Monday, May 07, 2012

Today's Complicated Storm Setup

This spring has been void of severe weather and widespread heavy rainfall here in Northeastern Ohio.  The setup today through this evening is different from the last several cold frontal systems in that most of the parameters needed for heavy rainfall and severe weather will be present:

Courtesy: American Wx

*  Humidity is climbing; precipitable water (atmospheric moisture) levels will climb sharply
*  Convergence (different air masses slamming together) along the warm then cold front at just the right time (late afternoon/early evening) when the temperatures are the warmest
*  Atmospheric energy will be high

What makes today's weather difficult is that we have two completely different sets of conditions present embedded within this system. Warm front is catching up with the rain that outran it late last night.  Warm frontal characteristics usually promote "clusters" of storms versus well-defined storm "lines". This morning, the cluster is well ahead of the high dew points. This is evident by the area of rain/storms in northwestern Ohio stretching out over Lake Erie.  The cold front trailing behind is driven forward by colder air lurking behind.  These storms--unlike the cluster earlier--will move into Ohio mid to late afternoon fueled by high dew points and sparked by the energy with the cold front.


The problem today?  The cold front is catching up to the warm front. The energy from the cluster of rain/storms over Lake Erie is blending together with the energy to the south resulting in a blending of the two areas of rain and storms. The physics of one doesn't necessarily describe the other all of the time! This makes the forecast details today very difficult to nail down. 

The Storm Prediction Center has us in a "slight risk"

Radar is showing one cluster in western Ohio ahead of the warm front.  Its not moving very fast as of 10AM.  If anything, its outrunning the warm front.  As the warm front lifts north, it will supply more energy (mid level lift) to enhance the cluster further.

The second wave is now developing along the cold front.  Given breaks of sunshine in southern Ohio and the increase in humidity along the cold front, the late afternoon/early line of storms will reach severe limits with locally heavy rainfall especially across our southern counties.

Now its just adjusting the timing of each "spoke" of rain and storms that jut out from the main area. More updates later today

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