4/9/09 Severe Weather Chances Return for Good Friday!

Your Thursday is turning out to be a beautiful day as the sun fights with a few cirrus and cirrostratus clouds i.e. “high clouds”. These clouds are in response to warmer air moving into the TN Valley and the leading edge our next rainmaker.  For the rest of today, look for a partly t cloudy sky with highs in the low to mid 70s. Winds will come from the South at 5-15mph.  Tonight, the clouds thicken locking in some of the heat. With the clouds and a wind from the south, look for lows in the low to mid 50s.  

By the time many of us head to work on Friday, showers and storms will be ongoing. Due to such cold air aloft, some of the storms tomorrow morning could contain small hail, although severe weather in not likely. Expect these showers to move through from around 5am-11am. By Friday afternoon, severe weather is becoming increasingly likely. The Storm Prediction Center has painted a slight risk over the entire viewing area, with an enhanced “bulls-eye” over us, noted below.

However, with any system like this, the question is how unstable do we become? What I am expected is clearing to take place after our morning showers, which will help re-energize the atmosphere. An area of low pressure will move over Memphis in the afternoon with a trailing cold front moving through our area in the afternoon. This cold front will meet up with our unstable air, leading to thunderstorm development in the afternoon and early evening.  

What we are watching:

    1. Divergence Aloft (pulling air up, like moving your hands apart quickly under water), which helps enhance thunderstorm development.

    2. Cape (energy, heat and moisture combined) values are some of the highest we have see so far this season.

1. Helicity values (wind speeds and direction with elevation, that lead to rotating storms) are fairly high in the TN Valley.  

These values along with the cold front to lift the air, make for a good chance of severe storms in the 3-8pm timeframe especially IF we see sunshine midday tomorrow. Average rain totals should be around a half inch.

 VIEW THE FUTURECAST HERE:  

At this point, ALL modes of severe weather area possible, including isolated tornadoes. Highs tomorrow will likely reach with low to mid 70s with gusty southwest winds.  The Easter Holiday weekend looks great with sunshine to a partly cloudy sky and highs in the upper 60s. More rain and storms are likely early on Monday.  

Patrick will have the latest tonight at 6pm and 11pm.  

See you soon,  

Brian