Conditions are starting to line up for us to have a threat of strong to severe thunderstorms starting before dawn on Saturday morning through much of the day on Saturday, with the threat potentially coming to an end during the mid-evening hours. The Storm Prediction Center has outlined severe storm risks on their day one graphic, which goes from now through 6 am Saturday morning, and on the day two graphic, which goes from 6 am Saturday morning until 6 am Sunday morning. Here is the breakdown for both Central and North Alabama areas:
DAY ONE SEVERE WEATHER OUTLOOK (NOW THROUGH 6 AM SATURDAY)
• Slight Risk (level 2/5): Along and north of a line from Melborne (Lamar Co.) to just north of Grayson (Winston Co.).
• Marginal Risk (level 1/5): Along and north of a line from Gainesville (Sumter Co.) to Sumiton (Walker Co.) to the slight risk area.
• Enhanced Risk (level 3/5): Along and north of a line from Pleasant Site (Franklin Co.) to Florence (Lauderdale Co.) to just north of Lexington (Lauderdale Co.).
• Slight Risk (level 2/5): Along and north of a line from Oakville (Lawrence Co.) to Decatur (Morgan Co.) to State Line (Madison Co.) to the enhanced risk area.
• Marginal Risk (level 1/5): Along and north of a line from Hanceville (Cullman Co.) to Guntersville (Marshall Co.) to Stevenson (Jackson Co.) to the slight risk area.
DAY TWO SEVERE WEATHER OUTLOOK (6 AM SATURDAY THROUGH 6 AM SUNDAY)
• Slight Risk (level 2/5): Along and north of a line from just north of Geiger (Sumter Co.) to just south of Gorgas (Tuscaloosa Co.) to just north of Sipsey (Walker Co.).
• Marginal Risk (level 1/5): Along and north of a line from Sanders Hill (Pike Co.) to Howe (Barbour Co.) to the slight risk area.
• Slight Risk (level 2/5): Along and north of a line from Dodge City (Cullman Co.) to New Hope (Madison Co.) to just north of Pleasant Grove (Jackson Co.).
• Marginal Risk (level 1/5): The remainder of North Alabama, south and west of the slight risk area.
THREATS AND TIMING OF SEVERE WEATHER
The main window for the threat of stronger to severe storms with the main line of storms will begin in the extreme northwestern parts of the state around 3-4 am and will progress slowly through the North/Central Alabama areas throughout much of the day Saturday until the mid-evening hours. Here is a breakdown by sections of the area:
• North and west of a line from Geiger to Dodge City to Skyline, the threat window will be from 3 am to 8 am Saturday morning.
• North and west of a line from Selma to Clanton to Heflin, the threat window will be Saturday from 7 am to 12 pm.
• For the remainder of Central Alabama (south and east of a line from Selma to Clanton to Heflin), the threat window will be Saturday from 11 am to 6 pm.
In the Enhanced and Slight Risk Areas, threats will be from damaging wind up to 60-70 mph and a few tornadoes, while the threats in the Marginal Risk area will be less likely but cannot be completely ruled out.
As the cold front approaches and moves into the area, there will be a decent amount of shear along and ahead of the front along with a modest amount of instability (energy for storms to feed off of). Pair that with a decent amount of helicity (potential for spinning updrafts), and we have the ingredients for the potential of damaging winds and a few brief spin-up tornadoes. However, a stronger tornado (EF2 or greater) cannot be ruled out in the enhanced risk locations.
This is a system that we need to really keep our eyes on as it approaches and moves into the area, as this type of setup will allow for the potential for storms to start spinning up rapidly. Be sure that you have fresh batteries in your flashlights, weather radios, and have those cellphones fully charged and ready to go just in case your location goes under a warning. Go over your severe weather safety plans and be sure that your safe place is free from clutter and is ready to go. #BePrepared #StayWeatherAware
Also, just a quick heads up, winds will be breezy starting tonight as the pressure gradient tightens ahead of the cold front. For this reason, Wind Advisories have been issued for parts of the area.
NWS Birmingham has issued a WIND ADVISORY which will go into effect tonight at 9 pm for the following counties in Central Alabama: Blount, Calhoun, Cherokee, Cleburne, Etowah, Fayette, Jefferson, Lamar, Marion, St. Clair, Walker, Winston. The advisory is set to expire at 1 pm Saturday afternoon. Here is the text from the advisory:
WHAT: Southwest winds 15 to 20 mph, with gusts up to 35 mph expected. WHERE: Northern portions of central Alabama. WHEN: From 9 PM this evening to 1 PM CST, Saturday. IMPACTS: Gusty winds could blow around unsecured objects. Tree limbs could be blown down and a few power outages may result. Use extra caution when driving, especially if operating a high profile vehicle. Secure outdoor objects.
NWS Huntsville has also issued a WIND ADVISORY which will go into effect at 9 pm tonight for the following counties in North Alabama: Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale, Lawrence, Limestone, Madison, Marshall, Morgan. The advisory is set to expire at 12 pm Saturday afternoon.