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Decision Support News and Info           Updated March 21, 2013

This blog is dedicated to information important to emergency managers, spotter group coordinators, weather partners, and other decision support groups interested in the latest news from the National Weather Service in Green Bay.  If you have any questions, contact Jeff Last <>

NWS Green Bay Participating in Impact-Based Warning Experiment
Posted March 21, 2013

The Impact Based Warning (IBW) experimental product is an effort to better communicate severe weather threats within National Weather Service warnings. Here's a video that summarizes the experiment:

And here's a comprehensive web page on the IBW project:

Flood Awareness Week, Severe Weather Awareness Week Info
Posted March 18, 2013

Flood Safety Awareness Week is March 18-22:
Severe Weather Awareness Week is April 15-19:

Decision Support Web Pages for Partners
Posted March 4, 2013

New web pages that are tailored to the needs of our DSS partners are now online. The pages are available here:

Spotter Training Schedule is Online
Posted March 1, 2013

The 2013 spotter training shedule has been set:

New Weather Spotter's Field Guide is Available
Posted March 15, 2012

Download the new spotter's guide here:

April 10 Tornado Outbreak Summary
Posted May 18, 2011

A summary of the record tornado outbreak in Wisconsin:

NWS Reference Guide
Posted November 3, 2010

The National Weather Service has completed a comprehensive reference guide for partners and customers. The guide covers many aspects of NWS products and services. To view or download the guide, visit this website:

October 26-27, 2010 Windstorm
Posted November 2, 2010

A review of the large storm that affected the region on October 26-27, 2010, is available online here.

Storm Spotters: Snowfall Info Needed
Posted November 1, 2010

Storm spotters are encouraged to contact the National Weather Service (either through eSpotter or the toll-free spotter hotline) to report snowfall during and after an event. If possible, call every few hours with your amount, and then after the snow has ended with a storm total. No amount of snowfall is too little! 

In addition to snowfall, reports of freezing rain, slippery roads, and dense fog (visibility less than 1/4 mile) are helpful. 

Click here for a helpful reminder on how to measure snow.

Winter Weather Awareness
Posted November 1, 2010

Winter weather will soon be upon us. Safety information is available here. When winter weather is approaching, you can monitor the latest by clicking here and here.

1" Hail Experiment a Success
Posted February 10, 2010

With the help of emergency managers, media, and others across Wisconsin and the central U.S., the 1" severe hail size experiment was successful. The entire nation has adopted the new severe hail criteria beginning this year. Hail that is 1" in diameter is about the size of a quarter. Severe wind criteria remains at 58 mph (50 knots).

Thanks to all who participated in the experiment by sharing their comments with the NWS.

Winter Weather Monitoring Website Developed
Posted January 6, 2009

NWS Green Bay has a new web page to help you monitor severe winter weather. Click here to monitor the latest weather across northeast Wisconsin.

January 7, 2008: Rare January Tornado Hits Southeast Wisconsin
Posted Jan 6, 2009

On January 7, 2008, for only the second time in over 100 years of Wisconsin January tornado records, a tornado was reported in the state; in fact, two tornadoes hit Kenosha County. The hardest hit area was the town of Wheatland in Kenosha County, where over two dozen homes were damaged or destroyed. A tornado intensity rating of EF3 was assigned to the larger of the two twisters. For more information on the rare January tornado outbreak, click here

Storm-Based Warnings--What Changed?
Posted Oct 1, 2007

The National Weather Service (NWS) in Green Bay officially began issuing Storm-Based Warnings in late September 2007. As a matter-of-fact, the NWS Green Bay office has been transitioning to storm-based alerts for several years.

Instead of selecting whole counties ahead of a storm, we are warning based on a threat area (in the shape of a polygon) ahead of the storm. If that threat area touches a section of the county, it is specifically listed in the actual written warning.

Storm-based warnings

(Click to enlarge)

The threat area, or polygon that is created by the radar meteorologist, is displayed on the front page of NWS web pages, viewable on NWS web page radar imagery, and on some television weather crawls. The text in the actual warnings will detail sections of a county under the threat, depending on how much of that county is actually covered.

Look at the example below.  Notice how the threat area (polygon) only covers a small section of two counties (southeast Forest and northern Oconto).  Far fewer people are actually under a Severe Thunderstorm Warning compared with if both counties were warned in their entirety.

Radar and warning example

(Click to enlarge)

Issuing warnings based on storms (and not on counties) means you could have two warnings in effect for the same county. For example, you could have a threat area in the northern half of the county and a second, separate storm in the extreme southeast part.

Warning example

(Click to enlarge)

So, there isn't much of a change from what we used to do. Warnings still list counties or sections of counties under a severe weather threat.  In addition, warnings are a bit more detailed and centered on the main threat area. Storm-based warnings offer much more flexibility and a more accurate depiction of what is expected.  Cell phones, PDAs, and GIS-enabled systems can take advantage of the warning area latitude/longitude information contained in the storm-based alerts. Software is already being developed by private weather companies that will take the storm-based warning information and tie that in with county siren systems.

Additional information on storm-based warnings can be found by clicking here.

Summaries of Major Northeast Wisconsin Weather Events Online
Posted August 30, 2007

After significant weather events, summaries are often placed online on our website. For a list of links to summaries of significant weather events and other interesting phenomena, visit our "Neat Stuff" page by clicking here.

Plan, Practice, Monitor, and Act
Posted April 20, 2007

Do businesses, churches, schools, and gathering places in your county have a severe weather safety plan? Click here for a weather safety plan outline.

Tornado Safety in Schools
Posted Mar 5, 2007

The tragedy at Enterprise High School in Alabama on March 1, 2007, brings to the forefront the destructive power of tornadoes. FEMA has a publication "Tornado Protection: Selecting Refuge Areas in Buildings" that will help in reviewing buildings for the purpose of selecting areas that are likely to be most resistant to tornadoes and high winds. Additional information is available on our School Preparedness Guide web site:

The Enhanced Fujita Scale
Posted Feb 5, 2007

On February 1, 2007, the National Weather Service fully implemented the Enhanced Fujita (EF) Scale to rate tornadoes, replacing the original Fujita Scale. The EF Scale will continue to rate tornadoes on a scale from zero to five, but ranges in wind speed will be more accurate with the improved rating scale. For more information, click here.

Warning and Advisory Tip Sheet
Posted Jan 23, 2007

Did you ever want to know when exactly a Winter Weather Advisory might be issued? Or what the difference is between a Heat Advisory and a High Heat Warning? A list of advisories and warnings issued by the NWS Green Bay are available on a single sheet by clicking here (PDF format).