Hello fellow marathon runners and volunteers. In 12 days, it will be all over but the recovery. And now that the big training runs are over, all that we can do is trust our preparation, and hope for good—cold—weather on the big day. To that end, for the rest of this week, I’ll be providing afternoon updates on what we can expect for Sunday, Jan. 14th.
Of course any weather forecast beyond about seven days out is going to have a lot of uncertainty, and anything beyond 10 days is even more problematic. But that does not mean such forecasts have zero value. The best way to look at weather this far out is to study the ensemble forecasts of the main global models. These are the 50 or so lower resolution runs of a given model, with slightly different initial conditions. By looking at the spread in output from these models, we can gauge the probability of cold, normal, or warm weather for 12 days from now. Looking at the 12z runs of the European and North American models, here’s what I have for you.
Starting with the European model I have broken down the possibilities for start line temperatures into four different categories:
Warm: 3 degrees F or more warmer than normal
Normal: +3 to -3 degrees within normal (average high is 65, low is 47 degrees)
Cold: -3 to -10 degrees below normal
Very cold: -10 degrees or more below normal
In looking at each individual ensemble member of the European model, here are the Houston temperature anomaly outputs sorted by category:
Warm: 5
Normal: 4
Cold: 33
Very cold: 8
Too obtain probabilities, just multiply those numbers by two. So, roughly, according to the European model this afternoon, there is a 20 percent chance of warm or near-normal weather for the marathon, and an 80 percent chance of cold or very cold weather.
Looking at the GFS model, the we can see the mean of the ensemble members for January 14th is about 2 Celsius degrees (4 degrees Fahrenheit) below normal. But this model isn’t as cold as the European model.
This is a much better forecast for the 2018 run than what we saw in 2017 (warm and very humid), but it is far from locked in. There are also some concerns.
The models are suggesting that some kind of fairly strong cold front moves through the region toward the end of next week, and this could bring with it some decent precipitation. If that front is late, we could still be warm for the marathon. Or the front could drag through on a Friday or Saturday, leaving behind some cold rain for the marathon itself. That, obviously, wouldn’t be ideal either. All that said, I’d still rather be looking at probable cold weather more than just about anything.
More tomorrow.
Sunday October 14?
Thanks for keeping us informed! I’m running the half marathon and hope the low will be around 50 degrees with a high of no more than 55 degrees. I don’t like it TOO cold or TOO warm. Good luck to everyone running!
BTW, looks like you’ve got a typo for the date—should be January 14, not October 14.
Best wishes to all the marathoners! Hope the wind is calm with cool, crisp temperatures!
I’m not a runner, so doesn’t bother me. But you have the date of the run listed as October 14th.
I did, thank you.
I assume you mean January 14th, not October 14th since forecasts beyond 100 days must be extremely questionable.
when is the marathon? 1st graph has Sunday, Oct. 14…
thanks
I believe you mean January 14th!
Are you running the Marathon Eric?? Good luck I ran it in 2015
I am. I ran in 2016, and sat out last year because of the oppressive heat. Training has gone well this year so I am looking forward to it. (Sort of).
Eric,
Hope the weather is dry, cool and crisp with ZERO WIND. Best wishes for a successful run!
Oh, good gosh. Man made a typo. Big whoop. How many of y’all gonna keep pointing it out?
I left my comment after checking that no one else had pointed it out. I don’t know if they moderate the comments or not but its likely everyone pointed out before they saw any other comments about it.
That’s exactly what happened! There were no other comments before I made mine.
Whoop! Bring on the cold to very cold! Anything but the oppressive heat that was last year!!
Hope you have a great marathon. Y’all are nuts. I live in Houston so I can run in 80 degrees with significant humidity most of the year. If it’s less than 60 and I have to go outside I bundle up like the kid on a Christmas story.