Very, very interesting weather for the next 24 hours.
The new 12Z model suite is in the house, and we are all together on an online conference now discussing the situation. Here are the main issues:
*Severe weather today? Instability is simply not there, but you have to be impressed with the dynamics. I will be surprised if there are no tornado warnings for counties in south Alabama and south Mississippi. We will be on our toes for convection around here; they will be elevated, not surface based, which usually doesn't mean a big threat.
*Wind! Winds have gusted to over 30 mph at many places already this morning, and I expect gusts to 40 in spots this afternoon, especially on the ridges. This gradient wind might be enough to knock down some trees and power lines.
*Wintry mix? We still have that window late tonight and early tomorrow for a brief, light wintry mix of freezing rain, sleet, or snow over northwest Alabama as Arctic air returns in a hurry. I do not see any evidence that we will have any major problems with this "backwash" type precipitation, but some brief icy spots are possible after midnight in places like Hamilton, Winfield, Haleyville, and Vernon. Quite frankly the best chance of any real issues will be up in the Muscle Shoals area of extreme northwest Alabama. We will hang on to the chance of a few flurries tomorrow morning, but they won't amount to anything.
*Cold! ETA suggests we stay below freezing all day tomorrow with single digit wind chill values. GFS not as cold. One way or the other, it will be a very cold, frigid day.
*Gulf coast snow for Christmas? Once again the GFS bends the moisture far enough inland for some snow at Mobile, Gulf Shores, and Pensacola late Friday night into early Christmas morning. Pretty amazing stuff.
Bill Murray is writing the afternoon forecast package and we will have it posted by 2:30... and the afternoon video update will be ready by 3:30.
The new 12Z model suite is in the house, and we are all together on an online conference now discussing the situation. Here are the main issues:
*Severe weather today? Instability is simply not there, but you have to be impressed with the dynamics. I will be surprised if there are no tornado warnings for counties in south Alabama and south Mississippi. We will be on our toes for convection around here; they will be elevated, not surface based, which usually doesn't mean a big threat.
*Wind! Winds have gusted to over 30 mph at many places already this morning, and I expect gusts to 40 in spots this afternoon, especially on the ridges. This gradient wind might be enough to knock down some trees and power lines.
*Wintry mix? We still have that window late tonight and early tomorrow for a brief, light wintry mix of freezing rain, sleet, or snow over northwest Alabama as Arctic air returns in a hurry. I do not see any evidence that we will have any major problems with this "backwash" type precipitation, but some brief icy spots are possible after midnight in places like Hamilton, Winfield, Haleyville, and Vernon. Quite frankly the best chance of any real issues will be up in the Muscle Shoals area of extreme northwest Alabama. We will hang on to the chance of a few flurries tomorrow morning, but they won't amount to anything.
*Cold! ETA suggests we stay below freezing all day tomorrow with single digit wind chill values. GFS not as cold. One way or the other, it will be a very cold, frigid day.
*Gulf coast snow for Christmas? Once again the GFS bends the moisture far enough inland for some snow at Mobile, Gulf Shores, and Pensacola late Friday night into early Christmas morning. Pretty amazing stuff.
Bill Murray is writing the afternoon forecast package and we will have it posted by 2:30... and the afternoon video update will be ready by 3:30.
on December 22, 2004, 3:46 pm
· Winter Storm Watch (WSW)
A "Winter Storm Watch" will be issued when conditions are favorable for hazardous winter weather conditions to develop. Unlike a Tornado Watch or a Severe Thunderstorm Watch, Winter Storm Watches are issued by the local office. Generally, this type of watch is issued for weather conditions that could occur 24 to 48 hours in the future. Information in the watch will include the affected area, the weather threat involved, potential precipitation amounts, explanation of what a watch is, the uncertainty involved, precautions recommended, and the storm's potential impact. NWS Huntsville issues a Winter Storm Watch when one or more of the following is possible (50% or greater confidence) during the next 12 to 36 hours:
· Snowfall of 2+ inches in 12 hours, or 4+ inches in 24 hours
· Accumulation of freezing rain (ice) greater than 0.15".
· Accumulation of sleet (ice pellets) greater than 0.50".
· Greater than 0.25" of ice expected.
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