A new liveblog has been published to ensure folks with slower internet connections can load the diary and comments. This one will no longer be updated.
The Storm Prediction Center has issued a rare "high risk" outlook for much of the Ohio Valley this afternoon, as a major tornado outbreak is beginning to develop at this hour. Numerous tornado watches are in effect, two of which are "Particularly Dangerous Situation" Tornado Watches -- enhanced wording to convey the violent, long-lived tornadoes these storms are expected to produce. In addition to the tornadoes, wind gusts over 70 MPH and hail at or above the size of tennis balls (2.50") is possible in the storms that develop.
The storms are moving into an environment ripe for explosive development and rotation. The 0-6km bulk shear (a calculation of how much the wind changes speed and direction between the surface and 6 kilometers above ground level) over central Kentucky is up around 70 knots, with 40 knots about the point where the environment is able to support a healthy supercell thunderstorm.
The storm relative helicity (a measure of how much rotation a thunderstorm's updraft is able to attain...crucial to the development of tornadoes) is well above the threshold needed for significant tornadoes to develop, with the latest numbers approaching 500+ along the leading edge of the storms in western Kentucky and southeastern Illinois. A value of 450 means that the thunderstorm is capable of producing and supporting violent EF-4 or EF-5 tornadoes -- both of which are distinct possibilities this afternoon and evening. Storm relative helicity values are expected to climb eastward throughout the day into the high risk area.
There is a large area of partly cloudy skies in the warm sector right now, which is allowing the surface to heat up greatly and add fuel to the fire. The model indicates that the latest CAPE (Convective Available Potential Energy...the amount of energy possible a parcel of air would have if it is able to lift up through the atmosphere; the higher the CAPE, the better) is up around 2500, which is more than sufficient lift to sustain thunderstorm development.
Right now there are two areas of thunderstorms -- the ones that will become problematic today are in southern Illinois and the southern tip of Indiana. As they continue eastward, they should grow in number and explosively develop. The other older line is in eastern Tennessee right now, prompting numerous tornado warnings for the Appalachians.
It's going to be a bad day. Again...it won't be as bad as April 27th or 1974, but by nightfall we'll see some significant damage and probably some deaths. Help to prevent those deaths by watching the skies and advising your loved ones to do the same.
Probability of a tornado within 25 miles of any one point:
Tornado Watch #57:
Tornado Watch #58:
As with all previous Severe Weather Liveblogs, the latest update will appear directly below this line. A new liveblog will be started if this one gets too image heavy or we reach 100-150 comments.
Update 10 300PM CT: Dammit.
“@breakingweather: News photographer @mvielhaber: "We have a school completely destroyed with 30+ kids trapped." #scanner" Henryville, IN”Update 9 248PM CT: Tornado EMERGENCY southwest of Cincinnati. This is going to be a very, very close call for Cincinnati. I'll let the NWS do the talking:
...TORNADO EMERGENCY FOR WESTERN GALLATIN...CARROLL...OHIO AND SWITZERLAND COUNTIES...
...TORNADO WARNING REMAINS IN EFFECT UNTIL 400 PM EST...
AT 337 PM EST...A LARGE AND EXTREMELY DANGEROUS TORNADO WAS REPORTED ON THE GROUND MOVING INTO THE WARNED AREA. RADAR INDICATED THAT THE TORNADO PRODUCING STORM WAS MOVING EAST AT 55 MPH.
Update 8 219PM CT: Got the radar back. There is a debris ball from a tornado on the ground directly over Henryville IN right now, moving towards the northeast. The tornado has cross I-65 in Henryville. Marysville, Lexington, Bedford, Scotssburg, Madisun, Chelsea, and Saluda are in the path of this violent tornado.
Update 7 213PM CT: I can't access the radars anymore. Either their servers overloaded or my internet is acting up. I'll try to update the best I can, but it's not looking good unless I can get the radar updates.
Update 6 155PM CT: Incredibly strong rotation in a storm northwest of Louisville KY right now, in southeastern Indiana. It will move north of Louisville. Washington, Orange, Harrison, Floyd, Clark, and Crawford Counties in IN are under the warning. In the below two panel image, the left is base reflectivity (precip) and the right is base velocity (wind).
Update 5 151PM CT: Nick Walker of TWC reports that there are injuries and damage in Tellico Plains TN (the very first image at the bottom of this diary) from a tornado. City hall and a KOA campground were hit.
Update 4 145PM CT: Trained weather spotters report a wall cloud just south of Paducah, moving east-southeast. A tornado may develop at any time.
Update 3 134PM CT: "Ample tornado damage" reported from the storm currently impacting Perry and Dubois Counties in southern Indiana. Strong hook showing up on the radar with this storm. There's another strong storm just to the east of this one with stronger rotation on it.
Update 2 126PM CT: A new tornado watch is in effect for parts of Mississippi, Alabama, and Tennessee. While the watch is not PDS, there is the potential for some strong tornadoes.
Update 1 111PM CT: I'm having major internet issues today...the radar is being slow to update and webpages are taking forever to load. My apologies for any delays in updating this liveblog. Remember to keep track of local TV news and the NWS for your warnings...never rely on what I post here as current. This is just here for informative purposes to turn your attention towards the weather if you live here.
Numerous tornado warnings across southern Indiana right now, with a tornado spotted on the ground northeast of Evansville. All of these little showers and mini-thunderstorms are spinning up today.
There are also numerous tornado warnings in eastern Tennessee, with a confirmed tornado in southeastern Tennessee near the TN/NC border.