What Does All This Mean?


Our Coverage Area

KSStorm.Info content covers only the area we actively chase.

Wichita-Hutchinson Plus ADI

The Wichita-Hutchinson ADI (gold counties) is our core chasing area.

This includes all of Kansas except the northeast corner (east of US-75 and north of I-70), the first two tiers of counties in Oklahoma south of the Kansas line, and the first tier of counties in Nebraska north of the Kansas line and west of US-81.

We occasionally chase further into Oklahoma, Colorado and Nebraska, but do not issue outlooks or discussions for those areas. If we are planning to chase somewhere, there will be a briefing produced the morning of the chase.

Categorical Risk

We use the same category names as the SPC. See http://www.spc.noaa.gov/exper/dy1-3example/ for their definitions.

In KSStorm.Info outlooks, we will generally be talking about the total risk for any severe weather. In briefings and discussions, the risk levels pertain to the one risk identified as the primary risk of the day (for example, large hail).

Probability of the primary risk happening within 25 miles of a point in the risk area.

  • Marginal: up to 5%
  • Slight: 10% to 20%
  • Enhanced: 25% to 35%
  • Moderate: 40% to 50%
  • High: greater than 50%

Impact

This is the forecaster’s determination as to the level of damage, economic impact, or life threat from the identified Primary Risk. By definition, the other identified risks are expected to have equal or lesser impact than the Primary Risk.

One important note about risks: at any risk level it is possible for an individual, family, or even a small town to have a higher-level risk than we’ve identified. It is possible to have an EF4 tornado on a risk day identified as “Inconvenience,” for example. This generally does not happen, but micro-scale details such as this are not within our capability to forecast six to 18 hours ahead of time.

Nuisance
Conditions such as brief heavy rain, non-severe hail, blowing dust. This risk level is for impacts that will be soon forgotten by anyone not directly impacted if the events are even reported.
Minor
These impacts include small branches being blown down, nickel to golf ball size hail, and weak tornadoes. Generally these events impact only a few people total, though the impact to any of the affected people could be more substantial.
Medium
These impacts are going to mess up the day for quite a few people, or be life-changing for a very few people. Examples would include baseball to softball size hail, any tornado in an urban area, and wind above 70 miles an hour.
Major
These are the kind of events likely to produce a FEMA disaster declaration. A solid expectation of strong and/or long-track tornadoes, hail larger than softball size, or winds greater than 100 miles an hour are examples of this kind of risk. These are the kind of days that will be remembered for years.
Catastrophic
We hope never to have to use this threat level. But events like Greensburg, Moore and El Reno (the last two of which were expected for several days in advance) are what this is reserved for. Our internal policies will only allow a Catastrophic threat level along with a forecaster who is certain of the forecast (see below).

Forecaster Confidence

This is a subjective measure of the forecaster’s confidence that the risks identified in the posting will be realized as described. Factors lowering forecaster confidence can include disagreements in the various model solutions, a personal forecast that’s not in general sync with the consensus in the forecasting community, and sometimes it is as simple as a gut instinct that the models are overplaying a particular event.

Low
While one or more models depicts the solution described in the posting, the forecaster does not feel confident the event will play out as described.
Possible
A couple of models agree in large terms on the event playing out as described, but there are substantial disagreements in important details.
Likely
The usual level of confidence. The models are reasonably consistent in major and minor details and the forecaster feels they are accurately describing what will happen.
Certain
This will most often be combined with the risk and threats at the extreme low end or high end of the scales. The forecaster sees nothing at all that would indicate the event will play out any other way than as described (in the large and medium scales…again, it’s not within our skill set to predict exact risks for an area smaller than 25-30 miles on a side half a day in advance).