Significant Severe Weather Event Tomorrow

| April 14, 2011 @ 6:14 am | 1,213 Replies

An all new edition of the ABC 33/40 Weather Xtreme video is available in the player on the right sidebar of the blog. You can subscribe to the Weather Xtreme video on iTunes by clicking here.

ONE MORE CALM DAY: Before we deal with the active stuff, we will promise one more nice day, with ample sunshine through high clouds and a high at or just over 80 degrees this afternoon. But, of course, we will be watching developments to the west, where a severe thunderstorm/tornado event will initiate east of the dry line across East Oklahoma and Northeast Texas this evening, where SPC has defined a moderate risk of severe thunderstorms.

ROUGH DAY TOMORROW: SPC has the western two-thirds of Alabama in a moderate risk of severe weather tomorrow and tomorrow night, along with the eastern half of Mississippi. Severe weather parameters are coming together for the potential for a significant outbreak of severe thunderstorms, and it will be a day where everybody will need to be in a place to hear severe weather warnings as they are issued.

TIMING: Out of respect to our RPM model, which has trended toward a faster solution over the past few runs, we are going to adjust the timing now to indicate potential for severe thunderstorms in West Alabama as early as 10:00 a.m. The threat will slowly shift eastward, and may extend into far East Alabama as late as 10:00 p.m. So, the bottom line is that we have a 12 hour window with severe weather potential for our state, 10 a.m. to 10 p.m.

NUMBERS: For the weather folks, here are some severe weather parameters for Birmingham late tomorrow afternoon from the NAM…

Surface based CAPE: 870 j/kg
Lifted index -4.0
SRH (storm relative helicity, 0-3 km) 418 m2/s2
SWEAT Index: 487
850 mb wind: 50 knots

The instability values remain a little on the low side for a major outbreak, but the other models are showing higher CAPE values. And, with limited convective inhibition, the door is certainly open for discreet supercell storms to form ahead of the squall line that is likely along the dryline.

WHAT TO EXPECT: Initially, the the threat will be from those isolated storms that pop up during the late morning and afternoon hours. They will have the potential to produce large hail, perhaps the size of baseballs, damaging straight line winds, and a few tornadoes. We can’t rule out the chance of one or two long track tornadoes. Then, later in the day into the evening hours, the threat will be from high wind along the line of storms that will sweep through the state.

NOTE TO SCHOOL OFFICIALS: For the superintendents… I know it has been fashionable in recent years for schools to close early on severe weather days, but please consider that many older kids will be home alone if school is dismissed, and high school kids don’t tend to pay close attention to weather warnings like they should in most cases and often don’t get warnings. And, in rural areas, many kids will go home to mobile homes, which are the worst possible places to be during a tornado outbreak. If you have to dismiss, please consider leaving the option for kids to stay at school where they will be safer.

NOTE TO TALLADEGA CAMPERS: About 20,000 folks will be camping around the Talladega Superspeedway this weekend, and again this year they will be dealing with a severe weather threat. Now is the time to be sure you have a way of hearing a tornado warning if it is needed for North Talladega County tomorrow afternoon or night (a NOAA Weather Radio is great and only about 30 dollars), and it is also important now to plan on what you are going to do if a warning is issued. There is no magic answer here, but needless to say, if a tornado is approaching you sure don’t want to be in a camper or RV. The folks at the Superspeedway do a great job in getting the word out, but everybody has to take individual responsibility for their own safety.

The severe weather threat will wind down after 10:00 tomorrow night as the storms move into Georgia.

WEEKEND OUTLOOK: We will forecast clearing and cooler weather for Saturday with a high in the 67-70 degree range, followed by a cloudless day on Sunday with a high in the mid 70s. Picture perfect for the running of the Aaron’s 499 at Talladega.

NEXT WEEK: Moisture will increase, but for now an upper ridge seems to be building which should keep the chance of rain for Alabama relatively low for the first half of the week. See the Weather Xtreme video for more long range ideas.

WEATHER BRAINS: Don’t forget you can listen to our weekly 30 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.

FOLLOW ALONG: Here are our weather team Twitter accounts….

James Spann Jason Simpson Ashley Brand
J. B. Elliott Bill Murray Brian Peters
Dr. Tim Coleman WeatherBrains Podcast E-Warn (AL wx watches/warnings)

I will be speaking this morning at Bumpus Middle School in Hoover… look for the next Weather Xtreme video here by 3:30 or so this afternoon. Enjoy the day!


Category: Alabama's Weather

About the Author ()

James Spann is one of the most recognized and trusted television meteorologists in the industry. He holds the AMS CCM designation and television seals from the AMS and NWA. He is a past winner of the Broadcast Meteorologist of the Year from both professional organizations.

Leave a Reply

You must be logged in to post a comment.