Saturday, February 05, 2011

WX Talk

I don't know how many of you are involved in decisions regarding your home events, but these are the times that try men's souls. Seriously. There is nothing more difficult for an administrator than school closures. Full disclosure -- I'm not in that loop anymore here, but I've been at that small table and want to share a little insight.

First, you are never right. It didn't snow enough -- why did we leave early/close school/delay opening -- or worse it snowed/rained/iced/natural disastered more than forecast -- why did you make us show up at work/class/etc. You are always working with the best estimates of your professionals, and making calls in the interest of the greatest number of people. It's a tough job.

A moment about snow. As a professional meteorologist what is the forecast he dreads the most. It's not tornadic storms. It's not hurricane landfall. It's not even long range climate. It's snow. Or, more precisely, winter precipitation. How much, what kind, what duration -- because the forecaster is not just working in three dimensions. He's really in four or five. Huh?

Consider these factors. The forecaster has to know where the moisture is. That's hard on a spring day with flooding by itself. He has to know where the winds are and how that pressure change will bring in the moisture. Factor in the movement of the cold air to cause that moisture to first fall from the atmosphere. Again, tough enough in summer. Now, you need to know the freezing line at the surface -- above 32 for a long period of time, it won't stick to roads and elevated surface. Below 32 -- how long? Day or night? Got that? Now, what's the temp aloft. How "deep" is the cold air. Is there a slice of warmer air near the ground? Your snow melts into rain. If it's higher, it might refreeze into sleet. If it's near the ground, the rain can't form to snow, but freezes on contact.

Again, much respect to the guys that have to figure that out. But then you hand off that best estimate to a public servant who must act on the forecast. Again, tough and thankless.

I give this advice to all of you -- close in and distant. Do you have the decision support pages of your regional National Weather Service office bookmarked? Not to make this a rant or endorsement, but almost all the data that goes into anyone else's forecast starts with your local NWS office. Just like I'd tell my history students, get as close to the original documents as you can and your interpretation of the past is best -- same here.

We are blessed to have at Tulsa NWS some of the leading edge guys on severe weather products, including a new tool called an Ice Damage Index. Pretty cool for decision makers because it is a graphic mashup of the data involved in icing events -- precip, temp, wind -- and turns it into factors. A "2" means limited power outages and damage anticipated; a "4" means longer term outages due to lines down, roads blocked, significant tree damage. And yes, in 2009, this product accurately predicted the 4 and 5 impacts we took with our ice event.

So, for my regional followers bookmark this Tulsa NWS decision page. Pretty graphical, nice little "Chiclets" of color to give warnings. Click on the threat and you get additional graphics and text. For our region, this runs year around, so when we get to tornado season we obviously don't see ice -- it becomes hail threat, etc.
Back to that small group -- safety comes first, and as much of a pain as it may be for extra days in the summer (especially when you're talking public schools) sitting in class in June beats full-body traction or worse in January because you slid off the road.

If you aren't here in Tulsa NWS region -- or you don't know what office you belong to -- go to the National Weather Service main site and search into region and district, then find that "warning decision" page or similar title to bookmark.

Once you get that info, it comes to the public servants to make decisions with that intel. Especially when you're public schools (or universities), safety is going to go first. Sure, no one wants to be sitting in class in June making up days, but it beats the heck out of full traction or worse in January.

So be safe out there.

1 comment:

pmarshwx said...

Hi Bill,

Great points! I couldn't have said it better myself!

Also, if UARK ever decides to need an outside consultent, I'm interested! =)