- Jul 28, 2022

TORNADO SEASON, HEAT TO COME...

The severe weather season started strong, especially in Iowa with an EF4 tornado in early-March and an EF3 April 12th. The Winterset tornado March 5th reached EF4 strength with 170 mph winds. It was the strongest in Iowa since October of 2013. 7 people were killed.

The 7 deaths were the most in Iowa since 2008. Iowa averages 1 tornado fatality per year. Alabama is first with an average of 18 followed by Missouri with 12. Illinois averages 2.

Just over a month after the Winterset storm, 8 tornadoes struck NW of Fort Dodge, Iowa. The strongest was an EF2 near Gilmore City. I was there and captured this picture of it shortly after it set down. No fatalities were reported.

After April 12th, the season ground to a halt. With the tornado count running way above the annual mean April 12th a steady decline now has the number at 1,383

You can see that's well under the annual mean for this point in the year.

In fact, after being close to the all-time maximum April 1st, the season is now below the 25 percentile rank.

The graphic below nicely depicts the decrease in tornadoes nationally after mid-April.

In my local area, the NWS office in Davenport has put out 20 tornado warnings. Most of those were low end intensity tornadoes or just Doppler indicated warnings for rotation.

For the nation as a whole, 1,708 tornado warnings have been issued. That's far below the record year of 2011 when 3,843 warnings were posted.

We certainly have no severe weather worries in the days ahead as NW flow keeps storms and precipitation at a minimum through the coming weekend. I say that as overnight showers move out early Thursday morning along with a weak disturbance in the NW flow aloft. Whatever rain manages to linger early Thursday quickly departs allowing sunshine and pleasant temperatures to dominate the afternoon. After that we are dry though the weekend. Here's what a few models suggest for rain through early Thursday.

The EURO

The GFS

The 3K NAM

Temperatures through the weekend will continue to be first rate with the EURO showing nothing higher than 84 in Davenport through Sunday. Then the wheels of change go into motion as the western heat dome makes a push into the Midwest. The EURO even cranks out a 101 in Davenport next Wednesday. All told, it knocks out 5 consecutive days of 90 or above.

The GFS is in its own universe with a torrid heat wave in Davenport with 6 consecutive days of 100 or more. Included in that are 111 and 110 degree days! I would bet the house we don't get anywhere near those numbers. In fact, it's been over 10 years since our last 100 degree day so just reaching that level would be a big deal.

Having said that, we may get a crack at the century mark for at least a couple days next week as the Climate Prediction Center indicates a high risk of excessive heat during August 3rd & 4th with a moderate risk the 5th and 6th.

By the way, these are the 850 temperature anomalies over the 7 day period August 3rd-10th. At 5,000 feet readings at that level are forecast to average 6-8 degrees above normal per day. That warm air aloft represents a cap which thwarts the development of thunderstorms. In other words, we are far from the ring of fire and its thunderstorm potential. Instead subsidence keeps us hot, humid, and likely quite dry.

Here's the 2 week precipitation anomalies on the GFS showing the wet weather split to the north in Canada or to the south in Arkansas and Kentucky. Under the heat dome we remain dry allowing rainfall deficits to close in on 2 inches.