Reconsidering Use of “Low” in TCIG Level Descriptors Rob Molleda National Weather Service Miami/South Florida Forecast Office

Impact Levels are Relative, But... Users may not be thinking in same relative sense. Impact severity is subjective. Local user feedback suggests that the term “Low” in the potential impacts can unintentionally send the wrong message.

Also... Fairly wide range of impacts within the Low category. Example: Low wind hazard describes impacts ranging from borderline TS to borderline Cat 1.

Examples of Current “Low” Definitions Inland Flooding: Flood waters may prompt a few evacuations and brief road closures. Wind: Unsecured light-weight objects easily blown about and become dangerous projectiles. Dangerous driving conditions on bridges and other elevated roadways, especially for high profile vehicles. These definitions fit better and can be better described under a separate “Elevated” category between Low and Moderate, with “Low” reserved for very minor impacts.

SPC Has Similar Issue SPC will experiment with an additional “Enhanced” risk level in Enhanced risk will be between SLGT and MDT

Proposed Changes 1. Replace “Low” with “Elevated (or similar wording). 2. Add a separate “Elevated” category between Low and Moderate. Color scheme would be: Low (light blue), Elevated (yellow). Personal preference is for #2 due to greater consistency with experimental SPC categories.

Pros/Cons Pro: Separate borderline moderate conditions from very minor ones (think SPS/SVR or Urban Flood Advisory/FFW. Less potential for underestimation of threat by public. Con: Adding an extra category could slightly add to forecaster workload.

Recap Current use of “Low” descriptor in TCIG may be correct in a relative sense, but can mislead the public into thinking that a low threat is unimportant. “Elevated” or a similar-worded term to cover borderline moderate conditions can more effectively convey a significant threat to life and/or property.

Questions? Thank you for your time! National Weather Service Miami/South Florida Forecast Office