Hi! We live in Fall City (east of Issaquah). Your DS is a week older than my DD. This may get kind of long, but your a neighbor and our kids are so close in age...
I agree with growth spurt. They are supposed to have one around 6 weeks. Myabe Jonah is getting it now.
Are you breastfeeding? If bottles, how much is Jonah taking at each feed and what is his daily total. My DD takes 3.5 - 4 ounces at each feed (less for the CFs) and can have a daily total of 20-25 ounces. We really try to get her to eat during the day and sometimes it can take 45 minutes or more. If he's getting enough during the day, he may not be waking because of hunger (my LO usually eats about 18-20 ounces by bedtime).
Does he take a full feed or just "top off"? If it's a smaller feed, you may try offering a paci and see if he goes back to sleep until the next wake. At the next wake, he'll probably be hungry and take a full feed. We do this with our little Katie who sometimes wakes at 2am and 5am. The 5am wake-up is when she's hungry. Not sure what 2am is, but with the paci, she'll usually go back to sleep.
Also, some other things that we use are white noise (actually rain sounds, but some have been successful with a radio turned to static), a nice tight swaddle (I can pass along a technique that keeps our Houdini snugly bound all night if you like), a dark room and a nighttime routine.
Also, how are his naps? We've found that problems with daytime sleep (too many errands, etc.) can really mess up the night.