HIGH RISK: Violent, Long-track Tornadoes Probable!

UPDATE FROM THE STORM PREDICTION CENTER:

A HIGH RISK OF SEVERE WEATHER HAS BEEN ISSUED for parts of the MS River Valley for late today/tonight..

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The Storm Prediction Center has issued a MODERATE RISK of severe weather for later today and tonight across a HUGE chunk of real estate centered over the Middle Mississippi River Valley where high winds, large hail and strong tornadoes will be possible.

The MODERATE RISK (red) area covers over 100,000 square miles while an ENHANCED (orange) to SLIGHT RISK (yellow) has been issued for an even larger area that extends from Kansas City to Cleveland and from Milwaukee all the way down to Northeast Texas.

FROM SPC... A dangerous severe weather episode appears probable across a large portion of the central states this afternoon into tonight. Primary change with this outlook is to combine the Moderate Risks together given the possibility of long-track, strong to potentially violent tornadoes across a broad region of the MS Valley.

Very strong winds aloft look to combine with seasonally high levels of instability reflected in CAPE (Convective Available Potential Energy) values in the 1500-2500 j/kg range look to provide fuel and energy for severe storms as they fire along and ahead of a cold front associated with a strong low pressure system currently spinning across the Nation's Heartland.

The combination of seasonally high instability and vigorous low level winds that turn with height will be more than enough for storms to rotate, especially initially as they develop across sections of Central and Eastern Iowa and Missouri during the early evening hours.

According to the 3 k NAM, STP (Significant Tornado Parameter) values will be pegged during that time frame and could result in an outbreak of violent tornadoes.

Discrete supercells look to quickly form a QLCS (quasi-linear convective system) as they progress east and south during the evening. This will likely cause a transition from a long-track tornado and large hail threat to more of a damaging wind threat with the possibility of brief tornadoes as the system evolves into a linear squall-line overnight.