Update on severe weather potential over the next 48 hours

A potentially significant severe weather outbreak is setting up for the Lower Mississippi Valley into the Tennessee Valley, including the Mid-South. A combination of factors, including extreme wind shear, abundant moisture, and necessary atmospheric lifting will all come together to create ideal conditions for the development of severe weather across the Mid-South. The event will likely unfold during two periods - one on Friday evening and the other Saturday morning and early afternoon.

On Friday afternoon, scattered thunderstorms are expected to form to our southwest over northern LA and southern AR, as well as the ArkLaTex region. These storms could quickly become severe as they go supercellular. The storms will move rapidly northeast and are expected to mainly affect areas near and west of the Mississippi River, with a few expected in the metro, sometime after 4pm and lasting through the evening until after dark (see graphic above). The main threats are large hail and damaging wind, though a few tornadoes are possible with these storms. In fact, the Storm Prediction Center has included areas just to our southwest under a Moderate Risk of severe weather tomorrow, while the metro area is under a Slight Risk (see SPC graphic at top).

There will likely be a break in the action early Saturday morning before the next, potentially more concerning, wave of severe weather hits. A low pressure system is expected to develop to our south and move across eastern AR during the morning and early afternoon hours as it gains strength, driven by very strong jet stream (see NWS graphic above). As it does, storms will quickly develop and become severe in areas near and east of the Mississippi River, including the metropolitan region. The timing of this severe weather episode is expected to be from early Saturday (after 7am) through early afternoon.

Currently, the Mid-South is under a Slight Risk of severe storms for Saturday, but I fully expect that to be upgraded to a Moderate Risk tomorrow. There is the potential for these storms to produce very large hail, damaging wind, and tornadoes - some possibly strong and long-lived. In addition, flash flooding will be an issue as rain amounts could be upwards of 2-3", locally higher, during the day Saturday.

Now is the time to review your severe weather safety plan. The most important tool during a severe weather event is a method of getting current information. The best way is via NOAA Weather Radio - make sure it works and is programmed (if applicable) and has good batteries, or get one if you don't have one. Other great sources of information are local media outlets (TV and radio), as well as MemphisWeather.net. Excellent severe weather safety information can be found here. Tornado tips, courtesy of West Tennessee Weather Online, are listed below.

MemphisWeather.net will continue to update you with the latest information. More frequent updates will be posted on Facebook and Twitter as the event unfolds.

TORNADO SAFETY RULES FROM WTWO

1. IN HOMES OR SMALL BUILDINGS, GO TO THE BASEMENT OR TO AN INTERIOR ROOM, SUCH AS A CLOSET OR BATHROOM, ON THE LOWEST LEVEL. GET UNDER SOMETHING STURDY SUCH AS A HEAVY TABLE OR A BED.

2. IN MOBILE HOMES AND VEHICLES, ABANDON THEM AND GO TO A STURDY STRUCTURE. IF THERE IS NO SUCH STRUCTURE NEARBY, LIE FLAT IN A DITCH, RAVINE, GULLY, CULVERT OR LOW SPOT WITH YOUR ARMS AND HANDS SHIELDING YOUR HEAD.

3. IN LARGE BUILDINGS, SUCH AS SCHOOLS, FACTORIES, HOSPITALS, NURSING HOMES AND SHOPPING CENTERS, GO TO THE PREDESIGNATED SHELTER AREA. INTERIOR HALLWAYS ON THE LOWEST FLOOR ARE USUALLY BEST. STAY AWAY FROM ROOMS THAT ARE LARGE IN AREA BECAUSE THEY HAVE WEAKLY SUPPORTED ROOFS.

4. IN HIGH-RISE BUILDINGS, GO TO AN INTERIOR SMALL ROOM OR HALLWAY.

5. STAY AWAY FROM WINDOWS. DON'T BOTHER OPENING OR CLOSING THEM. IT WON'T MAKE ANY DIFFERENCE TO THE STRUCTURE AND YOU'LL JUST WASTE TIME OR PUT YOURSELF AT RISK SHOULD GLASS BREAK AS YOU ARE NEAR.