only with tornado reports. Even here, not too intense by April standards. For the most part, a crashing cold front undercut storms as they were forming and kept tornado risks to a minimum, though several weak ones did touch down in places like Oklahoma and Iowa.

Oklahoma

540pm – front and dry line visible on Frederick radar. #texomawx pic.twitter.com/LMm4gnQZod

— NWS Norman (@NWSNorman) April 13, 2014

Brief tornado caught just east of #Duncan from our sister chopper, Osage SkyNews9. #okwx pic.twitter.com/IT66nltZ4F

— Michael Grogan KOTV (@GroganontheGO) April 13, 2014

Iowa

April 18

Not a big day, but a day with tornado risks, which makes it big this year. The main story here was a squall line coming ashore across Florida. As it first made “landfall,” some tornado concerns were present, thanks mainly to the risk of waterspouts coming ashore.

First Tornado Warning of the day over in Pinellas County, because of a strong water spout coming ashore. pic.twitter.com/q0XDXjhQjD

— Eric Burris (@EricBurrisWESH) April 18, 2014

One of the best shots over #Tampa Bay as #tornado warning in effect earlier #flwx (thanks John Garcia) pic.twitter.com/UtHrsnWx8M

— Brian Mcclure (@mcclureWX) April 18, 2014

Tornado drought

Update: NWS has confirmed at least 89 US #tornadoes across 21 states so far this year #USwx (263 tornado warnings) pic.twitter.com/ZNdzZ8VlAU

— Johnny Kelly (@stormchaser4850) April 16, 2014

Johnny Kelly recently reported that at least 89 tornadoes have been confirmed across the United States this year as of April 15. An additional tornado or two touched down on April 20 (covered in the next digest), so our numbers are in the vicinity of 90 (I’ll say +/- 10, as prelim number can be quite prelim).

The exact number is somewhat unimportant, more where it fits on the trend line.

Tornadoes in the United States by year through April 20. 2014 ranks quite low.

Way behind last year, which of course ended up rather quiet on average. 2010 started quiet, then roared to life. We don’t currently anticipate that happening this year, at least on that scale.

Other years besides this one with 100 or fewer tornadoes through the date include 2010, 1988, 1987, 1985, and four in the 50s and 60s back to 1953. Rare company.

Tornado researcher Harold Brooks also recently offered this on Twitter:

Unofficially, <50 EF1+ tors in '14, tied 7th latest to 50 in 61 yrs. By Mon, tied 6th w/ 5 of 6 latest in last 18 yrs, also 7 of 9 earliest.

— Harold Brooks (@hebrooks87) April 18, 2014

A piece at FiveThirtyEight by Matt Lanza is also worth a read.

What’s ahead?

The pattern is looking more active ahead as troughs cut through the country over the course of the next week or so. We’re also getting to the time of year where storms like to storm even in bad patterns.

System one is likely to have somewhat limited moisture to work with, but storms are a good bet. There should be some tornado threat associated with it particularly Wednesday along the dry line in places like western Kansas. Nothing major though, and it’s probably more of a big hail and storm structure type day overall.

Euro 500mb vorticity shows a trough pushing out of the west late Saturday. (Weatherbell.com)

A bigger threat may evolve next weekend as a large trough pushes into the West Coast and then out across the central United States. At least some of the looks with this one have high-end potential, but it’s way on out there.