Half marathon on 2 runs per week?

Could you finish?  Probably, but it'd be a suffer-fest, and you'll run a pretty high risk of injury.

If you can, look at the FIRST program.  That's 3 days of running.  Beyond that, I got nothing. 

I did a HIM and full IM this year on 2 runs per week.  Just like you, my training generally consisted of just 2 swims, 2 rides and 2 runs per week (almost never more, somewhat often less).  My races went well (not suffer-fests).

So, it works for me.  But, I've been at this awhile as this was my 7th season of training/racing HIM and longer.  I put a little more time into my training in my first couple years in the sport.

For me, it's all about the weekly long ride and long run.  The rest is filler.

-Steve

To the OP - if you want to just complete it, you sure can shoot for 2x a week, but if you don't have a good base it will be a tougher challenge and maybe a bit risky.

If I remember, I'll let you know in a month and a half. I'm up to 10 miles now on 2x per week running, although I plan to run 3x per week after my last tri of the season in just over a week. I feel like running more would be more of an injury risk. I increase my distance carefully over time so the half will be within my normal increase.

How long after the half mary is your 1st tri of the season? You may want to consider cutting a swim if all you have coming up near the half mary is 300 yard pool swim sprint tri, but if you have an oly 4 weeks later, just keep doing what you're doing.

I'm not fast, but I never intended to be fast my first season.

I was looking at your logs.  100 some miles in 06 and about the same so far this year.  Not a ton of volume.  But that doesn't mean you are not in shape.  While I was thinking about that another thought struck me.

Forget the other stuff about performance and injury, I'll let others hash that stuff out for you.  It's FUN to get better.  I've been following this marathon training plan pretty religiously and the benefits are a blast to experience.  Running 6xweek has me enjoying running in a whole new way.  Yeah, its hard.  Yeah, I get tired and it hurts too.  But I'm seeing times I never thought I'd see.  I'm able to do things at 39 y.o. I couldn't dream of doing when I was 18, or 25, or even last year.  If you are doing the half mary just to do it and as a very small part of your tri training then so be it.  But if you really want to do it to experience it and get better at running then pick a good plan and throw yourself into it.  I'm not saying you have to do 6 x, or give up swimming and running.  But I think 3x is a minimum and 4x sometimes 5x would be good.  You won't regret it.

As a side benefit this has convinced me of the benefits of following a good plan and will help me immensely when I begin training for my next tri event, whatever that may be.

I'd say it depends on your expectations for the race.  But, I think you'll be absolutely fine....if you make sure that at least one of those runs per week is a nice quality long run.   If you're saying that your max run workout time is going to be limited to only 35 mins, I'd say you'll be walking a good portion of the latter part of the race.

I see you ran a 5k averaging 8:12's per mile.  McMillan calculator puts you right around a 2 hour finish time....so, build your base up running around 10-11 min miles and get the distance up to at least 10 miles - preferrably longer.  You'll be set. 

Thanks for the advice.   I was just stating my current running base, but I plan to increase that to prepare for the race.    Sub 2 hr is about where I think I should/could be.  By sub 2 hr, I mean 1:59:59

Of course you could do it (barring injury issues).

I signed up for a marathon the day before on a whim, and had only run 3 times for the entire year for a grad total of about 10 miles, but had ridden around 1,200 miles.  I made it to the halfway mark before my left knee had a huge ITB issue and could barely walk from the humongous blisters on both feet.

Stupid as it was, it at least gave me a focus to train the next year to complete the marathon ........  running around 5 days a week ..........

x2. And you're the only one that knows how prone you are to injury.

I did a marathon last weekend with no injuries at all, having averaged between 0:45 and 1:00 of running a week since May. But I know my body, know that I had the base from prior years and even this spring, and knew I was going to be running a manageable pace - and therefore would likely not hurt myself.  So it's doable.

But you've gotta know yourself to make a determination on the injury.