They arrived early in the afternoon. The wind was out of the east at 12 to 15 knots. The airport was busy, with a string of jets, mostly Southwest 737s, on the approach to Runway 4. Approach control sequenced the Cirrus for a left base entry to the Runway 4 pattern, following a 737 on a 4-mile final, and issued the customary warning about wake turbulence. Handed off to the local controller, the Cirrus was cleared to land. But a second 737, now 9 miles out, was rapidly overtaking it, and the tower controller instructed the Cirrus to go around, maintaining runway heading, and then make a right turn onto a right downwind leg for Runway 35.