First Real-Time Computer Hurricane Forecast

On August 13, 1958, the first computer model forecast for a tropical system was issued.

University of Chicago scientists ran a forecast for Tropical Storm Becky. The storm had formed a few days prior.

Becky’s actual track

This computer model was not used in the official forecast for Tropical Storm Becky. Scientists tried computer models for three more storms that season, with 17 total forecasts issued in 1958.

For more information, click here.

For more information on the 1958 hurricane season, click here.

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Posted under Tropics, Weather History

This post was written by Rachael Peart on August 14, 2018

F4 Tornadoes in Eastern Iowa – 8/12/1974

Two damaging tornadoes tracked through eastern Iowa on August 12, 1974 casing major damage and several injuries.

The first tornado moved through the southern end of Ryan in Delaware County.  The tornado was an F4, damaging or destroying several dozen homes.  Two business were also hit hard, along with a school and Saint Patrick’s Church in town.  According to the National Weather Service Des Moines, the church and 20 other businesses were destroyed.  There were 12 injuries in Ryan.

 

Another tornado touched down in Iowa County, near Ladora.  Two people were injured, and the tornado swept away a farm house.  The Ladora tornado was also an F4.

The Fujita Scale (F-Scale) was retired in 2007, and replaced by the Enhanced Fujita Scale.  The F-Scale was based on the damage from the tornado.  Enhance Fujita Scale also takes into account the damage, but the ratings are put in line with coinciding wind speeds with the damage.  All based on estimates.

Below is the surface and upper air map from that day at 6 AM Iowa time.  You can see a cold front approaching from the northwest, and a dip in the 500 mb jet stream.

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Posted under Severe Weather, Weather History

This post was written by Kyle Kiel on August 12, 2018

One Year since EF-1 Tornado in McGregor

It’s been a year since an EF-1 tornado tracked through portions of Clayton County, and causes severe damage in the historic downtown area of McGregor.  Two buildings were destroyed.

The tornado began 0.4 miles northeast of Giard, and tracked through the town of McGregor, before lifting east of town in the Mississippi River.  It was on the ground for 5.7 miles and was 400 yards wide.

Estimated wind speeds for the tornado were 110 mph, which equates to EF-1 damage.  Two people were injured due to flying glass.

West of McGregor, several trees were damaged, a metal roof on an outbuilding was ripped back and a storage shed was damaged.

Several inches of rain also lead to flooding in northeast Iowa that evening.  For more information on that, including radar history and photos from the damage, here is the storm assessment from our friends at the National Weather Service in La Crosse, WI.

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Posted under Severe Weather, Weather History

This post was written by Kyle Kiel on July 19, 2018

Iowa-Wisconsin Flooding of July 2007

Iowa is no stranger to flooding events. On July 17, 2007, storms tracked through northeast Iowa and southwestern Wisconsin.

Severe weather alerts were in place that evening into the early morning hours of July 18th. Large hail and severe winds were reported within those counties in the large yellow polygon.

Storm reports July 17-July 18, 2007. Green values represent hail reports while blue values represent wind reports.

Winds damaged trees in Dubuque and Clayton counties. In addition to the hail and wind experienced overnight, very heavy rain fell along the Iowa-Wisconsin border into the morning of the 18th.

National precipitation ending 6AM Central, July 18, 2007

 

Heavy rain near the Mississippi during the early morning of July 18, 2007

 

The rain caused flooding on the morning of the 18th in counties and towns close to the Mississippi where Iowa and Wisconsin meet. Marquette and McGregor in Clayton Co, Iowa and Bagley in Grant Co, Wisconsin were some of the hardest hit areas, according to the National Weather Service (NWS) in La Crosse, Wisconsin.

More than 8 inches was reported in McGregor and Marquette. Prairie Du Chien had multiple reports of over 5 inches in Crawford Co, Wisconsin, with one report of more than 7 inches. 911 calls began coming in early in the morning in Grant Co, WI. Flooding and mudslides were seen in Iowa. The area near Bagley, Wisconsin experienced similar effects as well as sewage backup and power issues.

