Houston Marathon forecast at 12 days: Grim, but not without hope

I lacked the heart to post an update this morning about weather conditions for the 2017 Houston Marathon because, well, the forecast was really rather grim. Grim as in warm—or perhaps even really warm with race time conditions in the 60s, rising into the 70s. I’d hoped that maybe, just maybe, the 12z models that came out this afternoon would offer some hope for a cooler race day.

I’m happy to report that the outlook is a tiny bit better.

As ever there is extreme caution required when considering long-range forecasts, especially at 12 days out. However temperatures in winter are a little bit easier to forecast than, say, a hurricane. That’s because a hurricane is a relatively small meteorological phenomenon, which can be perturbed by relatively small changes. Temperatures are largely controlled by very large upper-air patterns, which are a little bit more predictable. And in this case the global models are showing a rather large area of high pressure building over the United States next week, for much of the central and eastern United States. This will bring temperatures up.

If you click the graphic below (which shows the GFS model forecast for daily temperature anomalies for the next 16 days) to enlarge it, it should make a little more sense.

(Space City Weather is sponsored by Westbury Christian School for this month)

The GFS model, then, largely expects warmth to linger for most of next week and through the weekend. In looking at the European ensembles this afternoon, 24 of them show significantly warmer than normal temperatures, 12 show near-normal or slightly above normal, and 14 show below-normal temperatures. Believe it or not this is a significant improvement from this morning, when the European model was somewhat warmer.

Putting all of this together here’s my thinking for the marathon next Sunday. I feel pretty confident in saying that temperatures next week will be warmer than normal, we’re probably looking at highs in the mid-70s, with lows from around 60 to the mid-60s during the work week. If the marathon were next Thursday, Jan 12th, for example, I’d be really concerned. But at this point I still think there’s a healthy chance we see some relief, perhaps in the form of a Pacific cool front, just before Sunday morning. That’s the hope, at least.

Most likely conditions at race time: Low in the low 60 degrees, rising to about 70 degrees.

Almost as likely: Low in the 50s, rising to the mid-60s

Least likely: Low in the 40s, rising into the 50s.

Posted by Eric at 3:10pm CT on Tuesday