Wednesday, April 10, 2013

Wednesday update on severe weather in the metro tonight

Tornado Watches have been issued for most of Arkansas except the Ozarks, southeast MO north to St. Louis, and much of southern IL as the much-anticipated and discussed spring storm system marches towards the Mid-South. This will be a brief update to yesterday's blog with a "final call" on what to expect in the metro.

Current watch boxes. Red = tornado. Blue = severe thunderstorm.
Storm type: Supercell storms over AR and MO will form into (or merge with) a squall line as they approach the area this evening. We expect very little in the way of individual cells ahead of this line, though a few are possible, especially over east AR and into the MS Delta. As the line draws closer, it will slow down as the line becomes oriented along the upper level flow, reducing it's forward momentum

Timing: While scattered cells are possible, mainly in the areas mentioned above, during the evening hours, the main line of storms will likely reach the Mississippi River between midnight and 2am and move slowly across the metro. Steady, occasionally heavy, rain and embedded thunder will be likely for several hours after the line moves through.  A wet Thursday morning rush hour is likely.

Threats: The primary threat with a squall line such as this will be strong and gusty, perhaps damaging, straight-line wind of 40-60 mph. In any storms that form ahead of the line, tornadoes will be possible, though that threat should be minimized in the metro. Occasionally, weak, brief spin-up tornadoes form in squall lines as well, so that threat is not non-existent.  Large hail will also be possible is any storms and flash flooding could occur in areas that get a couple of inches of rain in a few hours or less.

Prepare: Plan to have fresh batteries in your NOAA Weather Radio and your cell phones charged during the evening hours tonight.  You want both working throughout the night. Make sure your "safe place" is clean just in case a Tornado Warning is issued. It's also best to have a flashlight or other non-electric power source near your bed in case the power goes out while sleeping.  Shoes and photo ID should be nearby in case you need to move to shelter. We also recommend a smartphone app solution to wake you up in the event a severe storm is heading for your location. StormWatch+ is ours and works well on Android and iOS devices. Check it out below.

Overall, the threat of an "outbreak" is low, but it's still best to be prepared.  MWN will provide constant updates throughout the event tonight so follow us on Facebook and Twitter for the latest.  If you don't get all of our updates on Facebook (they like to show you some things and not others), check out this Facebook graphic.

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