Threats-In-Motion for Severe Storm Warnings - 2024 Update

The Threats-In-Motion (TIM) concept aims to provide National Weather Service (NWS) forecasters with the ability to update warning polygons, and associated products (warning text), to move with the severe convective storms for which they are issued. The goal of TIM is to provide more equitable lead time, as well as increase average lead time, for areas downstream of the storm’s path without negatively affecting false alarms.

Two versions of TIM have been under development at the NOAA Global Systems Laboratory and National Severe Storms Laboratory since 2020. The first variant, in which the warning polygon is only updated when the forecaster updates its position, shape, and duration, is known as “Tiny” TIM. The other variant, in which the polygon is updated by software at a frequency as high as 1-minute between forecaster updates, is known as “Taller” TIM.

In the Spring of 2024, Taller TIM was tested at the NOAA Hazardous Weather Testbed (HWT) and for the first time they shared the same core code. This common code is also shared by the operational version of the Hazard Services (HS) Convective workflow, which is replacing the WarnGen process. The refactoring of the TIM code to align with the HS-Convective workflow aims for greater operational readiness of the TIM concept. Furthermore, the TIM concept will contribute to the NWS vision for community-centric warnings by rapidly updating the areas affected by high-impact weather and to aid in providing greater decision support.

This presentation will provide an overview of the 2024 activities and forecaster feedback within the HWT.