Weather Wednesday –New Definitions from the Storm Prediction Center

There’s been much talk in recent weeks of a more detailed method of describing the potential for severe weather now being employed by the Storm Prediction Center in its Convective Outlooks. The SPC worked with National Weather Service offices, communications experts and consumers of its products to expand its long time use of the “Slight, Moderate and High” risk categories to “Marginal, Slight, Enhanced, Moderate and High.”

In addition, the chart below describes what the storms might look like under each newly-defined category and what the main threats would be.

Understanding Categories
The Storm Prediction Center has many products that can be used by broadcast meteorologists, emergency managers and the general public to look as far as 8 days ahead. These tools are especially valuable for planning purposes and should never supplant your detailed local forecast.

The Mesoscale Discussions are particularly helpful on days when severe weather is expected. The discussions are issued on an “as needed” basis as storm threats develop. Other tools are updated as often as four times a day. If you’ve never visited the site at, now would be a good time to familiarize yourself with the offerings.


Weather Wednesday – Hail

On this April Fools Day, we’ll be discussing hail. Hail is widespread throughout the world, but doesn’t often have the top of mind awareness of other storm-related topics…unless, that is, you’re growing crops or insuring buildings or vehicles. According to the National Weather Service’s hail page, the average loss from hail each year is about a billion dollars. However, in 2001 there was one storm event that eventually stretched from Kansas City to Illinois that caused $2-billion damage on a single day.

Hail is not normally considered a major threat to human life. The last reported fatality in the United States was in 2000 when a Texas man died after being struck by a softball sized hail stone. Two children reportedly perished in Russia in 2014. Livestock losses are reported from time to time.

The National Weather Service rates hail from less than a quarter inch or pea sized to over 4 inches or softball sized. The preferred references are actual measurements or approximations based on fixed sizes such as a quarter or a regulation sized softball. “Grapefruit sized” is a far less precise term. One of the reasons for using common objects as references is it allows storm spotters and others to report the size without venturing out into a storm with its associated risks to take actual measurements.

vivian_hailThe largest hail stone reported in the U.S was over 8 inches in diameter with a circumference of over 18 inches.

Phil Katz-MSU Extension

Crop loss from hail is a significant risk to producers. Depending on where crops are in the growth cycle and the extent of the damage, growers are often cautioned to have a little patience to determine if the crops can bounce back. Many state extension services can provide more information.


hail carDamage to vehicles is usually pretty obvious in terms of dents and broken glass. There are some DIY fixes for smaller dents including letting the vehicle sit in the hot sun so the metal expands a bit. The best advice though is to contact your insurance carrier and/or a competent body shop. A worst case scenario is when a new car dealer’s lot or other parking lot is hit. Damage can easily escalate into six figures or more. Several years ago here in the Champaign-Urbana area, dozens and dozens of cars parked at the local airport were badly damaged.

thHail can also damage roofs constructed of various materials. Again, working with your insurance carrier to arrange for an inspection by a qualified roofer is always a good idea. Some damage may be hard for the untrained eye to see and ladder work is often best left to professionals anyway.

Siding on homes also can be easily damaged. Steel or aluminum siding can be dented and still maintain its structural and weatherproof integrity.Bad_Siding_Hail_Damage Hail can absolutely shred vinyl siding and immediate action to cover exposed underlayment or insulation is necessary to avoid more widespread water damage.



NOAA Graphic

One question that is often asked is, does the presence of hail, especially large hail, tell us anything about the structure of a thunderstorm? Since hail is formed when water droplets freeze as they are lifted above the 32-degree line by updrafts, it stands to reason that the presence of ever larger hail stones in a storm reflects the strength of that updraft so it can be an indicator of both the strength and height of a thunderstorm cell. Hail is easily seen on radar because of its dense mass. Many videos shot by storm chasers show large hail as part of some tornadic thunderstorms.

It’s Just the Weather, Y’all



Those in the Deep South are not used to hearing the word “snow”  bandied about in December, but we are this year. Those in the Midwest and Northeast are a bit more used to hearing it. Regardless, as we move from fall into winter, we can help ourselves and our clients prepare for the changes. In addition to the Snow/Ice topic page on the EDEN Web site, you have access to and can search the catalog for resources submitted by EDEN delegates.

Tom Priddy, UKY Point of Contact, Extension Agricultural Meteorologist and director of the UK Ag Weather Center, and his colleagues have developed several weather resources that are available to everyone across the nation. From Tom…

UKAWC desktop severe weather information When we trained the meteorology students in my weather class to locate and identify severe weather safe places in all builds across the campus for StormReady, one of the items that everyone wanted was a comprehensive, but concise desktop severe weather web page for campus, which we developed. After we became certified by the NWS, county agents started requesting a similar desktop severe weather page, specific to their county. After presenting this desktop severe web page at the 2004/05 annual EDEN meeting, other schools ask us to develop similar desktop severe weather web pages for their state. The result was a nationwide desktop severe weather service page.

Nationwide rainfall estimate (Not for legal purposes) While every weather office provides local weather and climate date, rainfall totals is one of the most frequent items requested. Problem is…rarely is there a weather station where you need it. A solution to this problem is provided by the National Weather Service’s new web site, Advanced Hydrologic Prediction Service (AHPS). Among other resources, this site provides the Doppler rainfall total estimated for various time periods, (ie., yesterday, the last 7 days…) in a color-code map.

Digital rainfall estimate This service was developed by the UK Ag. Weather Center and provides the above daily rainfall totals for a selected site across the nation. Based on the daily information provided to us from the NWS’ Advanced Hydrologic Prediction Service, in conjunction with Google Map, we developed software that will allow the user to zoom into their site for the Doppler rainfall total for the past 60 days. The rainfall estimate is NOT for legal purposes.

The following (2) weather items are used by county offices when they want to setup a weather display at a field day where internet access is available.

  • National Weather Map Carousel display targets weather situation across the entire nation and scrolls from left to right and updates every 30 min.
  • National Climate Map Carousel does the same thing as above except it targets the climate and
    drought situation across the nation and includes medium and long-range NWS weather outlooks.

County-by-county precision agricultural, lawn and garden forecasts Since there is so much weather information available on the internet, we wanted to take everything on a county-by-county level and focus that information on one web page for a given county. Here is the entire nation; and here’s an example of the link for one state.

Farm-by-farm PointAgCast Weather services specific for our nations food production ceased to exist over a decade ago. But technology and internet resources have advance so rapidly, it’s difficult to keep up with new developments. For that reason, we wanted to utilize all of these resources to a new level of weather services that could be used by everyone and benefit our nation’s food production. After partnering with both national and regional levels of the National Weather Service, we developed a farm-by-farm agricultural weather service like never before available to our nations farmers. Based on the NWS’ National Digital Forecast Database, the PointAgCast provides site-specific (2.5 by 2.5 km) precision forecast information that we run through various algorithms to provide added information for agricultural farm operations, such as spraying conditions, drying conditions, livestock cold stress, livestock heat stress, etc. You can use your zip code, your county and state, or zoom into the Google maps to locate your site.

UK AG weather “on the go” Free nationwide weather service on your cell phone. Wonder about those clouds on the horizon? Now the radar and the PointAgCast are available on your web-accessible cell phone. This service combined the NWS radars and Precision Agriculture, Lawn and Garden products on your cell phone.

Regards, Virginia Morgan, EDEN Chair