Thursday, January 18, 2007

"Tick, tick, tick...."

And now we wait...just read over the latest information and weather models I can get my paws on, and I see no significant change to any of the NC forecasts, with the slight exception of a reduced QPF for the NW Piedmont. Models still push roughly 0.25" of liquid for there, but some indications shift the QPF fields east a tad...either way we now (at 1:30am) just waiting on the coastal low to fire up and start sending moisture back our direction.

Late last night a wave of jet-led precipitation coursed through north GA and eastward through SC, and if you looked at that alone you'd muse 'forecast bust'...that precip had zilch to do with what is supposed to start up in just a few hours. And that's the kicker in any weather scenario, of course: we have diverse and myriad models that give us all kinds of forecasts, but ultimately you have to remember it's only a suggestion of what could happen, not what will. There is no one 'best' model, though we each have our favorites we lean on in particular situations. For this write-up, I'm setting aside any other concerns for later this weekend and next week. Many bales of hay, therein, for weather cattle to feed on...

(FYI: the following remarks are more for the Greensboro/TRIAD market area, markers as I will now head in to work shortly...)

At 1am, GSO air temp is already at 29 degrees. The dewpoint is down at 11 degrees and a 47% relative humidity. East winds are blowing at the surface 6-10 mph. Excellent set-up for a tenacious and rather expansive "CAD" event for a lot of NC (stands for 'cold air damming'). When precipitation arrives, there will be a lot of evaporation aloft, which helps entrench the cold column through evaporative cooling. Bottom line for today's highs? They will struggle mightily to reach 33 degrees in the early afternoon. As long as we have the incoming precipitation fields around daybreak, we will lock the cold in for the day.

Remember, just because the air temperature is in the upper 20s does not make for precipitation to fall as snow. The great ice storm we had in 2002 was proof of that where it was 27 degrees and pouring rain in Charlotte. Thankfully we are NOT dealing with such a situation this time around.

I refer to today's system to be a 'nuisance' storm. At worst it will only temporarily stymie travel around the Triad. There isn't a massive amount of liquid poised to move in, either, though we'd all agree it takes little in the ice and sleet world to send vehicles sliding out of control. Bridges and overpasses are notorious for freezing well in advance of roads because the sub-freezing air can circulate all around the road surface. Of course, with our cold air of late and tonight's sub-freezing temps, road surfaces could quickly become slick as well.

Surface observations. Critical. Hard to get 'em, most times, which is why we love for viewers to send us quick email updates on temperature, precipitation, and conditions. So PLEASE if you have something you think we'd find useful, please email us at:

weather@news14.com


Those emails are posted to all 10 News 14 meteorologists immediately, and it helps us to piece together a patchwork weather quilt to get a more detailed feeling of the situation.

For now, shower time...will post more and add to this a little later on this morning....


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OK, here is my update at a little after 5am:

Limited moisture for the Triad should keep any accumulations to 1" or less (snow/sleet early, mixing in with freezing rain and then rain in the early afternoon).

Any glazing of ice should be 1/10th of an inch, and mostly on railings, vegetation, and power lines. Overpasses/bridge are always vulnerable; some secondary roads could get slick, as well.

Heavier amounts (read 'more problems') would be in the precip-favored areas which are those of you farther south and southeast (Montogomery and Randolph Counties, for example.)

Our WINTER WEATHER ADVISORY is in effect through this afternoon. A WINTER STORM WARNING is in effect for the Charlotte metro region just south of the Triad, where more acumulation is expected (though still limited.)

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