Severe Thunderstorm Warning for Johnson, Morgan counties until 5 p.m.

Warmest weather in two weeks could brew severe storms

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HIGHER HUMIDITY

As promised, the humidity has jumped.  We replaced the comfortable, north Wisconsin or Minnesota air with deep south tropical moisture.  The rise in the dew point will take hold for several days and with the approach of a cold front could bring a spell of storms.  Late Tuesday the dew point (most comfortable at 60° or less) has jumped into the 70s–about as high as it gets during the summer months here.  The thick air brings afternoon haze and late night fog.  Visibility at 10 p.m. is already dropping and locally dense fog is possible early Wednesday.

ADI Temps

Dew Point
Temps 10 PM

Visibility

Visibility at 10 PM
Tuesday

UNSTABLE AIR

The heating expected here Wednesday into the middle 80s would mark the warmest in 15 days.  The warm, humid air is more energetic and supports thunderstorm development.  There has to be added ingredients in order to utilize the energy like a cold front or a jet stream to provoke storm development.  Should storms develop Wednesday they could become severe.  A measure of atmospheric energy by meteorologists is CAPE (convective potential energy).  Think of it as voltage like from a battery.  The “volts” in this atmosphere tomorrow reach 2500 – more than enough to support severe storms, in fact an entry-level severe storm can form in 1000 to 1500 Cape or “volts”.  The most unstable time appears to come between the hours of 4 p.m. to 8 p.m. Wednesday.

Meteogram CAPE

CAPE or energy forecast
Wednesday

SLIGHT RISK

The Storm Prediction Center has outlined much of Indiana for the potential of severe storms.  This could mean a watch box will be issued Wednesday.  The main threat appears to be damaging wind gusts and possibly large hail.

Severe Outlook

Severe Outlook
Wednesday