The morning video is posted to the server:
http://beta.abc3340.com/weather/video.hrb
I am often torn between writing a technical discussion of weather here, or a general discussion for the public. I will lean toward the latter, but when I do get technical I will do my best to explain.
No change in my message since last week:
*VERY cold for the latter half of December
*I will be very surprised if we get through the rest of the month without at least one snow or ice threat.
We will be in the 30s all day tomorrow, and by Wednesday morning the coldest valleys will be in the 10 to 15 degree range, with 15 to 22 for everyone else.
Just about six days ago the stastical guidance from the main American global computer model, the GFS (Global Forecast System), had forecast highs in the 50s and lows in the 30s for Tuesday. Later today I will write about the GFS "50s and 30s" problem beyond three days! Sometimes it doesn't have a clue in those longer time frames, and I don't understand people who follow it blindly.
Another shot of cold air comes in here over the coming weekend, and once again, the GFS is out to lunch on the 50s and 30s. I am not sure we will get as cold as tomorrow and Wednesday (it is possible), but it will be very cold. And, a couple of impluses rotating through the base of the upper trough might squeeze out a few snow flurries here over the weekend. The stronger one comes through on Sunday, and might be enough to make the ground white over the northeast corner of Alabama, especially over 1,500 feet in places like Mentone. The problem is that the vort max will be starved for moisture. I will probably revise the forecast to include flurries on Sunday... and hold off on anything stronger until we see more model runs this week.
Christmas week: The fun and games begin again with yet another surge of cold air moving in. The high up in Canada early next week shows up as almost 1050 mb, and could very feature the coldest air of this series of cold air blasts. As the new surge of cold air arrives, a strong impulse moving through the upper air flow tries to spin up a storm system that would bring the risk of snow to parts of the deep south in the December 22-24 time frame. Then, after that system departs, there is some risk we get in a cold airmass like we saw here in late December 1983 or 1989.
REMEMBER: There is no way to forecast a specific event beyond seven days. These are just ideas based on the pattern and observed surface and upper air weather across North America (and beyond). Do not go out and tell people James Spann is forecasting a white Christmas. I am not right now. All I am saying is there is a chance. And, perhaps the best chance here in 15 years.
http://beta.abc3340.com/weather/video.hrb
I am often torn between writing a technical discussion of weather here, or a general discussion for the public. I will lean toward the latter, but when I do get technical I will do my best to explain.
No change in my message since last week:
*VERY cold for the latter half of December
*I will be very surprised if we get through the rest of the month without at least one snow or ice threat.
We will be in the 30s all day tomorrow, and by Wednesday morning the coldest valleys will be in the 10 to 15 degree range, with 15 to 22 for everyone else.
Just about six days ago the stastical guidance from the main American global computer model, the GFS (Global Forecast System), had forecast highs in the 50s and lows in the 30s for Tuesday. Later today I will write about the GFS "50s and 30s" problem beyond three days! Sometimes it doesn't have a clue in those longer time frames, and I don't understand people who follow it blindly.
Another shot of cold air comes in here over the coming weekend, and once again, the GFS is out to lunch on the 50s and 30s. I am not sure we will get as cold as tomorrow and Wednesday (it is possible), but it will be very cold. And, a couple of impluses rotating through the base of the upper trough might squeeze out a few snow flurries here over the weekend. The stronger one comes through on Sunday, and might be enough to make the ground white over the northeast corner of Alabama, especially over 1,500 feet in places like Mentone. The problem is that the vort max will be starved for moisture. I will probably revise the forecast to include flurries on Sunday... and hold off on anything stronger until we see more model runs this week.
Christmas week: The fun and games begin again with yet another surge of cold air moving in. The high up in Canada early next week shows up as almost 1050 mb, and could very feature the coldest air of this series of cold air blasts. As the new surge of cold air arrives, a strong impulse moving through the upper air flow tries to spin up a storm system that would bring the risk of snow to parts of the deep south in the December 22-24 time frame. Then, after that system departs, there is some risk we get in a cold airmass like we saw here in late December 1983 or 1989.
REMEMBER: There is no way to forecast a specific event beyond seven days. These are just ideas based on the pattern and observed surface and upper air weather across North America (and beyond). Do not go out and tell people James Spann is forecasting a white Christmas. I am not right now. All I am saying is there is a chance. And, perhaps the best chance here in 15 years.
on December 13, 2004, 7:44 am
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