Monday, April 7, 2014

MWN Lightning Round: Tornado Look-Alike, Hail Potential Tomorrow, and the River's Risin'!

This is Not a Tornado

Lets start another edition of the MWN Lightning Round off with an image that went viral over the weekend from a Double-A baseball game in McKinney, Texas.

As you can see from the title of this section, this is indeed NOT a tornado, despite the headlines and captions on the internet. However, the picture is rather deceiving as it has been taken from a location and at such an angle that you can easily mistake the cloud to be that of a funnel. It is always important to pay close attention to what you are sharing on the internet. Severe weather is no exception to this rule. What you are actually looking at is a shelf cloud from a thunderstorm that is oriented in such a way that at first glace appears to be a tornado, however the cloud is not actually lowering to the ground. This thunderstorm could have very well still been dangerous, but it is important to know what you are looking at!

Scattered Thunderstorms Likely Tuesday with a Chance of Hail

Perhaps you've already heard via our forecast that scattered showers and thunderstorms are likely tomorrow, mainly in the afternoon. We'll briefly discuss why there is a chance of hail with some of the stronger storms.

NAM Temperatures (in degrees Celsius) about 18,000' above the surface, valid at 4 PM tomorrow 
The above image shows very cold temperatures in the middle levels of the atmosphere tomorrow afternoon (15-20 below zero F) associated with a long wave trough. This combined with marginally unstable air at the surface will allow any thunderstorm that is able to grow to a modest height the ability to produce sub-severe hail (less than 1 inch in diameter). In addition, gusty wind and lightning will be likely from any storms. The most likely time for thunderstorms will be in the afternoon hours, though showers could start popping up by mid-morning. All activity will taper off quickly as the sun sets, causing instability to weaken.

Flood Advisory for the Mississippi River

The last thing we would like to cover in this edition of the lightning round is the flood advisory that is in effect for all of our counties along the Mississippi River.

Mississippi River at Memphis Hydrograph
The image above shows the current level of the Mississippi River at Memphis at around 20 feet, with a forecast to rise to 28 feet by Friday, April 11th - a rather dramatic rise of 8 feet in just 4 days! This level is considered the "Action Stage" when Dacus Lake Road under the I-55 bridge begins to flood, water is encroaching on the levee south of Blue Lake, and Island 40 Road begins to flood. The river is forecast to remain below Flood Stage of 34' though. It is also worth noting that the river level at Tunica will also rise some 10 feet by Saturday, reaching a level just short of Flood Stage. At the forecast level, Tunica casinos will be unaffected however. For a full list of impacts click here and scroll down to the "Flood Impacts and Photos" section.

--William Churchill (MWN Social Media Intern)

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