Flooding in Bagley, WI July 18, 2007

Mudslides July 18, 2007

When looking at the rain totals across the state of Iowa in that month, the heaviest amounts of rain were concentrated in counties closer to the Mississippi River.

Iowa rainfall July 2007

The highest rain totals in Iowa during August 2007 would be recorded in the northeastern part of the state.

Iowa rainfall August 2007

In fact, another flooding event occurred in northeast Iowa, southeast Minnesota and southwestern Wisconsin in August 2007.

For more information on the July 17-18, 2007 flooding event, visit the NWS La Crosse event recap.

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Posted under Flooding, Severe Weather, Weather History

This post was written by Rachael Peart on July 18, 2018

Eastern Iowa Tornadoes – May 25, 2008

May 25, 2008 was an active day for severe weather across eastern Iowa, with six tornadoes being confirmed across the KWWL viewing area.  Of note was the EF-5 tornado impacting Parkersburg, New Hartford and Dunkerton with estimated peak wind speeds up to 205 mph(to watch our special report “Tornado Turnaround”, click here), and the EF-3 tornado near Fairbank and Hazleton, with peak wind speeds up to 160 mph.

There was also an EF-1 tornado south of Lamont in Buchanan County, as well as an EF-1 south of Petersburg in Dubuque County.  Another EF-1 touched down near Interstate 80 in western Iowa County, fortunately not impacting many people.  And finally, an EF-0 was reported north of North Liberty.  To read the full assessments from the NWS Quad Cities, click here.

  1.  The tornado touched down 2 miles south of Aplington, before growing to 3/4 of a mile wide as it moved to the south side of Parkersburg.  300 homes and businesses were destroyed.  Seven people were killed, with many others injured.  From there, the tornado went down Highway 57 and tore through the northern part of New Hartford, where it killed two people, and damaged and destroyed many homes.  The Sinclair Elevator and the Oak Hill Cemetery took a direct hit.  Read the full assessment from NWS Des Moines here.
  2. The EF-2 tornado in Buchanan County touched down near Fairbank.  The tornado was 0.7 miles wide and was on the ground for 32.4 miles.  Three homes were destroyed, with many others damaged, along with several downed trees and power lines.  On the south side of Hazleton, many mobile homes were destroyed.  Three people were injured
  3. EF-1 tornado south of Lemont was about 100 yards wide with an estimated peak wind speed of 90 mph, and was on the ground for 2 miles.  There were many outbuildings and trees that were damaged.  No injuries or deaths were reported.
  4. An EF-1 was confirmed south of Petersburg in Delaware county.  The tornado was 250 yards wide with estimated wind speeds of 90 mph, and was on the ground for 7.75 miles.  Trees and outbuildings were damaged, along with more than 1,000 trees destroyed in New Wine Park.  No injuries/deaths were reported.
  5. An EF-0 was reported north of North Liberty in Johnson County. Estimated wind speeds were 85 mph, and it was 100 yards wide with a path of 0.1 miles.  Many trees were uprooted, and several homes were damaged.
  6. And EF-1 tornado was reported near Interstate 80 in Iowa County.  Estimated wind speeds were 90 mph, and it was 250 yard wide and was on the ground for 6 miles.  No injuries or fatalities were reported.  A grain bin near Victor was blown over, and a tree fell on a mobile home.  Many machine sheds were also damaged.

Here is a full list of the storm reports, mesoscale discussion, watches and outlooks for the nation that day.

 

The Enhanced Fujita scale is used to estimate wind speed based on the damage from the tornado.  They are not measured wind speeds.

 

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Posted under Severe Weather, Weather History

This post was written by Kyle Kiel on May 25, 2018

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F Scale vs EF Scale

This month we are highlighting some memorable weather events in eastern Iowa. Namely, we are remembering May tornadoes that made a lasting impact in some of our communities. However, what do you know of the way tornadoes are rated?

