  This deep, extended solar minimum and the slow start to Cycle 24 strongly
suggest that Cycle 24 will be a small cycle. A wide array of solar cycle
prediction techniques have been applied to predicting the amplitude of Cycle 24
with widely different results. Current conditions and new observations indicate
that some highly regarded techniques now appear to have doubtful utility.
Geomagnetic precursors have been reliable in the past and can be tested with 12
cycles of data. Of the three primary geomagnetic precursors only one (the
minimum level of geomagnetic activity) suggests a small cycle. The Sun's polar
field strength has also been used to successfully predict the last three
cycles. The current weak polar fields are indicative of a small cycle. For the
first time, dynamo models have been used to predict the size of a solar cycle
but with opposite predictions depending on the model and the data assimilation.
However, new measurements of the surface meridional flow indicate that the flow
was substantially faster on the approach to Cycle 24 minimum than at Cycle 23
minimum. In both dynamo predictions a faster meridional flow should have given
a shorter cycle 23 with stronger polar fields. This suggests that these dynamo
models are not yet ready for solar cycle prediction.
