The day the Sun had no spots
No spots were visible on the solar disk on January 28. The 10cm flux is crashing to a very low level.

posted: January 29

Let's take a look at a picture made on January 28 by MDI onboard of SOHO in visible light (figure on the left). We see a spotless Sun. SIDC observers and the Catania spotter reported no sunspots that particular day. The flaring activity was accordingly also low. 

On the right, we see a graph showing the 10cm flux in January. January 29 is day 0. 10cm solar radio flux is a measure for the noise emitted by the Sun at a wavelength of 10.7 cm (frequency around 2800 MHz) and is measured here on earth. The 10 cm flux is a full-disc measurement which means that all radiation with a wavelength of 10 cm (radio waves) from the whole visible solar surface is counted (integrated as we say). This flux is a proxy for the solar activity. The curve has a 27 days recurrence. Actually, the curve we see in the graph is not reaching very high tops compared to previous curves. The Sun is having a dip?