Half a century ago this month, an F5 tornado tracked through Charles City. It was one of two F5 tornadoes that day in eastern Iowa. The other tracked through the Oelwein and Maynard areas.

A little more recently – actually 10 years ago this month – an EF5 tornado tracked through Parkersburg, New Hartford and the surrounding areas.

The difference between these two rankings – F5 and EF5 – is time.

The EF, or Enhanced Fujita scale, went into operation in 2007. This is the scale currently used by meteorologists. Previously, the F, or Fujita scale, was used to rank tornado damage intensity. Click here to find the parameters used for the F and EF scale.

Regardless of which scale was used, the three tornadoes listed above were among the strongest and most destructive in Iowa history. Even EF0 or EF1 tornadoes can cause extensive damage. In 2017, an EF1 struck McGregor in Clayton County. You can read more on that tornado here. In fact, most of the tornadoes in 2017 were ranked EF0 or EF1. For more information on the 2017 tornado climatology, click here.

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Posted under Severe Weather, Weather History

This post was written by Rachael Peart on May 16, 2018

May 7, 1964 Waterloo Tornado

On this day in 1964, a tornado moved through Waterloo injuring 27 people. The tornado was rated and F-2

Below is the information from the National Weather Service in Des Moines. Click on the text to enlarge.

The map below shows the path of the storm as it traveled southeast dissipating near Raymond. Click map to enlarge.

The information below is the specifics from the F-2 tornado in Waterloo from Storm Events Database.

The chart below shows there were other tornadoes that day and damaging wind storms. Looks like it a wild and scary day.

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Posted under Severe Weather, Weather History

This post was written by Schnack on May 7, 2018

Record Snow Depth

The highest official snow depth recorded in Iowa was 42″. It was reported in Sioux Center February 20-22, 1936.

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Posted under Weather History

This post was written by Schnack on February 21, 2018

Snowy February, So Far

You don’t need us to tell you that the month has been off to a wintry start.  In Waterloo, we’ve seen at least a trace of snow over the last 10 days (Feb. 2-11). However, we’ve only had 7 of those days with measurable snow (more than a 0.1″).

Looking back at records for the most consecutive days with measurable snow for Waterloo, Dubuque, Cedar Rapids and Iowa City, we found some interesting facts.  Cedar Rapids has had 9 consecutive days with measurable snow this month, which is the all time record.  Dubuque also had 9 days, which is the longest streak, ever, at the airport.  Waterloo was the 4th longest streak, and Iowa City (based on the data we could find) did not make the top 10.

We certainly have been playing catch-up in the snowfall department this season.  With the recent snow, we are within a couple inches above and below average across the “Big 4.”  We’re also ahead in most areas this year, compared to last winter (which was a down year, to the date, as well).

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Posted under Weather History, Winter Weather

This post was written by Kyle Kiel on February 11, 2018

Flashback: Groundhog Day Blizzard

Today marks the 7 year anniversary of the 2011 Groundhog Day Blizzard, which brought a foot or more of snow to portions of eastern Iowa, as well as gusty winds 40-50 mph.  Blizzard Warnings extended from Michigan to Oklahoma.

Here’s a look at the snowfall across the region:

The heaviest band of snow fell in portions of Missouri, far eastern Iowa, and northern Illinois.  The wind caused snow drifts of 2 to 5 feet, with some drifts as high as 10 feet.  The storm caused major travel issues, closing many roads.

Here are the surface weather maps from February 1st, and February 2nd.  Low pressure strengthened in Texas and tracked northeast through Illinois, into Indiana and Ohio.  The heaviest snow fell on the northwest side of this system.

February 1st, 6 AM weather map

February 2nd 6 AM weather map

 

Click here for a nice write up of the event from the National Weather Service in the Quad Cities.

Here are some pictures from the Quad Cities (Meteorologist Kyle Kiel took them)

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Posted under Weather History, Winter Weather

This post was written by Kyle Kiel on February 2, 2018

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