The Tuesday morning edition of the Weather Xtreme video is available in the player below, and on iTunes:
All eyes today will be on a developing storm system to the west of Alabama; showers and storms should break out late today and tonight over much of Louisiana, the eastern parts of Texas and Oklahoma, and Arkansas. In advance of the storm, southerly winds will increase across Alabama tonight, and will begin to draw moist air northward from the Gulf of Mexico. The degree of moisture return near the surface will really determine the magnitude of the severe weather threat for Alabama tomorrow.
SPC has all of Alabama in a slight risk of severe weather tomorrow, and mentions in their discussion they will probably upgrade parts of the risk as the moisture return and instability fields become better defined. A deep, dynamic upper trough will support a major storm system, with a surface low well under 1000 mb in southern Illinois, a very favorable position for severe weather in Alabama.
Here are some of the severe weather parameters for Birmingham tomorrow afternoon, from the 00Z run of the NAM/WRF model:
Surface based CAPE: 569 j/kg
2M dewpoint: 61
Lifted index: -1.2
850 mb wind speed: 50 knots
500 mb wind speed: 72 knots
250 mb wind speed: 105 knots
Instability parameters continue to increase slowly… I still think there will be a “sweet spot” along the northern edge of the surface based instability with really good dynamics somewhere between Birmingham and Montgomery. And, all of South Alabama will also have a chance of severe storms.
Forecast soundings show very good veering in the lowest 1 km of the atmosphere, and tornadoes are also going to be a threat. Needless to say, everyone should be in a position to hear severe weather warnings tomorrow if they are required, and we will take a very close look at the 12z models, and have that data on our afternoon discussion later today.
Rainfall amounts of one to two inches are likely with this system tomorrow; some spots might see a little more.
THURSDAY: Still looks like a raw day; maybe a little lingering light rain or drizzle during the morning, a chilly north breeze, and clouds most of the day. A good chance we won’t see 50 degrees if the clouds hang tough.
FRIDAY-SUNDAY: Dry and cool weather is the story for the weekend; another shot of colder air should arrive Saturday night keeping temperatures below normal through early next week. At this point we won’t expect any rain with that secondary cold front; just a few clouds.
THANKSGIVING WEEK: Watch the video for a day by day account, but the overall pattern looks pretty uneventful for Alabama. Maybe some rain toward Thanksgiving day or the following Friday, but no major storm.
LIVE ON THE NET TONIGHT: We will be going live on the live stream tonight at 8:00 on abc3340.com to give you a complete briefing on tomorrow’s expected severe weather event… just go to our main page and click on the live stream graphic on the upper right.
I will be speaking out at ACIPCO this morning… but will be in the office by early afternoon and the discussion and Weather XTREME video will be posted by 3:00 to 3:30… stay tuned!
