A strong trough of low pressure will eject Northeast into the Ohio Valley and an extremely unstable atmosphere will set up across the region. By afternoon, strong to severe thunderstorms will develop to our West and begin to move across Indiana and into Western Ohio.

Extremely high lapse rates and very cold upper air temperatures will promote the development of some extremely large hail. Wind backed southeasterly surface winds, some tornadoes will also be possible.

The exact details of the severe weather event are still in question, but it is looking more and more likely that a major severe weather event will take place tomorrow (on Tuesday).

As some of you saw, IndianaWeatherOnline.com tried a new Live Severe Weather Mode during Friday's Severe Weather Event. We used what is called a live blog and also had live video coverage of radar data on the frontpage of the site. If you saw and used the website during the Severe Weather Event on Friday, we are looking for feedback on whether you liked the coverage and what you would like to see during severe weather outbreaks, so please feel free to drop me an email.

The Storm Prediction Center has placed the entire area under a moderate risk for severe weather. I also agree with that forecast, and belive that a fairly significant severe weather episode appears likely.

The line of severe storms that is currently in Northern Illinois and Iowa will continue to move to East and could affect portions of Northwestern Indiana later today.

Meanwhile, more storms will develop farther South and West across portions of Eastern Missouri, Illinois and into Western Indiana. Upon initial development of the storms, some tornadoes will be possible before the storms become congealed into a squall line. The main threat for tornadoes will exist West of Indianapolis.

As the storms become and form into a squall line, they will rapidly race Eastward across Indiana and into Ohio producing widespread damaging winds, isolated large hail and a tornado or two.

First of all though, we have to make it through this weekend which will feature cloudy skies, scattered rain showers and cooler than normal temperatures.

By Monday, warm front number one will slide Northeast across the Ohio Valley and will bring gusty winds, warmer air and some scattered after rain and thunderstorms.

By later this in the week, warm and moist air will return to the area and we will likely see the warmest temperatures of the year, with highs climbing into the 80's across a large portion of the area.

Unfortunately, this warm and moist air will set the stage for what could be a very stormy Memorial Day Weekend!

Stay tuned! 

From Earle, Arkansas:

Anyways, Friday did produce some severe hail across Southwestern and Western Indiana and we even saw a few tornado warnings near Gary.

As far as the rest of the weekend goes, we will see lingering showers and thunderstorms this morning and into the early afternoon hours, and those could affect the running of the Kentucky Derby.

Sunday will dry out but will also be cooler as the cold front sweeps through the area and causes winds to shift to the Northwest.

Ok so this could officially be the worst map I've ever made, lol and its very busy, but it shows what I'm thinking on Friday. I expect to see some early morning elevated convection along the warm front across Northern Illinois and that could produce some isolated hail and probably more heavy rain than anything. (Area in blue)

What still is yet to be determined is how fast that area across Illinois and Missouri clears out and how much instability is able to develop during the afternoon. The 950-900 MB layer will be close to saturated early Friday and that could mean that there could be some extensive low level clouds which limit heating and instability. Even with this possibility, the models are still cranking out some modest surface and mid level cape, and if any heating occurs it will only enhance the instability.

I do have some concerns because the NAM is already busting to high on dewpoints, but hopefully with a strong LLJ moisture won't be a problem. The NAM shows 65 degree dewpoints streaming north through the Ohio Valley, and even if that is a tad to high and we can get up or slightly above 60, it still should be favorable for severe weather and supercell development.

Winds backed to the SE across much of Northern Kentucky, Indiana, Illinois and into Eastern Missouri by early Friday Afternoon. There also looks to be strong some strong shear especially during the afternoon hours before the low slides farther to the Northeast.

With a possible outflow boundary from early morning convection, that could provide enough forcing to spark some pre-frontal thunderstorm development/supercells and segments during the afternoon hours. It looks like forcing will be very limited farther East across Indiana into Ohio, but Illinois into Northern Kentucky and Southeastern and Eastern Missouri could see some supercellular development conditional on sufficient heating and instability by the early afternoon hours. (Area in Red)

As the cold front sweeps East early Friday Evening, a squall line will likely race rapidly to East and Northeast and will bring some damaging winds and maybe some large hail with fairly steep lapse rates, but it looks like the tornado threat will be minimal by that time, so any tornadic development looks to stem from the afternoon convection and possible supercells.

The squall line will likely out race the cold front and continue to pose a threat for damaging winds as far East as Ohio, but with more limited instability and the squall line pulling farther away from the upper level dynamics, the severe threat will likely become more minimal the farther East you go. (Area in Dark Red)

Areas I see for the most widespread severe activtiy: Western and Southwestern Indiana, Northern and Northwestern Kentucky, Southern 2/3's of Illinois and Eastern and Southeastern Missouri and maybe down into portions of Arkansas and Western Tenn. (Didn't study those areas as much.)

Needless to say, it looks like it could be a moderate risk day in some areas.

An unstable atmosphere will be in place on Thursday, and some thunderstorms could fire along the warm front.

A cold front will then slide through the area on Friday and Friday Night and will bring another chance for severe weather to the area.