Major Severe Weather Threat For Alabama

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WATCH THE VIDEO: It is usually easier for us to describe major weather events using graphics, that is why it is important to watch the Weather Xtreme video… sometimes a picture is worth 1,000 (or maybe 500) words. Having said that… let’s dive in…

RIGHT NOW: All is quiet. The atmosphere is capped despite surface based CAPE values to 2,500 j/kg over parts of Alabama at mid-afternoon. Temperatures are mostly in the low 80s, with dewpoints well into the 60s.

STORMS ARE STILL POSSIBLE TONIGHT: However, we will still maintain a chance of showers and thunderstorms tonight as there is a chance the cap breaks due to surface heating, and cold air advection aloft. There is a chance you will get your youth baseball or softball game in tonight, but on the other hand, be aware that a storm could pop up at any moment, and they will pack a punch.

The best low level helicity values for tornadoes remains north and west of Alabama, so for storms that form tonight the main concern will be from hail and straight line winds. Some of the storms developing west of Alabama could drift in here late tonight, after midnight.

TO THE WEST: The big show is beginning. SPC maintains a high risk of severe weather for the rest of the afternoon and tonight from Northeast Texas to near Memphis. In this region a few strong, long track tornadoes are likely. I am watching the cell in Ellis County, Texas (just south of Dallas) with great interest… this is the breeding ground for the extremely dangerous storms.

DANGEROUS SEVERE WEATHER THREAT TOMORROW: Watch the video and you will see all of the synoptic elements for a major outbreak are in place. A deep (sub-1000 mb) low west of Memphis, steep lapse rates, strong veering of the wind with altitude in respect to projected storm motion, strong wind fields at the surface and aloft, dry air in the mid levels, and a very deep, long wave upper trough that is somewhat negatively tilted enhancing diffluence aloft over Alabama.

Projected soundings show the classic “loaded gun” look, meaning that a cap should keep storms at bay through the morning hours, but when that cap breaks early in the afternoon, storms will quickly become severe with all modes of severe weather possible. This means potential for large hail, damaging winds, and a few violent, long track tornadoes. This is dangerous weather setup.

Of course, long time readers know that mesoscale features play a huge roll in the ultimate severity of a severe weather day, and we really won’t know about those until early tomorrow.

TIMING: This is an event where it doesn’t make much sense to ask when storms will arrive in your county or home town; nobody knows since the initial storms will be cellular in nature. Just understand a severe storm is basically possible anytime from now through 3:00 a.m. Thursday. The storms tonight will mostly pose a threat of high winds and large hail, although an isolated tornado cannot be ruled out.

Tomorrow, the main risk comes from about 12:00 noon to 12:00 midnight. Again, we can’t rule out morning storms, but the most intense and dangerous thunderstorms will come during the afternoon and nighttime hours. The severe storms should merge into a long squall line late tomorrow night, with the main threat becoming damaging straight line winds after 10:00 p.m. or so.

REMEMBER: With potential for some severe weather today, and a red letter kind of severe weather day possible tomorrow, be sure you are in a position to hear severe weather warnings (never rely on a siren!), and have a good plan of action when warnings are issued. No need to panic; even large tornadoes are small compared to a large county. But, we must be prepared.

SCHOOLS: For school systems that do decide to dismiss early tomorrow, please consider giving students that live in mobile homes the option of staying in school buildings. In many rural parts of the state those school buildings are absolutely the safest place.

RESOURCES: As we get ready for more active weather… let me list some resources that will help.

ABC 33/40 WEATHER CALL: The service that will send you a phone call if you are within a tornado warning polygon. Works very well and is very reliable.

ABC 33/40 LIVE RADAR STREAM: This is also the stream we use for long form tornado coverage when warnings begin to fly.

APPS: The ABC 33/40 Weather app for your iPhone or Android phone lets you watch our live coverage anytime, anywhere.

STORM CHASER STREAM: Ride along with the ABC 33/40 StormChaser on this stream. The team will be out in the field later as the severe weather event unfolds.

THURSDAY/FRIDAY: Beautiful weather on these days in the wake of the storms; lots of sun with cooler temperatures. Highs in the low 70s Thursday, followed by upper 70s Friday. We have a chance of reaching the upper 40s early Friday morning.

THE WEEKEND: Saturday will be mostly sunny and warm with a high in the low 80s. The 12Z GFS now shows a stronger upper ridge Sunday, keeping the next front to the northwest; it holds off the next chance of rain until Sunday night and Monday. Severe weather with this system looks unlikely; see the Weather Xtreme video for more details on long range ideas.

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

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 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.

Stay tuned to the blog for running updates on the severe weather situation… the next Weather Xtreme video will be produced by 8:00 a.m. tomorrow…

Tags: severe storms

Category: Alabama's Weather