Now I remember why I hate winter. Winter weather forecasts! They are difficult, demanding and you don’t forget when I’m wrong.
You don’t. I live with it.
There is an especially difficult forecast coming this weekend for Nebraska and much of the Plains. A low pressure system moving in from the south will wedge a pocket of warm air above very cold air at ground level. The result is raindrops hitting the surface, freezing on contact.
It’s an ugly setup. The ice weight can bring down trees, power lines, (and my boss’s fear) even radio towers. It coats road surfaces eliminating most traction. You can’t drive on ice.
Ice storms aren’t rare, but they are unusual. That’s because so many parameters in the atmosphere must be exactly right at the same time. For me it means extra forecasts to follow the drops and take their temperature from cloud to ground. A few degrees change anywhere in the atmosphere could mean sleet, snow or even rain. So many places to go wrong.
A good ice storm forecast starts with a reliable QPF (quantatative precipitation forecast). It’s our Achilles heel. The morning and afternoon NAM model vary by a factor of six in how much liquid will fall over Norfolk, Nebraska. That’s not helpful.
A few days ago it looked like Grand Island might get all snow, easier to deal with than ice. Now they’re progged to get the most ice!
There are 66 forecast hours before this storms makes Nebraska. The precipitation just moved into the time domain of the NAM, so along with the GFS a chance for more numbers… more consensus or confusion. In the last 24 hours the HRRR (high resolution rapid refresh) adds to the fun. They seldom all agree.
This is so confounding at times NOAA puts out bulletins with their advice on which model seems most trustworthy: when and where.
Sunday’s ice storm is likely. The question is who gets the most and will it rise to “State of Emergency” status or be much ado about nothing?