UPDATED: High-Impact Severe Weather Event to Affect Alabama Over the Next 24 Hours [GRAPHICS, VIDEO]
A potential high-impact severe weather event is shaping up to affect Alabama over the next 24 hours; all modes of severe weather are possible, including violent tornadoes.
The Day 1 Convective Outlook from the National Weather Service's Storm Prediction Center shows much of north and west Alabama in the "enhanced" risk area, meaning these locations have a better chance of seeing severe storms and tornadoes.
UPDATE: A TORNADO WATCH is in effect from 2:30 p.m to 8 p.m.. Wednesday, December 23, 2015 for Autauga, Bibb, Chilton, Choctaw, Clarke, Dallas, Elmore, Greene, Hale, Lowndes, Marengo, Monroe, Montgomery, Perry, Sumter, Washington, and Wilcox Counties.
The National Weather Service in Birmingham's forecast shows storms impacting Alabama around 6 p.m. this (Wednesday, December 23) evening and will continue to do so through approximately 6 p.m. Christmas Eve. The forecast graphics below detail the forecast threats over the next 24 hours.
It is important to note that these forecast graphics are the National Weather Service's best estimation of where storms will develop. Tuscaloosa may not be in the "significant" threat area for tonight, but that does not mean that we are in the clear. All of our listening area needs to be on alert and weather-aware over the next 36 hours.
ABC 33/40 Chief Meteorologist James Spann stresses the significance of this weather event in his latest post on the ABC 33/40 Weather Blog (added emphasis mine):
POTENTIAL HIGH IMPACT SEVERE WEATHER EVENT: A significant, long duration severe weather event will begin in Alabama later today, extending through tomorrow. This is not unusual for this time of the year; the November/December tornado season is just as active as spring most years in Alabama. And, there is no reason for anxiety or worry; we have events like this often here in “Dixie alley”. It has just been unusually quiet for the past four years. We are Alabamians, and know how to get through these.
Here is what you can expect:
TIMING: Unfortunately we will need to open up a 24 hour window for severe weather in Alabama, from 3:00 this afternoon through 3:00 p.m. tomorrow. No, that doesn’t mean it will be storming at your house the entire time, but it means any storm that passes through could be severe.
Initially, severe storms will form over Northwest Alabama this afternoon between 3:00 and 5:00 p.m… with the area of storms slowly expanding to the east and south tonight. I should also mention we can’t rule out a severe storm before 3:00 p.m. over West Alabama.
The storms associated with this event will not be linear, they will be cellular, scattered, and random, meaning we can’t give you specific start/stop times for any one community. Just be ready for a severe storm at any time during this 24 hour period.
The highest risk of a strong/violent tornado will be over Northwest Alabama, where the “enhanced” severe weather risk is defined. But, the standard “slight risk” extends down into South Alabama, and storms there would also produce damaging straight line winds and a few tornadoes. Even in Southeast Alabama, a “marginal” severe weather risk is in place; the tornado threat is much lower there, but not zero.
I am very worried too many people are getting hung up with lines, colors, and risk categories (yes, I know there is some confusion with local weather services offices and the SPC using different colors, areas, and terms). Please know storms have no idea where those lines are drawn, and they can’t see colors on a map. They are just a guideline… everybody in Alabama needs to be vigilant and prepared for severe weather. It doesn’t matter where you live.
THREATS: In addition to tornadoes, severe storms will be capable of producing large hail and damaging straight line winds. Heavy rain will fall from stronger storms, but we don’t expect enough rain for flooding problems.
CONFIDENCE: Forecast confidence is high. The convection near the Gulf Coast early this morning will move eastward, and all guidance shows no widespread activity near the coast to block the inflow up into the northern half of the state. And, all high resolution models are showing supercell storms firing over Northwest Alabama this afternoon with potential for rotation.
TOMORROW: All of Alabama is in a “marginal” severe weather risk tomorrow…The threat of severe storms will continue; while the main dynamic support begins to lift away, the air will remain very unstable, and storms could produce damaging winds and some hail. And, the tornado threat is smaller, but certainly not zero. You will need to continue to pay close attention to the weather tomorrow. The overall threat will diminish after 3:00 p.m. as the dynamic support continues to fade.
For a more detailed look at the forecast, check out the latest ABC 33/40 Weather Xtreme Video below.