NASA does not post warnings about solar flares, however, the Space Weather Prediction Center provides a three-day forecast for space weather and a 27-day outlook for radio flux and geomagnetic indications. The SWPC is a division of the National Oceanic and Atmospheric Administration (NOAA). Predicted flare activity is also listed in these reports.
The Space Weather Prediction Center is in charge of tracking space weather and to assist with that endeavor NASA does provide some information to the SWPC about solar activities. Tracking solar flares is important, due to their potential to cause radio blackouts. When posting about solar flare activity, the SWPC indicates a danger scale of one to five for possible blackouts, with one being a minor danger and five being extreme. When flares are more likely to cause a blackout, a warning is released with the appropriate rating.