What is the red barb for in the NOAA weather briefing? Wind barbs are well-defined symbols, but I noticed in my WX briefing that there are now occasional red barbs in the chart.
The red appears on both the 5kt and 10kt barbs, and sometimes for largest 10kt barb or the smallest 5kt barb.
They do represent gusts:
From AviationWeather.gov:


Figure 1: Station Model Plot
In many cases, the data are plotted using standard symbols and
plotting models. Fig. 1 shows the station model used in the METAR and
TAF plots.

Ceil - Ceiling height in hundreds of feet. This represents the height of the lowest broken or overcast cloud layer.
Id - The 4 letter ICAO identifier for the site. KRFD is Rockford IL.
Windbarb - The wind barb. The stick points in the direction the winds are coming from. Each full barb represents 10 knots of wind.
Each half barb represents 5 knots. Red represents wind gusts. In this
case, you have winds from the SSW at 25 knots with gusts to 30 knots.


So for example, these:

The one on the left represents wind of 15 knots gusting 20, and the one on the right is 15 knots gusting 25.
Odd ones like this:

Mean 5 knots gusting 10. Why they don't overlay I'm not sure.