Wednesday, January 10, 2007
Data Supports Ice Storm Potential
This map highlights where we expect freezing rain to cause problems Saturday night into Sunday!
The latest oZ run of the NAM has come out, and it backs what our forecast has advertised over the last 2 days. The storm system in general is slowing down and deepening, allowing for more warm and moist air to move north from the Gulf of Mexico. This warm air will override a shallow cold air mass at the surface. The cold air at the surface will move across NE OK and NW AR on Saturday, creating a freezing rain potential by the afternoon and evening.
Freezing rain is the result of liquid precipitation falling through a surface based cold layer that's less than 4,000 feet. The height of our forecasted arctic air mass is relatively small. We're freezing from the surface to roughly 1,500-2,000 feet or around 950 mb. This will present ideal conditions for freezing rain. Travel may become slick and hazardous for Sunday.
Early indications point to freezing rain to continue on Sunday. As more data comes out, we'll continue to update our forecast.
Posted by Drew Michaels at 9:09 PM
4 Comments:
Hello Drew, Everyone.. I think you might be abile to drop that line.. just a little be IF the NAM trends even colder, and precip stays longer as it is doing now. I think areas around I-40 are still in the cards for some Frz Rain. Im not a pro, just someone that has an intrest in the weather.
In regards to the 1st comment...
First off thankyou for your comment and concern, we here at 40/29 are watching every aspect of this unfolding winter weather event.
The freezing line has been tweaked ever so slightly to the south and now areas along 1-40 could see some freezing rain towards the end of the precipitation, though the heavier ice accumulations will be confined to extreme northwest Arkansas and northeast Oklahoma. If your travel plans take you out to Lawton, Oklahoma City or Tulsa, Oklahoma be sure to call ahead for this area will likely see a major ice storm.
So is it safe to say the higher mountains south of Fayetteville will more or less stop the cold air? And since the cold air is only 2000 ft high at most then what about the the tops of these mountains which are notorious for getting more winter weather than the surrouding lowlands? Sounds like Highway 62 from Lincoln to Prarie Grove to Fayetteville would definitely be a natural freezing line
You bring up a very good point!!
Right now we are watching the depth of the cold air by looking at soundings (or a 3D view of the temperature profile through the atmosphere) at stations to our north. Yes the Ozarks will play a major role in this ice event, as they did well over a month ago when Fort Smith saw mostly rain, while Rogers, Bella Vista and Muskogee saw some ice/sleet. If the depth of the cold air is less than 1,500 feet the mountains will tend to block the cold air from making it south of Fayetteville. The coldest air therefore could ooze to the west of Fort Smith and Sallisaw giving central and south central Oklahoma the best shot of ice. I've seen some crazy situation coming from Asheville North Carolina where the shallow cold air actually drained to the east of the Blue Ridge Mountains, then funneled its way from south to north up through the French Broad Valley into the city. They called these CAD events AKA Cold Air Damming. Shallow cold air is a tough thing to forecast and the models are basically useless in these cases.
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